Mini Therapy Head build.

[wozt]

Hi, while I wait for a Therapy to appear on the 2nd hand market I'm building a mini version using 6v6's and parts I have in my bin. It is my largest build to date and will be a stepping stone for a future Therapy build.

I'm thinking of putting in fixed bias. I will be using a set of Marshall 18 watter tranny's. I have read these are suitable for a 6v6 cathode bias build but will they handle a pair of 6V6's with grid bias?

PT is 290-0-290 120ma.

Thanks.

[eschertron]

What are you hoping the B+ will be? Fixed bias nets you 10 - 12 volts over a cathode biased EL84, which is still not "high" voltage on a 6V6. I think. What kind of recto?

[wozt]

Hi, I was going solid state but could fit a tube recitifier in if it helps. I was hoping to get B+ up to around 370.

[eschertron]

Hi, I was going solid state but could fit a tube recitifier in if it helps. I was hoping to get B+ up to around 370.

370 is good for 20+ watts from a pair of 6V6s. You may want to think about controlling the grid voltage down around 350 to prevent over-dissipating. Is the OT is 8k a-a? I think you'll need that for 6V6s at that voltage.

[Chuck H]

Is the OT is 8k a-a? I think you'll need that for 6V6s at that voltage.

Hammond 1608 Hammond 1608 Hammond 1608 Hammond 1608 Hammond 1608 Hammond 1608 Hammond 1608 Hammond 1608
Hammond 1608 Hammond 1608 Hammond 1608 Hammond 1608 Hammond 1608 Hammond 1608 Hammond 1608 Hammond 1608
Hammond 1608 Hammond 1608 Hammond 1608 Hammond 1608 Hammond 1608 Hammond 1608 Hammond 1608 Hammond 1608
Hammond 1608 Hammond 1608 Hammond 1608 Hammond 1608 Hammond 1608 Hammond 1608 Hammond 1608 Hammond 1608
Hammond 1608 Hammond 1608 Hammond 1608 Hammond 1608 Hammond 1608 Hammond 1608 Hammond 1608 Hammond 1608
Hammond 1608 Hammond 1608 Hammond 1608 Hammond 1608 Hammond 1608 Hammond 1608 Hammond 1608 Hammond 1608

[Enzo]

What do you REALLY think?

[eschertron]

Hammond 1608 ...Hammond 1608

I think Chuck likes the 1608. I may have to save up my pennies for one soon.

I will be using a set of Marshall 18 watter tranny's.

I didn't realize til I looked it up that the Marshall 18W (from Hammond, at least) is 8.4k a-a. Can't find a source for one to compare prices though. Only out of curiousity. I have a couple OTs queued up for upcoming projects.

[Chuck H]

The thread has been going awhile and I didn't "back read". wozt did say he had a tranny set.

Yes. I like the 1608. I tried one for the first time on the suggestion of shea, a long time member we don't hear from anymore (unless he's using a different SN). He won a local, but somewhat known amp tone shootout with an 18W build using this tranny and he endorsed them often. I've liked them. In a side by side with a comparable Heyboer I like the 1608 better. I guess they've actually become a bit spendy, relatively. That wasn't always the case. The market has become more competitive and Hammond has stayed the same.

[eschertron]

wozt has another thread going about picking a tranny for a 2x 6V6 build. Same project? I dunno. I hope they check in soon with some comments