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Old 9th March 2003, 10:18 PM   #1
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Default I am slowing learning about the Pass products

I am slowly putting together a Zen V4. The wooden cabinet is finished, waiting to drill and tap the heatsinks to mount them and the boards.
Looking at the circuit for a Aleph 3, the lack of an output coupling cap is a big improvement. The voltage regulator and 47K input impedance of the Zen weighs in on its side.
My needs are low power (100 dB, 15 ohm speakers), low heat (air conditioning is run 10 months a year), and low noise (back to speakers used), and a normal input impedance. Looking over the line of products the Zen V4 and Aleph 3 look like the closest match.
Has anyone put together an Aleph 3 clone with capacitance mutiplier? I can even live with a single Mosfet per channel running at 1.2 - 1.5 amps idle.
I will have a better idea once the Zen is playing, but seeing the Aleph's with no cap on the output has me thinking the cap is going to be very audible.
I guess right now there is no right answer.

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Old 9th March 2003, 11:41 PM   #2
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No problem using a capacitance multiplier (or cap/coil/cap filter) and getting lower noise. Also, no problem with only one set of output devices.

A good cap inside a feedback loop as in ZV4 is not as audible as you might think; after all, it is very likely that the crossover in your speaker is using caps, and they are not even inside a corrective loop.
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Old 10th March 2003, 01:46 AM   #3
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do a search on Mini-A (GRollins thread starter)

...Zen V4 sounds like a winner though.

if you don't want caps build a SOZ

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Old 10th March 2003, 03:53 AM   #4
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Default Leaning more as I go

Thanks for the info, the sound of the V4 may be perfect. My speakers do not have a crossover but the OTL amp currently used has a large electrolytic on the output with a heavy feedback loop. The sound is excellent.
The SOZ and Mini A are unknown to me, but that shall change. I think a Aleph 3 with cap mulipliers on both rails would be more up my alley as a next project though.
With used Aleph 3's being very resonably priced, did anyone make up clone boards for this unit? The capacitance multipliers could be put on a custom board.

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