Garth wrote: Thu Aug 11, 2022 10:58 am Just assumed modern build techniques might have some added weight-saving benefits.

Nate Dort wrote: Thu Aug 11, 2022 11:34 am

Garth wrote: Thu Aug 11, 2022 10:58 am Just assumed modern build techniques might have some added weight-saving benefits.

This is something I don't get. Why haven't more manufacturers embraced switching DC supplies for tube amps? There's no real reason to use a power transformer anymore. People who claim they can hear the "sound" of a PT are full of shit. Modern switching supplies are certainly quiet enough for audio. You see them used in solid-state amps quite often, especially bass amps and pro-audio power amps.

It's probably nostalgia and marketing.

Dr Tony Balls wrote: Thu Aug 11, 2022 1:14 pm

Nate Dort wrote: Thu Aug 11, 2022 11:34 am

Garth wrote: Thu Aug 11, 2022 10:58 am Just assumed modern build techniques might have some added weight-saving benefits.

This is something I don't get. Why haven't more manufacturers embraced switching DC supplies for tube amps? There's no real reason to use a power transformer anymore. People who claim they can hear the "sound" of a PT are full of shit. Modern switching supplies are certainly quiet enough for audio. You see them used in solid-state amps quite often, especially bass amps and pro-audio power amps.

It's probably nostalgia and marketing.

Do they provide enough current for tube filaments? That seems like the limitation to me. And if you've gotta have a transformer for filament voltage, you might as well use it for HT.

biscuitdough wrote: Thu Aug 11, 2022 7:39 pm I wonder if it could be because regulated power supplies don’t drop voltage as the current demand increases. Amp makers had the option to do choke input rather than cap input pretty much from day one, which was the choice for hifi, but very few guitar amps went that way. I can only think of Sunn, and they used tube rectifiers, which would provide their own sag. And actually their system might be a sort of cap input that looks like a choke input.

A computer power supply would be even stiffer.

Dr Tony Balls wrote: Fri Aug 12, 2022 8:41 am

biscuitdough wrote: Thu Aug 11, 2022 7:39 pm I wonder if it could be because regulated power supplies don’t drop voltage as the current demand increases. Amp makers had the option to do choke input rather than cap input pretty much from day one, which was the choice for hifi, but very few guitar amps went that way. I can only think of Sunn, and they used tube rectifiers, which would provide their own sag. And actually their system might be a sort of cap input that looks like a choke input.

A computer power supply would be even stiffer.

You talking about amps without a choke on the power supply? Many, if not most, Sunns have chokes. Hiwatts generally dont, though.

biscuitdough wrote: Thu Aug 11, 2022 7:39 pm I wonder if it could be because regulated power supplies don’t drop voltage as the current demand increases. Amp makers had the option to do choke input rather than cap input pretty much from day one, which was the choice for hifi, but very few guitar amps went that way. I can only think of Sunn, and they used tube rectifiers, which would provide their own sag. And actually their system might be a sort of cap input that looks like a choke input.

A computer power supply would be even stiffer.

biscuitdough wrote: Fri Aug 12, 2022 9:14 am

Dr Tony Balls wrote: Fri Aug 12, 2022 8:41 am

biscuitdough wrote: Thu Aug 11, 2022 7:39 pm I wonder if it could be because regulated power supplies don’t drop voltage as the current demand increases. Amp makers had the option to do choke input rather than cap input pretty much from day one, which was the choice for hifi, but very few guitar amps went that way. I can only think of Sunn, and they used tube rectifiers, which would provide their own sag. And actually their system might be a sort of cap input that looks like a choke input.

A computer power supply would be even stiffer.

You talking about amps without a choke on the power supply? Many, if not most, Sunns have chokes. Hiwatts generally dont, though.

Doctor, I mean choke input vs cap input.

http://www.r-type.org/articles/art-144.htm

You can have a choke in a cap input design, but you could also just have a resistor, which I think the cheaper Marshalls usually have. Sunn is cap input, looking at the schematic. It's just hard to follow their crazy wiring.