JBVries

Re: EQN build thread
« Reply #360 on: February 17, 2011, 01:13:20 AM »
Two EQNs........

No Smoke!!! ;D but no sound either....... the hunt begins.

How are we supposed to set the two variable resistors?

 Also, nowhere on the boards including the heatsink are showing any expected temperature variation almost as if voltage were present at the tabs but not going any where beyond that. Anywhere I can poke to make sure voltage is getting to the right place? If so, proper value expected?

Cheers! 
A little bit of the sonic mayhem I bring to the table.....

http://www.soundcloud.com/jbvries


canidoit

Re: EQN build thread
« Reply #361 on: February 17, 2011, 03:33:55 AM »
Two EQNs........

No Smoke!!! ;D but no sound either....... the hunt begins.

How are we supposed to set the two variable resistors?

 Also, nowhere on the boards including the heatsink are showing any expected temperature variation almost as if voltage were present at the tabs but not going any where beyond that. Anywhere I can poke to make sure voltage is getting to the right place? If so, proper value expected?

Cheers! 
I set mine at 750r from what I recall, because that was like the safe zone as discussed in a few of the posts but I recall only discussing 1 resistor to adjust. Are we both on the same page?  ???
iva dunit formerly known as canidoit

JBVries

Re: EQN build thread
« Reply #362 on: February 17, 2011, 04:18:13 AM »
No, you are thinking of the bandwidth resistor. I am talking about the variable resistors pots (the ones with a set screw).
A little bit of the sonic mayhem I bring to the table.....

http://www.soundcloud.com/jbvries

canidoit

Re: EQN build thread
« Reply #363 on: February 17, 2011, 05:46:17 AM »
No, you are thinking of the bandwidth resistor. I am talking about the variable resistors pots (the ones with a set screw).
You mean the little blue trimmer pots? If so, you are meant to use an oscilloscope and measure for clipping.

I do not recall having to change any resistors besides that 750r one.

Have a look at the BOM I have, I referred to two parts list I received from two builders here before making my own parts list. Maybe the solution is in there??

I would like to know as well incase I did something wrong?
iva dunit formerly known as canidoit

Re: EQN build thread
« Reply #364 on: February 18, 2011, 08:19:50 AM »
jbv,
Are you 51x, or standard?
http://www.lazpro.com
I reserve the right to not sell to idiots

JBVries

Re: EQN build thread
« Reply #365 on: February 19, 2011, 02:54:16 AM »
I was testing with +-16v on my test little jig. I do use 51x and when I threw one in the rack I had no difference in results.
A little bit of the sonic mayhem I bring to the table.....

http://www.soundcloud.com/jbvries

Re: EQN build thread
« Reply #366 on: February 19, 2011, 06:30:31 AM »
I'll re-phrase... is it fully populated, or are you in 51x mode?
http://www.lazpro.com
I reserve the right to not sell to idiots

JBVries

Re: EQN build thread
« Reply #367 on: February 19, 2011, 11:15:20 AM »
Ahhh, 51x.
A little bit of the sonic mayhem I bring to the table.....

http://www.soundcloud.com/jbvries

Re: EQN build thread
« Reply #368 on: February 19, 2011, 06:27:06 PM »
Then plus and minus 16v is nfg. Feed it 24v.
http://www.lazpro.com
I reserve the right to not sell to idiots

JBVries

Re: EQN build thread
« Reply #369 on: February 19, 2011, 07:42:02 PM »
Bollox!! (and i'm not taking the piss I do say that all the time, even though I'm coastal Californian, haha ;))


C60 started to go as soon as I jumped that spot on CC6 and fed it 24v. I heard it first then saw it start to bulge so I killed power. If I find the problem will that cap still be ok, or is it shot already?

and  Orientation and general assembly form aside(as I'm triple checking that now), any advice on where to look would be greatly appreciated.
A little bit of the sonic mayhem I bring to the table.....

http://www.soundcloud.com/jbvries


Re: EQN build thread
« Reply #370 on: February 19, 2011, 08:17:08 PM »
any advice on where to look would be greatly appreciated.

C60 and everything else..!!
http://www.lazpro.com
I reserve the right to not sell to idiots

JBVries

Re: EQN build thread
« Reply #371 on: March 07, 2011, 11:27:50 PM »
So close I can taste (or hear) it.....

Is there supposed to be significant level coming out of the OUT(-) of the input transformer? When probed I see very little signal.

When I poke around I do see signal various places all over the board. Plenty of signal out of the op amps, but still nothing at the output.

Any thoughts much appreciated.
A little bit of the sonic mayhem I bring to the table.....

http://www.soundcloud.com/jbvries

crisotop

Re: EQN build thread
« Reply #372 on: March 08, 2011, 03:03:50 AM »
Quote
Plenty of signal out of the op amps, but still nothing at the output.

Follow the schematic from the opamps to the output - somewhere along these lines you might have got a problem.

Good Luck!
Christoph

Re: EQN build thread
« Reply #373 on: March 09, 2011, 12:50:23 AM »
Is there supposed to be significant level coming out of the OUT(-) of the input transformer?

No. The negative output goes to ground.
http://www.lazpro.com
I reserve the right to not sell to idiots

JBVries

Re: EQN build thread
« Reply #374 on: March 09, 2011, 06:56:16 AM »
I did get one of them running..... Sounds beautiful. Thank you much for the great projects Peter!
A little bit of the sonic mayhem I bring to the table.....

http://www.soundcloud.com/jbvries

Marcocet

Re: EQN build thread
« Reply #375 on: April 12, 2011, 08:13:03 PM »
Okay, ran up on a problem I can't solve.

On one of my EQs the High Pass filter is WAY too high. As in when it's set to 45 its cutting at like 4k. I've replaced caps 11-18, all the resistors on the switch and the two tantalum caps and nothing's changed. I can't figure out what else in the circuit it could even be. Anybody have any insight?

Thanks

ruairioflaherty

Re: EQN build thread
« Reply #376 on: April 12, 2011, 08:22:32 PM »
Okay, ran up on a problem I can't solve.

On one of my EQs the High Pass filter is WAY too high. As in when it's set to 45 its cutting at like 4k. I've replaced caps 11-18, all the resistors on the switch and the two tantalum caps and nothing's changed. I can't figure out what else in the circuit it could even be. Anybody have any insight?

Thanks

Hi Marc,

Don't have the schemo handy and mid session anyhow but it sounds like a component factor to me, it's probably cutting at 4500Hz, ie 100 times what it should be.  Are all the high pass values on that one unit similarly elevated?  If so then it could be a rogue resistor in the wrong bin or even marked wrong.  Did you measure them all when fitting?

Cheers,
Ruairi

Marcocet

Re: EQN build thread
« Reply #377 on: April 12, 2011, 10:27:05 PM »
Okay, ran up on a problem I can't solve.

On one of my EQs the High Pass filter is WAY too high. As in when it's set to 45 its cutting at like 4k. I've replaced caps 11-18, all the resistors on the switch and the two tantalum caps and nothing's changed. I can't figure out what else in the circuit it could even be. Anybody have any insight?

Thanks

Hi Marc,

Don't have the schemo handy and mid session anyhow but it sounds like a component factor to me, it's probably cutting at 4500Hz, ie 100 times what it should be.  Are all the high pass values on that one unit similarly elevated?  If so then it could be a rogue resistor in the wrong bin or even marked wrong.  Did you measure them all when fitting?

Cheers,
Ruairi


Stupidly I didnt on this batch. I swapped out all the resistors and caps that I know are in the hpf section though. I'm gonna keep trying to trace it and see if I spot anything else.

ruairioflaherty

Re: EQN build thread
« Reply #378 on: April 12, 2011, 10:50:45 PM »
Hey Marc,

If you pulled the parts from the same bins as the other builds the chances are small but still there that you grabbed a 100R instead of a 10K or something like that, or your cap is 100 times too small....  The other thing it could be is short around the resistors, a very low resistance there would elevate the HPF frequency. 

Are all the HPF frequencies out or just the 45Hz?

Is there a schemo somewhere for the EQ-N, can't find it (and I have a pair to build at some point)

Cheers,
Ruairi

Marcocet

Re: EQN build thread
« Reply #379 on: April 12, 2011, 11:38:56 PM »
it was an inductor! Anybody have a source for 9043's in the states?



 

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