Restoring ReVox G36 MKIII - Expert Opinions Solicited

[kevinkr]

Originally posted by honinbou



You might kill me for saying this but the G36 MKIII with new heads is no match to the Sony TC-777 made in the same era.

Back in the 1960s the MSRP of TC-777 was $700, while the G36 was only $500. Remember back then 300 yen = US$1

There are always exceptions, but I think the comment in general is true. I've no concerns one way or the other - most late 1980s Technics r-r decks blow all of them away... (That's why they cost so much more than just about anything else available used. Look at what 1500 series and 1800 series stuff is going for.. Ouch. )

[miklos]

The Technics r-r stuff prices are inflated because of the look.
The tape recorder it self nothing special , mine had all kind of contact problems and it was unreliable. The only thing I liked in it, beside the look, was the capstan motor. Which was probably the best motor I ever seen in a tape recorder. To me the best full track stereo tape deck is the Nagra IVS, but it only takes 7" reels and it is no 1/4 track version exist. If you only using 55u (normal thickness) studio tapes the Studer B67 is a good reliable machine, but it tape handling puts a strain on the tape. For older longplay or doubleplay tapes one have to use a tape recorder which are gentle on the tape. Such a machine is a Uher Royal de Lux with interchangeble head block for 1/2 or 1/4 track, but again only takes 7" reels.

[kevinkr]

FYI JM Technical Arts in Old Hickory TN has lots of parts for the G36 recorder.

[kevinkr]

Originally posted by miklos
The Technics r-r stuff prices are inflated because of the look.
The tape recorder it self nothing special , mine had all kind of contact problems and it was unreliable. The only thing I liked in it, beside the look, was the capstan motor. Which was probably the best motor I ever seen in a tape recorder. To me the best full track stereo tape deck is the Nagra IVS, but it only takes 7" reels and it is no 1/4 track version exist. If you only using 55u (normal thickness) studio tapes the Studer B67 is a good reliable machine, but it tape handling puts a strain on the tape. For older longplay or doubleplay tapes one have to use a tape recorder which are gentle on the tape. Such a machine is a Uher Royal de Lux with interchangeble head block for 1/2 or 1/4 track, but again only takes 7" reels.

I have several friends with Stellavox recorders with the outrigger setup for using 10.5" reels - they do sound very nice, but one recently got a Lyrec because of the hassle of setting up and the extremely fragility of the Stellavox.

I have had some limited exposure to Nagra and Uher decks, but not at all recently - they're just not that common around here unfortunately. The ReVox was built in relatively large quantities and is if not common, not incredibly rare around here.

The design shortcomings of the G36 in my mind include the lack of take up mechanisms on the supply or take up reels, a relative lack of capstan motor torque in MKI and MKII decks at 7.5ips - I've been baffled by off speed operation in cold weather with these decks - and make no mistake it gets cold here, I expect to experience this problem with the one I have in my 10 - 15 degree C winter basement. The frequency response of the heads and overall deck SNR are not all that impressive either, but it does manage to sound pretty good.

I can't imagine that a TC-777 based on Germanium transistors would be all that wonderful at this juncture, perhaps later units have silicon transistors. The big advantage I see in this deck is the fact that it has a take up mechanism on the supply reel side. As to how a good one sounds I have never seen let alone heard one so I can't say one way or the other. They seem to command a bit less money than the G36 on the used market (not much difference) so I am not quite sure what to make of that.

The Technics decks are highly recommended by the Tape Project and a lot of people are using them for that reason. A whole boutique industry has sprung up around restoring and customizing these machines.. They certainly are eye catching and are well regarded for their industrial design, the heads, and that capstan motor... I have heard that custom outboard tape amps perform far better than the stock internal electronics. (Have yet to hear one so modified.)

[honinbou]

The technics is a great piece of late modernist design, no doubt about that.

I also like the Ampex ATR-700 (4 head version), Teac 510 (tubes) and the Sony TC-777s because they are cheap. All these decks could play both 1/4 and 1/2 track tapes.

That said, I already saw someone trying to sell their TC-777 on eBay... and the starting price is $500.

[kevinkr]

I have a level mismatch between the left and right channels which I have traced back to the very input of the playback amplifier, the left channel is somewhere between 10 - 12dB lower in level than the right.
I measured a head dcr of approx. 400 ohms for both channels so I am assuming that the problem is probably a head contact issue - upon closer inspection with a very bright light I can see that there is a groove cut into the head surface which is probably of the order of 0.025" or so. I assume this preventing the tape from making good contact with the head.

The level issue exists at both 3.75ips and 7.5ips so I think that probably exonerates the switched cap at the input.

How practical is it to lap the heads in this thing - is it even worth it? I think unfortunately I know the answer to that, and I am definitely not going to invest $600 in a new head set..

[Steerpike]

Does it have the original cylindrical heads, or the newer 'squareish' heads?

[kevinkr]

Originally posted by Steerpike
Does it have the original cylindrical heads, or the newer 'squareish' heads?

It has the cylindrical heads despite its relatively late vintage (MKIII) probably due to the fact that it is a half track machine.

I'm assuming I can lap the heads if need be. Electrically the head is probably ok.. The one other thing I am going to try is a home brew alignment tape made on my Otari deck and see whether or not there is a combination of azimuth and other adjustments that might mitigate the issue. I will use some of that probably not long for the world Scotch 201 for that purpose. I have the ReVox alignment instructions so hopefully that might help. Lap next perhaps.

I think replacement heads are beyond reasonable expense for this machine.

[Allen Wright]

Kevin,
You wrote:

"I have the ReVox alignment instructions so hopefully that might help".

Is it possible tht you could send me a copy of this? I also have a half track G36 in pretty good condition but it hasn't had a tune-up in *at least* 10 years, and certainly wasn't set up for the Maxell tape that I can still get - and I have started needing it for live recording.

If you can it would be wonderful.

Regards, Allen

[kevinkr]

Originally posted by Allen Wright
Kevin,
You wrote:

"I have the ReVox alignment instructions so hopefully that might help".

Is it possible tht you could send me a copy of this? I also have a half track G36 in pretty good condition but it hasn't had a tune-up in *at least* 10 years, and certainly wasn't set up for the Maxell tape that I can still get - and I have started needing it for live recording.

If you can it would be wonderful.

Regards, Allen

Hi Allen,
The information is all available here:
http://www.johnmcculloch.net/documents.aspx just look for the G36. Otherwise I can send you the pdfs.

I don't think anything other than Maxell UD is going to be fully compatible with the ReVox due to excessive bias requirements. The later EE tapes (UD XLI/XLII) definitely are not due to differing eq and bias requirements.

BASF Audio Professional is still to be found on eBay and this is quite a good tape.

IMO I would not trust a deck of this vintage for live recording, and I am none too happy about the head situation on my machine. I'm looking at Nortronics NOS heads as a replacement option on this machine, but they are probably going to be too expensive. No one is making heads any more except for a few expensive pro/semi pro decks still in production. I am going to get the materials required to lap these heads - I've done it in the past, but they may just be worn out. I can't imagine yours are in very good shape if original and the deck has been used. Mine is relatively low hours and the evidence is there to support that contention, but the heads are not ok at this point in time - salvageable possibly..