Crazy problem- Tascam 32 sounds bad after rebuild

[Mark Brazeau]

Hey there!

Newbie here, I have a challenge that both myself and the tech cannot solve...

Have a Tascam 32; did a total rebuild (New Caps, alignment, mechanicals, and even a NOS tape head). We’ve aligned with it and MLS alignment tape and it shows smooth Frequency response to 28khz on the scope.

Hears the problem...Pun intended J

I was lucky enough to find a Safety copy of Dark Side of the Moon years ago, and whoa it sounds like no other. However, now (Post rebuild) it sounds flat, loss of dynamic range and high-end. And it’s not just that tape, it’s all tapes (Even some Masters I purchased from ABC international). Even tried aligning by ear and putting the old head back- same results.

A head-scratcher- Zero idea of what could be wrong?

Anybody? Solution will truly be appreciated!

 

[Laszlo]

Hello Mark,

welcome to this forum. I am not a pro here either, however I am trying to get something out of your note. I am sure that someone more day to day practicioner will pick up the issue and give some professional answer.
It would be good to know better what eyactly you did during the rebuild. Did you replace the opamps too for example? Does the issue persist only during playback, or also while recording? When you say a record sounded well it was with the same tape recorder with the original setup? To me the issue sounds like the equalisation (and probably the bias) are not set well.
L

 

[Mark Richards]

It's been quite a while since I've done maintenance on a reel-reel.

That said,
If your reference calibration tape is known to be accurate, and your o'scope and measurement gear are calibrated accurately, and you've followed in order the sequenced maintenance steps in the service manual, then the result should be accurate playback of pre-recorded tapes.

Even if the heads are worn, if you've been able to bring the unit up to spec with calibrated measurement gear then the issue likely is in the headphone monitor circuit of the 32, elsewhere in your playback chain if not using the 32's headphone circuit to monitor playback, or the pre-recorded tapes you have are shedding (very common for any tape more than 7 years old) and now are clogging the playback head gaps.

Sorry not to able to offer any useful comment beyond that.

 

[Mark Brazeau]

Hello and many thanks for the response(s)!! ,

I only use the deck for playback (playing the same tapes I always play) and the opamps were not replaced. To add more clarity, it does play, but just lost the wide dynamic range and smooth high end. It's definitely noticeable; now sounds like an MP3 player.

The tech working on it is stumped- he's been a tech for 30+ years and rebuilt all of my other gear (muse audio). He's really, really good, but thinking (hoping!) this is some kind of unique tuning or other anomaly to a Tascam/Tascam 32.

I do not think he has checked the headphone circuit as I've only listened to it on the line out
No tape shedding, I checked that first - heads are clean

Like I said- this one is a head scratcher...

 

[Mark Richards]

I found this "Theory of Maintenance" for a TASCAM 34B. It applies equally to the 32. Perhaps something in there will trigger an idea of where to look. My other thought is perhaps the tape guides or lifters are off just enough to reduce head contact slightly.

You may also get some good feedback at this website:
http://www.tapeheads.net/forums.php?s=c9003b4112a9d1f2bb6cffacb7aaa230