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Old 12th December 2012, 07:50 PM   #91
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Thank you Pars for your excellent and clear help...

Thanks others for their contribution as well. To fix the problems I searched 150uf-200uf / 350-400v electrolytic caps for C55/C57/C58. Digikey give me some unknown-to-me Nichicon's and CDE's. I really get tired of searching them each.. Partconnexion has Jensen's around $40-70. So I decided to buy Black Gate VK's from a trustable source. PM me if you want to learn the source. I paid slightly higher than the Jensen's but considering that BG was Elliott's top choice I'm happy with this decision. I know some of you don't like Black Gate's but I'm get tired of searching the things I don't understand. It is better to give an end to this.
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Old 18th December 2012, 11:07 AM   #92
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Hi people, Can anybody tell me where is the resistor #64 located in chassis? I can find it.
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Old 18th December 2012, 04:05 PM   #93
VivaVee is offline VivaVee  New Zealand
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Quote:
Originally Posted by Firochromis View Post
Can anybody tell me where is the resistor #64 located in chassis?
On the rear of the vertical PCB, between V5 and V6. It is a 22R 2W resistor.
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Old 19th December 2012, 07:05 PM   #94
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Hi all,

Thank you Alan for your help. It make me clear the position of the resistor but it is still absent and luckily Pars helped me with that.

Quote:
Remember that I told you Mike's schematics may not be accurate. The resistor you ask about is a relic from the SA5 and will not be in your unit. The SA5 used heaters that were wired in pairs in series with a 12V heater supply. Per the service manual detailing changes to the SA5.1:

Tube filaments re-wired to parallel operation. This change is designed
to make certain that each tube sees exactly the right filament voltage
(6 volts). The previous version (12 volt) did not assure exact voltages
for each tube, due to filament resistance variations.
Now, while I was studying the resistors on the line stage I noticed that ME has changed them to different value ones. According to schematics, R30 should be 681R; R19 and R18 should be 51R; R20 should be 10K but on my board they are 49.9R and 100R and 49.9K respectively. He also changed the R5 and R10 of the phono stage from 47K/27K to 49.9K both. Again an inaccurate schematics?
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Old 19th December 2012, 07:16 PM   #95
tinitus is offline tinitus  Europe
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reminds me of once I asked a known skilled EE to help me adjust my amp
he said yes, and started looking at it
suddenly he was very silent and did nothing for some minutes
just looking at something
then he changed a few resitors
it looked a bit weird and somewhat messy
the funny thing, he only did it with one channel

I got home and it now sounded very different
I found a it bit too soft, and removed his mod, and remounted original resitors

when he later noticed I had changed his 'adjustment' he got very angry
he would never work for me again
and I still wonder what it was he had adjusted
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Old 19th December 2012, 09:01 PM   #96
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Quote:
Originally Posted by Firochromis View Post
According to schematics, R30 should be 681R; R19 and R18 should be 51R; R20 should be 10K but on my board they are 49.9R and 100R and 49.9K respectively. He also changed the R5 and R10 of the phono stage from 47K/27K to 49.9K both. Again an inaccurate schematics?
The schematic is correct in the sense that that is what values the SA5 was shipped with originally. The changes, if made by Mike Elliott, presumably reflect his latest thinking

R30 is the line stage valve grid stopper. Changing from 681 to 49 would theoretically lower the noise (not sure about the significance of that) but is otherwise benign.

R18/19 are the line stage current sharing resistors. The change will improve current sharing so the change is benign.

R20 is the line stage plate load. Changing from 20k to 49k is significant. The line stage gain will increase proportionally but the change in R18/19 may compensate for this.

R5/R10 are the phono stage plate loads. The R5 change seems insiginificant but R10 will increase second stge gain in the phono stage and increase the phono stage output impedance

Not sure if that helps at all.
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Old 19th December 2012, 10:07 PM   #97
tinitus is offline tinitus  Europe
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could the gain changes have been done to better suit a high output MC pickup, instead of MM pickup ?

or someone have been driving a medio/normal output MC pickup directly without further MC preamp ?
(would be perfectly possible with sensitive speakers)
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Old 28th December 2012, 08:00 AM   #98
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Quote:
Originally Posted by tinitus View Post
could the gain changes have been done to better suit a high output MC pickup, instead of MM pickup ?

or someone have been driving a medio/normal output MC pickup directly without further MC preamp ?
(would be perfectly possible with sensitive speakers)
Probably... With my 5mV cartridge the volume pod is normally around 7 - 8 o'clock level.
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