A guide to building the Pass F4 amplifier

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#2,489
Me having both, too, but only one chassis (and PSU) for the two of them - need to swap ...


by the way, at the moment listening to Tandberg 1040P I just got myself for restoration ... will go into system of one of my sons afterwards 😉
 
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#2,491
dBel84 said:
and I found my auidophool problem

I decided I would get some better "audiophile" parts for this build and bought some KLEI RCA connectors - turns out my RCA doesn't fit snugly and with even the slightest of movement - the ground connection gets lost.

Lesson learned - stick with neutrik which I know works well and has never failed me.

..dB
Click to expand...

Or maybe you just need to get better female RCA jacks for your F4!

I'm not arguing with you, but I have some KLEI ends on my RCA cables and have never had a problem. That's across numerous pieces of gear they've connected.
 
#2,492
And congrats on the amp. Very happy to help and glad you like it. Love mine every day and never really think about changing amps (aside from the chance to build rare things like the SE SIT amp), just figuring out ways to extract every inch of performance from this circuit.

Somehow I quit receiving e-mail updates for this thread until a random one today.
 
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#2,493
Thanks Bob
Preamp in the picture is actually a UNITY gain bootstrapped tube buffer - this is in my study with nearfield speakers. Had no trouble driving them and did an exceptional job of it. Moved it over to see how it handled the Maggies earlier this evening and there the preamp is a Cavalli Audio Liquid Glass which has plenty of gain. I wasn't sure what to expect but I am well pleased..dB

re the KLEI RCA - they are very good, I switched out RCA cables for WBTesque versions that allow you to screw clamp - no trouble
 
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#2,499
Hmm, perhaps not the optimum tubes in that Cavalli preamp? I clicked on that link, and in the tech specs gain is described as "1/2 the mu of the triodes in use" so if you have 6SN7s in use, you have a gain of 1/2 * 20, or a gain of 10. You could try a high-mu tube or two, like the 12AT7 or 6SL7 and you'd have a gain of 30 or 35. If that's enough, or too much, you could work your way down (12AY7, 6DJ8?) until you find the optimum gain structure.

If I understand correctly (not a given, by the way) the solid-state buffer section should alleviate any concerns about lack of drive from the high-mu tubes. Worth a shot?
 
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