audio-talk

Greg,
That was exactly my thinking when getting the amp, ..figured Nick's knows a bit about DIY

The amp (and the valves) were a 'do it once and do it right' kinda thing.
Did my homework on the valves, was looking at the KRs based on Ali's reccy, but online folk on SET Asylum and AudioGon forums were selling their Takatsuki 300Bs and even original WE's to get the Elrogs.
Good enough for me, wanted to make the most of the amp and as it was a one off "last amp' purchase I pushed the boat out for the Elrogs.
Compared a lot of 5687s too until I found what worked for me.

Theres another North East Bake Off organised by the guys on AOS, be taking the amp down if anyone fancies a listen.

Cressy Snr wrote:

Greg wrote:Paul, you have such a photographic mind. Please link us to Thomas' post on this or where we can read about it.

He means Thomas Mayer.
http://vinylsavor.blogspot.co.uk/search?q=elrog+300B

Yes, sorry Greg, because we have a Thomas on here I slipped up there.

I would love to hear the Elrog's, Gaz. Especially against something I know, eg. the KR's. If there's someone I'd choose to develop a new valve that's at the very top of the tree, then Thomas is yer man.
My only aim in mentioning the GK-71's is to reassured anyone thinking they can never get near the performance of the Elrog's that there's a budget option that could get close.
The GK-71 is so close to a high-end 300B that's it's worth mentioning. You can use the same circuit and think of it like a high-dissipation 300B. It's thoriated, like the Elrogs. You just need to provide a slightly higher B+, around 500 or 550V to get some power ( I have run them at 450V on sensitive speakers ).
Output trannies will have to be 6k>8R so a different spec, but not too expensive ( I bought a pair of Bud's O-Netics for about £550 ) .
Other minor disadvantage is a top-cap for B+ , if you have kids or pets.
Filament, use a laptop supply at 24v/5a, and Andrew's 3A DHT boards.
Otherwise lots of fun for £12 per valve

Can I just say that I run my GK-71 (as a triode) with 5K/8R transformers.

I think I did try 10K/4R at one time but don't remember any better or worse sounds.

If that was with 8 Ohms speakers, then the primaries were 20k? Increasing the primary impedance but keep same power output will require bigger anode Voltage swing. OK if it's got the supply Volts.

I should have said 5K on the 4 ohm tap which is 10K ?

Ah right, OK yes.