Help. I lost the left channel.

TonyMc · 4092

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Offline TonyMc

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on: August 17, 2011, 05:01:27 PM
Hey all.
I turned on the crack today and saw a small flash. I lost the left channel. Tubes sill glow fine and I don't see anything burned in it.
Where do I start?
Also. Both leds still light up.



Offline TonyMc

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Reply #1 on: August 17, 2011, 05:46:32 PM
OK.
I check all my voltages and they are within spec. Both LEDs light up, and nothing looks or smells burned. I tried it with a different tube and it's the same. No left channel.



Offline Paul Joppa

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Reply #2 on: August 17, 2011, 06:15:57 PM
If the voltages are right, then it has to be at the input or output. Swap channels on the input to rule out the source, and try a different headphone to rule that out. It's usually a solder joint or a connector, just going on the odds.

Paul Joppa


Offline TonyMc

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Reply #3 on: August 17, 2011, 06:50:34 PM
If the voltages are right, then it has to be at the input or output. Swap channels on the input to rule out the source, and try a different headphone to rule that out. It's usually a solder joint or a connector, just going on the odds.

Hi Paul.
 I think your right. I thinks its the headphone jack. I plugged in another set and they worked so I plugged my Beyers back in and it's a no go, but I plugged the Beyers into my Topping SS amp and both channels work. So it's not the source. So when I get some time tomorrow I'll re-wet the joints on the headphone jack and report back.

Thanks again Paul.



Offline TonyMc

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Reply #4 on: August 18, 2011, 04:59:11 AM
You ever heard of a 1/4" adapter going bad?
Here's the thing.
I plug the Beyers into the Crack... No left channel.
I plug my ATH-A700 into the Crack... Works perfectly.
I take the 1/4" adapter off the Beyers and plug into a different amp... Works perfectly.
I plug the Beyers into my HT receiver via the 1/4" adapter... I get left channel, but it's very faint.
It leads me to believe it's the 1/4" adapter, but what in the adapter could go bad? Seems like an ordinary simple adapter.
Anyway. I think what I will do it pick up a new adapter and a Nuetrik locking jack(I've been wanting to do that anyway) and get this sucker back to working. :)
I see why Doc named it "Crack". It's only been a day and I'm already having withdrawl. :)



Offline Doc B.

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Reply #5 on: August 18, 2011, 05:11:48 AM
Yes, I have seen 1/4" adapters taken out at Head Fi meets, from all the plugging and unplugging. We ended up buying a half dozen of them to have around as backups.

Dan "Doc B." Schmalle
President For Life
Bottlehead Corp.


Offline Laudanum

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Reply #6 on: August 18, 2011, 05:12:44 AM
Maybe a bad/cracked/broken insulator or internal contact within the adapter.  Hey, atleast it's a cheap replacement part.  You dont have to find a threaded adapter although it's nice not to have to worry about it pulling off when you unplug the phones. Anyway, I believe a standard, unthreaded plug in adapter will work fine.  Something else to consider ... I made up a shortish cable ... 1/4" right angle TRS male plug to 1/8" TRS mini female jack. Plugs into Crack and then headphones with a 1/8" plug can plug right into the jack without the adapter.  It's nice with the Beyer pro's because of their coiled cord and also allows for less strain on the headphone cable at the plug with the plug no longer sticking straight up from the headphone jack.
« Last Edit: August 18, 2011, 05:14:52 AM by Laudanum »

Desmond G.


Offline TonyMc

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Reply #7 on: August 18, 2011, 06:27:52 AM
Yes, I have seen 1/4" adapters taken out at Head Fi meets, from all the plugging and unplugging. We ended up buying a half dozen of them to have around as backups.

Thanks Doc. I appreciate the feedback.

Maybe a bad/cracked/broken insulator or internal contact within the adapter.  Hey, atleast it's a cheap replacement part.  You dont have to find a threaded adapter although it's nice not to have to worry about it pulling off when you unplug the phones. Anyway, I believe a standard, unthreaded plug in adapter will work fine.  Something else to consider ... I made up a shortish cable ... 1/4" right angle TRS male plug to 1/8" TRS mini female jack. Plugs into Crack and then headphones with a 1/8" plug can plug right into the jack without the adapter.  It's nice with the Beyer pro's because of their coiled cord and also allows for less strain on the headphone cable at the plug with the plug no longer sticking straight up from the headphone jack.

Agreed. A cheap fix. I have another 1/4" but it's not threaded like the original and would not work. It looks like the threaded unit allows for the stock 1/8" jack on 880 to go into the adapter a little deeper or could be the one that came with the A700 is just different ad won't allow the 880 to go in far enough.
Either way I'll just pick up a couple 1/4" adapters and locking jack.
Hey that brings me to another question. I assume I'll need to expand the hole on the chassis for the locking style Neutrik?



Offline Laudanum

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Reply #8 on: August 18, 2011, 11:45:14 AM
Im not using a locking Neutrik jack, Im using the stock jack so cant help with specifics.  But, I think it does require a larger hole, try a  search here, others have used them.  Or check out the Crack builds in the Gallery, someone has probably posted a picture of their amp with a locking jack ... shoot them a PM.

All I did I was build what amounts to a headphone cable extension, except with a 90 degree 1/4" plug that plugs into the stock Crack headphone jack on one end and a 1/8" mini jack on the other.

A regular 1/8" - 1/4" adapter should work.  The 1/8" plug of the Beyers works with any music source that has a 1/8" jack/socket without threading in and an adapter isnt any different.  Maybe the adapter that you tried is proprietary because of the threads.  I just tried the Beyers with a generic adapter (non threaded) and they work fine.  I think I got it from Parts Express.

Desmond G.


Offline 2wo

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Reply #9 on: August 18, 2011, 02:17:52 PM
While your getting parts and all, why not add a 1/8 jack to your Crack and be done with it...John

John S.


Offline SteveH

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Reply #10 on: August 18, 2011, 03:03:46 PM
A regular 1/8" - 1/4" adapter should work.  The 1/8" plug of the Beyers works with any music source that has a 1/8" jack/socket without threading in and an adapter isnt any different.  Maybe the adapter that you tried is proprietary because of the threads.  I just tried the Beyers with a generic adapter (non threaded) and they work fine.  I think I got it from Parts Express.

Yep - my DT880s work with half a dozen different 1/8" - 1/4" adapters that I have around the house.  I have to say, though, that the threaded adapter that comes with the headphones is cool.  Makes it look like the phones have a 'real' 1/4" plug on them, just like I remember from the 70s!

SteveH



Offline TonyMc

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Reply #11 on: August 18, 2011, 05:27:00 PM
While your getting parts and all, why not add a 1/8 jack to your Crack and be done with it...John

I thought about that too John, but I just sent them back to Amazon for a replacement. I have only had these for two weeks so I figure there's no point in fussing with it and Amazon has a great replacement policy.
Shoot they already shipped the new ones today before I even put these in the mail. Pretty great service. :)
I think I will take Doc's advice though and pick up a couple 1/4" spares.