Transformer selection for SSS type amp

[beasleybodyshop]

Hello everyone, im starting to gather materials for my SSS type amp, and I was wondering:

Ive seen people use a fender twin set of iron for these, but is this optimal in terms of B+? I was considering going with some custom Heyboer iron this time around, and was playing with the idea of lowering or upping the B+ from the 640 range? maybe having one build with a higher ma rating? Thoughts?

[talbany]

Hello everyone, im starting to gather materials for my SSS type amp, and I was wondering:

Ive seen people use a fender twin set of iron for these, but is this optimal in terms of B+? I was considering going with some custom Heyboer iron this time around, and was playing with the idea of lowering or upping the B+ from the 640 range? maybe having one build with a higher ma rating? Thoughts?

IMO..This is totally a personal preference type question?

If you build enough tube amps you will through trial and error and experimentation begin to draw your own conclusions as to what voltages on certain tubes and output transformers sound and perform best for your style and sound you are after!!
Some prefer certain type tubes to be run at slightly higher voltages..Some at lower voltages..If you are not exactly sure how to make that translation then I recommend sticking with the HAD Spec sheet!!
Always check the tubes max screen and plate voltage ratings!!!

BTW.. Where did you get 640V from?
Tony

[eniam rognab]

hey buddy that's a tall order, SSS (dumble in general) are not easy builds. im proud that you are progressing as far as you have!!! im sure it will turn out awesome!

keep it up dustin, you are going places, i can tell/feel the enthusiasm.

please keep us posted, oh and pictures!

subscribed

neal

[Colossal]

and was playing with the idea of lowering or upping the B+ from the 640 range?

In referencing Twin iron, did you mean 460VDC?

[Roe]

for a 100w, I'd try a twin style PT; for a 150w, I go for 500-530v b+ voltage

[xtian]

Hey, beas, I've got a serious hunk of iron here for cheap. Let me know if it suits your needs.

https://reverb.com/item/71438-fender-to ... 77-project

[beasleybodyshop]

and was playing with the idea of lowering or upping the B+ from the 640 range?

In referencing Twin iron, did you mean 460VDC?

I was looking at MCI Iron for a twin, according it its spec sheet its 640V?

[beasleybodyshop]

For starters, ive done a very foolish thing and made a chassis out of SS

I want this one to be the best thing ive ever built, period. Im pulling out all the stops (Amplified nation cabinet, custom iron, quad of NOS Tung Sol 5881s, teflon wire, belton sockets, etc etc.) Basically I want to go out with a bang because married life is beginning to take priority for a while and well, i think I owe her that much for putting up with all my amp shenanigans

[Colossal]

and was playing with the idea of lowering or upping the B+ from the 640 range?

In referencing Twin iron, did you mean 460VDC?

I was looking at MCI Iron for a twin, according it its spec sheet its 640V?

Ah ok, that is the AC peak to peak on the secondary so 640/2 = 320-0-320VAC
320VAC * 1.414 = 452VDC SS rectified

http://www.classictone.net/40-18004.pdf

[beasleybodyshop]

In referencing Twin iron, did you mean 460VDC?

I was looking at MCI Iron for a twin, according it its spec sheet its 640V?

Ah ok, that is the AC peak to peak on the secondary so 640/2 = 320-0-320VAC
320VAC * 1.414 = 452VDC SS rectified

http://www.classictone.net/40-18004.pdf

Yes. Sorry Colossal, I should have clarified!

er...can you break the maths down for me? I dont understand what your formula is

[Colossal]

I was looking at MCI Iron for a twin, according it its spec sheet its 640V?

Ah ok, that is the AC peak to peak on the secondary so 640/2 = 320-0-320VAC
320VAC * 1.414 = 452VDC SS rectified

http://www.classictone.net/40-18004.pdf

Yes. Sorry Colossal, I should have clarified!

er...can you break the maths down for me? I dont understand what your formula is

For solid state (diode) rectification, the rectified DC voltage is approximated by:
A given PT's AC Secondary x SQRT(2) - (forward diode voltage loss);
SQRT(2) = 1.414;

ex.
320VAC on the MC Twin PT secondary * 1.414 - (0.7VDC) = ~452VDC for B+1 on your Twin OT centertap

If you are using a tube rectifier, the multiplier is dependent on the rectifier tube used. The diode plate resistances in series with the PT secondary create a significantly greater voltage drop than a silicon diode.

A GZ34/5AR4 is about 1.24x the secondary
A (real) 5Y3GT is about 1.00x the secondary
And so forth.

Great looking chassis Beasley! Thats gonna be a beast of an amp. Are your panels Front Panel Express milled aluminum or laser on plastic?

[beasleybodyshop]

Ah ok, that is the AC peak to peak on the secondary so 640/2 = 320-0-320VAC
320VAC * 1.414 = 452VDC SS rectified

http://www.classictone.net/40-18004.pdf

Yes. Sorry Colossal, I should have clarified!

er...can you break the maths down for me? I dont understand what your formula is

For solid state (diode) rectification, the rectified DC voltage is approximated by:
A given PT's AC Secondary x SQRT(2) - (forward diode voltage loss);
SQRT(2) = 1.414;

ex.
320VAC on the MC Twin PT secondary * 1.414 - (0.7VDC) = ~452VDC for B+1 on your Twin OT centertap

If you are using a tube rectifier, the multiplier is dependent on the rectifier tube used. The diode plate resistances in series with the PT secondary create a significantly greater voltage drop than a silicon diode.

A GZ34/5AR4 is about 1.24x the secondary
A (real) 5Y3GT is about 1.00x the secondary
And so forth.

Great looking chassis Beasley! Thats gonna be a beast of an amp. Are your panels Front Panel Express milled aluminum or laser on plastic?

Thanks for the math, thats good info to know! My faceplates are raster engraved plexiglass. She aught to be a beauty when she is done!

[amplifiednation]

Basically I want to go out with a bang because married life is beginning to take priority for a while and well, i think I owe her that much for putting up with all my amp shenanigans

Ha you should turn 1/3 of your house into a gear factory and see how well she puts up with that.

[beasleybodyshop]

Basically I want to go out with a bang because married life is beginning to take priority for a while and well, i think I owe her that much for putting up with all my amp shenanigans

Ha you should turn 1/3 of your house into a gear factory and see how well she puts up with that.

Yeah, she wouldnt like that all too much. lol.

Taylor, i sent you an email regarding the cab for this project. Thanks.

[beasleybodyshop]

Also ordered a new step bit for the stainless steel chassis. I hope this works, because I can already tell the stainless is going to be a bitch and a half.