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August 24, 2019, 04:47:37 AM

Author Topic: Sweet Whispers  (Read 403 times)

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Offline Paul Birkeland

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Re: Sweet Whispers
« Reply #15 on: March 31, 2019, 05:26:10 PM »
I can't remember the difference between Sweet Whispers and Sweetest Whispers. 

I remember that the Sweetest Whispers were 15K controls just acting as a shunt element with a variety of fixed series resistors to provide some pre-attenutation. 

Somewhere I have a Sweet Whispers paper manual, I'll have to go digging!
Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man

Offline Paul Joppa

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Re: Sweet Whispers
« Reply #16 on: March 31, 2019, 06:12:59 PM »
Oh, there's a bunch of differences. Yes the original FP switched only the "hot" signal lines to select the source. The level controls had quite a number of variants, especially if you count the ones popular on the Forum that never became Bottlehead kits but were widely used, and the various approaches to reducing the gain which was excessive for some power amplifier/speaker combinations.

Also the chassis was grounded to signal ground at some point; I'm not sure when. We were still learning about grounding, ground loops,  and shielding. Well, honestly, we aren't done learning yet!

The design started with George Wright, then for several years the modifications were done sort of collaboratively with several people including various Forum members. When I re-did the design as FP-III - 2005 maybe? - I changed the operating points of the triodes and introduced the Sweetest Whispers topology - yet another level control. As I recall, I was over at the Schmalle's that weekend and the idea occurred to me during a morning run with Dan. Since then, I did the volume/balance control in Stereomour, and later Paul Birkeland made the BeeQuiet coarse/fine switched attenuator which is currently our best.

I still run the FP-III in my own system.
Paul Joppa

Offline mojo

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Re: Sweet Whispers
« Reply #17 on: April 02, 2019, 12:29:07 PM »
wow...I'm a bit more confused now. That's a lot of info to take in. I definitely want to keep the mono controls, and I don't want to go backwards in regards to sound quality. As I mentioned, I did not build these...I'm not much of a DIY electronics guy, so when the time comes I will need someone to solder everything up. It would be nice if someone from the Bottlehead community could work on it for me. I should mention that when John built these he cut the base of the Foreplay to 1/2 height, so between the carbon PEC potentiometer, ready-made switched attenuators, or attenuators built with new resistors, is there an option that would fit best or one that would definitely not fit? From that which would be the best long term solution with sound close to the Sweet Whispers?

When the time comes, I will order all the parts and hopefully someone here who understands the circuit will solder everything together!

Thanks a ton everybody.
Sean

Offline Paul Birkeland

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Re: Sweet Whispers
« Reply #18 on: April 02, 2019, 12:38:34 PM »
I do lots of refurbishment of our legacy kits, and I can certainly replace the attenuators provided your kit is mostly stock.  While I'm in there, I would replace the power supply capacitors as a precaution. 

When I service these old Foreplay preamps, I will tend to convert them to a stereo potentiometer in one hole and a rotary switch in the other.  The stereo pot works in the conventional manner we are all accustomed to, and the rotary switch is an adjustable pad to provide some preattenuation. 

If you'd like to chat more about these possibilities, I can be reached at pb(at)bottlehead(dot)com.\

-PB
Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man