Toa RX-7 Update
- Thread starter Somnium7
- Start date
Somnium7
Noise Criminal
is it really a so high price?
i kinda' don't think so.
Build one from scratch, and then see what you'd want for it to "compensate" for the struggle
I would want much more than just a dozen of free gas fill-up(s)
Comparatively yes. I paid less than that for my 32 channel model and it was in a complete state, no missing parts. See that's my main gripe with that listing is the unit has stuff missing and he's asking THAT much...
Dr ZEE
Anti-Pro Circles Insider
huh, you know what ..heh heh
the first version actually looks cooler to my eye
I know, i know ... but the second version looks more like a block pulled from a commercial industrial piece of gear Made in somewhere in People's Rebulic or something
*********
make couple more of those, sell them to toa(s)' praud dads around the world
the first version actually looks cooler to my eye
I know, i know ... but the second version looks more like a block pulled from a commercial industrial piece of gear Made in somewhere in People's Rebulic or something
*********
make couple more of those, sell them to toa(s)' praud dads around the world
Somnium7
Noise Criminal
huh, you know what ..heh heh
the first version actually looks cooler to my eye
Well the 1st one had a better picture....
Have some practice at it.I know, i know ... but the second version looks more like a block pulled from a commercial industrial piece of gear Made in somewhere in People's Rebulic or something
*********
Back in the day when I worked as a R&D tech it was my job to take plans from the engineers and turn them into an actual piece of commercial/industrial gear.
I have two more of the PCBs. I'm planning to use another for a different project that needs a power supply. Third one is up for grabs, $20 + s&h for anybody who needs a good quality low noise regulator.
Somnium7
Noise Criminal
I recently called Toa tech support to get some information regarding my mixer. Just for the heck of it I decided to see if by chance they actually still had any replacements for the PC-2011 line output DOAs in the RX-7. Turns out they had 1 left in inventory. I thought wow that's cool lemme grab it
I paid like $30 for it. The thing arrived in the mail yesterday and my first thought was WTF is this? Instead of the nice black cube it is a bare PCB in the same footprint as the DOA with the same pinout BUT all that is on it is a lame little JRC5532 monolithic opamp chip.
DOH!
I guess they decided to cut costs in a big way for the replacement parts. This thing is worthless...
I paid like $30 for it. The thing arrived in the mail yesterday and my first thought was WTF is this? Instead of the nice black cube it is a bare PCB in the same footprint as the DOA with the same pinout BUT all that is on it is a lame little JRC5532 monolithic opamp chip.
DOH!
I guess they decided to cut costs in a big way for the replacement parts. This thing is worthless...
Somnium7
Noise Criminal
So results are such...
Power supply has the new regulator board installed and it's working nicely. I spent some extra time testing the new regulator PCB. Even some destructive testing
I shorted it out. Ran it with too much voltage input. Hooked it up to very heavy loads. Even connected the input voltage with the wrong polarity. Took it like a champ. Obviously, when connected backwards the protection diodes martyred themselves and went to join the silicon Allah. The rest of the board survived.
Turning on the console and listening to the noise floor now - what noise floor!!!???
It ain't there anymore. NO LOW LEVEL HISS OR NOISE, period. Gone, nada, sayonara... etc.
The lo-noise part of the design wasn't a joke. I can't believe this kind of performance was possible from a 3 terminal regulator IC.
So that leaves me with the $6 chip deal. Was it worth it? In a word, yes. So much so I went and ordered $230 worth of new chips
LME49860 rocks the house! Never heard a cleaner monolithic opamp ever before.
I seem to have developed a high frequency whine in my Echo 1 buss though. It's proving difficult to track down the cause. I removed all modified modules thinking it was something I changed that could be the problem but no luck. Some old fart of a compensation cap must have went bad somewhere. I'll get to it eventually...
Power supply has the new regulator board installed and it's working nicely. I spent some extra time testing the new regulator PCB. Even some destructive testing
I shorted it out. Ran it with too much voltage input. Hooked it up to very heavy loads. Even connected the input voltage with the wrong polarity. Took it like a champ. Obviously, when connected backwards the protection diodes martyred themselves and went to join the silicon Allah. The rest of the board survived.
Turning on the console and listening to the noise floor now - what noise floor!!!???
It ain't there anymore. NO LOW LEVEL HISS OR NOISE, period. Gone, nada, sayonara... etc.
The lo-noise part of the design wasn't a joke. I can't believe this kind of performance was possible from a 3 terminal regulator IC.
So that leaves me with the $6 chip deal. Was it worth it? In a word, yes. So much so I went and ordered $230 worth of new chips
LME49860 rocks the house! Never heard a cleaner monolithic opamp ever before.
I seem to have developed a high frequency whine in my Echo 1 buss though. It's proving difficult to track down the cause. I removed all modified modules thinking it was something I changed that could be the problem but no luck. Some old fart of a compensation cap must have went bad somewhere. I'll get to it eventually...
Dr ZEE
Anti-Pro Circles Insider
sounds good
*****
When are you planning on closing the patient up. He (or she?) has to start breathing on his own some day, don't you think?
while were are here, here is a nice amount of pretty damn hot cool knobs:
http://cgi.ebay.com/Lot-of-49-Red-3-4-Electronic-Test-Equipment-Knobs-NOS_W0QQitemZ170206851944,
just in case, maybe you need some, and these are kind of rare and are from CHICAGO !.
...maybe for some perspective synth project or something
keep up.
*****
When are you planning on closing the patient up. He (or she?) has to start breathing on his own some day, don't you think?
while were are here, here is a nice amount of pretty damn hot cool knobs:
http://cgi.ebay.com/Lot-of-49-Red-3-4-Electronic-Test-Equipment-Knobs-NOS_W0QQitemZ170206851944,
just in case, maybe you need some, and these are kind of rare and are from CHICAGO !.
...maybe for some perspective synth project or something
keep up.
Somnium7
Noise Criminal
sounds good
*****
When are you planning on closing the patient up. He (or she?) has to start breathing on his own some day, don't you think?
I think my friend you are more impatient to see this project finished than I am
.And I am quite anxious to be done. However, please consider the SCOPE...
This is a gigantic SOB. On group modules I am replacing something like 80+ resistors, 30+ cap, adding 17 bypass caps, 6 opamps, 1 LED, and thoroughly cleaning each switch and pot. Of which there are legion.
Add to that an almost completely rebuilt power supply, 32 input channels, 8 program channels, the phones channel and talkback module. Yeah, it's a huge undertaking.
With me commuting 200 miles to DC and back every week plus visitations with my boy twice a month I'm lucky to be making any progress. I have a travel kit of parts and tools I take with me on work trips and spend my night soldering by the bedside lights in my motel room. So far I see no end but the blue LEDS I put in each finished module sure are purdy
I really appreciate the hookup for those knobs. Yes my synth project needs lots of them... I'll be sure to nab that lot!
PS: I have named this console Mixosaurus Rex. Not quite he or she I guess but fitting.
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Somnium7
Noise Criminal
Man, that's one beautiful console.
----
Thank you cjacek. During it's life it had many of Country Music's greats play through it including Johny Cash. So I guess that makes it a bit of a historical legend.
Believe me, old Rex is getting the 1st class treatment now. I'm using only the best in terms of parts and practices. This ain't no hack job. I'm paying close attention to every detail no matter how small. This is another reason it is taking so long.
I have probably put in at least 40 hours just in researching and selecting the parts I am putting in it.
Reading the specs on everything and making careful decisions about which parts are used where.
In crucial circuits like the summing amps I am using military spec Dale 1% resistors for lowest noise. In the PSU I am using parts rated for double or triple the voltage and current they will ever see.
Crap ceramic caps replaced by high tolerance polystyrene, polypropolene or glass caps. Electrolytic caps replaced with good quality Nichicons and in crucial areas very expensive and rare ROE audio grade caps.
You already know about the chips...
I'm even using $20/can DeoxIT to clean pots, switches and connectors.
Rex is a king and receiving the royal treatment.
I found the exact source of the high pitched whine, but the why of it is still a mystery.
Further testing on the power supply with it hooked up to the mixer has been very impressive. Using my oscilloscope, I poked around to measure the ripple voltage. Got flat lines even with Volts Division set to microvolts ranges. This is under load too. Damn this thing is QUIET. Those guys whose ideas I used in the design knew their shit. My hat is off to them.
B
Beck
Guest
Nice rig indeed.
You've got me interested in the LME49860... never tried it.
Oscillating op-amp… bad bypass cap or bad op-amp, maybe?
You've got me interested in the LME49860... never tried it.
Oscillating op-amp… bad bypass cap or bad op-amp, maybe?
Somnium7
Noise Criminal
Thank you Beck. I'll pass your compliment along to his royal highness King Rex.
It's power hungry so make sure your supply can handle the extra current. I'll provide more subjective listening tests at a later time.
Here are the specs (National website):
LME49860.html
Actually I traced the problem back to the power supply of all places. One of the pass transistors was misbehaving and creating a weird high frequency resonance within the main smoothing filter. I didn't show up in my tests before because I wasn't looking for such a high frequency signal. I changed the transistor and that took care of the problem. Very strange errorOscillating op-amp… bad bypass cap or bad op-amp, maybe?
Somnium7
Noise Criminal
I've done some fun listening tests this weekend to determine the characters of the various opamps I'm using.
Mind you these tests are highly flawed since all audio passes through Toa 2011 DOAs and Toa output transformers on the output side. So the colors of these devices is dominant. But, for shits and giggles I configured one program module with all LME49860 and another with all OP275. Yes there is a distinct difference in the sound between the two modules now.
OP275 module has a more aggressive in-your-face tone. The lows are a little hyped and the highs have a glossy crisp sound. The depth is good but not natural sounding. I really enjoyed listening to electronic music through this module.
LME49860 module is very flat in comparison. Also very natural with really spacious depth. Highs are crisp but flat, while lows are a bit reserved and woody. Details in reverb and delay affects are quite strong too. This module sounded better with acoustic and ambient atmospheric material.
Both worked great for traditional Rock music. I suppose another way of describing the sound difference is in terms of mics. The LME49860 sounded more like a high-end dynamic mic. Smooth and slightly compressed.
OP275 was more like a glassy bright condenser with a big hump in bottom response or used close up.
Two very different animals but surprisingly they work well in combination. Signals that path through both devices are very interesting and detailed. I'm having a difficult time describing the combined sound but I really like it.
I'll have to try the same experiment with the TLE2141 yet. I'm only using these in the channel EQ circuits. So far I can't hear any difference at all when I switch EQ in with controls all nulled.
When I find some extra time I'll post some clips of how the channel pres sound now. The change here is nothing short of shocking
Even my lowly Audix i5 sounds like a million dollars through the upgraded pres....
Stay tuned!
Mind you these tests are highly flawed since all audio passes through Toa 2011 DOAs and Toa output transformers on the output side. So the colors of these devices is dominant. But, for shits and giggles I configured one program module with all LME49860 and another with all OP275. Yes there is a distinct difference in the sound between the two modules now.
OP275 module has a more aggressive in-your-face tone. The lows are a little hyped and the highs have a glossy crisp sound. The depth is good but not natural sounding. I really enjoyed listening to electronic music through this module.
LME49860 module is very flat in comparison. Also very natural with really spacious depth. Highs are crisp but flat, while lows are a bit reserved and woody. Details in reverb and delay affects are quite strong too. This module sounded better with acoustic and ambient atmospheric material.
Both worked great for traditional Rock music. I suppose another way of describing the sound difference is in terms of mics. The LME49860 sounded more like a high-end dynamic mic. Smooth and slightly compressed.
OP275 was more like a glassy bright condenser with a big hump in bottom response or used close up.
Two very different animals but surprisingly they work well in combination. Signals that path through both devices are very interesting and detailed. I'm having a difficult time describing the combined sound but I really like it.
I'll have to try the same experiment with the TLE2141 yet. I'm only using these in the channel EQ circuits. So far I can't hear any difference at all when I switch EQ in with controls all nulled.
When I find some extra time I'll post some clips of how the channel pres sound now. The change here is nothing short of shocking
Even my lowly Audix i5 sounds like a million dollars through the upgraded pres....
Stay tuned!
Dr ZEE
Anti-Pro Circles Insider
cool!
Mike, Audix i5 still "sounds" like Audix i5. Million dollars is a value that comes from entrepreneurship of an "upgrader". You could be one of them ,
Oh, wait, You ARE! one of them already, just with no enterprise.
Now, Mike, what are you going to do with all the choices you've already discovered and will discover more as long as you keep "him" open.
Close him up, surgeon.
See less - Know less - Worry less.
************
seriously,
GREAT work. and keep posting.
Mike, Audix i5 still "sounds" like Audix i5. Million dollars is a value that comes from entrepreneurship of an "upgrader". You could be one of them ,
Oh, wait, You ARE! one of them already, just with no enterprise.
Now, Mike, what are you going to do with all the choices you've already discovered and will discover more as long as you keep "him" open.
Close him up, surgeon.
See less - Know less - Worry less.
************
seriously,
GREAT work. and keep posting.
Somnium7
Noise Criminal
Mike, Audix i5 still "sounds" like Audix i5. Million dollars is a value that comes from entrepreneurship of an "upgrader".
Ok I admit I get excited pretty easily. I suppose a better way of rephrasing that i5 statement is - I never thought the i5 could sound as good as it does through the upgraded pres.
This applies to all my mics. I have done A/B comparisons along with a friend who has a good ear for all of my mics between upgraded and untouched channels. Pretty much the same result for them all...
My friend said that the old channels sounded the way he expected a beat up 30 year old mixer to sound but the upgraded ones sounded like he imagined they would the day the mixer rolled off the assembly line.
Now, Mike, what are you going to do with all the choices you've already discovered and will discover more as long as you keep "him" open.
Close him up, surgeon.
See less - Know less - Worry less.
************
seriously,
GREAT work. and keep posting.
Thanks. I hope my flawed listening tests were helpful. Obviously, those same opamp chips will sound much different on their own. I highly recommend both of those products to anybody modding or upgrading their gear. I have read alot of debates over the "Analog Devices Sound" where some folks hate and other love the sound from that companies opamps. Personally, I like it. I have used several of there models in my various projects including my mic pre design and my synthesizer modules. I do hear the difference when comparing the AD chips to other brands but never find it objectionable. They are noticeably more punchy sounding than most and can run the risk of being fatiguing in some applications.
As far as choices go. I really am trying to make sound decisions on how to use all the new parts in the best application for each. For example, I've decided the LME part is best suited in summing amps because of it's extremely low noise figure and also for monitoring outputs and line driver stages. The group modules on the console are now all employing the LME49860 throughout. While the OP275 is much better suited for my input channels. Since it is a JFET input device it performs very nicely here and provides nice detail for buffering the mic preamp DOA output. On channel line inputs I love the punch it gives to my instruments - especially my synths.
As of now, all group channels and all program channels are completely upgraded and I'm working my way through the input channels. Of these four are completed. The hold-up is because I have already run out of many values of resistors and caps so I'm waiting for the re-up to arrive.