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 NEW  Matt presents bias and operation data for the 6V6 tube in SE operation - 6V6 Single-Ended (SE) Ultra Linear (UL) Bias Optimization.

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It is currently 13 Nov 2019, 16:10

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PostPosted: 07 Nov 2019, 13:50 

Joined: 21 Sep 2014, 12:07
Posts: 26
Hello Bruce,
I'm getting ready to build and expand on your "Funkywatt" design. I see on the schematic that the current needs to be set at 41.5mA per tube. You don't show them in the schematic, but can I put 1-ohm, 1% resistors between the cathodes and the LM317 for measurement like in the Oddwatt amps?
My plan is to use 6Q7GTs in place of the 12AX7s, and 2-6F5GTs for a bass and treble control. I think I'm going to call it the "5150", which is the police code for an involuntary 72-hour hold in a psychiatric facility :).

PostPosted: 07 Nov 2019, 14:43 
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Joined: 04 Jun 2008, 20:59
Posts: 4041
Location: Arizona, USA
Hi, if you use the 832s they have a tied together internal cathode arrangement and the 1 ohm resistors have to be in the anode circuit so you can tell which section is getting what current. For any tubes with separate cathodes or any separate tubes the 1 ohms could and should go in the cathode circuit, it is much safer as the voltages there are typically in the 20-40 volt range. In the anode circuit you have the full B+ and measuring it requires some care. The sound of the amps is ok but the output power is relatively small compared to typical power tubes (KT77-88 etc) . Its claim to fame IMO is its cool looks. 8-)

Good listening

Some of my DIY Tube Amplifier Projects:

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