Looking at several mesa schematics, they have choosen to bias the inverter
useing the -V bias supply, from 1.5 v to 3v at the cathode. Which makes
sense, but what is the advantage to do so? Is it to avoid the feedback that
a long tailed cathode-coupled invertor employ's?.
mesa inverter bias
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Andy Le Blanc
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mesa inverter bias
lazymaryamps
Re: mesa inverter bias
Exactly!Wayne wrote:More headroom, maybe?
It's the same advantage as a for the same voltage enhanced supply voltage to the PI's plate R's - but an enhanced supply voltage not always is a benefit tonewise.
Larry
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Andy Le Blanc
- Posts: 2582
- Joined: Sat Dec 22, 2007 1:16 am
- Location: central Maine
Re: mesa inverter bias
OK..... its not a typical set up, for guitar amp. Ill be trying it out. It looks
like a simplifaction of the circuit. Feedback is applied to the grid of the inverting tube.
I'll assume that the voltage gain is similar to other cathode coupled inverters.
mesa's bass 400 has this type with the inverting grid at ground,
like a cathode phase inverter decribed by O.H. Schmitt.
like a simplifaction of the circuit. Feedback is applied to the grid of the inverting tube.
I'll assume that the voltage gain is similar to other cathode coupled inverters.
mesa's bass 400 has this type with the inverting grid at ground,
like a cathode phase inverter decribed by O.H. Schmitt.
lazymaryamps