Heathkit A9-xx chassis

[knockbill]

Update:
The 7581As sound really good in this amp, but the circuit isn't using them near their potential,,, I got a few 6GB6-Gs last week, and figured since the amp is designed closer to them, and they look a lot like teh regulators, why not try em here,,, Had one running on teh "test mule" all day, and it sounded fine, so I changed teh pin basing, and am running a pair on the amp...
Afer a few albums/CDs we'll decide if it was good move...still may want to raise teh plate V a bit from teh original schem, but, still need to decide on teh OPTs...
Some fun, eh!!!!

Regards,
John

 

[knockbill]

Added about 17VDC to teh plates, see how that sounds for a while...

Regards,
John

 

[gadget73]

plate cap tubes are too cool for school.

 

[knockbill]

Yep ,,, and with teh regulators, its a mini light show!
Got em for a buck a piece,,, couldn't get bad 6L6s for that!!!! Saw a schem using the 811s that use 6L6s for teh 2nd stage, was thinking of saving them for for that project, lots of plate cap tubes... But, I just couldn't wait!!!!
This thing sounds wonderful! I bumped the plate V up again, think its in its sweet spot,,,
Gotta settle on OPTs pretty soon....

Regards,
John

 

[knockbill]

Got up early this morning, and turned the amp on in the dark,,, noticed a blue corona like glow around the top of one of teh 6BG6s, don't think its a problem, but it sure is cool looking,,, Only one tube has it tho, and Voltages are the same on both side, maybe one tube is older than the other?

Regards,
John

 

[gadget73]

Make sure the glass is clean, but otherwise I wouldn't worry about it much. Blue glow is fairly common, and often indicates a good strong tube. There are actually mentions about that in the manual for my 1934 Scott radio that a blue haze in the output tube was normal.

 

[knockbill]

Thanks,,, good to hear,,, more of my 1$ tubes,,, really looks cool in teh dark, never noticed it before,,,

Regards,
John

 

[knockbill]

Finally got all the ducks in a row and finished(???) this guy... Got the Edcor OPTs last week, and finally got em mounted, they sound good... Couple more coats of oil on teh base...
Think I'll enjoy it for a while...
Now to finish teh 811 amp!!!
Thanks to all for the input...

 

[s-petersen]

Nice amp John, looks awesome!

 

[knockbill]

Thanks a lot Scott! I appreciate all your help along the way...