Hello all,
Grandkids are getting old, so I'll finally have some time to get back to the bench.
Will be building one of two topologies, both loosely based on Decware's SE84 series.
One is 6922-IT-EL84 ( TS ).
the other is EF86(TS), RC coupled to EL84 ( TS ).
the power supply will be identical for either.
Config will be C-L-C-L-C ( for power tubes ), tube rectified. Would like to keep the first rectifier under 8 uf for various reasons. Which brings me to my question.
All parts used ( have everything in hand ) will be top notch. Years ago when I modded the crap out of my SE84CS I swapped all the lytics out for ASC motor runs and loved what they did. the last two caps will be ASC, which brings me to the first cap after the rectifier.
I've got a bunch of ASC 15uf X386 caps, so a pr in series will get me at 7.5 uf for the first cap. My question to you guys.
Should I keep that cap as an ASC motor run cap, or would a higher quality ( say Mundorf ) foil cap be better sonically in that position ? I'm trying to squeeze as much out of the circuit as I can, and don't want to limit it because of one cap.
So, keep the ASC in that first position or look for a true film/foil?
Aas always, thanks in advance for your advice,
Cheers, and be safe,
Crazy Bill
Grandkids are getting old, so I'll finally have some time to get back to the bench.
Will be building one of two topologies, both loosely based on Decware's SE84 series.
One is 6922-IT-EL84 ( TS ).
the other is EF86(TS), RC coupled to EL84 ( TS ).
the power supply will be identical for either.
Config will be C-L-C-L-C ( for power tubes ), tube rectified. Would like to keep the first rectifier under 8 uf for various reasons. Which brings me to my question.
All parts used ( have everything in hand ) will be top notch. Years ago when I modded the crap out of my SE84CS I swapped all the lytics out for ASC motor runs and loved what they did. the last two caps will be ASC, which brings me to the first cap after the rectifier.
I've got a bunch of ASC 15uf X386 caps, so a pr in series will get me at 7.5 uf for the first cap. My question to you guys.
Should I keep that cap as an ASC motor run cap, or would a higher quality ( say Mundorf ) foil cap be better sonically in that position ? I'm trying to squeeze as much out of the circuit as I can, and don't want to limit it because of one cap.
So, keep the ASC in that first position or look for a true film/foil?
Aas always, thanks in advance for your advice,
Cheers, and be safe,
Crazy Bill
Sound is completely subjective so I'd go with whatever pleases your ears. Realistically there should be no audible difference between filter capacitors unless they stop doing their job.
I went through a period of experimenting with PSU caps. I could hear differences, and to me the motor run caps sounded better than electrolytics. I've read that some motor runs are better than others, though I have no idea how to tell differences. Maybe I just got lucky.
I too am wondering about replacing the first and last cap with film and foil rather than metallised polypropylene. If anyone has done this, please report back!
I generally use a small cap first (2.2-4.7uF for instance) in a CLCRC configuration. This cap can be better quality without being too expensive. The last cap before the OPT is usually 10uF in my case, just because I have several motor runs in this value. Not too expensive for this to be film/foil either. I'd be interested in some good value recommendations for film/foil. Maybe Russian surplus?
I too am wondering about replacing the first and last cap with film and foil rather than metallised polypropylene. If anyone has done this, please report back!
I generally use a small cap first (2.2-4.7uF for instance) in a CLCRC configuration. This cap can be better quality without being too expensive. The last cap before the OPT is usually 10uF in my case, just because I have several motor runs in this value. Not too expensive for this to be film/foil either. I'd be interested in some good value recommendations for film/foil. Maybe Russian surplus?
Russian surplus are expensive now, and shipping from Russia may double the cost.
Also, be careful about sellers' claims. Many capacitors that are NOT paper-in-oil are peddled as such. The only true big can PIO caps with foil electrodes are KBG type; everything that has "MB" in the name is metallized paper.
In my experience, vintage American PIO capacitors may be more affordable than Russian caps.
Nothing is better than foil PIO caps in power supply.
Also, be careful about sellers' claims. Many capacitors that are NOT paper-in-oil are peddled as such. The only true big can PIO caps with foil electrodes are KBG type; everything that has "MB" in the name is metallized paper.
In my experience, vintage American PIO capacitors may be more affordable than Russian caps.
Nothing is better than foil PIO caps in power supply.
I think the subjectivity warning previously made is correct. FWIW, quite a few folks are "raving" about DC link capacitors.
Let's be fair to electrolytic capacitors. Some of the modern stuff has very low ESR. Now if the seals hold for 2+ decades, things are really improving.
Some want to eliminate capacitors from the signal path completely.
Alternatives to capacitors:
Amplifier section: Interstage transformers
Power Supply: Solar Cells, Treadmill wired as a Generator, Windmill, and Batteries.
I will always use capacitors, they work OK for my ear.
As much as I like capacitors, my favorite B+ circuits use choke input filters.
Alternatives to capacitors:
Amplifier section: Interstage transformers
Power Supply: Solar Cells, Treadmill wired as a Generator, Windmill, and Batteries.
I will always use capacitors, they work OK for my ear.
As much as I like capacitors, my favorite B+ circuits use choke input filters.
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RS has a range of Vishay metallised polypropylene labelled as DC Link. I'm not sure what distinguishes these from ordinary metallised polypropylenes. Useful sizes and not too expensive, though not cheap as motor runs. Kemet has a similar range which are pretty cheap.
Buy dc link capacitor online from RS Components
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It was amusing to read about people buying those high dollar Audio Note oil capacitors and having them leak in a few years.
My purely subjective experience: nothing is worth than paper in oil caps, no matter where.
You forgot rotary converter 😀
If the capacitance in the power supply doesn't dim the lights when you turn it on, is it really enough capacitance? 😛 (Usually, yes it is.)
Kodabmx,
That is what choke input B+ filters are for . . . Less Inrush current.
Less light dimming at amplifier turn-on.
That is what choke input B+ filters are for . . . Less Inrush current.
Less light dimming at amplifier turn-on.
10H 500mA choke cost me 93$CAD... The 3300uF/450V cap cost me 6$. The cap doesn't throw off magnetic flux at the tubes and make a magnetically coupled hum I couldn't get rid of, either. The cap takes up less space and weighs less. A choke was a great way of doing things before the high current SS diode, but there's a reason why almost nothing uses a choke input filter (linear PSU) anymore.
Besides, the CL140 or any other number of inrush limiting devices could be used, and if I'm honest the part about dimming the lights was sarcasm aimed at pointing out that people who use 100,000uF for a 5W amplifier are ridiculous.
Besides, the CL140 or any other number of inrush limiting devices could be used, and if I'm honest the part about dimming the lights was sarcasm aimed at pointing out that people who use 100,000uF for a 5W amplifier are ridiculous.
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