ARC VT100 driver adjustment

kenneth · 26th July 2009, 11:09 PM

Has anyone experience on how to install and adjust the driver tubes on my Audio Research Vt100 MkI. I dont find the junction between R7,8 and R11,12. The instructions and schematic seems to belong to a MkII. Shouldnt the MkI and II be identical in this regard.

Thanks,

Kenneth

kevinkr · 28th July 2009, 01:25 AM

Unfortunately, not necessarily. You might try contacting ARC directly, and their site archive might even have the schematics for the VT-100. I long ago quit servicing ARC gear so I can't help you further.

HollowState · 28th July 2009, 02:04 AM

I think you will find the VT-100 schematic below.
http://www.arcdb.ws/VT100/VT100.html

kevinkr · 28th July 2009, 04:08 AM

The schematic listed on arcdb is for a VT100 MKII which differs in some ways from the MKI although I do not know the specifics.

Contacting ARC for a service manual and schematics is probably the best bet.

HollowState · 28th July 2009, 06:07 PM

Quote:

Originally posted by kevinkr
The schematic listed on arcdb is for a VT100 MKII...

Ok, now you have me scratching my head. The diagram is listed under the VT-100 heading. Not the MK-II or III heading. The schematic clearly says VT100 in the lower left corner. Are you saying the website is just wrong? Below the VT100 designation is "AUDIO REV11" (eleven, not II) whatever that means.

I do know that at some point in time, AR stopped putting componet values on their diagrams in the instruction manuals and only referenced parts as R1 and C2 etc. Because values are given I would suspect this to be an older schematic. Just wondering. Can you shed some light?

kevinkr · 28th July 2009, 11:00 PM

True, and it appears erroneously to me perhaps that rev 11 is rev II in adobe 8 linux version so I am not really sure. It could be the MKI schematic, but rev 11 seems odd for a design that lasted just two years before being replaced by the MKII version, and the MKII was made for a long time. The MKIII uses 6H30 so it is not hard to tell them apart..

Cobra2 · 23rd January 2010, 01:38 PM

VT100 MkII; what jfets are used?
I,m trying to repair one, and the fets are painted...

Arne K

26th July 2009, 11:09 PM	#1
kenneth diyAudio Member Join Date: Mar 2006 Location: jämtland	ARC VT100 driver adjustment Has anyone experience on how to install and adjust the driver tubes on my Audio Research Vt100 MkI. I dont find the junction between R7,8 and R11,12. The instructions and schematic seems to belong to a MkII. Shouldnt the MkI and II be identical in this regard. Thanks, Kenneth

28th July 2009, 01:25 AM	#2
kevinkr diyAudio Moderator Join Date: Sep 2004 Location: Boston, Massachusetts Blog Entries: 6	Unfortunately, not necessarily. You might try contacting ARC directly, and their site archive might even have the schematics for the VT-100. I long ago quit servicing ARC gear so I can't help you further. __________________ www.kta-hifi.net

28th July 2009, 02:04 AM	#3
HollowState diyAudio Member Join Date: Aug 2006 Location: Taxland, New Jersey	I think you will find the VT-100 schematic below. http://www.arcdb.ws/VT100/VT100.html __________________ "The supercomputer is technologically impossible. It would take all of the water that flows over Niagara Falls to cool the heat generated by the number of vacuum tubes required." ~ Professor of Electrical Engineering, New York University

28th July 2009, 04:08 AM	#4
kevinkr diyAudio Moderator Join Date: Sep 2004 Location: Boston, Massachusetts Blog Entries: 6	The schematic listed on arcdb is for a VT100 MKII which differs in some ways from the MKI although I do not know the specifics. Contacting ARC for a service manual and schematics is probably the best bet. __________________ www.kta-hifi.net

28th July 2009, 11:00 PM	#6
kevinkr diyAudio Moderator Join Date: Sep 2004 Location: Boston, Massachusetts Blog Entries: 6	True, and it appears erroneously to me perhaps that rev 11 is rev II in adobe 8 linux version so I am not really sure. It could be the MKI schematic, but rev 11 seems odd for a design that lasted just two years before being replaced by the MKII version, and the MKII was made for a long time. The MKIII uses 6H30 so it is not hard to tell them apart.. __________________ www.kta-hifi.net

23rd January 2010, 01:38 PM	#7
Cobra2 DIY ! diyAudio Member Join Date: Apr 2002 Location: Stavanger, Norway	VT100 MkII; what jfets are used? I,m trying to repair one, and the fets are painted... Arne K __________________ Ars longa, vita brevis

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