Bottlehead Forum

Bottlehead Kits => Legacy Kit Products => Paramount => Topic started by: Guy Boisvert on February 07, 2014, 09:12:17 AM

Title: help needed
Post by: Guy Boisvert on February 07, 2014, 09:12:17 AM

does anyone know to what voltage I have to adjust  the small tube 5960 on the Paramount.?  using the little blue trimmer on the board. Someone mentionned to me that the target voltage should be 146 volts....but the instructions seem to indicate 175 volts. I'm using 300B tubes

many thanks to anyone who can help a senior finish his kit

Guy

Title: Re: help needed
Post by: Paul Joppa on February 07, 2014, 09:46:23 AM

The manual is correct. 175v for 300Bs, 1/3 of the high voltage (usually around 155v) for 2A3s.

Those are 5670's by the way - not 5960s  :^)

Title: Re: help needed
Post by: Guy Boisvert on February 07, 2014, 10:00:01 AM

Thank you Paul. Where on the amp, do I measure my high voltage [i.e. 550v ?]

Title: Re: help needed
Post by: Paul Birkeland on February 07, 2014, 10:31:12 AM

The point is that you don't need to set the 5670 to anything other than 175V for the 300B.

If you built the 2A3 Paramount, then the instructions are different.

Title: Re: help needed
Post by: Guy Boisvert on February 07, 2014, 10:53:18 AM

Fine. I understand now.

Simply 175v with 300 B. tube

Guy

Title: Re: help needed
Post by: Paul Birkeland on February 07, 2014, 12:43:46 PM

Exactly.

In the 2A3 amp, that voltage actually influences the operation of the 2A3, so it can be dialed in for optimal operation.

In the 300B version, the 0.1uF cap blocks that DC voltage from appearing on the 300B, so the 300B isn't bothered if it's a little bit off.

-PB