Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Swap Meet Sell your stuff here, who knows, some other fanatic might be interested!

Precision Fidelity C-7A Revised
Precision Fidelity C-7A Revised
Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Thread Tools Search this Thread
Old 26th March 2009, 03:29 PM   #1
marine-boy2 is offline marine-boy2  United States
diyAudio Member
Join Date: Mar 2009
Default Precision Fidelity C-7A Revised

I have a Precision Fidelity C-7A Revised I was considering putting up for auction on the big E and while surfing for estimated value stumbled onto this site. In a thread regarding this Pre-amp the value was suggested at approximately $300. That person was politely chastised for that estimate and noted that it is worth at least twice that. My thinking is that it's worth whatever someone is willing to pay in regards to supply and demand. Any help would be appreciated. Or if anyone on this site is interested please contact me.

The pre-amp is in top condition, no physical damage or marks that I can see. I will be testing the functionality in a couple of days. It should work fine as it did the the last time I listened to it. I have the original manual and warranty card but I do not have the original box.

There had also been requests on this site for the schematics. The manual does include the schematics and I will gladly scan and email to anyone needing.

I also have a Walker CJ55 turntable with a Linn Basik arm that may go onto the block as well. Any interest?

Thanks in advance,
  Reply With Quote
Old 9th April 2014, 07:08 PM   #2
Lloyd Foster is offline Lloyd Foster  United States
diyAudio Member
Join Date: Apr 2010
Location: Boston, Massachusetts
Default Precision Fidelity C7 schematic

Hi Jeff,
I bought a C7 in mostly stock condition and would like to bring it up to A-Revised level. If you could dig up the schematics I would be grateful.
I have replaced the RCA's in mine and the two volume pots with Goldpoint and it makes for a huge improvement.
It just occurred to me that my old email business address is on the DIY server and I just retired. I will try to change that right now but my new address is Becfin55@gmail.com.
Thank you
  Reply With Quote
Old 9th December 2014, 06:12 PM   #3
shunsmuse is offline shunsmuse  United States
diyAudio Member
Join Date: Oct 2005
Default C7 Schematics available?

If this thread is still alive, I also wold love to have a copy of the schematics for the C7. I had mine modded to C7-AR in '85, and am contemplating selling it. Thanks!
  Reply With Quote
Old 9th December 2014, 09:52 PM   #4
brianco is offline brianco  Ireland
diyAudio Member
brianco's Avatar
Join Date: Aug 2005
Location: Scottish Borders - Kelso; on the famous Tweed River!
I sold one to a guy in Spain/Portugal a couple of years ago. I too had contemplated updating it to the final spec., but was warned by a few people both here and elsewhere that the easily found (on the web) circuit for these updates has errors. If wanting one I would now build from scratch (point to point) as the components are easy to source and many of the original components can be improved.

I also had a C4 (the big multi facility version) which I used as a go to pre amp. It was an American domestic version and I had to run it through a 120-240 transformer. The power supply frequently needed rebuilding. So I think that you would do better to do a total rebuild (scrapping the PCB and every original component) using a good proven PS in place of the original. I suspect that one of the Aikido PS versions would fit in the chassis and also be a vast improvement on the original. Also replace the original switches and attenuator with new decent quality versions.

I have searched my Mac for the schematics and some 4 TB of disc space, but seem to have thrown them out when I bought a newMac. The attached pic is all I could find! (This was a European model sourced from Germany…probably originally bought in a PX store!!)
Attached Images
File Type: jpg pf-c7 copy.jpg (534.6 KB, 153 views)
  Reply With Quote
Old 8th January 2015, 11:15 PM   #5
CrazzyAbtTubes is offline CrazzyAbtTubes  Canada
diyAudio Member
CrazzyAbtTubes's Avatar
Join Date: May 2009
Location: Nova Scotia
Bumping a year old thread... is this the schematic you are looking for?

Click the image to open in full size.

I have the power supply around here some wheres too....
  Reply With Quote
Old 25th February 2015, 01:36 PM   #6
fmjunkie is offline fmjunkie  United States
diyAudio Member
Join Date: Oct 2011
Location: Arlington
Hey there gentleman. I just picked up a dusty, old C7 off the big E myself. CrazzyAbtTubes, do you have the power supply schematic? On mine, someone modded the power supply by removing voltage regulators(?), capacitors, and resistors. In place they installed some big resistors and put a cap across two legs of the existing regulator. The seller bought it like this over 20 years ago so he's not sure what or why this was done.

A lot of parts in this thing need to be updated, so a schematic would be nice, but I'd settle for some high res photos and/or a part list of what used to be there. Pretty much anything would be really helpful. And anyone got any idea why this mod was made?
Attached Images
File Type: jpg FullSizeRender.jpg (773.3 KB, 63 views)
  Reply With Quote


Precision Fidelity C-7A RevisedHide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Precision Fidelity M8 reon Solid State 6 21st April 2015 06:48 PM
Precision Fidelity - C7 Mods...help Wanted! brianco Tubes / Valves 18 18th April 2010 01:38 AM
precision fidelity chevy_lvu Solid State 0 26th March 2008 08:42 AM
Newbie Q: Revised SI T-Amp PCB? rallison Class D 2 22nd February 2007 07:32 PM

New To Site? Need Help?

All times are GMT. The time now is 09:15 PM.

Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.79%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright ©1999-2017 diyAudio