Revox A700 vs B77?

[titanstats]

Hey tape guys, need an opinion or two. Always liked the look of the A700 but never had my paws on one; I have the opportunity to pick one up but am uncertain if I really want it or not. I already have a B77 and am pretty familiar with the design, so can do most of the work on it myself. It's a great machine, so can't help but wonder if the A700 is a sideways move or not.

I know the A700 has the desirable 3 speeds, but is a complex machine without a ton of spare parts like the A77 and B77 have available. I'm also completely unfamiliar with the guts of this machine and would have to hand it off to someone else to go through so I don't eff it up and own a big paperweight.

I guess the question is for those who have owned one: is the A700 enough of a step up on the B77 to ignore the other issues that come with owning one of these less common Revox units?

Thanks all!

 

[Thierry]

I have both and I prefer the A700, which is a milestone in Studer's tape machines : its professional heir was the A810.

The A700 was a major step in the company's RTR design, taking great care of the tape itself, involving motor's torque management, gentle but efficient braking at fast forward or rewind speeds. Its reel motors are used for braking and tape tension is permanently monitored by sophisticated circuitry. As a consequence, the A700 is a lot more complex than the B77 of course, but its tape management is a wonder.

The B77 mostly inherited from the A77 design and isn't much different from it, including the flaw of heads block buried in the front panel, making tape manipulation a bit tedious (I also have several A77s, including high-speed 7,5/15ips and a Dolby version).

I have the 2 tracks versions of these machines, so SNR is quite on same par.

Only subject of concern with the A700 is the TCA561, in charge of reel motors drive. They are almost unobtainable, except from an eBay seller who makes a fortune on them. A dead TCA561 renders the machine completely unuseable. For the rest, once you have replaced all of the 9 Rifa firecrackers in there, it is a reliable machine, all parts are very easy to source and most of them are shared with other Revox tapes recorders.

 

[radiokom]

I have both and I prefer the A700, which is a milestone in Studer's tape machines : its professional heir was the A810

Professional version of A700 was Studer A67 (with the same problems). However tape transport mechanical layout remains the same for all small Studers, including B67 and later A810 and A812 and in many ways was copied around the world.
If A700 works it is better than B77 because of better transport, including servo tape tension and scrape flutter roller. But it can be real PITA. I am not familiar with B67 so have no idea if it has similar problems.
But A810 is the best within small Studers.

 

[Tinman]

I fell out of love with the A700 long ago. They do have problems, and unless someone re-designs a lot of the electronics from scratch and markets them... I'd stay away from them. I no longer service them, as they are no longer reliable. The IC's are going bad from the inside, used or not. Good luck finding the TCA-1000 for the capstan, etc. Not impossible, but why have a machine that you are never sure will run each time you turn it on.

I sold both my own restored decks while they ran, and before they ate up ALL my spare IC's.

If you don't like the recessed head block of a B77, get a PR99. I have a PR99MKIII slow speed NAB that I converted to 1/4 track and absolutely love it!

If you really want to go upscale, get an A810. Lots of parts for them.

 

[Thierry]

I also have three PR99s, Mk1 to MkIII, excellent machines, and a Studer B67 with the bridge VU-meter and butterfly heads. The most rugged machine I have is a Schlumberger F500, now that's a beast. Anyway, all these recorders are obsolete dinosaurs, I keep them only because I like fine electro-mechanical devices.

 

[titanstats]

Thanks guys, some great opinions, very helpful. I'm still on the fence, but am leaning towards continuing the hunt for a nice Otari; it'd be really helpful to have a machine that can playback both 2 & 4 tapes. I really like the A700 but worry about it becoming a paperweight due to parts availability and already own a pretty reliable B77.
Still thinking tho.

I fell out of love with the A700 long ago. They do have problems, and unless someone re-designs a lot of the electronics from scratch and markets them... I'd stay away from them. I no longer service them, as they are no longer reliable. The IC's are going bad from the inside, used or not. Good luck finding the TCA-1000 for the capstan, etc. Not impossible, but why have a machine that you are never sure will run each time you turn it on.

I sold both my own restored decks while they ran, and before they ate up ALL my spare IC's.

If you don't like the recessed head block of a B77, get a PR99. I have a PR99MKIII slow speed NAB that I converted to 1/4 track and absolutely love it!

If you really want to go upscale, get an A810. Lots of parts for them.

A810 never seem to surface within driving range, beautiful machines.

.

 

[bop7]

I had the B77, A700 and B67 (I had to sell them all because I bought a Studer C37 and needed money ). For me, the best and most reliable machine was the B67. The A700 with all its faders and amps inside can be a bit of a Diva (or pain in...). And the A700 has only cinch connectors and not pro audio levels. But it is a very fine machine. The B77 and especially its tape transport did convince me less. But it depends of course for what you use it for. I would recommend the B67, reliable, quite easy to repair and the prices are still ok.

 

[Tinman]

I see no way in the world that a B67 was or is more reliable than a PR99 or B77 unless neither was serviced and the B67 was.

The B77 and PR99 are designed to be simple and robust. That's why the tape transport is the way it is. I also owned a B67, sold it for the same reason. Yes, they are wonderful machines when running correctly. BUT.... unless YOU are your own tech, can you realistically keep them running?

Buy whatever deck floats your boat, but take a moment to consider that. I finally had to give up my 38 year old truck because it became impossible to get critical parts for it. Electronics are no different.

The Otari decks are also a fine choice, robust, and plenty out there. That's the key word... PLENTY!

 

[radiokom]

I see no way in the world that a B67 was or is more reliable than a PR99 or B77 unless neither was serviced and the B67 was.

The B77 and PR99 are designed to be simple and robust. That's why the tape transport is the way it is. I also owned a B67, sold it for the same reason. Yes, they are wonderful machines when running correctly. BUT.... unless YOU are your own tech, can you realistically keep them running?

Buy whatever deck floats your boat, but take a moment to consider that. I finally had to give up my 38 year old truck because it became impossible to get critical parts for it. Electronics are no different.

The Otari decks are also a fine choice, robust, and plenty out there. That's the key word... PLENTY!

If B67 has the same electronic problems as A67 and A700 it is not more reliable and I would avoid it. Reason Tinman noted above. Otari has servo tape tension in MTR and BTR, but not in MX series. I have MTR-15 and MX-55. MX-55 is nice workhorse with easy accessible calibration from front, flux switch 3 positions, NAB and CCIR switch, and 4 speed (2 speed together). But - no servo tape tension, only switch small/large spools separate for take up and supply reel. 2 and 4 track on the same head block is not a good idea in my opinion. Heads wears out unnecessary and better idea is to have separate head blocks - 2 and 4 track + install scrape flutter roller instead of 4th head. MTR-15 is outstanding recorder with auto calibration, Dolby HX-Pro 4 speed etc. I made 4 track head block with Revox record head and Teac erase head. Auto calibration works well. But if MTR is not fully working, you need really good technician.

 

[bop7]

I see no way in the world that a B67 was or is more reliable than a PR99 or B77 unless neither was serviced and the B67 was.

The B77 and PR99 are designed to be simple and robust. That's why the tape transport is the way it is. I also owned a B67, sold it for the same reason. Yes, they are wonderful machines when running correctly. BUT.... unless YOU are your own tech, can you realistically keep them running?

Buy whatever deck floats your boat, but take a moment to consider that. I finally had to give up my 38 year old truck because it became impossible to get critical parts for it. Electronics are no different.

The Otari decks are also a fine choice, robust, and plenty out there. That's the key word... PLENTY!

I owned all of these decks. And what I say is not just my opinion, but also what Studer /Revox Service technicians say here in Switzerland. And there is a reason why the B67 is more reliable than a B77 - because it is a professional machine. The B77 is very good, but it always was a consumer machine. And the B67 and the A700 have the same transport mechanism, but the rest, especially the electronics are quite different - so: They don't have the same problems -

 

[Tinman]

If you say so.... I am sure in Switzerland you have much easier access to parts for those decks. In the USA, I'd avoid it.

 

[KiwiME]

Personally I'd swap my A700 for a good B77 any day. I was gifted a one-owner A700 last Oct that had not been powered up in decades but when I powered it up after a major recap and mechanical refurbishment it took out all three TCA561 ICs in a matter of minutes, about NZ$1k worth for me. If the example you're looking at works it may continue to do so but as mentioned parts are not cheap, if even available. The very later production examples did not use that chip but still has the TDA1000. Another weakness I'm reading about are the cheaply made and delicate VUs, but mine are fine.
I also have an ex-radio industry MX5050B-II and although it's not quite as elegant mechanically as the Revox, it's a rugged and likable machine.

 

[bop7]

I agree, most important is to have a good supply of spare parts and good techs for the things you can not repair yourself.

 

[titanstats]

Thanks all, some great, knowledgeable responses here.

 

[paul bi]

Personally I'd swap my A700 for a good B77 any day. I was gifted a one-owner A700 last Oct that had not been powered up in decades but when I powered it up after a major recap and mechanical refurbishment it took out all three TCA561 ICs in a matter of minutes, about NZ$1k worth for me. If the example you're looking at works it may continue to do so but as mentioned parts are not cheap, if even available. The very later production examples did not use that chip but still has the TDA1000. Another weakness I'm reading about are the cheaply made and delicate VUs, but mine are fine.
I also have an ex-radio industry MX5050B-II and although it's not quite as elegant mechanically as the Revox, it's a rugged and likable machine.

I think the meters are damaged through switch on spikes there is a modification but without this mod it is beat to switch to input when switching on and off