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Re: D-LA2A Support Thread
« Reply #1360 on: November 13, 2014, 09:32:33 PM »
Hi Guys,
Having an issue with my D-LA2A now.  The left channel seems to have this high pass filter that comes on when no signal is going through the channel.  I have included an audio file of it.  Sorry for the TV in the background and the clicking clock, the wife was home hahahah.  What should I start looking at to get rid of this issue.  It doesn't seem to do it when I first turn on the unit.

I am running a elam251 clone into a 1073 clone which work just fine.  I have narrowed the signal channel issue down to the left channel on my la2a.  the right channel seems ok for now.   Thanks so much.

http://www.ehornstudios.com/media/LA2A.aif

anyone?  I got a visual on all the caps and everything looks great.
« Last Edit: November 17, 2014, 04:30:48 PM by saxmonster »


Rocinante

Re: D-LA2A Support Thread
« Reply #1361 on: November 14, 2014, 12:37:06 PM »
Ugg. 
I am so close I can taste it. 
Okay so I have read (and reread) this thread and have taken days (then weeks) off to meditate on it and work on other projects hoping I would come back to it and it would hit me.  Hit me it has not.
I have been reluctant to ask for help on this thread cause i figured somewhere, someone had already posted a problem similar enough to mine and that I just needed to find it but I haven't been able to.  I am sure it's in here somewhere since i am so close and I think I remember someone posting with a similar problem but just can't find it and I give up and need to ask for help.
Or at least a point in the right direction.
First things first; this has been my favorite project to date.   By far.  I have learned soooo much reading this thread and building this thing.  It feels like ten projects in one awesome one.   Thank you Volker and everyone else; it's been a trip.
Onto what's up;
So I have only built one side using  Edcor in and out (wsm 600/15k and vice versa) as well as using Kenetek's T4B.  I am currently saving up for Sowter in and outs but might just grab some more Edcors until then.   
I have also implemented the 25k pot mod using the required 75k resistor and 12ay7 tubes.
I have power and all my voltages are pretty on.  I ran shielded wire throughout except for lights and what not. 
When putting music through I have gain and not really compression or it feels like too much and it's drenched in low frequency I would even say there's a high frequency cut off.  Everything sounds like its in a reverb tank.  Vocals are almost non existent.   They are in the background.  It feels like a grounding issue but I have every ground in place, my star ground looks good and i have run wires to the front panel and sides.  I also have zero noise or hum.
Audio comes through and the bypass works perfectly.
The gain works but I have to crank it and reading this thread that should not be like that at all.
I would really appreciate it if someone could point me in the right direction.  Maybe its a wrong resistor value somewhere but they all look right after checking and rechecking a bunch of times.
Here are some pics of the inside.

In the above pic the bh7 and ay7 are in the wrong places which I noticed right after taking it. I have swapped tubes since then and still my problem persists.

Here's the side without the tubes or T4B in.

and during daylight


Finally, just look at how awesome that looks, this needs to get working.   ;)

Please help me make it sound awesome too.
If there's a harder way to do this, I haven't found it yet.

jipsu

Re: D-LA2A Support Thread
« Reply #1362 on: November 15, 2014, 03:34:13 PM »
Everything sounds like its in a reverb tank.  Vocals are almost non existent.
[/quote

Just a wild guess: the other channel is inverted at some point so there's some sort of "stereo without mono signal" combination?
Sometimes pluging a stereo jack about the mid-way in causes an effect that reminds your description...

But as said, just a wild guess...

darkus

Re: D-LA2A Support Thread
« Reply #1363 on: November 19, 2014, 06:01:17 AM »
Hi there!

I have a problem with my build. I just put my new Kenetek's in this unit and started to calibrate it only to see i have a problem with my meters.

Im feeding a 0.775V signal into it and when the unit is IN and i crank the gain i can hear the signal. My meters jump right to -7 and stay there. I can hear the attenuator working cause when i turn it the signal gets weaker. But my meters show no movement no matter if i put them on GR or VU.

The only way i can get my meters back down to -20 is to tap them. Are they broken? I have the resistor on the positive side and ive checked trafo wiring etc.

MountCyanide

Re: D-LA2A Support Thread
« Reply #1364 on: November 19, 2014, 08:51:13 AM »
Sounds like pressure. Loosen the screws if you've mounted them too tight.

Rocinante

Re: D-LA2A Support Thread
« Reply #1365 on: November 19, 2014, 09:44:07 AM »
Hi there!

I have a problem with my build. I just put my new Kenetek's in this unit and started to calibrate it only to see i have a problem with my meters.

Im feeding a 0.775V signal into it and when the unit is IN and i crank the gain i can hear the signal. My meters jump right to -7 and stay there. I can hear the attenuator working cause when i turn it the signal gets weaker. But my meters show no movement no matter if i put them on GR or VU.

The only way i can get my meters back down to -20 is to tap them. Are they broken? I have the resistor on the positive side and ive checked trafo wiring etc.

I had the same problem and fixed it when I redid (tighten) my switches and relays. Make sure your vu meter wires are going to going to the correct location on the switch as well as the relay wires. After I super secured everything and followed Kingstons diagram perfectly it worked fine. Those relay connections need to be tight. Also make sure to adjust the meter via the trimmer. 
If there's a harder way to do this, I haven't found it yet.


 

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