Bottlehead Forum

Bottlehead Kits => Legacy Kit Products => Paramount => Topic started by: Rob C on December 19, 2021, 12:45:58 PM

Title: Foreplay 3 extended kit Extremely loud popping
Post by: Rob C on December 19, 2021, 12:45:58 PM

Hey what's up I am experiencing a very loud speaker popping when I turn on the 4 play 3 w extended kit. and when I turn it off.
 I have the bent audio volume control in it.
 I can also hear when I tap on the left tube through the speaker.

Title: Re: Foreplay 3 extended kit Extremely loud popping
Post by: Paul Birkeland on December 19, 2021, 12:59:46 PM

I would suggest turning your amp on last and off first.  Regarding tapping the tube, you can move that tube to the center socket and the microphonic issues won't be so noticeable there.

Title: Re: Foreplay 3 extended kit Extremely loud popping
Post by: Rob C on December 20, 2021, 04:53:23 AM

Thanks for the tube swap tip. It seems that the tube is bad I see arching inside.  Is there a certain type I should replace these with? Brand wise. Is it a dual hybrid or something? Thanks.

Title: Re: Foreplay 3 extended kit Extremely loud popping
Post by: Rob C on December 20, 2021, 05:45:39 AM

Should all three 12au7's be gain matched? Or 2 matched and one not?

Title: Re: Foreplay 3 extended kit Extremely loud popping
Post by: Paul Birkeland on December 20, 2021, 06:05:06 AM

The outer pair of 12AU7s should be the same type, but the center can be different.  You do not need to pay for electrical matching.

Title: Re: Foreplay 3 extended kit Extremely loud popping
Post by: Rob C on December 20, 2021, 06:07:22 AM

Thanks! I found 3 matched new EH for 45 .

Title: Re: Foreplay 3 extended kit Extremely loud popping
Post by: Rob C on December 20, 2021, 06:12:47 AM

I'm assuming the Paramount amps are fixed bias?

Title: Re: Foreplay 3 extended kit Extremely loud popping
Post by: Paul Birkeland on December 20, 2021, 06:14:19 AM

They are cathode biased, with the caveat that the later revision has some adjustment for proper biasing in the 2A3 version of the amp.

Title: Re: Foreplay 3 extended kit Extremely loud popping
Post by: Rob C on December 20, 2021, 06:58:07 AM

Cool to know. 300b version here. Ty

Title: Re: Foreplay 3 extended kit Extremely loud popping
Post by: Rob C on December 20, 2021, 07:06:05 AM

The tubes in my foreplay are 12au7a
Can I use the 12au7s I ordered?

Title: Re: Foreplay 3 extended kit Extremely loud popping
Post by: Paul Birkeland on December 20, 2021, 07:52:34 AM

For the Foreplay circuit, there is no difference in functionality between a 12AU7 and a 12AU7A.

Title: Re: Foreplay 3 extended kit Extremely loud popping
Post by: Rob C on December 20, 2021, 08:14:18 AM

Great thanks!