My SSS completed!

[sergio]

my PT is a Heyboer manufactured! maybe it hasn't enough current to handle this bias circuit! maybe a Mercury Magnetics can do.

[ToneMerc]

my PT is a Heyboer manufactured! maybe it hasn't enough current to handle this bias circuit! maybe a Mercury Magnetics can do.

It wouldn't surprise if the Heyboer is slightly heavier on the HT. Sergio running warm might just be the norm.

TM

[CHIP]

TM, Would a Mercury Magnetics Twin Reverb PT be able to handle this bias circuit? I have one I was hanging on for the purpose of a future SSS project.

Chip the stock units work, however there other ways to skin this bias cat that at least on the surface would appear to more robust than hanging it off one side of the HT winding.
Next, what is your end goal? If it's a 150W amp with 6550 or even a 100W EL34, you will be exceeding at least the filament rating of the stock unit. If you combine this with the CF PI scheme, my belief is that you will be really taxing that PT.

I'm not really interested in the amp perse', but I would like to build a 150 or 200W SSS because the circuity is intriguing. That would require a nice piece of iron on both ends.

TM

Thanks TM,
First, I was planning on using 4 6L6's,like SSS 002, but I do have an extra PT tranny that I got when David Root had some made up that are for a #183, 4 EL34's.
I realize now that I should just use that Marshall type iron instead,
but still begs the question of how HAD was able to use stock Fender Twin Reverb iron?
I too, find the amp intriguing, and am planning to build this amp over an extended period of time. I don't even plan on hauling the monster any where other than my home. I just think it would be gangs of fun to play at home with a strat. I have the iron, so why not. I do have a old 022889 OT.

[ToneMerc]

but still begs the question of how HAD was able to use stock Fender Twin Reverb iron?.

Each SSS appears to be an enigma, so which amps actually had a Twin PT? Just because it runs a little warm doesn't mean you cant use it.

I would love to do a quad KT88 version.


TM

[mhartman]

I used twin iron on mine without any problem. The PT stayed cool. I wired the PI and bias circuits very similar to SSS002.

BTW, if you're having trouble with your PT, you can always use a separate transformer to handle bias. Hammond should have something that will work.

[sergio]

FWIW, I had a heavier PT wound that included a dedicated HV/high current bias winding.

ToneMerc , what are the specification of the your PT? , bias voltage tap?

thanks
Sergio

[David Root]

Excellent build Sergio. Now I have to get off my butt and finish the filter section on mine!

I used that same PT you got thru that group buy with me on my SSS build (001) and it works fine for me. Are you going to use the stand-up version which Heyboer sent us in error or the laydown version that they finally got right?

I used the stand-up version with Mesa STR 415s and a 100W Edcor OT, 2K1 primary. Sounds good.

[sergio]

Hi , yes I have a laydown version , when I ordered I even requested a custom transformer, with a little more amperes on the secondary (HT and heater) ,but evidently this is not!

I tried to simulate bias voltage with a external trafo and my PT stay cool!

I think Heyboer have sent me a normal PT 125P343AX , but I don't understand why for other guys , work fine!

now I have doubt about the OT!

I ordered a 2k1/ 4-8-16ohm 100w trafo, and it seems to me more big compared to a output twin transformer

[CHIP]

[quote="sergio"]Hi , yes I have a laydown version , when I ordered I even requested a custom transformer, with a little more amperes on the secondary (HT and heater) ,but evidently this is not!

I tried to simulate bias voltage with a external trafo and my PT stay cool!

I think Heyboer have sent me a normal PT 125P343AX , but I don't understand why for other guys , work fine!

now I have doubt about the OT!

I ordered a 2k1/ 4-8-16ohm 100w trafo, and it seems to me more big compared to a output twin transformer[/quote
Sergio,
I wouldn't worry about that OT. Bigger may be better.

[CHIP]

Excellent build Sergio. Now I have to get off my butt and finish the filter section on mine!

I used that same PT you got thru that group buy with me on my SSS build (001) and it works fine for me. Are you going to use the stand-up version which Heyboer sent us in error or the laydown version that they finally got right?

I used the stand-up version with Mesa STR 415s and a 100W Edcor OT, 2K1 primary. Sounds good.

David, Haven't decided on which to use, may be the stand-up.

[grtamp]

Hi ,interesting topic!

BTW, if you're having trouble with your PT, you can always use a separate transformer to handle bias. Hammond should have something that will work.

which external transformer could go well for bias?

[67plexi]

I got one of the standup PT from David Root tried it in 3 builds runaway bias
I used five different bias circuits same results. Watching my NOS STR 415 red plate current flow 165mA
at idle. Replaced the power transformer worked great in all 3 builds. It's beyond my comprehension why
No disrespect to David Root I like David.

[tictac]

You can generate a good bias supply without a separate bias winding; the bias tap resistors can be adjusted between 100k to 220k depending on your B+ winding and the bias voltage you need. The zener diode sets the max B-

Here's one I used for a 2 x 6V6 power amp; this should work for 6L6 too...

TT

[jelle]

Nice build! Really clean.

[PaisleyTube]

regarding the bias-tap:
that's designed for very, very low current uses like supplying the bias-voltage, most (post pi) drivers do use more current

the other method, as posted, can deliver mo mAs.....