stereokillah

Re: D-LA2A Support Thread
« Reply #140 on: June 15, 2009, 07:56:43 AM »
thank you bernbrue and Crisotop
i think i will take swoter for the input, but for the output is it edcor xsm 10k/600 or other please?
if your neighbour is hunger .. don't give him fish, teach him how fishing ...


tskguy

Re: D-LA2A Support Thread
« Reply #141 on: June 15, 2009, 09:15:42 PM »
Ok boys I have something very strange happening. So far everything seems to working great. It does a great job compressing and works very well. I was trying to listen to the noise floor so I cranked the gain and at past 5 it made a click and then it blew both my tweeters!!  crap!!!

Very strange...What could cause this?

I am using a strange combo of transformers but I dont think that would be the problem. Im also not using the gridstoppers, any ideas??

Eric

[silent:arts]

Re: D-LA2A Support Thread
« Reply #142 on: June 16, 2009, 12:41:28 PM »
HF oscillation. sorry for the tweeters :o
try the gridstoppers, or reduce the gain range (what I did).
you will never need gain past 5.

tskguy

Re: D-LA2A Support Thread
« Reply #143 on: June 16, 2009, 01:38:16 PM »
Cool thanks again,

I will try thos fixes this evening and let you know. Atleast It seems like a probleam that has a known fix. The gain range fix is the 25 ohm pot with a 75 resistor correct?? I plan on the grid stoppers first though. I also am running the input at 1:2 I may try 1:1 and see if that helps as well.


Eric

[silent:arts]

Re: D-LA2A Support Thread
« Reply #144 on: June 16, 2009, 02:06:20 PM »
I don't think a change to a 1:1 transformer will change the oscillation, since it is input level independent.
and I don't know if it is tube or (PCB) layout dependent. some people have it, some not.
with my PCBs, with Drip PCBs, and I have read from P2P units too.

gain range fix in my unit is the 25K ohm pot with the 75K ohm resistor, yes.
(and I still never moved the gain over the middle).
if you need more gain you could try a 50K ohm pot with a 50K ohm resistor.

tskguy

Re: D-LA2A Support Thread
« Reply #145 on: June 16, 2009, 02:16:28 PM »
Thats good to know... I will leave the transformer the same. I really dont have any issues with the amount of gain. It has plenty!!!
And I would never really need to go past five my testing usually has it around 2 or 3 for makeup gain. I really just want to fix it in case someone pumps it past five again and blows my overly sensitive tweeters!! Im just glad Im not in the middle of a project!
They dont sound very nice without tweeters..

Eric


[silent:arts]

Re: D-LA2A Support Thread
« Reply #146 on: June 16, 2009, 02:27:00 PM »
in this case try the "gain mod".
better adjusting range as a benefit too.
(but before testing with your loudspeakers do with a meter)

tskguy

Re: D-LA2A Support Thread
« Reply #147 on: June 16, 2009, 02:35:44 PM »
Very cool,

Thanks again for your help.

Eric

tskguy

Re: D-LA2A Support Thread
« Reply #148 on: June 16, 2009, 08:52:44 PM »
Ok
I did the grid stopper and it didnt do anything...Bummer. Oh well I guess I wil try the gain mode.
Did the original do this? Or is it a issue related to tube diffrences? It seems strange that I couldnt fix the real cause not just bandaid it.

Eric


tskguy

Re: D-LA2A Support Thread
« Reply #149 on: June 16, 2009, 10:12:10 PM »
Ok,

If I unplug my output transformers from the board my strange gain issue goes away??? I am using cinemag tx's and I wonder if I have it wired wrong.

I also have a pair of the edcor wsm tx's maybe I should give them a try? 

Eric


tskguy

Re: D-LA2A Support Thread
« Reply #150 on: June 16, 2009, 11:17:48 PM »
So I double checked my wiring on the output and it seems fine. The only real diff is that the cinemag doesnt have a black wire so I just left it out. I guess its for ground. Is that ok??

Eric

crisotop

Re: D-LA2A Support Thread
« Reply #151 on: June 17, 2009, 04:11:41 AM »
Jens or Bernd once noticed that the oscillation depends how close the output tranny is to the I/O XLRs. Try moving the trannies around until the hf oscillation dissapears.

hth, christoph

bernbrue

Re: D-LA2A Support Thread
« Reply #152 on: June 17, 2009, 05:25:13 AM »
Jens or Bernd once noticed that the oscillation depends how close the output tranny is to the I/O XLRs. Try moving the trannies around until the hf oscillation dissapears.

hth, christoph

Thx Chrisoph for mentioning this. Indeed, I found out that the transformers shouldn┬┤t be too close to the XLR inputs/outputs. I moved them a bit and the oscillation problem was solved.
regards
Bernd


tskguy

Re: D-LA2A Support Thread
« Reply #154 on: June 17, 2009, 08:25:26 AM »
Well that didnt make any diffrence... :-\ Well I guess I will get some 50k pots and see if that works. Im sure it will fix it. But I would love to fix the heart of this issue. One thing I wanted to mention is that it doesnt mateer if anything is plugged in or if its in bypass or not. If you watch the output gain when it does this it gets slammed hard to the right at just above 50% gain. The exact same behavior is happening on either channel as well.

I have been doing a ton of searching as well and havent seen anything like it....

Eric

tskguy

Re: D-LA2A Support Thread
« Reply #155 on: June 18, 2009, 09:54:40 AM »
Ok I finally figured this out!! It was a combo of unshielded wires and and wire placement. Things are good now! Silent:arts, thanks for all your help!

Here it is....





And Yes I know the T4 cells are huge!! But they fit and sound great!!!!

E
« Last Edit: July 20, 2010, 11:36:34 AM by tskguy »

crisotop

Re: D-LA2A Support Thread
« Reply #156 on: June 18, 2009, 10:06:27 AM »
wohoo! congrats!

tskguy

Re: D-LA2A Support Thread
« Reply #157 on: June 18, 2009, 10:13:44 AM »
Thanks man!

It is a big project its nice to have it finished!

E

rob_gould

Re: D-LA2A Support Thread
« Reply #158 on: June 18, 2009, 10:27:58 AM »

Nice work - looking good :)

Can't wait to get my one of these up and running...

[silent:arts]

Re: D-LA2A Support Thread
« Reply #159 on: June 18, 2009, 10:32:35 AM »
congrats  ;D
great you featured out the oscillation  :) :) :)
is this a Gustav PCB ?


 

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