marshall Astoria dual

[leevc5]

"The Power Reduction pull switch drops the amplifier’s output power from 30 Watts to 5 Watts, which produces softer tones and a less ‘in your face’ sound."
How do they pull this off?
Are they switching from a push pull with the power section tubes to a single ended? If they are doing that it would definitely move to the head of the line on my wish list. Plenty of power when you need it and a beautiful single ended tone when you want it. I don't know though any ideas?

 

[dystrust]

Re: marshall Astoria dual

"The Power Reduction pull switch drops the amplifier’s output power from 30 Watts to 5 Watts, which produces softer tones and a less ‘in your face’ sound."
How do they pull this off?
Are they switching from a push pull with the power section tubes to a single ended? If they are doing that it would definitely move to the head of the line on my wish list. Plenty of power when you need it and a beautiful single ended tone when you want it. I don't know though any ideas?

30W from a pair of KT66s, dropping to 5 watts with a switch. That sounds a lot like the new mini Jubilee which gets 20W from a pair of EL-34s, dropping to five watts. I haven't seen a schematic, but I'd guess that both amps are cathode bias, and the switch probably drops the plate voltage.

 

[leevc5]

Re: marshall Astoria dual

30W from a pair of KT66s, dropping to 5 watts with a switch. That sounds a lot like the new mini Jubilee which gets 20W from a pair of EL-34s, dropping to five watts. I haven't seen a schematic, but I'd guess that both amps are cathode bias, and the switch probably drops the plate voltage.

Wouldn't you end up with a starved overdrive tube(s)?

 

[Lake Placid Blues]

Re: marshall Astoria dual

No, I don't think it would result in starved plate distortion in that case. Lower plate voltage on power tubes lowers the head room and the output at clipping, however- see the Soldano 25 watt explanation below.

I haven't seen a schematic of the new Marshalls either. This is just speculation on the designs on my part here. However, two EL34s in class A normally produce 20 watts, and switched to triode still in class A, 2 EL34s produce about 5 watts....

The JTM45 produces 30 to 35 watts at clipping (a rating is properly at clipping in all cases with tube amps) with two KT-66s in class A/B. So a switching to 5 watts could be done on the Astoria by switching the two KT-66s from class A/B to class A, also switched to triode.

Soldano created the 25 watt Hot Rod 25 (actually sounds more a mini SLO than a mini Hot Rod) using two 5881s in tetrode, which normally puts out 50 watts, by using a low plate voltage on the output tubes only. It is like a built in, but fixed, variac, lowering the plate voltage in that case. See the video explanation in this link:

http://www.soldano.com/products/guitar-amplifiers/hot-rod-25/

 

[Empty Pockets]

Re: marshall Astoria dual

I want to hear these amps in person but i don't know anybody who wants to drop $3000 on a brand new Marshall. I need somebody to be the guinea pig and convince me i need the green one, then sell me his used for half of what he paid.