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Old 29th October 2010, 08:32 PM   #671
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Originally Posted by Salas View Post
Does the CCS have a local bypass lytic where it gets its B+?
This is similar to what I have. Resistor values are slightly different and I use 1K trim-pot to adjust the current.
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Old 29th October 2010, 08:38 PM   #672
Salas is offline Salas  Greece
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Give it an electrolytic locally from where it receives its B+ to ground. See if that will change something. Its a cascode and if it upsets the reg in very high frequencies there will be not much we can do, it will be one or the other. Try 1k R2,R3 also. With R1 120R it pulls circa 30mA. Is the reg having spare?
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Old 29th October 2010, 08:54 PM   #673
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Quote:
Originally Posted by Salas View Post
Give it an electrolytic locally from where it receives its B+ to ground. See if that will change something. Its a cascode and if it upsets the reg in very high frequencies there will be not much we can do, it will be one or the other. Try 1k R2,R3 also. With R1 120R it pulls circa 30mA. Is the reg having spare?
Thanks Salas. I'll try this.

Salas..what sort of harm it will do if I continue using passives instead of other plate loads? Will this residual DC cause problem to my other equipment in a long run? I like the sound using passive as the plate load and wish to continue if there is nothing much of a concern.

Anyway, what do you recommend for plate load with SSHV?

Last edited by coolzero; 29th October 2010 at 09:21 PM.
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Old 29th October 2010, 09:15 PM   #674
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If you like it best (it is better) try smaller/bigger coupling capacitor and 1Meg resistor from its output to gnd. Maybe you will find a phase turn more compatible. If the next in chain has capacitor input, DC will not pass. Still, you did not tell me, what is the set current in the Reg CCS? Should be 55mA to feed such an anode CCS to start with.
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Old 29th October 2010, 09:31 PM   #675
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Quote:
Originally Posted by Salas View Post
If you like it best (it is better) try smaller/bigger coupling capacitor and 1Meg resistor from its output to gnd. Maybe you will find a phase turn more compatible. If the next in chain has capacitor input, DC will not pass. Still, you did not tell me, what is the set current in the Reg CCS? Should be 55mA to feed such an anode CCS to start with.
Bit confused. What you mean is the SSHV needs to be set to 55ma?

What sort of plate load best goes with SSHV? I will try what ever you recommend.

Last edited by coolzero; 29th October 2010 at 09:39 PM.
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Old 29th October 2010, 10:20 PM   #676
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Its simple. If you use a 30mA anode CCS on your audio circuit, the local reg's CCS has to be set higher, so to provide for the audio circuit's consumption plus 20-25mA minimum for its own reg use. So check the voltage drop on your reg's CSS setting resistor, divide it by its value, and know first of all that there is enough current. We should know before going further.
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Old 30th October 2010, 06:29 AM   #677
regal is offline regal  United States
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I don't get the first schematic with a CCS feeding an expensive choke.

If I were to run the #26 ~3mA is a cascade 10m45s OK at this low current ? (I understand some of these mofset current limiters have toruble with low current.)
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Old 30th October 2010, 07:18 AM   #678
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Here is the concept I have been kicking around. It seems the advancements in SS powersupplies by Slas and Coleman may make it possible (ie hum free with 32 ohm 98 spl 1mV headphones.) The pream should be strong with the 600 ohm tap. The headphone out of a preamp is usually an afterthought and a huge compromise, not the case here. Headphone amps aren't easy to get right but magic happens with a good design and quality headphones. Anyway I am considering building this, any thoughts/criticisms appreciated.


Click the image to open in full size.

Last edited by regal; 30th October 2010 at 07:20 AM.
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Old 30th October 2010, 08:33 AM   #679
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Its all a matter of testing together. A couple of people have reported on using the SSHV on small tube headphone amps with OPTs successfully. But its not universal. There is 85 degrees of phase margin. If violated, music stops, lights go down. If not, party time. Just do a real test, if it won't work, plan B is a Maida. Tone worsens against an SSHV, still quiet though. You can't do more. ''Slas & Coleman'' sounds cool, like a banking firm from Oliver Stone's Wall Street - Money Never Sleeps, by the way.
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Old 30th October 2010, 09:04 AM   #680
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Thanks Salas, I'm testing the concept with a cheap 5842 spud , figure if the Salas HVSS works with that it would work with this, always get ahead of my self though
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