Bottlehead Forum

Bottlehead Kits => Legacy Kit Products => Foreplay III => Topic started by: iLikeSound on December 09, 2016, 07:31:38 AM

Title: Help identifying Bottlehead preamp & rectifier
Post by: iLikeSound on December 09, 2016, 07:31:38 AM
Hello all,

New here. At some point I'll buy and build a kit. In the meantime:

I recently bought (via craigslist) a Bottlehead preamp. Hoping you could help tell me which one it is (or if it's a FrankenHead). The small tubes are both 12au7.

I also can't identify the rectifier. The base says RCA Electron Tube, and has Made in USA, and 3-39. The internal parts look interesting to me: The upper and lower spacers are toothed, like a bike cog, and the plate is cylindrical. It glows blue.

Pictures below. Thanks in advance!

Title: Re: Help identifying Bottlehead preamp & rectifier
Post by: Natural Sound on December 09, 2016, 07:46:28 AM
Thats a Foreplay III. The "regulator" is an 0D3, 150V regulator. The rectifiers are solid state. Does it work OK?
Title: Re: Help identifying Bottlehead preamp & rectifier
Post by: iLikeSound on December 09, 2016, 07:56:57 AM
Thanks a lot - that was fast!

Yes, it works fine. Sometimes I need to wiggle the input cables a little to get one channel to work, but I'll clear that up as soon as I open it and check the solder connections.

Will changing the regulator (to a different brand, or a different type) affect the sound much (or at all)?

Title: Re: Help identifying Bottlehead preamp & rectifier
Post by: Natural Sound on December 09, 2016, 08:04:27 AM
I never found regulator tube rolling to have an effect on the sound.
Title: Re: Help identifying Bottlehead preamp & rectifier
Post by: Doc B. on December 09, 2016, 08:29:13 AM
It looks like it uses the basic Foreplay III circuit and probably one of our power transformers. But it's not a Foreplay III factory chassis. So yes, it is in some ways a Frankenstein.