EL95 bit’s this and bit’s ‘a that amp (from Wanted section) …
 

Hi,

From the post for large B7G bases in the wanted section as I felt a separate thread was in order here.

It’s uses a pair of EL95’s in push pull with a Radiospares Hygrade output transformer. The EL95 specifies 10K a-to-a, however the Hygrade is 8K a-to-a, but given this amp is being made with parts from the spares/toy box there is going to have to be some artistic licence! I’m hoping the Hygrade has a reasonable primary inductance to give a decent LF response. I could slightly re-bias the EL95’s to accommodate the 8K a-to-a though.

For the driver I’m thinking of using the Jeffery (Wireless World Aug 1947) high gain phase splitter using EF184 valves, again using valves found in the spares/toy box.

The chassis is an early Sterns 5-10 chassis which had been liberated of its transformers and other “useful” parts – this explains wanting the bigger B7G valve bases.

The mains transformer could be a 2x 50V medium sized toroid with series windings configured as a full wave voltage doubler to get the necessary HT. An alternative to this is a Radiospares Standard transformer with a 275V-0-275V at 100mA which is more than enough.

I'm not aiming to set the world alight with audio performance, but make something using parts from the spares/toy box :)

Regards
Terry

Re: EL95 bit’s this and bit’s ‘a that amp (from Wanted section) …
 

Driver valves fatter than the output valves - that's the way bits-and-pieces amps should be ;D !

The 100W/ch Radford STA100 uses a pair of EF184s as the phase-splitter/driver stage behind a pair of KT88s. I don't think you're going to be short of drive.

Cheers,

GJ

Re: EL95 bit’s this and bit’s ‘a that amp (from Wanted section) …
 

I shall watch this with relish Terry.

You're going to shame me into finally getting up and running with my pair of Hygrades………………………...

Andy

Re: EL95 bit’s this and bit’s ‘a that amp (from Wanted section) …
 

Hi GJ,

Hadn't looked at it that way - I could call it the Little and Large amplifier... If it weren't for using an EZ81 - if I decide to use the Radiospares Standard mains transformer - I could use the GZ30/5Z4GT and then you'd have small medium and large valves.... Then it could be called the three Bears amplifier with Baby valve, Mummy valve and Daddy valve..... :-D;D:-D .... Sorry must get out more often :)

Hi Andy,

Fingers crossed.... as you know I've been saying I'll do projects like this, now that I'm semi retired.

I think you should raid your spares/toy box and use those nice 6V6GT's in single ended amplifier.

Terry

Re: EL95 bit’s this and bit’s ‘a that amp (from Wanted section) …
 

I guess you have a point Terry.

I found the mains transformer from the scrapped Japanese EL84 amp with the 220V primaries and as I have a transformer I can use to "buck" the primary to use with our 245+V Mains I figure it'll work nicely on the 6V6.
Now then where's that circuit diagram for the radio Constructor "neophyte" in my pile of papers...………………..

I've got a 6V6 amp working SE at the moment but its running a low HT and I figure it runs out of steam at about 2W.

A.

Re: EL95 bit’s this and bit’s ‘a that amp (from Wanted section) …
 

I've just built an amp using oddments from stock. It has an EF37A front end, 6SN7 phase splitter, a pair of AC/Pen's output and an 80 rectifier. 5 bottles, 3 different base types! The reason for using AC/Pen output valves was that I wanted to use an odd mains transformer that had 4V, 5V and 6.3V LT secondaries! The transformers came from an old dud amp which I stripped. I am highly suspicious of the alleged output transformer - it has a centre tapped secondary! I suspect it is a heater transformer pressed into service...

Re: EL95 bit’s this and bit’s ‘a that amp (from Wanted section) …
 

Hi,

I suppose the transformers pretty much dictate the direction of the design of a bits ‘a this and bits ‘a that project. Ah, the AC/PEN that’s a proper ‘ole bottle…

Quick update… I did a quick trawl of the Forum and found the EL95 got some quite bad press, however, I’ll still use the EL95 with the Hygrade transformer, although, I did find 4x 6BW6’s I’d forgotten about (thought I’d swapped them with a friend a while back), these along with using a pair of Radiospares EL84 output transformers from the pension fund :) or if I don't want to raid the pension fund I could use a pair of EL84 output transformers salvaged from a basket case Jason J2-10 a good wile back, anyway either of these and the 6BW6's would make a nice bits ‘a this and bits ‘a that project.

Regards
Terry.