iIt had a very clear,but bright tone.
, but if I tell you mekanixz, that I have one in my garage, you realize that its not a 29
WOW, I missed a bit of discussion around this last night!!
So to clarify a few points,
1. The grid stoppers are vishay CMF60 1K and I did reposition so that one leg is soldered directly to the tube socket, no dice.
2. I could not measure AC on the B+, my DMM gave me a reading of 720 or something, I think I need a new DMM, this one has been chewing through batteries as of late.
3. I have placed an order for the specified Kiwame resistors and a new pair of Silmic's to do P2P.
4. I had an interesting observation, I shorted something when I was measuring and made a POP and B+ was gone but not before I put the amp in the system. I thought that I had solved it because it was QUIET but really badly distorted. I thought it had to do with changing the grid stoppers but it ended up being one of the last resistors in the PSU. Replaced said resistor and B+ was back but so was the hummm.
So, with just tube heaters running at non referenced 6.3V they did not hummm. When B+ was introduced humm was back.
I plan to try 2 more experiments before I P2P it.
1. Swap the PSU from my Phono pre - guaranteed quiet.
2. Disconnect the B+/4 reference on existing PSU
probably not in that order though...
I am beginning to thing Salas is on to something with the regulator not playing nice with this PSU.
There is a C right after rectification so another option might be to P2P and RC off the board and try that to Mythbust the regulator myth...
So to clarify a few points,
1. The grid stoppers are vishay CMF60 1K and I did reposition so that one leg is soldered directly to the tube socket, no dice.
2. I could not measure AC on the B+, my DMM gave me a reading of 720 or something, I think I need a new DMM, this one has been chewing through batteries as of late.
3. I have placed an order for the specified Kiwame resistors and a new pair of Silmic's to do P2P.
4. I had an interesting observation, I shorted something when I was measuring and made a POP and B+ was gone but not before I put the amp in the system. I thought that I had solved it because it was QUIET but really badly distorted. I thought it had to do with changing the grid stoppers but it ended up being one of the last resistors in the PSU. Replaced said resistor and B+ was back but so was the hummm.
So, with just tube heaters running at non referenced 6.3V they did not hummm. When B+ was introduced humm was back.
I plan to try 2 more experiments before I P2P it.
1. Swap the PSU from my Phono pre - guaranteed quiet.
2. Disconnect the B+/4 reference on existing PSU
probably not in that order though...
I am beginning to thing Salas is on to something with the regulator not playing nice with this PSU.
There is a C right after rectification so another option might be to P2P and RC off the board and try that to Mythbust the regulator myth...
Make sure it takes the current.
Try tie it to ground
Very plausable
Good way to go.
Swapping time 
Why have capacitors so much difference to them? According to measurement folk it's all in the L and R of these C's Perhaps dielectric absorbsion, loose winding or just ordinairy resonance. I visited a guy a few years back who went into this and his outcome was that old block capacitors (the Dubilier and like) are best because they produce the least amount of noise when presented with a powerful audio signal. Asked for a demonstration he had some modern plastics actually screem on a tone generator.
Anyway, the brownies (MF) gave a nasty edge to the music. They were replaced by not-so-good-either Arcotronics which removed some hard sound from the music I'm acquinted to. It might be imagination but I had the idea the brownies were warm after three hours of operation. Might test 'm for leakage.
Zen Mod: Gary did a decent job on optimizing this serial reg. Works fine for me, with an overhead of 150 volts that is.
Why have capacitors so much difference to them? According to measurement folk it's all in the L and R of these C's
Perhaps dielectric absorbsion, loose winding or just ordinairy resonance. I visited a guy a few years back who went into this and his outcome was that old block capacitors (the Dubilier and like) are best because they produce the least amount of noise when presented with a powerful audio signal. Asked for a demonstration he had some modern plastics actually screem on a tone generator. Anyway, the brownies (MF) gave a nasty edge to the music. They were replaced by not-so-good-either Arcotronics which removed some hard sound from the music I'm acquinted to. It might be imagination but I had the idea the brownies were warm after three hours of operation. Might test 'm for leakage.
An externally hosted image should be here but it was not working when we last tested it.
Zen Mod: Gary did a decent job on optimizing this serial reg. Works fine for me, with an overhead of 150 volts that is.
OK, I bypassed the regulator with an RC and plugged it into my amp. The hummm was still there but it seemed to be greatly reduced.
So I am thinking that I may insert an more careful RC section before the regulator and see if that helps.
This, however, still leads me to a layout problem on my PCB.
I could yank a choke out of an amp that is sitting on a shelf collecting dust to see if adding an LC section improves things. Thoughts?
So I am thinking that I may insert an more careful RC section before the regulator and see if that helps.
This, however, still leads me to a layout problem on my PCB.
I could yank a choke out of an amp that is sitting on a shelf collecting dust to see if adding an LC section improves things. Thoughts?
OK with the hum test, but you are able to hear good signal also above the remaining hum?
That hum test shows some abnormal situation with the reg. If a simple RC on the power line shows much less hum (not absolutely low but indicative), that's a strong clue. Make a better filtering arrangement with mixed passive cells, LC is good addition, you filter more. Its a resistor loaded line amp, passes power rail hum but its no high gain phono, you should be able to check if it reduces hum further with simple means. Keep the reg bypassed. If its gonna work positively better like that, then you got no real problem in the audio part of the build.
That hum test shows some abnormal situation with the reg. If a simple RC on the power line shows much less hum (not absolutely low but indicative), that's a strong clue. Make a better filtering arrangement with mixed passive cells, LC is good addition, you filter more. Its a resistor loaded line amp, passes power rail hum but its no high gain phono, you should be able to check if it reduces hum further with simple means. Keep the reg bypassed. If its gonna work positively better like that, then you got no real problem in the audio part of the build.
If your going for a linear supply I suggest we work it out togethere here. We would need your
Staffan
- xformer data, unloaded voltage and total dcR (measure primary and secondary resistance with DMM)
- rectifier data
- choke data, dcR and inductance
Staffan
Xformer - Allied Electronics TRANSFORMER, PRI:110-120V, 50/60HZ, 500VCT @40DCMA, 6.3V @ 2.0A, LEADS
Choke - Triad C-7X Inductor; Filter; Ind 10H; Tol -20%; +50%; Cur 90mA; Leads; DCR 270 Ohms
Rectifiers I have on hand are HER108 ultrafast
See attached...I have all the parts on hand to build this...
Choke - Triad C-7X Inductor; Filter; Ind 10H; Tol -20%; +50%; Cur 90mA; Leads; DCR 270 Ohms
Rectifiers I have on hand are HER108 ultrafast
See attached...I have all the parts on hand to build this...
Attachments
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