Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: tubenit on February 12, 2019, 05:48:56 am

Title: PR- 6BM8 minimalist
Post by: tubenit on February 12, 2019, 05:48:56 am

So about a year ago, I built my HoSo56 "the minimalist" with 5879 in V1, active FX and 6BM8 tubes.  I love the amp!  And I play it frequently.
http://el34world.com/Forum/index.php?topic=23013.0

On a  thread on this forum, someone was expressing an interest in an amp with 4 tubes only that has both reverb and tremolo.  So, I drew this up.

This is a DRAFT idea (that I think would sound great).  Check for errors, compare schematic with layout & IF there is a discrepancy, go with the schematic. 

I looked at a Princeton Reverb idea and thought what is the closest I might be able to get to that sound with only 4 tubes & this is what I came up with.  I hope someone will build one someday & in the meantime, I thought I'd give the idea it's own thread.

Since the HoSo56 minimalist has great bass response and stays clean reasonably well, my guess is that this amp would also?  There are some sound clips in the link earlier in this thread.

IF one had a 225-0-225 PT with 120 ma & used solid state rectification,  I'd guess around 300v on the 6BM8 plates.  I used a 5E3 OT on my HoSo56.
https://www.edcorusa.com/xpwr152

With respect, Tubenit

Title: Re: PR- 6BM8 minimalist
Post by: bmccowan on February 13, 2019, 09:17:10 am

Hi,
Weren't there some replies to this thread yesterday? Or am I losing my mind? Could be both of course.
Anyways I thought the following was relevant. I have a Gibson GA-8T with 6BM8s (there were other version too.) It was a pain to work on with a tiny board with jumpers running diagonally on top of the board but behind resistors and caps, as well as under the board. But it has a nice tremolo and a sweet tone. The B+ on the power tube plates is just under 260V.

Title: Re: PR- 6BM8 minimalist
Post by: DummyLoad on February 13, 2019, 10:42:54 pm

there was... i think some of the missing content here was moved to a new thread - https://el34world.com/Forum/index.php?topic=24328.0


--pete

Title: Re: PR- 6BM8 minimalist
Post by: bmccowan on February 14, 2019, 08:53:39 am

Thanks Pete - those are the ones I recall. Since my post is regarding the tremolo and the B+ voltage on a 6BM8 amp, I guess it is in the right place.

Title: Re: PR- 6BM8 minimalist
Post by: Toxophilite on February 17, 2019, 02:38:47 am

I really wish I had more than one 6BM8
Could I get away with 6GW8s in this design?

Title: Re: PR- 6BM8 minimalist
Post by: sluckey on February 17, 2019, 03:27:37 am

Absolutely.

Title: Re: PR- 6BM8 minimalist
Post by: TIMBO on February 17, 2019, 03:30:36 am

OT is 10k primary.
Hammond 125d will do the job.