5f1 slight audible oscillation

[mac dillard]

Heyboer's are really good transformers and Heyboer is big in the custom design business. That is probably the reason you did not get a wiring diagram with it. I personally think that Weber is remiss in showing that transformer (HYO22772) for use in the Champ. The voltage is much too high. Compare it with Weber's own WO22772 transformer..Take a look at Magnetic Components transformers( Magnetic Components, Inc. Home Page), their ClassicTone line, 40-18019 or 40-18027. I have had good luck with them..As a note, if you are looking for that Fender Tweed sound from the 5F1 then you are going to have to get the 6V6 plate voltage down to around 340 VDC up to about 380 VDC and the plate voltage of the 12AX7 to around 150 VDC. JMO. Another note: Check that the plate voltage and the screen voltage is not too high for those NOS tubes you are using.

[Chuck H]

The amp is fine at 12 to 13 watts. Rember that some of the current in your measurement is being used by the screens and the bias specs are for the plate. So your probably spot on for center bias

I've seen MANY SF Champs with over 400Vp using the stock 470R cathode resistor!!! They work fine. Though I did have one in that blew the (very old) RCA 6V6 on the dime test. I replaced it with an EH and the amp worked great... That's another thing to consider. If you REALLY want to be sure your not overdissapating the tube you can save your NOS tubes and get a modern tube. They're better at taking the abuse and higher voltages.

[martinman]

Mac - Chuck,

Thanks for sticking with me on this thread.

I'm wondering now if I can run 6l6 and kt66 tubes w/o a problem in the amp given the high plate voltage. Maybe the money is better spent on a new kit (that is, if I want the tweed vibe). Winter is coming... and I need a new project

I already have a 5e3 so I have tweedland covered.