Output Transformer Frequency Response

[Andy Le Blanc]

yes.... its a large value..... listen for changes.....
A\B it and see if its more to taste.....

[Andy Le Blanc]

theres also an E-seriers tone stack on duncans tone stack sim.
but it doesnt include the feedback either

[BluzMike]

To: Andy Le Blanc

OK, I'm going to try jumping the whole section. While looking at the 5D8 that you mentioned, I noticed that there was no negative feedback in the tone circuit. I'd like to try removing just the 10 Meg negative feedback resistor. Could I do that in the 5E8-A tone circuit without any serious repercussions?

Thanks

Are you sure you are familiar with that amps' tone and that this is what you are after?

I have not played a low power twin so far, but once owned its twin brother, the 5E6 Bassman. It had also less bass than my 5F6As and my 5F8 as well as a totally different tonal character. No wonder, if you look at the differences of the circuits, whith special attention to the phase inverters.

[Tweedguy]

Well, I figured out what the problem was.

There are two 56k resistors that feed the positive and negative sides of the cathodine phase inverter. If they are not perfectly matched you get the "low bass/dominant woofy mids" tone that I was dealing with. The two power tubes were getting unballanced signals. Once I used two matched resistors the amps tone problems went away. It was amazing, the difference was only about 5 ohms!

Anyone with an amp with this kind of phase inverter should check these two resistors, if they are off by even 3 ohms you'll here a difference if you make them identical. The frequency response will become much more ballanced.

[BluzMike]

I did not remeber yesterday, but installing matched 56k is a standard treat to narrow panel Deluxe amps when I service them.

Great that you are happy with your amp now!

[Andy Le Blanc]

glad to see the post revisited.... glad to be wrong too.... I've been looking
at inverter balance in other types as well ...... typically when balanced all types benifit in performance......the statement about the chathodine that
repeats from refference to refference is that it offers good balance...
learn something every day....