Question about paramour II caps

Jim R. · 3388

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Offline Jim R.

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on: February 13, 2011, 06:00:52 AM
I'm looking over the manual for the paramour IIs in preparation for replacing the defective 12at7 socket and as I'm tracing out the schematic and checking against the parts list, I see a couple of things that need clearing up.

The parts list specifies that there are 4 0.1uF film caps, which mean there would be two per side, but I only see one cap in the circuit and only one instance of a cap like this in the instructions.  I'll assume that the quantity is a typo.

Regarding the cathode bypass cap, is there a reason why this is a 350 volt rated part?  Maybe another inventory management decision as with the stereomour??  My quickie calculations say that a 63-100 v rated cap here should be fine for either 45 or 2a3 config.  Does this sound about right?

Also, any problem going to a 100 uF dual 450v jensen cap for the PS caps?  I have a couple of these and would like to use them here if it won't pose any problem.  I don't see where it will, but just want to make sure.

Also, regarding the sonically critical resistor on the C4S board, is that the smaller one located directly next to the transistor?

Thanks,

Jim

Jim Rebman -- recovering audiophile

Equitech balanced power; uRendu, USB processor -> Musette DAC -> 5670 tube buffer -> Finale Audio F138 FFX -> Cain and Cain Abbys near-field).

s.e.x. 2.1 under construction.  Want list: Stereomour II

All ICs homemade (speaker and power next)


Offline Jim R.

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Reply #1 on: February 15, 2011, 10:58:54 AM
Nobody?

BTW, I meant to say the resistor next to the TO-3 power transistor. .

Thanks,

Jim

Jim Rebman -- recovering audiophile

Equitech balanced power; uRendu, USB processor -> Musette DAC -> 5670 tube buffer -> Finale Audio F138 FFX -> Cain and Cain Abbys near-field).

s.e.x. 2.1 under construction.  Want list: Stereomour II

All ICs homemade (speaker and power next)


Offline Paul Joppa

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Reply #2 on: February 15, 2011, 11:18:06 AM
Somehow I missed this the first time.

Yes, I also see only one 0.1uF cap per channel.

Also yes, the 100uF/350v bypass is the right form factor (leads can be stretched to terminals 2" apart) and was in stock for the Paramount - in the direct-coupled 2A3 mode, Paramount needs a higher voltage rating. I would use at least a 100v rating to allow for various transient conditions.

The power supply would benefit from the larger capacitance, if you can find a way to mount and wire a dual cap to the terminals - the two positive terminals are more than 3 inches apart.

The C4S transistor is a TO-220, and the 237 ohm resistor is adjacent to it, near the same edge - roughly between the transistor and the mounting screw.

Paul Joppa


Offline Jim R.

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Reply #3 on: February 15, 2011, 01:18:14 PM
Paul,

Thanks for the verification, and duh, yes, I meant a TO-220 - sheesh.

Thankks again,

Jim

Jim Rebman -- recovering audiophile

Equitech balanced power; uRendu, USB processor -> Musette DAC -> 5670 tube buffer -> Finale Audio F138 FFX -> Cain and Cain Abbys near-field).

s.e.x. 2.1 under construction.  Want list: Stereomour II

All ICs homemade (speaker and power next)