JE Labs 300B Stereo

[ecir38]

A couple of pics of this amp I am finally getting around to building, This will be my first point to point build :). Waitng on a couple more parts then will wire it up.







Min, I know this isn't the amp you would recommend going off of your past few builds but am chalking this up as a learning experience.

[ecir38]

oops wanted to put this in diy hifi. Shannon, can you move this thread?

[SDS-PAGE]

Looks great! It matters not what you build, so long as YOU are happy with it and have a blast building it, which I am sure you did. The more I build these things, the more I realize that a lot of it is in your head that ears.

JE amps are great for builders of all skill levels. It's hard to go wrong with any of his designs. -Min

[mesherm]

Thats a nice layout but I bet its gonna get crowded under the hood....keep us posted!

[audiowize]

Before you get too far on that build, I would highly recommend you go and buy some very viscous epoxy, mix up a batch, and put a drop or two over each rivet on each tube socket contact. Most of the 4/5/6/7 pin Chinese ceramic tube sockets that I have used like that tend to fall apart within 3-8 tube insertions, but a little chemical support on the rivet may solve that issue.
-Paul

[ecir38]

That's odd, it's the first time I heard this. I stabbed these at least 8 times and haven't notice anything even after inspecting them after your post.

Actually some of the parts I am waiting on are some black phenolic 4 and 5 pin sockets from Radidaze. I wasn't happy with the ceramic ones with how the hole in the top plate was too large for the 76 tubes and just bought the 4 pins to see if I like them better for the 300B's. Any left overs will just go in the parts bin.

[ecir38]

Couple of noob questions coming up. For the OT I am thinking the B goes to the B+ and the 2.5K goes to the output tube. Is this correct?

[mesherm]

Couple of noob questions coming up. For the OT I am thinking the B goes to the B+ and the 2.5K goes to the output tube. Is this correct?

Yes. That is correct! If you use it, the S goes to the screen grid.

[ecir38]

Thaks mesherm, should finish this up tomorrow.

[ecir38]

Finished up this afternoon and checked all the voltages, everything looks good Yellow_Light_Colorz_PDT_11 . I am going to let things break in for a while then I thinking of swithing from the 2.5K to the 3.5k and 5k taps on the OT.

[Blackburn Audio]

Looks real nice, very clean wiring. How does she sound?

-Matt

[ecir38]

Thanks Matt, initial impressions are great, I need to give it more time.

Here is the schematic I redid to make it easier to read and follow.

[ecir38]

In the schematic above would the 36k resistor and 22uf 500v cap be considered part of the power supply?

[SDS-PAGE]

Yes, it looks like it's a part of the CRC filter. When I wire something like that I would just cluster all those caps in the PS section.

[ecir38]

Thanks, that's what I thought.

I opted to use a 22uF 450v cap in this posistion. I took a reading and it spikes to 400v on start up then settles down to to 277v. Do you think this is alright or will this cap be short lived?