- Posted by Patrick (i) on January 06, 2001 at 17:36:08:
Well, I've just completed the simpler version of VoltSecond's hum reduction circuit, and it definitely works. Hum is way down. I still have a little bit of bass hum, and I haven't tried it with the subwoofer yet, but this is a HUGE improvement. Thanks, VS.I tried to measure resistances across the 400K series and the results just kept on fluctuating -- usually starting at about 500K and then gradually dwindling to 300K and then suddenly going down to 43K. Is this to be expected? I reheated the solder joints but it didn't help.
Aside from this, I'd suggest a reorganization of VS's instructions for newbies (if you try to solder terminal 20 last, it's next to impossible because the joints are so buried beneath components), as follows (taking into account VS's updated recommendations):
A) Solder four resistors in a straight line: Solder a 100 1/4W to a 100K 1/4W. Take the free end of this 100K 1/4W and solder it to another 100K 1/4W. Again, take the free end of this 100K 1/4W and solder it to a fourth 100K 1/4W. Across this last 100K, solder a 0.1 uF >200V (I used a 1kV ceramic. * W resistors would have been a better choice.)
B) Attach (don't solder) the free end of the 200K goes to terminal 20. Do not let any of the resistors touch any of the nearby capacitors. The resistors will be running a little warm.
C) Attach (don't solder) the end with the 0.1 uF/100K to terminal 16.
D) Attach (don't solder) a 22uF 500V from 20 (+) to 16 (-). (I used an axial leaded capacitor; it was all I had in my junk box. The capacitor was originally purchased from www.Tubesandmore.com.)
E) Route a wire from 16 [NOTE: original instructions say 20, but it should be 16] (the - side of the capacitor) along the body of the capacitor, make a right hand turn at terminal 15 and solder it to the lead of the resistor going to terminal 12.
F) Solder Terminal 16. Don't melt the caps.
G) Disconnect (cut) the wire from 15 to B1 at 15.
H) Attach (don't solder) the end of the wire that used to go to terminal 15 to terminal 20.
I) Solder terminal 20. Don't melt the caps.
J) Place a 5.1K 1W resistor from 15 to 20. Solder to the lead of the 5W resistor going to 15, not to 15 itself. Solder to lead of capacitor on 20, not to 20 itself. Be careful not to short anything out.
K) On the end of the 0.1 uF not going to terminal 16, solder a wire from this point to B5. (Don't melt the capacitor.) Route the wire under all the other wires on the board and route it on the power transformer side of both the RCA jack and the tube socket.
Follow Ups:
- Thanks VS and Patrick Charles 04:43:31 01/08/01
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- In Reply to: Completed Paramour hum reduction circuit posted by Patrick on January 06, 2001 at 17:36:08:
I added the hum reduction circuit to my Paramour yesterday without difficulty. My DIY speakers are around 97 dB/W/M efficient, and the amp is now dead quiet from 2 feet away. Thank you both for your efforts and for sharing them with others. I shall now retire my soldering iron, sit back, and listen!
- Add step L) VoltSecond 19:28:58 01/07/01
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- In Reply to: Completed Paramour hum reduction circuit posted by Patrick on January 06, 2001 at 17:36:08:
We'll need to add:
L) After a few minutes of warm up, re-adjust hum pot for lowest perceived hum.
- Resistance across the 400K VoltSecond 18:33:09 01/06/01
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- In Reply to: Completed Paramour hum reduction circuit posted by Patrick on January 06, 2001 at 17:36:08:
You won't be able to measure the 400K resistance with the 400K across the 22 uF. The 22 uF is too leaky and even if it is not leaky, the charging up of the 22 uF will fool the meter in to reading wrong.
- Great, that's a relief (nt) Alexis 19:15:46 01/06/01
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- In Reply to: Resistance across the 400K posted by Voltsecond on January 06, 2001 at 18:33:09:
- Whoops, above post should be from Patrick (nt) Patrick 19:29:30 01/06/01
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- In Reply to: Great, that's a relief (nt) posted by Alexis on January 06, 2001 at 19:15:46:
- Whoops, above post should be from Patrick (nt) Patrick 19:29:30 01/06/01
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- Great, that's a relief (nt) Alexis 19:15:46 01/06/01
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- Thanks. VoltSecond 18:18:27 01/06/01
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- In Reply to: Completed Paramour hum reduction circuit posted by Patrick on January 06, 2001 at 17:36:08:
I actually soldered my 1/4 W resistors to the leads of the 22 uF capacitor. Only the ground connection of the 0.1 uF capacitor is important.
I installed the 5.1K 1W resistor and 22 uF capacitor for the driver tube filtering first. I checked the operation out with my scope with just this filtering alone and was not satisfied. I then installed the 1/4W resistors and 0.1 uF capacitor and though it was worth giving it a listen.
- Re: Thanks. Patrick 19:15:24 01/06/01
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- In Reply to: Thanks. posted by Voltsecond on January 06, 2001 at 18:18:27:
Hi VS,
I didn't mean to come off as critical of your instructions -- it was clear that that was the order you originally did things, and you were documenting your work.
I just thought it might be useful to offer an easier order for other newbies like me who might be doing only their second or third project!
Once again, thanks again for all the great work you do.
Best,
Patrick
- You're now linked! VoltSecond 19:43:21 01/06/01
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- In Reply to: Re: Thanks. posted by Patrick on January 06, 2001 at 19:15:24:
Your instructions are already linked on my Paramour page!
- Wow, cool! (nt) Patrick 19:45:33 01/06/01
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- In Reply to: You're now linked! posted by Voltsecond on January 06, 2001 at 19:43:21:
- Wow, cool! (nt) Patrick 19:45:33 01/06/01
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- You're now linked! VoltSecond 19:43:21 01/06/01
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- Re: Thanks. Patrick 19:15:24 01/06/01
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