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Power supply for Single Ended Amplifier

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I tried to use different types of capacitors in the power supply for the Single Ended Amplifers that I built. I noticed that the capacitors used and different circuitry would have different results.

With use of Black Gate electrolytic, Solen polypropylene, ASC oil capacitors, they would result with different sound characteristics. I still have not come up decision which one is the best. I believe it is just fun to try them all.

Johnny
 

jlsem

Member
2003-06-17 1:12 am
Dallas,TX
I tried to use different types of capacitors in the power supply for the Single Ended Amplifers that I built. I noticed that the capacitors used and different circuitry would have different results.

The last capacitor before the output transformer is the most critical in a single ended amp. Unlike in a push-pull amp, it is directly in the signal path (the AC return path). I use a smallish (8 - 10uF) cap of the highest quality in this position. You can get away with a small value if you use an LCLC power supply.

John
 
I recently used ASC caps around an 8H choke in the PS of my SE monoblocks. They have been excellent with virtually no ripple on the HT. I haven't tried low priced electrolytics but Blackgates are outstanding also. The ASC caps were less expensive though much larger.

I'm working on the design of a new SE EL84 amp (not monoblocks this time) and am leaning toward ASC caps again.
 
Hi, I'm starting a 300B as well. It took awhile to try and figure Duncans PSUD but I think I am starting to get a handle on it. The one thing I discovered in my practise was the a double choke showed an substantial smoothing of the ripple when I compared it to a CLCLC configueration. I attached the file of both CLCLC and CLC configuerations if anyone would like to put keen eye on them and make some reccomendations. The zips are .psd files for Duncan PSUD2 Freeware.

http://www.duncanamps.com/psud2/index.html



Stan
 

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Speaking from my own experience I've found that haing the second LC stage in the PSU makes a big difference.My latest SE2A3 has a CLCLC for the output stage followed by an LC stage and shunt regulator(half a 6SN7)for each of the 6SN7 input tubes.The sound is incredibly clean and detailed.DC heaters for the 6SN7's and AC for the 2A3's.Hum on the output is 1.7mV per channel.I also use big (60uF) ASC oil caps in my HT supplies.
 

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ThorstenL

Previously: Kuei Yang Wang
Konnichiwa,

ErikdeBest said:
This is a nice discussion about the influence of power supply in the amp's sound! Have any of you tried a regulated PS? And what kind of regulation? Vantages, disadvantages...or why would you do/don't do it?

I tried all sorts of approaches and I find that you need to consider amplifier and PSU as one and tune them together. Do that and you can get very good results from any configuration that gets the basic right.

Sayonara
 
Hi Slimek,

I am just wondering why you employed a RC filter in the last stage of your power supply. I added a RC filter of 250-ohm 100uF for the last stage which forms CLCRC so that I could lower the B+ from 455V to 430Vdc for my 300B SE amp.

With this change, my 300B amp sound rather differently. It has more sweet and detailed sound.
 
If you mean the 5k pots before the 6SN7 regulator then I wanted to be able to tweak the voltage from 300v to 225v to use different tubes,eg:6SN7/5692 or it also works with 6SL7 but gives a lot more gain.The extra PIO caps before the anodes also make the sound a lot smoother and detailed.Bass is incredible.I tried it without the 6SN7/32uF and it sounds better with than without.
 

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