push-pull output with no d.c. utc a-26

GroupDIY Audio Forum

Help Support GroupDIY Audio Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

shabtek

Well-known member
Joined
Jun 8, 2005
Messages
2,375
Location
midwest usa
Does anyone have examples or suggestions for feeding a pp opt with no d.c.?
Could it be direct coupled to the plates with no capacitor? If a section of the tube failed the primary coil may burn open...what is wrong with putting a low value fuse in series with one side?
 
I don't understand the question....

A UTC A-26 was designed to connect to a pair of P-P plates and then drive a low Z load.

Fusing might be a good idea...never thought about it.  Or, use a pair of low resistance "fused" resistors (metal oxide) in series with each plate.

Best,

Bri

 
I have seen a number of home-brew PP outputs with A-26.  I doubt it would burn up, and you'd notice the sound go to shit immediately. 
 
The only reservation might be that the primary winding current spec. is 0 mA; in other words, the A-26 is not designed to handle significant DC offset current between the 2 sides. It may be advisable to use some kind of CCS arrangement or servo balancer to reduce the DC imbalance to no more than a few hundred microamps or less.

Personally, I would think about parallel feed using the A-26 but it does require more components and possibly higher B+.
 
That is indeed interesting.  I found a second UTC catalog sheet, and the A-26 description says "single or PP plates to line".  Yet, in the column labeled "Unbal DC". it indeed says 0 mA.  A bit of a contradiction <g>.

Best,

Bri

 

Latest posts

Back
Top