Tape Project Forum

General Category => General Discussion => Topic started by: mep on February 02, 2009, 11:12:23 AM

Title: REVOX G-36 REPRO QUESTION
Post by: mep on February 02, 2009, 11:12:23 AM

I am posting this question to be answered by the G-36 gurus we have available on this forum.  I have a G-36 with mechanical/electrical issues (with power off, you can push the FF, RW, Play buttons and they will detent, as soon as the power is turned on, they will not detent).  Anyway, I was thinking of removing the tube repro electronics and I was wondering if anyone knew what parts would have to be changed in order to allow 15 ips NAB/IEC equalization?  If anyone has done this or knows how to do this, I would greatly appreciate the info.  Thanks.
Mark

Title: Re: REVOX G-36 REPRO QUESTION
Post by: Studer Fool on February 02, 2009, 12:24:58 PM

Mark,

This really is not the best place to put this post as those with a similar question are unlikely to look here. 

That said check out:
ftp://ftp.studer.ch/Public/Products/Revox/Revox_G36/ (ftp://ftp.studer.ch/Public/Products/Revox/Revox_G36/)
In particular note the file:Revox_G36_60Hz_Conversion.pdf
at the bottom are the needed circuit changes from CCIR to NAB.  Yes, the CCIR is the same thing as IEC.

I recomend downloading the operations and service manuals as well if you don't already have them.  Especially the service manual.

cdw

Title: Re: REVOX G-36 REPRO QUESTION
Post by: mep on February 02, 2009, 12:52:53 PM

Thanks.  I am not clear if that is for high speed (15 ips) equalization or 7 1/2 ips.
Mark

Title: Re: REVOX G-36 REPRO QUESTION
Post by: Studer Fool on February 03, 2009, 10:18:12 AM

You are correct, that is for the low speed version with 3 3/4 & 7 1/2 ips.  For the high speed IEC eq see pages 64 and 65 of the Service Manual.

cdw

Title: Re: REVOX G-36 REPRO QUESTION
Post by: sound signal on February 09, 2009, 08:20:43 AM

Hi Mark,

Quote from: mep on February 02, 2009, 11:12:23 AM

I am posting this question to be answered by the G-36 gurus we have available on this forum.  I have a G-36 with mechanical/electrical issues (with power off, you can push the FF, RW, Play buttons and they will detent, as soon as the power is turned on, they will not detent).  Anyway, I was thinking of removing the tube repro electronics

Seems a pity to trash a G-36 and gut the electronics out of it for what seems to be a minor problem.  Also, the reproduce electronics in a G-36 are a very small circuit using three ECC83/12AX7 tubes.  The circuit draws just a few milliamps of B+ at a couple of hundred volts, and needs less than one amp of 12.6V DC on the heaters, it would be very easy to build from scratch.  This is like scrapping a vintage car to get the seats out of it...

If your G-36 is a Series III, your fault could simply be a problem with the photoelectric end stop device.  Look on the right hand tape guides, if the large one has a hole through it to let the light from a small light bulb through, and the small one has a photocell in it, then it is a Series III.

Otherwise it could simply be a minor problem with the switches that control the detent-cancelling relay.  It's probably a problem that doesn't even need parts replacement to solve.

PM me if you have any questions,

With best regards,