Modded circuit question

[gregarious]

I've been reading and accumulating info on the 5E3 and it's variants in preparation for a build.

One design I came across (file attached) is a circuit for reduced bass which has the .1 caps changed with .02 and the .02 cap changed to .001 .

Some resistor values are also different to the stock 5E3 circuit - the first cathode resistor is 1.5k instead of 820r, 220k on the plates of the preamps instead of 100k, the 6V6 cathode resistors are 240k instead of 220k.

The resistor between the second and third filter caps is a 24k 1/2w instead of the 22k 2w. What I haven't seen before is the additional 620k 2w placed between the ground of the second filter cap & the junction of the 24k resistor & positive end of the third filter cap B+3.

Would appreciate folks thoughts on this circuit and the addition of the 620k resistor.

Thanks in advance.

[Bruce / Mission Amps]

I've been reading and accumulating info on the 5E3 and it's variants in preparation for a build.

One design I came across (file attached) is a circuit for reduced bass which has the .1 caps changed with .02 and the .02 cap changed to .001 .

Some resistor values are also different to the stock 5E3 circuit - the first cathode resistor is 1.5k instead of 820r, 220k on the plates of the preamps instead of 100k, the 6V6 cathode resistors are 240k instead of 220k.

The resistor between the second and third filter caps is a 24k 1/2w instead of the 22k 2w. What I haven't seen before is the additional 620k 2w placed between the ground of the second filter cap & the junction of the 24k resistor & positive end of the third filter cap B+3.

Would appreciate folks thoughts on this circuit and the addition of the 620k resistor.

Thanks in advance.

Well, I doubt I would like the .001uF cap in place of the .022uF... that is 1/22 the size it should be! I'd find that very thin and sterile sounding.
The lowest I would use is .01uF@400v.
Many builders change the .1uF caps to .047uF, or .022uF if wanted. Those values are not too far off the path and can sound good with overly woofy/bassy pickups, guitars and speaker combos.
The 24K resistor in place of the 22K has almost no to very minimal effect on the voltage supplied to the preamp tubes... about a 8vdc to 12vdc drop.
The 620K resistor looks like it is a filter cap bleeder, draining B+ voltage from the filtered supply when the amp is off... it's not really needed for any other reason.

[gregarious]

Thanks for the reply Bruce.

Well, I doubt I would like the .001uF cap in place of the .022uF... that is 1/22 the size it should be! I'd find that very thin and sterile sounding.
The lowest I would use is .01uF@400v.

My bad on the .001 cap - it is .01 (must be the itchy trigger finger - again).

The 220K resistor looks like it is a filter cap bleeder, draining B+ voltage from the filtered supply when the amp is off... it's not really needed for any other reason.

Appreciate the clarification on the 620k bleeder resistor.

What is your take on using chokes with the 5E3, and generally in cathode biased circuits?

Thanks again - Greg