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Author Topic: Revox A77 as a Tape Project machine candidate??? - sure why not!!!  (Read 9468 times)

Offline stellavox

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Those of you who may have followed some of my posts over the years know that I am a big fan of the Revox A77.  Was my first deck - have to revise that, a G36 was first.  I have always suggested to tape "newbies" who ask about a starter deck to check out the A77.  Built like a tank; decent tape handling; and decent sound.  High speed, two tracks are fairly easy to find and parts will ALWAYS be available due to the sheer quantity of machines out there.  BUT what about it's pretensions to "audiophile quality".

Since a recent, very pleasurable sonic experience with a Studer 810 - thought the "wired-out" stock heads sounded GREAT, I hoped to find a '77, wire out those stock heads and give them a try.  Along came a broken machine for repair and you bet I took the opportunity to try out my theory. 

Listened to that machine with the heads temporarily wired out to my Cello electronics.....AND...the envelope please....I think there we have a winner here.  Dynamics and imaging were VERY good (using my "reference" TP "Arnold Overtures" tape).  Couldn't judge tonality properly as the deck was running slow but opine that this characteristic is fine also.

So, for you'se tapesters on a budget (TP oxymoron) I suggest checking out the A77 - hook it up to a seduction and you could be in bliss territory.  Wiring out the heads appears to be very easy, and as these heads were probably used in the A77's successor machines like the B77 and PR99, finding and experimenting on one shouldn't involve too much expense of effort. 

As always - your mileage may vary...

Charles       

Offline Dave Cawley

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Re: Revox A77 as a Tape Project machine candidate??? - sure why not!!!
« Reply #1 on: February 10, 2010, 01:37:19 PM »
Hi Charles

How does the A77 compare to the B77 ?  Isn't the A77 at least 30 years old?  I would like one to play with, here the A is cheap as chips but the B's are pricey.

Regards

Dave

Offline stellavox

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Re: Revox A77 as a Tape Project machine candidate??? - sure why not!!!
« Reply #2 on: February 10, 2010, 03:00:59 PM »
Dave,

You're right, the A77 is a relic and according to my info was introduced in 1967.  There were various "Mark X"  updates to it before the "B" was introduced.  I remember, except for cosmetics, the original B didn't change much from the later A's.  The PR99 was a major revision and was in production till the late 90's.  A 30 year "run" for the same basic "consumer" deck - not bad, eh!

Surely there are a bunch of TP Studer/Revox aficionados out there that can tell you a more accurate story.  I can point to a bunch of A mods if anyone is interested.

Charles   

Offline astrotoy

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Re: Revox A77 as a Tape Project machine candidate??? - sure why not!!!
« Reply #3 on: February 10, 2010, 07:57:02 PM »
Charles, watch that "relic" language. I graduated from college in 1967 and already had a Sony recorder by then.  :-)  Larry

Dave,

You're right, the A77 is a relic and according to my info was introduced in 1967.  There were various "Mark X"  updates to it before the "B" was introduced.  I remember, except for cosmetics, the original B didn't change much from the later A's.  The PR99 was a major revision and was in production till the late 90's.  A 30 year "run" for the same basic "consumer" deck - not bad, eh!

Surely there are a bunch of TP Studer/Revox aficionados out there that can tell you a more accurate story.  I can point to a bunch of A mods if anyone is interested.

Charles   
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Offline Brian C.

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Re: Revox A77 as a Tape Project machine candidate??? - sure why not!!!
« Reply #4 on: February 11, 2010, 05:23:42 AM »
I'm not interested in the A77 mods but I know someone who is. He's a tech friend who has been making some transcriptions for me on his A77. He has two so that he can modify one while still spinning reels. I am sure he would appreciate any pointer from you I could pass on Charles.
Brian Clark, One Inch Studio, London, UK.

Offline CanoeShop

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Re: Revox A77 as a Tape Project machine candidate??? - sure why not!!!
« Reply #5 on: February 11, 2010, 08:24:59 AM »
I would also be interested in details of a direct-head mod, as I just picked up a B77 mkII 2-track that hopefully someday will play TP tapes. 

Did you have to use any kind of external eq circuit, or since you're bypassing the machine's repro section, perhaps it becomes irrelevant?

Nick Barr
Artist, father, husband.


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Offline stellavox

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Re: Revox A77 as a Tape Project machine candidate??? - sure why not!!!
« Reply #6 on: February 12, 2010, 06:42:26 AM »
Larry: Looked up "relic" and the part I'll quote is "...kept as an object of reverence".  Mention that to your wife and kids.  BTW, I'm class of '69.

Brian: there have been lots of mods made to the deck some may be even posted.  I posted a compendium of them and its somewhere in the files section of the yahoogroups reel to reel chatroom - under Studer / Revox.  Basically, you want to fit roller bearings (added to later '77s) to both sides of the headblock.  Upgrading coupling caps works wonders for the stock electronics BUT then you'll find that most all of the inside variable controls stop working when touched as the wipers have lost spring tension.

Canoeshop: Pulling off the plastic head cover gives you easy access to the heads.  Playback on the right closest to the capstan shaft. "Easy?" to unsolder the wires to it and add the ends of cables to the outside.  Could file a slot in the cover to allow wire access out the front, or snake the cables through the frontplate towards the back.  Use good quality cable.  Outboard tape electronics must have necessary NAB/IEC equalization.

BTW, for you DIY'ers, National Semiconductor's 1977 "Audio Handbook" has an excellent discussion of tape and phono equalization circuits.  Also Rod Elliot's website has good general preamp design info.

Charles

Charles     


mep

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Re: Revox A77 as a Tape Project machine candidate??? - sure why not!!!
« Reply #7 on: February 12, 2010, 10:00:41 AM »
I find this thread somewhat amusing.  Sure, you can make an A-77 into a TP machine-but why?  If this is the best deck you can afford, then you probably can't afford TP tapes in the first place.  The A-77 was a mass consumer deck (think Dynaco ST-70) and it sounds pretty good. Compared to a professional deck, the A-77 looks like a toy and does not have the sound quality you would expect from a professional deck.  The stock electronics are noisey as hell.  The tape path is so-so.  Although Revox made a two track 15 ips version of the A-77, these are much rarer than the 4 track versions commonly sold or the two track versions that only play at 3 3/4 ips and 7 1/2 ips.  I am sure you can spend a gazillion dollars on it and improve the tape path, direct wire out the heads to an outboard preamp, etc., but why not just buy a really good deck to start with??  And I say all of this as someone who owned an A-77 and loved it (for awhile) to play back 4 track tapes.  That love affair has since ended and the A-77 has found a new home.  If you keep an eye out on Ebay, you can get a really nice deck sometimes for cheap that is actually a professional tape deck and built accordingly.  You could end up dumping a bunch of money into an A-77 in order to make it play TP tapes and at the end of the day, you stilll have an A-77. Ampex ATR-700 decks go for dirt cheap and they fulfill all of the TP requirements (assuming you get the high-speed version).  They have both IEC and NAB equalization built in, balanced inputs and outputs, and decent sounding electronics.  This is a professional deck that was designed for recording studio use.  People shy away from it because it was actually built by Teac for Ampex (and the Ampex purists will have none of that).  The bottom line is that the ATR-700 commonly goes for around $200 in decent shape and you would be hard pressed to buy a good condition working A-77 for that money.   This is just one example.  My point is, why settle for a so-so consumer deck and dump a bunch of money into it when you can start off with something much nicer for possibly cheaper? 
Mark