Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: dwinstonwood on December 29, 2021, 10:57:16 am

Title: Lower voltage PT of interest?
Post by: dwinstonwood on December 29, 2021, 10:57:16 am
I was browsing through the Hammond website and came across a power transformer with a lower secondary voltage with adequate current ratings for two 6L6's and four or more 12A_7's.

With today's wall voltages this PT would probably put around 380V on the power tube plates, but is rated at 200mA, 5A for the 6.3V winding, and 3A for the 5V.

I just thought I'd share this; it could be good for tubes like NOS 5881's, etc., that you might not want to run up near 500V. Hawk has it for $105. Sorry if this is old info.

https://www.hammfg.com/files/parts/pdf/260G.pdf
Title: Re: Lower voltage PT of interest?
Post by: bmccowan on December 29, 2021, 07:44:14 pm
Many Valco and Gibson 6L6 amps, especially the earlier ones, had plate voltages around 400v. I typically went to ClassicTone for those PTs, but with them gone the options have narrowed.
Title: Re: Lower voltage PT of interest?
Post by: PRR on December 29, 2021, 09:05:32 pm
The original-recipe 6L6 was (re-)rated 360V because it had base insulation breakdown at 400V in RF applications. So a fair number of the original factory suggestions were in this range.
Title: Re: Lower voltage PT of interest?
Post by: bmccowan on December 30, 2021, 04:02:41 pm
PRR, that's interesting. You know a lot of stuff. I really like the sound of 6L6s run at lower plate voltages 350-400. I seem to remember some threads on here discussing some builds in that range - and lower. The 5e5 Pro was in that range I think.
Title: Re: Lower voltage PT of interest?
Post by: dwinstonwood on December 30, 2021, 07:13:42 pm
And, the 6G11-A Vibrolux that notes 365V on the 6L6GC plates (an amp I'd like to build):
https://el34world.com/charts/Schematics/files/Fender/Fender_vibrolux_6g11a.gif