All things LA2a related
- Thread starter Scenaria
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Deepdark
Well-known member
So it's normal for the heaters?
Deepdark
Well-known member
I measured in ac. It's really strange since it's a really simple circuit. What can cause this issue?
Deepdark
Well-known member
Sorry, i measured in dc. :-[ but all my measuring were in dc. Is it ok? I guess that if the heaters dosn't work, the tubes Will not light up? They lit and came hot.
Deepdark
Well-known member
Ok got 3vac at a heater point on v3. Is that ok? I realise that I put a 22k at r34 instead of 10k. Is that make sense why i got some high voltages?
sr1200
Well-known member
If again, make sure you're measuring heaters in AC and the rest in DC. (the AC on the heaters you have to measure between the 2 heater pins, no reference to ground like when you measure DC)
As far as voltages being off, I just built a pair of these and had the same issues. Check all your grounds and make sure they're all connected properly and make sure all insulated standoffs are just that, INSULATED standoffs.
As far as voltages being off, I just built a pair of these and had the same issues. Check all your grounds and make sure they're all connected properly and make sure all insulated standoffs are just that, INSULATED standoffs.
Deepdark
Well-known member
Thanks. I measured heaters with gnd ref. So it make sense. For the gnd point, i put some insulated solder terminal, like the ones on the cayocosta layout. I'll Check my ground and my resistors values. I think i Forgot to scratch some paint when i installed my pots. Other than that, what else can make those voltages that high? Some issues with v4 or v3?
sr1200
Well-known member
http://www.groupdiy.com/index.php?topic=53144.0 Check this over... its my struggle to get the first one i built working. lol.
Deepdark
Well-known member
Another question, because I have another issue with my la2a. Is the meter on output +4 supposed to be sit on 0 or at the far left, when no signal is passing in?
sr1200
Well-known member
meter should be far left on anything but GR.
Deepdark
Well-known member
Ok. Looks that i reverse my wiring with the dpdt switch. In that case, my meter is jumping when I'm on output +4. The needle is at the far left, but when i Turn the gain switch, the needle begin the jumps. What can causes that? It's a really basic circuit in that case so i dont see what the hell is going on haha
Deepdark
Well-known member
Found it ;D
The wire from r36 to r3 was mising. Now I have 256v at b+
And i wired the dpdt switch in reverse, and i forgot to scratch some paint before mounting the pots. So now, everything looks good. I'll make some more testing soon. Thank you guys for your help. :
The wire from r36 to r3 was mising. Now I have 256v at b+
And i wired the dpdt switch in reverse, and i forgot to scratch some paint before mounting the pots. So now, everything looks good. I'll make some more testing soon. Thank you guys for your help. :
sr1200
Well-known member
Awesome. Hopefully you'll be enjoying it soon. I don't think i've ever used a nicer compressor. I used new cinemag transformers, I'd be interested in seeing (well... hearing) the difference between the UTC trafos and the cinemags.
sr1200
Well-known member
I used the keneteks
Deepdark
Well-known member
I purchased them around 2 months ago. Really well made and not that expensive.
sr1200
Well-known member
Yeah, i think I got mine quite a while ago as well. they seem to work great. No real difference between that, the drips and the UA's.
hi folks-I just finished my build of the Drip opto 4 LA2A. It's passing signal, and now compressing, but i seem to have a bit of a higher noise floor than expected. can you please take a look at my wiring and see if anything looks like it could be raising noise(particularly my xformer placement?).
http://www.tumblr.com/blog/rjd2stuffandthings
the only other thing i can think is that the T4B selector switch is routed thru the power area. otherwise, as best i can tell, it's all per the instructions. i used UTC A10 and A24, wired as the opto 4 manual details(HAX100, but pinouts are the same as the A10).
thanks for the help!
http://www.tumblr.com/blog/rjd2stuffandthings
the only other thing i can think is that the T4B selector switch is routed thru the power area. otherwise, as best i can tell, it's all per the instructions. i used UTC A10 and A24, wired as the opto 4 manual details(HAX100, but pinouts are the same as the A10).
thanks for the help!
