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Origin valves?
Posted: 21 Apr 2018, 09:31
by burnsy
Can anybody verify the power section of the Origin 20.
Spec for the Origin 50, on the Marshall website, shows it is powered by 2xEL34s. Perfectly normal for a 50w amp.
The website also shows the Origin 20 powered by 2xEL34s ?? Is this a misprint or is the amp really using 2xEL34s to produce 20w.
Re: Origin valves?
Posted: 21 Apr 2018, 09:53
by The Ballzz
They both use the same power tubes, but the 20 is cathode biased and the 50 is fixed bias. In general, cathode bias is a bit less efficient in wattage production, though I suspect there much more to the different wattage ratings than just the bias method. If all else were generally equal, I would expect a 20%-30%-ish wattage difference instead of 60%, from the bias difference. Likely voltage differences, etc!
Re: Origin valves?
Posted: 05 May 2018, 05:30
by Mats A
Not beeing a tech wizard since these are Cathode biased and Fixed biased how is the bias on like a Plexi or a 2203/2204 amp?
Re: Origin valves?
Posted: 05 May 2018, 08:58
by Anitoli
2203/4-Plexi is fixed.
Re: Origin valves?
Posted: 05 May 2018, 09:17
by surfnorthwest
Mats A wrote:Not beeing a tech wizard since these are Cathode biased and Fixed biased how is the bias on like a Plexi or a 2203/2204 amp?
All 2203 and 2204 amps are fixed bias. Meaning you have to get the voltage meter and set them yourself. With cathode bias amps you do not need to make this adjustment.