6G9-A Tremolux bias question

[goldstache]

I have a blonde tremolux that has a new OT.  It's the spec'd 4k primary replacement. 

My B+ after rectifier is 445V.  That is awfully high considering the schemo says it should be around 365V. 

My bias is at around 38ma. .7 X 23/422 X 1000
When I use a meter from OT CT to Plate for current shunt method I get around 33ma.  I suppose this is due to screen current not being read?

The amp has been worked on. Recapped filters, rebuilt trem circuit (partially), etc. 
But all values are stock. 

The Vibrato is ticking pretty hard at faster speeds and I'm trying to correct it a bit.  I know that this circuit has that built in thump as part of it's charm, but i'd like to get it to an acceptable level.  And it is close. 
In bias trem circuits I've read that it is best to make sure all values in the LFO and CF portions of the circuit be close to spec for best performance.

I just really want to know why my B+ is so off the schematic?
Try another GZ34 perhaps????

Any Ideas or input?
Thanks
 

[sluckey]

Is this a real amp from the '60s?

My B+ after rectifier is 445V.  That is awfully high considering the schemo says it should be around 365V. 

Note 1 on that schematic also says "VALUES SHOWN + OR - 20%". And during the '60s line voltage was much lower (usually 110VAC) as compared to the norm for today (120-125VAC).

445V is fine for a 6L6 fixed bias amp. I doubt another GZ34 will help.

Your 6L6s are idling very cool at only 33mA. .033x445=14.7watts. If you modify the bias circuit such that you can get the idle dissipation up to about 21W (70%) the high B+ will drop considerably, the amp will probably sound better. Might even improve the tremolo tick too.

Just curious, how much bias voltage do you measure on the intensity pot? I would guess it is more than -45vdc just as your B+ is higher. Increasing the bias voltage causes the 6L6s to run cooler which reduces the load on the B+ causing it to increase.

[goldstache]

Thanks Sluckey. 

That's exactly what I did while I was waiting for a response. 

It sounds good and I have the B+ around 400V.

Didn't significantly help the thump of the LFO but it's dialed in pretty good, so I buttoned it back up.

Thanks

[sluckey]

It sounds good and I have the B+ around 400V.

I'd be very happy with that.