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Revox A77

3 Motor 2 Speed Reel to Reel Tape Recorder

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Revox A77


The well known reliability of the Revox A77 is a result of a professional design concept, a concept which successfully combines the advantages of a solidly built tape transport mechanism with those of an advanced electronic circuit design.

A 3 motor transport mechanism with electronically regulated capstan motor and solenoid operated servo brakes possesses few parts which are subject to mechanical wear.

The use of a die-cast motor chassis and head support ensures that a high degree of mechanical precision and long term stability are maintained, even under excessively heavy use.

The mechanical and electrical properties thus complement each other in a most successful way.

Models include the A77 professional, A77 SLS (super low speed) for up to 12 hours of recording, and the A77 Autostart (Vox) for security applications.


Motor: 2 x reel, 1 x capstan

Reel size: up to 10.5 inch reel

Equalization: NAB, IEC

Tape speeds: 3 34  7 12 ips

Wow and flutter: 0.08% (7 12 ips)

Frequency response: 30Hz to 20kHz (7 12 ips)

Signal to Noise Ratio: 62dB

Total harmonic distortion: 0.6%

Crosstalk: 45dB

Input: 35mV (line), 0.15mV (mic)

Output: 1.2V (line)

Output power: 8 watts

Semiconductors: 54 x transistors, 32 x diodes,

Dimensions: 415 x 359 x 180mm

Weight: 33lbs


instruction/owners manual  English Deutsch Francais

service manual  English

brochure  English

Dolby B operating instructions  English - tusksut

1971 handbook  Deutsch - classicar

If you have any problems opening files please read the download FAQ. All files are provided under strict licence and reproduction without prior permission or for financial gain is strictly prohibited.

If you have additional documentation please consider donating a copy to our free archive.


re: A77

Brought one for my husband's Birthday and it does not work, we seem to be having a run of bad luck with reel to reel tape recorders and now have three that does not work. Have anyone got an idea of an electrical engineer that fixes reel to reel tape recorders around Northamptonshire, England. Thank you. Alison

millie12's picture

re: A77

I have seen a revox repairer in the Burnley, Lancs are on ebay who advertises repairs on Revox analogue decks, don't know if that will be any help?
Also taperecorder.co.uk may be of help.

re: A77

i got mine from germany and was damaged in shipping.
Main problem is all function keys can not lock in.
Can any one offer help?
Tks from hong kong

Chungalin's picture

re: A77

Function keys (<<, >>, Play, Rec...) do not mechanically lock after pressing. When you press them, a relay activates the function, but the key returns to previous position. This is normal. One possible cause of your problem is that there’s not a Remote Control jumper in the Remote Control connector (back-top panel). When there isn’t neither a remote control nor a jumper, the functions just work while you press the keys, but stop as soon as you release the key.

re: A77

So good that someone gives their time for no reward to provide information for people buying old equipment. For myself I have always wanted a Revox A77 but in my uni years I could not afford it, now in my 60's I can afford it and although its not a patch on my hi end hi fi its a dream come true - thank you. Andy New Zealand

re: A77

Thank you very much for this wonderful site.
I found out that the recorder does not work properly without
the dummy remote control plug. Where can I get one?
It seems to me that meanwhile I can operate the machine
by shorting poles 1 and 2 of the remote control socket.

re: A77

I made one up using two banana plugs which I now keep with the Service Manual. Michael (UK)

re: A77

My experience; I suggest replacing all the .047 caps on the relay board at least, on mine one had shorted it took out a resistor, machine went into play by itself and smoked the resistor. I also found a shorted electrolytic on the oscillator board. Indicator is a flashing end of tape light. Certainly a good design, well made and easy to service, the manual here was invaluable, thank you.

re: A77

Great thanks for the documentations!

Revox A77

Big thanks for your Manual download,it makes the mechnical and electrical more easy to use and service for me!
Best regards

Revox A77 Operating Instructions & Service Manual

Machine hasn't been touched for over 20 years. Cranked up immediately. Once I got the operating instructions works like new. Tape counter not working. Service Manual got the case open and the tape counter assembly out. Needed a 30mm toothed belt (not shown). (Off to Maplin for a 30mm drive belt (ok, for a cassette player). Everything now working fine. Only 400 x 10" and 7" tapes to check!!

The manuals are a real bonus. Thanks


Many thanks for your documents!
Perfect job.

Thank you

Thanks a lot for all your great work!

revoxA77/user manual

I just purchased a reel to reel /revoxA77mkiv[THANKS to this site I was able to receive operating manual] THANK YOU AGAIN.

Revox A77

Thx, for the manual and service manual if you whant see www. igoramp.it vintage amp .

from Siberia with love! Thank

from Siberia with love! Thank you! very use of a-77 and b-750 mk2


I just received A77 and a TEAC A3340S both in Super condition and where kept in climate controlled environments. I remember my Dad and My Grandfather both using these. They were both career Musicians. I need to find a Power cord for both.

Best Regards


me too, now i can repair my

me too, now i can repair my a77.
Thank you for upload manuals and etc...

Thanks very much

I can now work and repair my A77 :)

Ciao from Italy



Thank you very much!!! for service manual

is there an old version captan speed regulation board schematic?


i have a A77 which plays fine at 7.5 ips but can not work on 3.75 ips.

the switching signal of red AE1 (0/21 v) is available from switching board while switching to 3.75 ips but the speed is same as 7.5 ips.

the reading from Techno sensor is always the same as 1/0.6ms approximately.

in this A77. the capstan speed regulation circuit is discrete discriminator circuit instead the later monostable 555 circuit in Studer's service manual.

i would appreciated if i could receive an old version schematic to speed up my investigation.



Thanks so VERY much. My A77 has been setting up and now has a terrible distortion on record, still works fine on playback of previously recorded material. Don't know if I can fix it or not but with the manual I have a chance. Thanks again. rrc

check bias

Check if the bias is ok.


Grazie per il servizio reso a buon rendere


Grazie per i manuali messi a disposizione.

bigbozer's picture

Revox A77 Manuals & Brochure

Great service! I love it and use it all the time. Thank you Hi-Fi Engine.

A77 Manuals

I just have to say one thing. You made my day. God Bless!
Thanks a million.

great resource

awesome service and resource thanks again

Revox A77

Superb information

This website is not affiliated with or sponsored by Revox. To purchase A77 spares or accessories, please contact the company via their website or visit an authorised retailer.