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Old 1st October 2007, 04:32 AM   #1
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Join Date: Nov 2006
Default 6SL7 EL34 300B amp

Hi folks.

My first DIY amp is 6SN7 cascade to drive 300B, similar to Sun Audio circuit.

The 6SN7 is very good tube sound but my next project is with pentodes drive the 300B.

Here the circuit

I thank for yours commentaries and suggestions, thanks
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Old 1st October 2007, 03:00 PM   #2
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Location: Cayman Islands
that circuit looks familiar
It appears you have changed the original 12AT7 input tube to a 6SL7 but have kept the original component values. Also replaced the vacuum rectifier with SS diodes.
Also, while the EL34 is a pentode it is being used as a pseudo triode, notice the 100R resistor between the plate and G2.

What is wrong with the original circuit in your opinion?

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Old 1st October 2007, 06:21 PM   #3
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Thanks, the original circuit is this:

The differences are minimum, 6SL7 bases octal is very similar electrically to 12AT7, the resistance operates like a bride.
Very I am not convinced of the use of pentodo like driver of 300B, have my doubts on the matter, Perhaps goes pior the WE-91 amp or 6C41Pi IT 300B, thanks again
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