SS to tube recto....what kind of voltage drop can i expect at PT plates?

[12AX7]

I had a tube recto when i first built this marshall type amp. But i can't recall the voltages. Right now i have 440 on the el34 plates with a SS recto and 100/100uf main cap can that i would swap to a 32/32uf along with the tube rectifier if i do this. from 440v on the plates, what do you think it will drop to with a 5AR4? Also, can i just swap in various rectos (yes, i know i'd have to rebias) and if so what kind of drop with a 5U4GB or a GZ34, assuming i can use either. PT is a hammond, but i can't recall the model.

[sluckey]

Yes

[12AX7]

I know it WILL drop, i was just asking if anyone knew by how much.

[John]

Extremely useful chart put together by Tubenit and I think Geezer? Anyway, it's all there.

[sluckey]

I know it WILL drop, i was just asking if anyone knew by how much.

Very vague info. You have the amp. Why don't you just do it then tell us the results. Should be safe.

[HotBluePlates]

And while the chart reflects actual observations, actual resulting B+ is a complex interaction between PT voltage output, PT current ratings, rectifier tube voltage drop (usually seen as a set amount of resistance, so more drop for more current), filter cap size and load current drawn by the amp.

RDH4 doesn't give any kind of equations, but a series of ways to evaluate the different variables above, then have you make reference to a series of charts that summarize the hard math for you. It's an involved process to predict the actual resulting B+ from a power supply.

[12AX7]

Thanks.