LA2A build

[Nick6691]

This is my second DIR-Racked build. The case is black but turns out really nice, I think.
Calm before the wiring storm:

Thats Nice. Im going Pcb for my first one and than we´ll se

 

[Toobme]

Help me choose for C5

 

[CJ]

Sprague.

 

[Toobme]

Ok, that one’s in my last LA - and I love it.

Since the giant Mundorf would require some kind of mount, the Sprague it is.
But somethings’s gotta use that cap - next build.

Thanks, CJ and Rob.

 

[CJ]

Let me know how your T4b sounds. I had a guy bring an LA2a over and the aftermarket T4b sounded nothing like mine, it was very sluggish and the compressor did not seem to do much. I bet it was the EL panel since you can not get the originals anymore.

 

[Toobme]

My last one, and this one are regular speed Kenetechs.
I found my first one grabby enough, but gentle. Might wanna try a third build with another type.

 

[myers1st]

This is my second DIR-Racked build. The case is black but turns out really nice, I think.
Calm before the wiring storm:
View attachment 124611

Wow, looks great. Nice workstation too. I've got a P2P project ready to start this summer, will defo be referencing this.

 

[Toobme]

Awesome, @myers1st - you’ll love the process and the result!
BTW, your location is so nice - I was there in the late 90s. Beauty city!

 

[Nick6691]

Can anyone tell me the diffrence between 12BH7a and 12BH7.
Can I have the 12BH7a in an LA2A

 

[rock soderstrom]

Can anyone tell me the diffrence between 12BH7a and 12BH7.
Can I have the 12BH7a in an LA2A

There is no relevant difference in your application. Don't worry.

 

[Nick6691]

There is no relevant difference in your application. Don't worry.

Thanks Rock!

 

[Mr. Moscode]

Ok, that one’s in my last LA - and I love it.

Since the giant Mundorf would require some kind of mount, the Sprague it is.
But somethings’s gotta use that cap - next build.

Thanks, CJ and Rob.

I can tell you the Mundorf is a great cap. I use the the silver gold oil as coupling caps. Yes big but nothing a tywrap and an adhesive wiring sticky can't handle. Worth the hassle.

 

[Toobme]

Ok @Mr. Moscode thanks for that tip. I’m already buttoned up here on this one - just finished - but will throw it in the next one!
Easy enough to swap out on this one, but at the moment, the pair I now have is going to be stereo-able, so will keep it as Sprague for the pair.
Next one, though, will be the big Mundorf. I know this sounds dolty, but I’m also loving how huge clean and chunky they look! If they sound as big, well . . .

 

[Toobme]

Buttoned up:

 

[slipperyflax]

Buttoned up:

Fantastic! Looks great

 

[Toobme]

Buttoned not!
Maybe tidy, but is only passing nice sounding audio - no gain reduction.
If it were a mic amp, I’d be ok, but nope.

Can I trouble anyone for another hint?

Here’s my voltages:

V1
Pin 1: 110 V
Pin 3: 0.96 V
Pin 6: 113.6 V
Pin 8: 1.02 V

V2
Pin 1: fluctuating around 70 V +/- 10 V
Pin 3: 3.5 V
Pin 6: 204.7 V
Pin 8: 99.5 V

Between R22/R33: 17 v (should be 27 V, right?)

V3
Pin 1: 80 V
Pin 3: 0.77 V
Pin 6: 80.7 V
Pin 8: 0.76 V

V4
Pin 2: 6.56 V
Pin 5: 117 V
Pin 6: 68 V
Center Pin: 85.5 V

Heaters all at 6.4 V AC, reading 3.2 along the string on each,

That fluctuating reading on pin 1 of v2 has me thinking cold solder or bad tube.
Going to try reflowing that one, but thought I’d post some numbers in case someone saw something glaring.

Back to my head scratching and checking.
If I find the gremlin(s), I WILL post the answer.

Thanks for looking!

 

[thomasdf]

Forgot a connection somewhere ?

 

[Toobme]

Forgot a connection somewhere ?

I forgot to list some pins.
Thanks for the reminder.

I did reflow some things and it's clean sounding, but still no deflection on GR mode.
Meter works as expected in +10 or +4 modes.

I remember my meter wiring in my last build took me a few nights of redoing things until it worked, so maybe I need to do that.
But it's a simple switch. I really should have cleaned it up well before installing and wiring it. I may take that off and clean the terminals they were a bit dark. It's an NOS Mallory.

Also,
Is it normal for only one half of my neon bulb to light up?
Hard to photo, but here’s a go:



Cheers

 

[Brian Roth]

\

Also,
Is it normal for only one half of my neon bulb to light up?
Hard to photo, but here’s a go:



Cheers

Yes. It's connected to a DC voltage line.

Bri

 

[Toobme]