james 6123hs

[totaltech]

Hi all,
Has anyone tried the James 6123hs with valve art 300b's?
If so were you inpressed???

Also in a thread I saw a while ago someone was thinking of using 845's at 500V into a 5k plate load to give around 10W.
Has anyone heard one of these designs?

Cheers

Rob

 

[gtrmkr]

Hi Rob,

A number of years ago I heard several of these lower-power 845 amps, including the one mentioned here:
http://www.aiko.com/ultrafi.html

There isn't a schematic but as I recall it was 5842 IT coupled to 845, running at about 500Vp. I've heard this style of amp driving FL and BL horns, and various Proacs, Spendors, Audio Note, etc.

Very, very good sound. Of course, parts and supply design play a huge role. This style of amp is what led me to play around with low-power 813's. I'd have used 845's, but I had a bunch of 813's on hand.

You might try searching on the Bottlehead forum--I believe several folks over there have built some low power 845's.

 

[korneluk]

qtrmkr,

care to share your 813 experiments?

TIA,

-- josé k.

 

[gtrmkr]

Jose,

Here's a mention I made of my "final" iteration of it:

http://www.diyaudio.com/forums/showthread.php?postid=1591996#post1591996

I wound up with 6DE4 rectifiers, LCLC supply, triode-strapped 8233 cap coupled to 813 triode, fixed bias through grid choke, 5k OPT. It work well in my system and was very stable.

I've got a schematic of it somewhere ... I'll look around this weekend and post it if you are interested.

Jim

 

[korneluk]

Jose,
I've got a schematic of it somewhere ... I'll look around this weekend and post it if you are interested.

Jim

Jim,
please do post or email me a schematic - I have some 813s lying around that need to be put to good use....

Have a good long weekend,

-- josé k.