K50 Build

[snuffy]

Hey guys,

Two years ago, I knew nothing about amp building. Found this forum, got bit by the bug, and now have several great amps. Thought I would share my current build in-progress and ask for any changes I should make. I am still waiting on some missing parts, but this is where I am currently at with the build.

Chassis and iron from R.J. All other parts are what I had on-hand.

Thanks for all the info and advice you guys provide.

-Jim

[img2219]http://i.imgur.com/VRzPT.jpg[/img]

[img1994]http://i.imgur.com/sOvb9.jpg[/img]

[img2251]http://i.imgur.com/VCWZ1.jpg[/img]

[Big Jim]

Looks cool Jim,
I've been interested in those type of builds lately. Looks nice. I hope you continue this thread through it's completion. Nice work!

[pablogt]

In my own k50 build I've got a 450v B+3. Be careful.with those 400v Sozos...

Pablo

[M Fowler]

Yes the Concorde uses a PT with 730vct solid state rectified so there is high voltage present.

The build looks very good. This a loud and powerful amp Here is where Dana Hall's foot switch fast/gradual kit would have been a good addition.

Mark

[Colossal]

Hey Jim,

Sweet build! Are you missing a cathode resistor over on V1b? I see a lonely 22uF Sprague cap

[snuffy]

Hey guys,

I will swap out the sozos. Thanks, Pablo.

The missing resistors are on their way, should be here today.

Mark, I thought about the footswitch, but couldn't find the link where to buy it.

Thanks for looking it over guys, I appreciate it.
-Jim

[M Fowler]

You just have to email Dana and he'll set you up.

I didn't know if he still made the pedal kit so I emailed and asked. He's overworked and always busy with a project.

Mark

[stephenl]

I'm curious, as I'm building one of these, how useable a footswitch is for Fast / Gradual - Is there a big volume difference between the two modes?

[M Fowler]

Huge difference in volume.

[pablogt]

In my case, volume difference depends on mastervolume setting. I installed a bootstrapped master volume to compensate for different power scale settings. If it is set for easyly clipping the PA, the difference in volume is not significant. If set for super clean gradual mode, then the difference is huge.

Pablo

[stephenl]

Thanks for the replies. It would be handy if the footswitched function could be used as a lead boost but if the volume difference is that drastic.... I'm using a class A PP PA which should have a lot less headroom than the EL 34's w/ high plate voltage.

[snuffy]

Hey guys, I've been sidetracked on another build, finally got this amp finished with the exception of V1 coax. What coax would be good for this build? All I have is some very small diameter coax, doesn't look as beefy as what is used on these amps.
Also, if anything looks wrong, please let me know.
Thanks for all the help.
-Jim

[img1687]http://i.imgur.com/P0iL7.jpg[/img]

[Reeltarded]

Beautiful! RG-174/u for the coax!

You could use a coil just like in the switching for the f-g selector. I think it usually sounds better.

[snuffy]

Thanks Reeltarded. Much appreciated!

[jaxx]

i can't see the first pulldown resistor, the 22k CC soldered between the two 80uf sreies cap and the first 22uf.

why did you change it with a 10k one?