Anybody know about the Sony TC-770 portable open reel tape recorder ?

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Hello

Anybody know about the Sony TC-770 portable open reel tape recorder ?

Like specs, bias and level adjustements, price wen it was new, etc... ?

Is there any modifications to made it sounding better ?

It's a rare machine.

I have this machine, and today, after cleaning all belts, etc, and lubricating it, it's doing very good recording at 7 1/2 IPS, it's very musical with an excellent soundstage.

It's a four track recording head, but it have two playback head, one four track, and one two track.

I'm not sure, but I think it sound as good as my Revox A-77 wen I was using it at 7 1/2 IPS, but it's being long time since I've ad my Revox A-77 at home.

I was thinking to sell it, but since it sound very good I'm not sure if I will keep it or sell it.

Thank

Bye

Gaetan
 

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Sony tape decks

I've got a TC230 service manual, and it claims 30-18000hz @ 7.5ips, flutter & wow <.1%, Harmonic distortion <3%@ .775V out, S/N 50 db.
I have a Sam's photofacts for my Sony TC355 and it has no specifications. Bias oscillator nominally 130Khz. Record bias instructions- Move left monitor switch to tape, select record mode, apply a 1000 hz tone at .0006 V rms to left mic input, connect VTVM to left line output. Adjust C72 for max l-channel output and increase bias until output decreases .5db. Repeat for right.
Play head azimuth adjust head until top of pole is .02" below top of tape.
It looks as if the 770 has added solenoid control to the top of the line 366 manual control deck.
 
Hello

I allready have a Revox, so after some thinking, I decide to sell it, here is the link;

Sony TC-770-4 portable reel to reel professional tape recorder - Canuck Audio Mart

Thank to all

Bye

Gaetan

Sorry to hear that, the TC-770 is generally somewhat better regarded than the ReVox A-77 and a lot rarer.. I'd have probably kept the Sony... To each his own. Given the R2R market these days you'll sell it at that price which IMHO is probably on the low side.
 
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Hello

New quality tapes cost a bit high for me.

I only have somes 15 years old Scotch brand tapes, they are a bit too old, there is some slight level variations with those old tapes.

Maby one day I will also sell my Revox.

Thank

Bye

Gaetan
 
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Hello

There is some small level variations at playback with those tape I've use to recorded with the Sony, is it possible that it's because I use those old tapes ?

The output varies within the tape itself, it's small and fast variations, it's low level and can be heard with piano music only, it sound like a small wow and fluter or maby a very little variable distorted sound.

Wen I record, I alway keep it under 0 vu.

It would better if you can ear the recorded music I've done.

So, I've recorded; a short piano music for the first part and a short jazz music for the second part of the recording, and I've transfer it in a MP3 file.

Here is the link to download my MP3 file.


Free File Hosting, mp3 file hosting, Host, Online Storage for Music, Videos, and Documents

You have go down the webfilehost page, down at the right side of the page, you will see a timer of arround 30 second, you just need to wait until the timer go down to 0 before downloading the file.

Thank

Bye

Gaetan
 
It could be scrape flutter if your tape is old and the surface lubricant has given up the ghost. It could also be a sign of problems with the capstan motor. (much less likely)

Unfortunately my surfing laptop does not have decent sound, and I am lucky when the speakers work at all, so tomorrow I will listen to your capture on the system connected to my desktop.
 
It could be scrape flutter if your tape is old and the surface lubricant has given up the ghost. It could also be a sign of problems with the capstan motor. (much less likely)

Unfortunately my surfing laptop does not have decent sound, and I am lucky when the speakers work at all, so tomorrow I will listen to your capture on the system connected to my desktop.

Hello

I've done the MP3 at 320k.

Better to download it today since the direct link was for today.

Thank you

Bye

Gaetan
 
Hello

Maby it's a too low bias, because of the background noise and distorted a bit in loud parts, maby it needed more bias ?

Btw, the music was record using my Adcom cd player as a source and it was from a Naim music cd.

I have a scope and I can do a thd spectrum analysis with my sound card.

I presume that if it's the bias, I need to record a 1khz signal and monitor the output with a scope to get the highest signal, or doing a FFT of the signal to adjust the bias for the lowest THD ?

Thank you

Bye

Gaetan
 
Hello

Maby it's a too low bias, because of the background noise and distorted a bit in loud parts, maby it needed more bias ?

Btw, the music was record using my Adcom cd player as a source and it was from a Naim music cd.

I have a scope and I can do a thd spectrum analysis with my sound card.

I presume that if it's the bias, I need to record a 1khz signal and monitor the output with a scope to get the highest signal, or doing a FFT of the signal to adjust the bias for the lowest THD ?

Thank you

Bye

Gaetan

Usually you try to assure that the response at 1kHz and 10kHz in terms of amplitude match well - this should be done at typically -10dB or the specific amplitude Sony recommends. (Cassette is typically done at -20dB) Under-bias and you usually end up with a rising response at 10kHz and more thd%, under-bias and the opposite will be true. (IIRC there is also a trade off with modulation noise as the bias is increased.) The best thoughts on this subject are most likely found at tapeheads.net - I've abandoned largely abandoned tape, and now only have a mildly massaged ReVox G-36 MKIII with half track heads. It's sounds very good, but I find tape too expensive a medium to indulge fully.
 
Last edited:
Hello

Anybody know about the Sony TC-770 portable open reel tape recorder ?

Like specs, bias and level adjustements, price wen it was new, etc... ?

Is there any modifications to made it sounding better ?

It's a rare machine.

I have this machine, and today, after cleaning all belts, etc, and lubricating it, it's doing very good recording at 7 1/2 IPS, it's very musical with an excellent soundstage.

It's a four track recording head, but it have two playback head, one four track, and one two track.

I'm not sure, but I think it sound as good as my Revox A-77 wen I was using it at 7 1/2 IPS, but it's being long time since I've ad my Revox A-77 at home.

I was thinking to sell it, but since it sound very good I'm not sure if I will keep it or sell it.

Thank

Bye

Gaetan

The TC770 was made in two versions, one that recorded and played 1/2 track stereo with the option of also playing 1/4 track tapes, and one that recorded and played 1/4 track with the option of also playing 1/2 track tapes.
Both versions featured balanced XLR mic inputs, 3 head design, very fine electronics, DC servo motor and operation on internal battery pack or AC making them serious field recorders for recording music in locations where AC power was unavailable. I've owned one since new and made many fine live music recordings in the 1970's and 1980's but since have used other machines for that purpose. The battery pack has been unavailable for many years and now few folks even know what the TC-770 was. I'm just cleaning and putting mine back into service to service because it's the only 1/2 track machine I currently own on which to play tapes I made 30-40 years ago on my 770 and on a Revox A-77 1/2 track which I no longer own. I don't recommend modifications because it's hard to work on, manual seems to be unavailable and frankly, it's already soooooo good. If you have any specific questions, I'll try to answer them.
 
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