Tascam 424 mki fast playback

A. Lacy

New member
Hi all,

I recently purchased a Tascam 424 mki from eBay, and the playback for the normal speed setting is pretty fast. It sounds almost normal if it put it on the slowest speed and turn the pitch all the way up. Anyone know how to fix this?

Thanks!
 

skywaveTDR

Active member
You need a speed tape called MTT111 or MXT111 depending on what speed you are adjusting. Then you need either a wow and flutter meter or a frequency counter. The service manual is going to say where to adjust. Decks from E bay are sold by idiots most the time and they do not know how to correctly service them even though they will tell you that they work. HA. I see a lot of restored decks from E bay and they are all worn out which constitutes fraud- E bay should erase the ID of these people that do this.
 

A. Lacy

New member
Oh ok thanks! So if I got a service manual, would it tell me I would need the same tools as well as how to do it?

I also did a google search for a MTT111, MXT111, wow and flutter meter, and frequency counter, but I wasn't sure was if I was seeing the right things. (A lot of them were talking about radio frequency meters, the wow and flutter seemed super expensive, and I really couldn't find anything for the MTT111 or MXT111.)

Are some of these products just on Amazon or Sweetwater?
 

skywaveTDR

Active member
Most big companies (Full Compass) do not have test equipment as they only sell new devices and so the Leader LFM39A which is what I use if not a Audio Precision One plus Portable unit. I have two benches operating. Yes, the repair business does cost some money to get into. Test tapes, tools, meters, service manuals- some of them I have paid for from the late Rick at Stereo Manuals. That resource is about gone now. I tell my trainees that it could cost about $1500 over time to get all the stuff you need. You can not do the job without the right tools as much as some guys time tapes and think that is going to work. There are computer programs that can be used and I think they are made in Germany and some are on the ANT web site. That and a cheaper test tape from off E bay- there used to be a 3KHz tape for about $6.00. I don't know if it is still there. Most test tapes either new old one or those from Genn lab are $80 on up. I think Genn Lab in NZ is the only one producing alignment tapes in the real world. Service manuals are what you need and it tells you where the speed pots are but they are assuming the person doing the work is a Technician not a beginner so there is not detailed instructions in there.
The Leader LFM39A used to be found on E bay for as low as $39 but they have all been absorbed and I think the prices I see now are around $300. Keep in mind that in the 80's these were $800 meters new and so were the LVM181A I also use on the benches which is the AC millivolt meter. This has dB scales and used to do level adjustments. People that own equipment think they can just go in and adjust all this stuff but when they find out what a real Technician does they would be greatly surprised. I just did a 424 Mk III and it took like 3 hours to get it right. These portastudio devices are not all the easy to work on without extender cables which have to be custom made.
 

A. Lacy

New member
Oh wow. That's a lot I didn't know. I didn't realize that it could be potentially so expensive and time consuming.

I know you said that some people think that tinkering around would fix their issues (I guess I'm one of those people), but based on what my issue is, do you think I could fix it just by tinkering with it and using a tape for reference? Or would I need to get it fully serviced?

Thanks again for all the info!
 

skywaveTDR

Active member
Well if you get a service manual and a tape that is reasonably accurate then you could adjust the speed. This is not tinkering as that will result as it has in many other problem caused by people that go into these not knowing how delicate some parts are. So you need a 3KHz reference tape and a way to measure the output frequency. I just plug the line out on my bench and play a 3KHz tape I have here then look at both wow and flutter meter and frequency counter hooked together. Then adjustments can be made to the high side of 3KHz. The high side because the human era hears slower audio faster than it does faster audio. I set machines at 3004 to 3007Hz. The controls are commonly positioned near the area where the motor plugs in but you best know where the manual tells you to adjust it. The 424Mk III I had here the other day has two pots in it that were for each speed. Of course the speeds are adjusted with the Pitch pot at center position. I would make sure the capstan belt is in good shape as that can also be the problem or lack of oil in the capstan bearing.
 

A. Lacy

New member
Ok so just repeating back everything you've said, the only things I'm going to need are:

- service manual,
- 3KHz cassette tape (and if anyone else is reading this, I found some here: https://www.gennlab.com/speed_cass.html),
- a lot of attention to detail

Am I understanding that correctly?

And what is the "high side" of the 3KHz tape? And does correcting the machine to accurately display that sound correct the speed of the machine?

Thanks again!
 

skywaveTDR

Active member
Well you are missing the measuring devices either a wow and flutter meter which you set speed using the drift meter or a frequency counter. Trying to set speed by hearing music does not work for accuracy and so the deck will still be off. High side means 3000Hz or up to 3009HZ and anywhere in that area. The low side of 3000Hz is anything below that as in 2997Hz and so on. Listening to music will end you in that area a lot of times. The service manual can be a Pdf even but I have not seen one for that model yet. The frequency counter with a MTT111 tape will allow you to set the high speed just use 6000Hz but the wow and flutter meter will not know what to do with the 6000Hz signal as they are made to detect 3000Hz only and some have switches for 3150Hz which is the DIN standard.
 

A. Lacy

New member
Ok, so what I need is:

- service manual,
- 3KHz cassette tape
- Frequency counter
- MTT111 tape
- a lot of attention to detail

And the "high side" of 3KHz is up to 3009Hz and "low side" is down to 2997Hz. I think I get that part.

So, the MTT111 is a type of tape that emits 6000Hz?

And I was thinking I could just play the Tascam 424 into Logic on my computer and use the visual EQ to see if frequency being emitted is the same as the one labeled on the cassette. Would that be a way of working around not having a frequency counter? Or is a frequency counter do something different?

And how does wow and flutter work into all of this as well? how would dI measure and adjust those?


Again, thank you for all of the info. It's been a huge help.
 

skywaveTDR

Active member
The MTT has a 3KHz signal on it but if one plays it in a double speed porta studio the frequency will read 6000 Hz because it is going 2X the regular speed.
The wow and flutter tell you about the condition of the transport system and there are values to be met. The AMSoil I put in the capstan bearing allow the transport with a good motor and belt to work with great values. If a computer was to be used I would download the free software from the ANT site and just use that as it has wow and flutter in it too.

I don't use this because I have the real stuff but I highly recommend anything on the ANT site-
 

A. Lacy

New member
Ok, so wow and flutter are the result of issues in the transport system. Got it.

I just looked up what AMSoil is, and it makes sense you'd put that grease on it to run more smoothly.

I just looked up the ANT Audio program, and it looks like its a program only Windows can run. Unfortunately, I have a Mac. I think there are code switches that allow Macs to run Windows programs and visa versa.


In conclusion, what I would need to fix this is:

- service manual
Also, for anyone reading through this, I found a Tascam 424 mkI service manual:

- MTT111 tape (a tape with a 3KHz signal, used for adjusting speeds of 4 tracks)
- Frequency Counter (reads back what the Tascam plays when it plays the 3KHz signal)
- a lot of attention to detail

Ok, now I think I understand what everything does and why it matters. Am I missing anything?
 
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skywaveTDR

Active member
Thanks for the manual link as I went there and downloaded it for my collection which I read to help people on the computer with questions. You are well on the way to getting it fixed up with this manual. It is very well scanned I must say- I left such a comment as well.
 

A. Lacy

New member
Awesome thanks so much for all of the information! Glad I was able to help you out as well. That guy has a pretty awesome YouTube channel too:

And for those reading through this, here is everything you need and the links:

- service manual

- MTT111 tape (a tape with a 3KHz signal, used for adjusting speeds of 4 tracks)

- Frequency Counter (reads back what the Tascam plays when it plays the 3KHz signal)
Free Download for Windows:

- A LOT of attention to detail


Thanks again for all your help! I learned a ton!
 
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A. Lacy

New member
One more question, is a frequency counter and a wow and flutter meter the same thing? I think I started using them interchangeably by mistake.

Thanks!
 

rob aylestone

Well-known member
No - the wow and flutter meter measures deviation away from a constant tone - slow deviations being wow and fast ones, flutter. The frequency counter just tells you the tone is 4995Hz rather than the 5KHz you expected. With all test gear, you need to interpret the results. A test tape will be accurately recorded with a constant tone marked on the box - your frequency meter will report what frequency it detects which reveals how faster to slower than the indicated IPS setting is. The wow and flutter meter reveals the fast and slow deviations from slipping belts, debris in the guides, dodgy bearings - that kind of thing. These are not detailed in the service manual - it simply gives you the pcb location of the controlling component - reading and using the test gear is assumed competency - as it would be with an engineer. They'll give you test point locations and voltages that would be read with a sensitive meter or scope, depending on what the signal was. Things like square waves would be a scope measurement and not a meter - they assume you know what test gear to use. Other test gear helps with generating pink noise or other tones you record and replay and then allow you to align input and output levels. You do need meters with proper probes - missing the test point and accidentally bridging a couple of circuit board tracks is not good. Scope probes tend to have little hooks so they attach properly - but meters need you to touch the right bit, and then look away to read the meter - so it is a set of skills to be learned.
 

skywaveTDR

Active member
Makes perfect sense. The two items on some benches are contained in one. In my bench 2 there is a Leader Frequency counter hooked in parallel to the LFM39A wow and flutter meter. The reason for this is with one test tape you can set the speed of a two speed machines in that a 3KHz tape will read 3000Hz for the 7.5 IPS speed setting and give you wow and flutter data. But if you switch to slow speed the 3000Hz now goes to 1500Hz and that is the value you set for half speed. The wow and flutter meter does nothing for you here as it has a filter system only made for 3KHz and so it is effectively out of the picture. Yes you can thread a 3.75 IPS speed tape on the unit but there is a saying in the business that time is money and you will waste it if doing things the slow way. Not to mention the additional 3.75 IPS speed tape will cost you another $100 to buy.
 

A. Lacy

New member
Ok, so frequency counter would output the frequency that is being played, and that shows what adjustments need to be made. That makes sense.

So, would I need a different kind of tape to use a wow and flutter meter? Do they just measure the fluctuations of a normal cassette tape? Because that would mean the cassette tape, if it isn't adjusted perfectly to 7.5 IPS, would be a variable too, correct?
 

skywaveTDR

Active member
The speed tape that is sold for alignment purpose is the same tape (MTT111). The frequency counter just reads the frequency of the signal on the tape and it should be 3000Hz. A deck that goes double speed will be 6000Hz but a frequency counter will display that but the 3KHz filters in the Wow and Flutter meter will ignore it. That is why with double speed decks the tape that you must use is the MXT111 where 3KHz is recorded on it at that speed. Wow and flutter meters are displaying to you a error signal. If there was no wow and flutter the meter would just go to rest at 0. So far on an open reel deck I have only seen one go to .0135% which is damn good for a belt drive deck. This was a BR20.
The drift meter on a wow and Flutter meter is showing you a null or analog presentation of frequency. You set the meter for exact middle and then input a signal to see where it goes- left means slow and right means fast then they give you graduations on the meter in percent. This means when dealing with a 3000Hz tape that 1% is meaning the tape is at 3030Hz or is 1% fast. likewise the meter showing -1% is at frequency 2970Hz.
 

A. Lacy

New member
Ohhh ok. That makes much more sense. Let me see if I can sum it all up again and let me know if I'm understanding correctly. I have one more question, but I want to ask that after me restating everthing:

I need a:
- Service manual
- MTT111 tape recorded at 3Khz
- Frequency Counter
- Wow and Flutter Meter
(From what I read on the A.N.T. audio, it looks like he combined the Frequency Counter and Wow and Flutter meter. So that's a 2 for 1.)

And that question is, if I start working on my Tascam 424 while it's plugged in, that's pretty hazardous. So would you happen to know of any gloves that would protect me from injury? I think the unit is about 240V AC.
 
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