Tascam M520 Story...

[flyingace]

It’s interesting they would choose that console because there’s some mildly unconventional topology. I think the book I recommended also features the M-520 somewhere in there.

Yeah, I bought that book too, no mention of the M-520 yet but it's a great book with SOOO much good information, I've been learning a lot from it and I really appreciate that they don't try to get too technical (electrical engineer-style technical) with it, but very practical information. Plus, as you or someone said, it's got Peter Gabriel on the cover, it must be good, right? ha ha

 

[Acequia]

My first time posting on this historic thread and on homerecording.com!

Thank u everyone for providing this important knowledge to keep the m520 alive. Special thanks to sweetbeats for his detailed journey of reconditioning this board.

**The most important thing about this old board is there is no Master Out and Fader!** to utilize the program out busses for final mix

(This is mentioned in thread many times)

The reason I’m posting is I want to confirm that the only true “stereo master out”when you are using the 8 program busses is the headphone jack. Please correct me if I’m wrong.

I’ve noticed this is the best sound and use of the board. Yes, you can route each track to program 1&2 out but that does not allow u to use the other buss tracks when recording a stereo master. Only 1&2 program buss.

This is a head scratcher to say the least.

So….I happened to chat recently with Danny White who repairs boards for a living. He proposed the idea of modding the board and creating a master out.

He told me this, “We could build you a Dual Class A line box with out transformers for between $1k-$1500 max. If you like the Tascam keep it. You probably just need a line lift.”

He also asks, “Is your headphones -10 or +4” (can anyone help with that?)

This conundrum reminds me of a story in tape op about the late great Richard Swift ,featured in this thread, using the headphone out for his master. Does anyone have more info regarding this? I consider the guy a musical genius.

Anyway, trying to retrace his steps.

Any help would be appreciated



My Story quickly:
I was looking for a vintage board on Craigslist in Los Angeles. Many options and many quite affordable. I had a tascam 58 reconditioned by Adrian Pro Audio and wanted a suitable match from that era of tascam. I came across an ad for an M520. It looked cool and unique and had all my RCA ins and outs that I needed for the 8track. In the ad it mentions “as used by Richard Swift”. I was like who is this guy? Well I soon found out and I was blown away by this guys “ears” and his musical ability. Then I figured out he passed the summer before and I was super bummed. But this guy worked and worked and left a huge dent in the music scene and still influences today. This thread preserves his legacy. It’s actually an amazing read. Before his website Richardswift.us was taken down u could browse his life leading up to his death. (I hope someone can bring it back) The m520 was featured regularly in photos with a homemade apple bong resting on the console.

Check out DIRTY JIM by Richard Swift off the Hex album as a starter

 

[sweetbeats]

My first time posting on this historic thread and on homerecording.com!

Thank u everyone for providing this important knowledge to keep the m520 alive. Special thanks to sweetbeats for his detailed journey of reconditioning this board.

Thanks and welcome!

**The most important thing about this old board is there is no Master Out and Fader!** to utilize the program out busses for final mix

(This is mentioned in thread many times)

The reason I’m posting is I want to confirm that the only true “stereo master out”when you are using the 8 program busses is the headphone jack. Please correct me if I’m wrong.

Yeah so that’s not correct. There are STEREO A and STEREO B master faders and output jacks, the source of these summing busses is the same and is also the same as the headphone amp, and it is whatever you have selected as the source in the MONITOR SELECT switchrack, the vertical row of switches directly above the PGM group 3 fader. I don’t know why anybody would generally use the headphone output as their master out…the M-500 series’ headphone amp uses a pair of NJM386 opamps as the output driver and they’re noisy. This amp design is found throughout a number of period Teac/Tascam devices. It’s a fine amp for monitoring but I don’t like it for critical listening. But if you’re after a particular sound maybe the headphone out provides that sound. Don’t let me or anybody else tell you what you can or cannot do or try. I can tell you what something was *designed* to do or what might be a good solution for a particular objective you have, but there’s nothing wrong with deviating and experimenting. Anyway, this is where people get confused. What I’m saying is *different* about the M-500 series compared to a typical contemporary mixing console that has subgroups and at least one master summing buss, is that there is no way to directly assign input sources connected to any of the input channels to that STEREO A or STEREO B buss. You have to assign to one or more of the PGM groups, then source those groups in the monitor mixer, then select “MON” in the MONITOR SELECT switchrack, and now you hear your stereo sum at STEREO A/B output jacks and in the headphones. Notice that over on the input channel strips they have individual PGM group assign switches, but no “L-R” assign switch like one might usually see. This is what I mean. The path to your STEREO master output jacks goes through the PGM groups, monitor mixer, and then you source the output of the monitor mixer via the MONITOR SELECT switchrack. The M-500 series console topology affords some more creativity about how you want to use the console depending on the setting and your setup, but it also requires some investment in understanding the control surface and routing and how it’s a little different at the summing and monitoring stage than a lot of other consoles.

Sometimes I think about what would happen if I setup an online class regarding the M-500 consoles. It might clear a lot of this up.

I’ve noticed this is the best sound and use of the board. Yes, you can route each track to program 1&2 out but that does not allow u to use the other buss tracks when recording a stereo master. Only 1&2 program buss.

I don’t think I’m following what you’re saying here…why can you not use the other PGM groups if you are using PGM 1&2 as your stereo master buss? This is how some use the console during mixdown, and in fact I would recommend it, because it keeps your master mixdown from going through all the monitor mixer path. The intended use for the STEREO A buss is to connect these outputs to your studio monitors in the control room. The STEREO B buss was intended to be connected to loudspeakers in the recording or “studio” room. The STEREO A buss also carries the SOLO and PFL buss signals, STEREO B does not. So typically you monitor off the STEREO A outputs, and typically have the PGM outs connected to multitrack inputs and patch two of them to your master recorder when mixing down.

This is a head scratcher to say the least.

Read the manual Grasshoppah…

So….I happened to chat recently with Danny White who repairs boards for a living. He proposed the idea of modding the board and creating a master out.

But it already has this capability…

He told me this, “We could build you a Dual Class A line box with out transformers for between $1k-$1500 max. If you like the Tascam keep it. You probably just need a line lift.”

I don’t have a clue who Danny White is, so I don’t want to disrespect, and it’s your money, but the console already has the functionality you need. That sounds like a lot of money to duplicate functionality, and the signal path of the custom line amp would likely be better than anything on the M-520, but the source is still the M-520. What’s to be gained here?

He also asks, “Is your headphones -10 or +4” (can anyone help with that?)

Neither. It’s not a line level output. It’s an amplifier output…headphone level…maximum rated output is 100mW at 8ohms. -10dBv and +4dBu are common nominal levels for line level signal paths. Line level outputs are typically rated as a measure of voltage amplitude, while amplifier outputs are rated as a measure of power; voltage x current.

Short answer: the headphone out is neither -10dBv or +4dBu, but significantly higher than either as an amplified output.

This conundrum reminds me of a story in tape op about the late great Richard Swift ,featured in this thread, using the headphone out for his master. Does anyone have more info regarding this? I consider the guy a musical genius.

Anyway, trying to retrace his steps.

Any help would be appreciated

I don’t have any specifics…not familiar with the article, but I AM familiar with Richard, having met him when I sold him the M-520 that is the subject of this thread, and then later on spending some time hanging out with him in his studio. I too enjoy his music…ahead of it’s time…unique flavors and textures and content…and regarding the headphone amp I don’t know…he liked to do a lot of seeing what happened when you overloaded and input or pushed an output. And the headphone out being a bit noisier and higher in distortion with the particular design, and the fact it is higher power than line level, it may have had the flavor he wanted to drive the input of his master recorder in whatever setup he was using at the time. He really liked the line inputs on the M-520 because of what they did when overdriven…not extremely so but just pushed to the edge to get a gritty edge. Now, there’s nothing particularly special about the line amp design on the M-520, it’s all opamp-based and relies heavily, like many, many, many other devices across many manufacturers over many years, on the TL072, as well as the 4556 and 2041. There’s nothing particularly magical about those opamps. And remember it’s not the opamp, it’s the design of the whole circuit that really matters, and beyond that, and even more importantly, the operator and talent using the gear. So Richard was jazzed about how the M-520 performed as a summing device, but you have to consider the flavor of his projects, he was, IIRC feeding the M-520 with a Studer A80 2” machine, so high quality output drivers…I recall he wasn’t excited about the mic amps on the M-520, he had outboard gear for that…anyway…you know, you can do a lot with a device if you experiment a little to explore boundaries. I think that’s a big factor to Richard’s sound and approach.

My Story quickly:

I was looking for a vintage board on Craigslist in Los Angeles. Many options and many quite affordable. I had a tascam 58 reconditioned by Adrian Pro Audio and wanted a suitable match from that era of tascam. I came across an ad for an M520. It looked cool and unique and had all my RCA ins and outs that I needed for the 8track. In the ad it mentions “as used by Richard Swift”. I was like who is this guy? Well I soon found out and I was blown away by this guys “ears” and his musical ability. Then I figured out he passed the summer before and I was super bummed. But this guy worked and worked and left a huge dent in the music scene and still influences today. This thread preserves his legacy. It’s actually an amazing read. Before his website Richardswift.us was taken down u could browse his life leading up to his death. (I hope someone can bring it back) The m520 was featured regularly in photos with a homemade apple bong resting on the console.

So, wait…is it possible you have my old M-520?

 

[flyingace]

Sometimes I think about what would happen if I setup an online class regarding the M-500 consoles. It might clear a lot of this up.

Sweetbeats - I would pay for that online class. I have read over the manual but have yet to install my M-520 into my studio to “use” it, when I do, I’ll re-read the manual but something tells me, I’ll still be a little confused on many parts of this complex and very versatile console! let us know if you decide to set something up!

 

[Acequia]

Thanks and welcome!

Wow, thank you sweetbeats. That was a quick reply. I am going through all this. A very detailed answer with all sorts of great info. Just adding to the forum’s wealth of knowledge.

Yeah so that’s not correct. There are STEREO A and STEREO B master faders and output jacks,

I guess I thought this was only for control room monitors and studio monitors, although I did use it as an out initially but didn’t realize how the monitor knobs were incorporated in final mixing of busses. It’s unique.

the source of these summing busses is the same and is also the same as the headphone amp,

I was at least coming to a similar conclusion about the circuitry. I guess I thought u could tap into the headphone out before it hits the op amp on headphone jack. By modding to creat another output level and jack.

and it is whatever you have selected as the source in the MONITOR SELECT switchrack, the vertical row of switches directly above the PGM group 3 fader. I don’t know why anybody would generally use the headphone output as their master out…

I think Richard swift did this, but I might be wrong. He was the King of making recordings sound authentic to the 60’s sound, like Motown stuff. Check out his Ground Trouble Jaw ep.

the M-500 series’ headphone amp uses a pair of NJM386 opamps as the output driver and they’re noisy. This amp design is found throughout a number of period Teac/Tascam devices. It’s a fine amp for monitoring but I don’t like it for critical listening. But if you’re after a particular sound maybe the headphone out provides that sound. Don’t let me or anybody else tell you what you can or cannot do or try. I can tell you what something was *designed* to do or what might be a good solution for a particular objective you have, but there’s nothing wrong with deviating and experimenting.

You are a valuable resource for us all.

Anyway, this is where people get confused. What I’m saying is *different* about the M-500 series compared to a typical contemporary mixing console that has subgroups and at least one master summing buss, is that there is no way to directly assign input sources connected to any of the input channels to that STEREO A or STEREO B buss.

I did misunderstand this from the posts. Thank u for clarifying.

You have to assign to one or more of the PGM groups, then source those groups in the monitor mixer, then select “MON” in the MONITOR SELECT switchrack, and now you hear your stereo sum at STEREO A/B output jacks and in the headphones. Notice that over on the input channel strips they have individual PGM group assign switches, but no “L-R” assign switch like one might usually see. This is what I mean. The path to your STEREO master output jacks goes through the PGM groups, monitor mixer, and then you source the output of the monitor mixer via the MONITOR SELECT switchrack. The M-500 series console topology affords some more creativity about how you want to use the console depending on the setting and your setup, but it also requires some investment in understanding the control surface and routing and how it’s a little different at the summing and monitoring stage than a lot of other consoles.

Definitely the charm of the board. A real recording studio board to be used as a tool.

Sometimes I think about what would happen if I setup an online class regarding the M-500 consoles. It might clear a lot of this up.

That’s a neat idea. It would be good.

I don’t think I’m following what you’re saying here…why can you not use the other PGM groups if you are using PGM 1&2 as your stereo master buss? This is how some use the console during mixdown, and in fact I would recommend it, because it keeps your master mixdown from going through all the monitor mixer path.

This is how they describe correct operation in owners manual. But obviously there is a work around to this if u want to send grouped tracks to busses or wet effects.

The intended use for the STEREO A buss is to connect these outputs to your studio monitors in the control room. The STEREO B buss was intended to be connected to loudspeakers in the recording or “studio” room. The STEREO A buss also carries the SOLO and PFL buss signals, STEREO B does not. So typically you monitor off the STEREO A outputs, and typically have the PGM outs connected to multitrack inputs and patch two of them to your master recorder when mixing down.

Read the manual Grasshoppah…

U the man! Here is a nice picture from my manual. Basic 8track recording set up. Master out coming from program out 1&2.

On a final note, I did a nice mix out last night coming out of the B stereo Monitor master out. Thank u very much!

 

[sweetbeats]

I guess I thought this was only for control room monitors and studio monitors, although I did use it as an out initially but didn’t realize how the monitor knobs were incorporated in final mixing of busses. It’s unique.

It’s not that the monitor mixer is incorporated into the final mix, unless that’s how you choose to set it up. Technically it’s that the PGM groups are available sources to the monitor mixer for…drum roll…monitoring. And as we are discussing the intended setup is for the master recorder to be connected to a pair of the PGM groups at mixdown, and the PGM group outputs are upstream from the monitor mixer inputs.

I was at least coming to a similar conclusion about the circuitry. I guess I thought u could tap into the headphone out before it hits the op amp on headphone jack. By modding to creat another output level and jack.

Okay, sure, you could do that, but I beg the question “why” would you do that. Looking at the schematics that’s exactly what you already have with the STEREO A/B outputs. There is an input amp stage that uses a 2041 opamp to drive the inputs of the output drivers for the STEREO A and STEREO B busses as well as the headphone amp. So if you want an output with a level control that taps the headphone circuit ahead of the headphone amp, just grab the STEREO A or STEREO B faders. Done.

This is how they describe correct operation in owners manual. But obviously there is a work around to this if u want to send grouped tracks to busses or wet effects.

Well there’s no magical reason if you’re using a pair of the PGM groups at mixdown the 6 other PGM groups aren’t still 100% available to use for anything you want or need to do with them. Where are you seeing specifically in the manual? If you can tell me the page and section then I can read what you are reading and maybe understand better what you are seeing and help clarify if there’s anything to clarify. And I’m not sure I understand your statement “…if u want to send grouped tracks to busses or wet effects.” Maybe we can come to consensus on some terminology first. “Tracks” refers to recorded tape or DAW tracks. I often see reference to mixer tracks. Mixers don’t have tracks unless they’ve been run over by a car. Mixers have channels and busses. Busses refers to any pathway on the console that can take multiple inputs or channels…sources…group them together and send them somewhere. Like a…drum roll…bus. So the M-520 has 20 channels, each with multiple input options. And there are 4 AUX busses, 8 “mix” busses (the 8 program groups or “PGM” as labeled on the console), and several other more specialized busses like the stereo sum of the monitor mixer (we’d call that the monitor buss), the SOLO buss, etc. And we wouldn’t send anything to a wet effect. “Wet” refers to printing or recording a track or tracks with effects…printing wet. So this is why I don’t quite follow your sentence above. Are you talking about submixing tape or DAW tracks (“…if u want to send grouped tracks…”) or are you meaning if you want to submix mixer channels? I’m not trying to be a PITA here. I just want to help us speak the same language so I can help you get the most out of your M-520. There’s no need for any work around, and I’d like to be able to explain in a meaningful way why and how.

 

[Acequia]

It’s not that the monitor mixer is incorporated into the final mix, unless that’s how you choose to set it up. Technically it’s that the PGM groups are available sources to the monitor mixer for…drum roll…monitoring. And as we are discussing the intended setup is for the master recorder to be connected to a pair of the PGM groups at mixdown, and the PGM group outputs are upstream from the monitor mixer inputs.

Sorry for getting back to u so late.

Thank u for this explanation.

Okay, sure, you could do that, but I beg the question “why” would you do that. Looking at the schematics that’s exactly what you already have with the STEREO A/B outputs. There is an input amp stage that uses a 2041 opamp to drive the inputs of the output drivers for the STEREO A and STEREO B busses as well as the headphone amp. So if you want an output with a level control that taps the headphone circuit ahead of the headphone amp, just grab the STEREO A or STEREO B faders. Done.

Thank u. U r helping me understand the signal flow better.

Well there’s no magical reason if you’re using a pair of the PGM groups at mixdown the 6 other PGM groups aren’t still 100% available to use for anything you want or need to do with them. Where are you seeing specifically in the manual? If you can tell me the page and section then I can read what you are reading and maybe understand better what you are seeing and help clarify if there’s anything to clarify. And I’m not sure I understand your statement “…if u want to send grouped tracks to busses or wet effects.” Maybe we can come to consensus on some terminology first. “Tracks” refers to recorded tape or DAW tracks. I often see reference to mixer tracks. Mixers don’t have tracks unless they’ve been run over by a car. Mixers have channels and busses. Busses refers to any pathway on the console that can take multiple inputs or channels…sources…group them together and send them somewhere. Like a…drum roll…bus. So the M-520 has 20 channels, each with multiple input options. And there are 4 AUX busses, 8 “mix” busses (the 8 program groups or “PGM” as labeled on the console), and several other more specialized busses like the stereo sum of the monitor mixer (we’d call that the monitor buss), the SOLO buss, etc. And we wouldn’t send anything to a wet effect. “Wet” refers to printing or recording a track or tracks with effects…printing wet. So this is why I don’t quite follow your sentence above. Are you talking about submixing tape or DAW tracks (“…if u want to send grouped tracks…”) or are you meaning if you want to submix mixer channels? I’m not trying to be a PITA here. I just want to help us speak the same language so I can help you get the most out of your M-520. There’s no need for any work around, and I’d like to be able to explain in a meaningful way why and how.

I agree with you on everything. I’m more of a musician trying to be a recording engineer. I always confuse people when I talk. I was saying tracks are the channels, because I’m thinking about the tracks I recorded. But u r right. Love the BUS analogy. When I say “wet”, I’m talking about a reverb channel that I can send to a bus alone and mix it in with the bus section.

Correct me if I’m wrong, but if I’m mixing out to program 1&2 bus I depress all channels to 1&2? Including reverb? That output bypasses the monitor mixer and goes straight to the recording device? It should be the highest quality. I have a tascam 58, so I want to utilize the highest fidelity.

But then I can’t use bus 3-8 for anything else?

It’s not that the monitor mixer is incorporated into the final mix, unless that’s how you choose to set it up. Technically it’s that the PGM groups are available sources to the monitor mixer for…drum roll…monitoring. And as we are discussing the intended setup is for the master recorder to be connected to a pair of the PGM groups at mixdown, and the PGM group outputs are upstream from the monitor mixer inputs.







Okay, sure, you could do that, but I beg the question “why” would you do that. Looking at the schematics that’s exactly what you already have with the STEREO A/B outputs. There is an input amp stage that uses a 2041 opamp to drive the inputs of the output drivers for the STEREO A and STEREO B busses as well as the headphone amp. So if you want an output with a level control that taps the headphone circuit ahead of the headphone amp, just grab the STEREO A or STEREO B faders. Done.







Well there’s no magical reason if you’re using a pair of the PGM groups at mixdown the 6 other PGM groups aren’t still 100% available to use for anything you want or need to do with them. Where are you seeing specifically in the manual? If you can tell me the page and section then I can read what you are reading and maybe understand better what you are seeing and help clarify if there’s anything to clarify. And I’m not sure I understand your statement “…if u want to send grouped tracks to busses or wet effects.” Maybe we can come to consensus on some terminology first. “Tracks” refers to recorded tape or DAW tracks. I often see reference to mixer tracks. Mixers don’t have tracks unless they’ve been run over by a car. Mixers have channels and busses. Busses refers to any pathway on the console that can take multiple inputs or channels…sources…group them together and send them somewhere. Like a…drum roll…bus. So the M-520 has 20 channels, each with multiple input options. And there are 4 AUX busses, 8 “mix” busses (the 8 program groups or “PGM” as labeled on the console), and several other more specialized busses like the stereo sum of the monitor mixer (we’d call that the monitor buss), the SOLO buss, etc. And we wouldn’t send anything to a wet effect. “Wet” refers to printing or recording a track or tracks with effects…printing wet. So this is why I don’t quite follow your sentence above. Are you talking about submixing tape or DAW tracks (“…if u want to send grouped tracks…”) or are you meaning if you want to submix mixer channels? I’m not trying to be a PITA here. I just want to help us speak the same language so I can help you get the most out of your M-520. There’s no need for any work around, and I’d like to be able to explain in a meaningful way why and how.

I appreciate all this knowledge. We all do who own this board. It’s a very unique piece of equipment.

I wonder if u could just describe how u would mix on it? After tracking is completed. The procedure step by step. If u have time.

I find myself using bus 1&2 as the program out for all the channels including effects for a stereo mix to my daw system. As you have stated, this should be less electronics to go through. A better signal path. That is why tascam wants you to use program 1&2 out on the back of the board to go to the 2track system.

I only started using the buss channels and the monitor mix as an out to compensate for panning issues on my channels. For whatever reason my mixes were lopsided on one side. (My board has not been reconditioned, but it’s in very usable shape).

 

[sweetbeats]

Correct me if I’m wrong, but if I’m mixing out to program 1&2 bus I depress all channels to 1&2? Including reverb? That output bypasses the monitor mixer and goes straight to the recording device? It should be the highest quality. I have a tascam 58, so I want to utilize the highest fidelity.

Yes, if you are using PGM groups 1 & 2 as a stereo mix bus, you would latch the PGM 1 and PGM 2 assign buttons for any input channel you want assigned to the mix bus, and set the PAN knobs to taste. Yes including the reverb return, if you want that in the mix. You get to pick what you want in your sonic soup, the PGM groups are your kettle, and the assign buttons are the utensils that carry your ingredients (sources open on your input channels) to the kettle. You want reverb in the mix? Assign it. You don’t want it? Don’t assign it. And yes the PGM OUT jacks are upstream of the monitor mixer. They don’t bypass or go around the monitor mixer in some magical way, it’s just the same pathway that feeds the output jacks also feeds the BUSS source select switches in the monitor mixer. So the PGM OUT jacks are upstream of the monitor mixer and all its circuitry.

But then I can’t use bus 3-8 for anything else?

You’re stuck on this. What did you read or what did somebody tell you to give you the idea that if you are using PGM groups 1 & 2 as a mixbus, groups 3 ~ 8 are unavailable? I want to know this first so I can give you a more relevant answer.

I wonder if u could just describe how u would mix on it? After tracking is completed. The procedure step by step. If u have time.

Well it kind of reads like you already know what to do. I mean, if it was me I’d source the input channels to whatever sources I was mixing, tape tracks, DAW tracks, I’d assign all those channels to my mix buss and I’d probably be using PGM 1 & 2, I’d have any insert effects patched into the relevant channel ACCESS jacks, have my send effects hooked up to the AUX outs and return those effects to any available open channels and also assign those channels to PGM 1 & 2, connect my mix recorder to the mix buss outputs, set the monitor mixer channels to BUSS for the two PGM groups I was using as a mix buss, pan the two monitor mixer channels hard L and hard R, set the LEVEL controls on the monitor mixer channels, set the MONITOR SELECT switchrack source to MON, raise the STEREO MASTER A fader time the shaded area, press play on the playback device and start rehearsing my mix…tweak levels, pans, effects, rehearse my real-time adjustments until I had some notion of what I was doing with the piece and then hit record on the mix recorder and see what happens.



Does that help?

I only started using the buss channels and the monitor mix as an out to compensate for panning issues on my channels. For whatever reason my mixes were lopsided on one side. (My board has not been reconditioned, but it’s in very usable shape).

Tell me more about that. Are you saying that, like if you took a test tone and input that to an input channel, and then assigned that to a pair of PGM groups, and then left the PAN control centered, that you’d have to push one of the PGM group faders higher than the other to keep the tone centered between the two channels?

 

[bleachboy]

Hi everybody ! I hate to hijack the thread but I figured it was the best place to ask my question rather than to make a new thread.

I just snagged a Tascam M512 board for almost nothing (with a Tascam 58 + remote and DBX, all for 800$!). Cosmetically it's in very good shape, apart from two VU leds who are dead, but I'm in no real hurry to fix those for now.

As for functionality, here's what works and what doesn't. All busses work (are channels all jumpered on the back). All phono/HiZ/Tape Ins/Monitor outs/Stereo Masters/Aux/Headphone etc...work. All channel preamps and line ins work except for channel 3. The tape in + the mic preamp doesn't seem to work at all. All I get is a very faint signal, almost nothing really, with the gain pots all maxed out. It doesn't matter which buss I route that channel to, I get nothing. Any suggestions as to how I can troubleshoot that problem ?

The other problem is more general (and I think it's more than likely a cleaning issue), is that all of the channels seem to have trouble passing signal if the input level is too low. I already have used DeOxit on all RCA jacks in the back. I get frequent channel dropouts, either when just passing signal through the board or when I engage the channel ON switch/EQ or when I just use the trim pot, I get "scratching" sounds for a couple of seconds. I'm pretty sure I'll have to DeOxit everything, and I'm willing to do it but I have never ever opened a console and I want to do that properly, since it's a pretty heavy beast. So any advice on that regard is more than welcome !

Thank you all for that goldmine of info !!

Louis

 

[sweetbeats]

Hi, Louis.

So for channel 3 what happens if you monitor the input (mic or tape…doesn’t matter), and dicker with the ACCESS jumper? Like gently wiggle it or manipulate it? Do you get intermittent signal? If so, exercise it (plug and unplug it a few times). If the exercising doesn’t fix it, but you can definitely make signal pass if you manipulate the jumper, then you probably have a bad solder joint on either the SEND or RCV jack. Or both.

The other general thing for your issue with the skritchies/static and intermittent signal at low levels could just be dirty source select switches. Teac used good quality switches for those toggles at the top of the strip, but because the switch chassis opening faces up, years of dust/debris makes its way down there. And all there is to prevent that is that little felty piece which does something but not a lot after decades of exposure. Take your DeoxIT, and make sure it’s something like the D5 for metal-to-metal contacts as opposed to the F5 Faderlube, flip the switch all the way to the left, and guide the straw down along the right side of the switch shaft until it bumps up against the body of the switch. It’s down in there a little ways. Give a nice healthy squirt. Then exercise the switch back and forth rapidly maybe 25 times. More is fine. Then one more squirt but do it opposite this time, switch to the right, and straw along the left side of the switch shaft. Do all this with the power off, let it sit overnight to dry out a bit. Let us know if that helps. You can do this with the pad and phase revers toggles too, but note those only apply to the mic input.

Applying DeoxIT to jacks doesn’t usually do anything, unless they are obviously corroded and if that’s the case it’s just a band-aid fix.

If none of the above helps it may be time for a recap. Skritchy sounds and static is usually DC artifacts and all the coupling caps in the signal path are there to block DC, which is a normal product of most opamp designs (there is often some DC offset at the output of an opamp stage). As the caps dry out, they don’t do this so we’ll and we get static, or more pops or clicks when switching things or adjusting pots. But that’s an extreme case. So try the above first and let us know.

 

[Acequia]

Sorry for the delayed response.

Yes, if you are using PGM groups 1 & 2 as a stereo mix bus, you would latch the PGM 1 and PGM 2 assign buttons for any input channel you want assigned to the mix bus, and set the PAN knobs to taste. Yes including the reverb return, if you want that in the mix. You get to pick what you want in your sonic soup, the PGM groups are your kettle, and the assign buttons are the utensils that carry your ingredients (sources open on your input channels) to the kettle. You want reverb in the mix? Assign it. You don’t want it? Don’t assign it. And yes the PGM OUT jacks are upstream of the monitor mixer. They don’t bypass or go around the monitor mixer in some magical way, it’s just the same pathway that feeds the output jacks also feeds the BUSS source select switches in the monitor mixer. So the PGM OUT jacks are upstream of the monitor mixer and all its circuitry.

Thank u, I'm doing much better now. My board is slowly coming back to life with continued use and twisting of knobs, etc. I'm using the 1&2 program outs now with success. One of the problems I was having was my stereo Reverb. It was sending a lower signal out one side, so that was adding confusion to my pans. Its a very funky stereo reverb (PIONEER SR-101), but it is tube reverb.

You’re stuck on this. What did you read or what did somebody tell you to give you the idea that if you are using PGM groups 1 & 2 as a mixbus, groups 3 ~ 8 are unavailable? I want to know this first so I can give you a more relevant answer.

I'm using pgm 1&2 out to my computer to record my stereo mix. How would I incorporate the other busses?

Well it kind of reads like you already know what to do. I mean, if it was me I’d source the input channels to whatever sources I was mixing, tape tracks, DAW tracks, I’d assign all those channels to my mix buss and I’d probably be using PGM 1 & 2, I’d have any insert effects patched into the relevant channel ACCESS jacks, have my send effects hooked up to the AUX outs and return those effects to any available open channels and also assign those channels to PGM 1 & 2, connect my mix recorder to the mix buss outputs, set the monitor mixer channels to BUSS for the two PGM groups I was using as a mix buss, pan the two monitor mixer channels hard L and hard R, set the LEVEL controls on the monitor mixer channels, set the MONITOR SELECT switchrack source to MON, raise the STEREO MASTER A fader time the shaded area, press play on the playback device and start rehearsing my mix…tweak levels, pans, effects, rehearse my real-time adjustments until I had some notion of what I was doing with the piece and then hit record on the mix recorder and see what happens.



Does that help?

This helps anyone with this board. Thank u for detailing this. You have spent so much time on this thread for people like me. Your contribution is greatly appreciated.

Tell me more about that. Are you saying that, like if you took a test tone and input that to an input channel, and then assigned that to a pair of PGM groups, and then left the PAN control centered, that you’d have to push one of the PGM group faders higher than the other to keep the tone centered between the two channels?

I think this was my Stereo Reverb causing balance issues and pan knobs that needed to be twisted more. My board is coming back to life. It's really cool.

If anyone wants to hear the board that sweetbeats fixed listen to THE HEX by Richard Swift. Incredible.

 

[sweetbeats]

Thanks for the update.

Just a general comment, the one issue with your Pioneer reverb unit is that there is no way to isolate the reverb only output. The output of the SR-101 is always a mix of dry and reverberated signal. Normally when connecting send-type effects processors to a console the effect return would carry only the effect, and not a mix of the dry and effected signal. Why? Because you have the dry signal passing through the console and then can use the console controls to balance or mix your dry signal with the 100% wet signal coming back to the console wherever you are returning the reverb (or whatever the effect is). It doesn’t mean you can’t use the Pioneer, I think I’m just bringing this up so you are aware of this, that as you increase or decrease the level of the effect return, you are also increasing or decreasing the level of the dry signal present at the output of the Pioneer reverb unit, and may need to adjust the level of your dry signal passing through the console input to wherever you have that assigned. This becomes more of a hassle the more inputs you have sent to the reverb unit. Every time you adjust the return level of the reverb return you have to adjust the faders of each input channel sent to the reverb opposite however you are adjusting the reverb return to maintain your mix.

Regarding PGM 1 & 2 and the other PGM groups, well now I’m confused. You were saying you understood PGM 3~8 were “not available” if you were using 1 & 2 when mixing down, and I was trying to lead you through understanding that it never matters what you are using any of the PGM groups for, they are all always available to use however you want to use them. The console is not intelligent…it doesn’t know if you are tracking, overdubbing, mixing, mastering, video sweetening…it just does what it’s told. So when you are using a pair of PGM groups for mixdown, the other 6 groups are available to use however you need, or not if you don’t. How would you incorporate the other busses? Maybe you have two master recorders, a main one and a backup and you’re feeding the backup with another pair of PGM groups. Maybe you’re using the PGM groups as an additional cue feed for talent because you’re adding some additional sources during mixdown but all your AUX sends are being used for effect sends. Those are just a couple ideas off the top of my head. It’s really whatever presents as a need in your circumstance. Typically you wouldn’t need them during mixdown, but, again, they are *available*.

Hope that helps.

Oh and I’ll have to check out that Richard Swift piece. That’s neat to know of a song that actually utilized my old M-520.

So I ask again, am I understanding correctly your M-520 is my old M-520?

 

[Acequia]

Thanks for the update.

Just a general comment, the one issue with your Pioneer reverb unit is that there is no way to isolate the reverb only output. The output of the SR-101 is always a mix of dry and reverberated signal. Normally when connecting send-type effects processors to a console the effect return would carry only the effect, and not a mix of the dry and effected signal. Why? Because you have the dry signal passing through the console and then can use the console controls to balance or mix your dry signal with the 100% wet signal coming back to the console wherever you are returning the reverb (or whatever the effect is). It doesn’t mean you can’t use the Pioneer, I think I’m just bringing this up so you are aware of this, that as you increase or decrease the level of the effect return, you are also increasing or decreasing the level of the dry signal present at the output of the Pioneer reverb unit, and may need to adjust the level of your dry signal passing through the console input to wherever you have that assigned. This becomes more of a hassle the more inputs you have sent to the reverb unit. Every time you adjust the return level of the reverb return you have to adjust the faders of each input channel sent to the reverb opposite however you are adjusting the reverb return to maintain your mix.

This is exactly right.

Regarding PGM 1 & 2 and the other PGM groups, well now I’m confused. You were saying you understood PGM 3~8 were “not available” if you were using 1 & 2 when mixing down, and I was trying to lead you through understanding that it never matters what you are using any of the PGM groups for, they are all always available to use however you want to use them. The console is not intelligent…it doesn’t know if you are tracking, overdubbing, mixing, mastering, video sweetening…it just does what it’s told. So when you are using a pair of PGM groups for mixdown, the other 6 groups are available to use however you need, or not if you don’t. How would you incorporate the other busses? Maybe you have two master recorders, a main one and a backup and you’re feeding the backup with another pair of PGM groups. Maybe you’re using the PGM groups as an additional cue feed for talent because you’re adding some additional sources during mixdown but all your AUX sends are being used for effect sends. Those are just a couple ideas off the top of my head. It’s really whatever presents as a need in your circumstance. Typically you wouldn’t need them during mixdown, but, again, they are *available*.

You are right as well about this.

Hope that helps.

Oh and I’ll have to check out that Richard Swift piece. That’s neat to know of a song that actually utilized my old M-520.

So I ask again, am I understanding correctly your M-520 is my old M-520?

THE HEX is his last solo album he was working on before he passed. Your board is featured on many albums he mixed, engineered, and played on for many artist. Another good one would be Jesse Baylin's DARK PLACE and Foygen's We Are The 21st Century Ambassadors Of Peace & Magic. That's just the tip of the iceberg. He recorded so much.

Sorry for the confusion, my M520 is not your old M520. I don't know what happened to it. It was in his studio National Freedom in Oregon. I hope someone is taking care of it. It's a piece of music history.

 

[bleachboy]

Wow, Richard Swift is one of my (many) musical heroes.

Hi, Louis.

So for channel 3 what happens if you monitor the input (mic or tape…doesn’t matter), and dicker with the ACCESS jumper? Like gently wiggle it or manipulate it? Do you get intermittent signal? If so, exercise it (plug and unplug it a few times). If the exercising doesn’t fix it, but you can definitely make signal pass if you manipulate the jumper, then you probably have a bad solder joint on either the SEND or RCV jack. Or both.

The other general thing for your issue with the skritchies/static and intermittent signal at low levels could just be dirty source select switches. Teac used good quality switches for those toggles at the top of the strip, but because the switch chassis opening faces up, years of dust/debris makes its way down there. And all there is to prevent that is that little felty piece which does something but not a lot after decades of exposure. Take your DeoxIT, and make sure it’s something like the D5 for metal-to-metal contacts as opposed to the F5 Faderlube, flip the switch all the way to the left, and guide the straw down along the right side of the switch shaft until it bumps up against the body of the switch. It’s down in there a little ways. Give a nice healthy squirt. Then exercise the switch back and forth rapidly maybe 25 times. More is fine. Then one more squirt but do it opposite this time, switch to the right, and straw along the left side of the switch shaft. Do all this with the power off, let it sit overnight to dry out a bit. Let us know if that helps. You can do this with the pad and phase revers toggles too, but note those only apply to the mic input.

Applying DeoxIT to jacks doesn’t usually do anything, unless they are obviously corroded and if that’s the case it’s just a band-aid fix.

If none of the above helps it may be time for a recap. Skritchy sounds and static is usually DC artifacts and all the coupling caps in the signal path are there to block DC, which is a normal product of most opamp designs (there is often some DC offset at the output of an opamp stage). As the caps dry out, they don’t do this so we’ll and we get static, or more pops or clicks when switching things or adjusting pots. But that’s an extreme case. So try the above first and let us know.

Thanks so much for your message. I will definitely try everything you advise and let you know next week when I'll start mixing again. One thing that I've observed is that after a whole day of using the console, the noise problems appeared to be less noticeable. It seems that the louder the signal I send to the console and the longer I send it, the less noticeable the noises seem to be. I didn't think about the caps simply because the console is dead silent otherwise (absolutely no background noise/hiss/hum whatsoever). I should also point out that none of the faders are noisy/scratchy.

I'll keep you updated. Thanks again !

 

[bleachboy]

Hi again,

So I have sprayed DeOxit on each of the input switches + each of the on/off switches / each of the eq on/off switches. I'm happy to say that this was enough to make the intermittent channel dropouts disappear. Yay !

On the other hand, I have sent a signal to the tape in on channel 3, maxed out the trim input, and although the OL led was on, the VU meter needle only went as high as -20db. Wiggling the channel RCA jumper didn't seem to have any effect whatsoever, only when I take it off, the signal disappears (which is normal). I have used the direct out of channel 3 to monitor the test, and while there appears to be some signal on my DAW, it is extremely low (pretty much inaudible) almost at the bottom of the digital VU meter. The same problem happens when I use the mic input of that channel.

I have also tried to swap the ACCESS jumper with another one, no change whatsoever.

 

[sweetbeats]

Questions:

When you say the VU meter only peaked at -20, what VU meter? Were you patching the direct out of channel 3 to an external input on one of the meters, or were you assigning channel 3 to a PGM group, and raising the relevant PGM group fader to the shaded area and then only seeing -20 peaks on that PGM group’s meter?

What happens if you pull the ACCESS jumper and connect the SEND jack directly to your DAW input?

 

[bleachboy]

Sorry, I was indeed assigning channel 3 to PGM group 1 yes. So I was looking at VU 1, all faders between 7 and 8 in the grey area.

When I unplug the ACCESS jumper and use the RCA from the SEND to my DAW, I get signal ! Normal, heathly level signal. Is the send pre-fader ? Because the fader has no effect on the signal I have in my DAW, neither does the channel ON switch, only the tape TRIM pot effects the level of the signal that is sent to my DAW, when I use the SEND jack to go to my interface.
However, even with all 8 ASSIGN switches engaged on channel 3, I can't send the signal to the PGM groups, all VU's stay inactive.

 

[sweetbeats]

That’s all normal. The ACCESS jacks are your insert points. When the jumper is pulled and nothing is plugged into the RCV jack it is like sending the signal out (SEND jack) but not returning the signal back to the channel (RCV jack). So no signal will pass to the rest of the channel in this state, but we are doing this to narrow down where the failure is in the channel, because I suspect you have a zorched opamp. I think I know which on it is but we’re going to try and narrow it down as much as possible.

 

[sweetbeats]

There’s no magic trickery here. I am just looking at the Block Diagram on page 69 of the manual. The Block Diagram is a pictographic layout of the functions, features and signal flow of the entire console. The input channels are along the left and you can just follow along from the input jack through each function and access point and try each stage until the signal fails. That gets you at least a macro assessment of where the failure point is. Then you get out your diagnostic equipment and go to the schematics to narrow in on the specific failure point, -OR- make a reasonable assumption and start shot-gunning parts in the narrowed area.

So things are good at the SEND jack, we can see that comes right off the input amp whether it’s the line level amp or mic amp. The RCV jack feeds the EQ section and PRE fade source of the AUX section. To be thorough you could check that you have good signal at the AUX buss in PRE mode…I already know you do. So let’s go to the next stage we can access and that’s the stage right before the input fader using the PFL buss. So stuff your ACCESS jumper back in and hit PFL, turn up your headphone knob and see if you have clean strong signal there. I bet you do. Now deactivate the PFL buss and activate the SOLO buss. Make sure the input fader is raised. I bet the signal is crap in the SOLO buss. Make sure your headphone knob is turned up and the SOLO master knob is up as well. Where the PFL buss picks up signal right before the input fader, the SOLO buss picks up the signal right after the input fader and PAN control. My suspicion is you have a bad fader booster opamp.

 

[bleachboy]

Thank you so much ! So here's what I get : using the headphone jack, when sending signal to channel 3, SOLO is actually where I have the weakest signal. If I switch to PFL, I get a slightly higher signal. When I release PFL, I get yet a slightly higher signal. From low to high signal : SOLO > PFL > just channel ON. But all in all, all three modes are extremely weak sounding comparing to other channels.

I've repeated the test with channel 2, same settings, and I'm glad I was careful because I could have killed my ears instantly. The signal is unbelievably higher on all other channels. In short, I'm not sure that PFL test was conclusive...