Herbert Channel 3 - fuzzy/troubleshooting

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nbarts

nbarts

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I've tried a few preamp tubes for V2 & it sounds fuzzy. Should I order some more tubes & keep trying? Do I need some special tube for V2? Channel 1 & 2 sound like they are supposed to sound. Anything other than V2 tube that can cause this?
 
The manufacture is Shuguang from China.

They are distributed by Ruby, Doug´s tubes, etc
 
Just ordered a new set of preamp & power amp tubes, hopefully it will fix the problem.
 
Just installed a new set of highgrade preamp tubes, SED EL34s & rebiased the amp. Did not fix the problem.

I guess I'll have to ship it to Salwender, but this is REALLY NOT a good time for it.

Will it harm the amp if I keep using 1st & 2nd channels until I have the time & finances to ship this thing back & forth? I pretty much never use ch3 anyway.
 
Peter Diezel":3mt0nc6a said:
I would replace the two 22µF/500V caps
Click to expand...

Hi Peter,

Thanks for the reply. Is this easy to do? Can my local tech do this? Where can I get those caps?
 
Hey dude,

If you remember my thread, that's what I did. You can get them from Parts Express if you want to do it yourself. A tech could do it no problem. If you want to do it yourself it's not really hard but you MUST be careful, they pack a punch if you ground yourself out. If your not an ace at soldering don't try to de-solder them from the board, instead cut the leads and twist the new cap leads around the old leads then run some solder over them(MAKE A NOTE OF POLARITY). It would be a good idea to get some silicon caulking(type II(2) ONLY!!!) to put under the caps to give them some cushion from vibration. If you can't get new quick ties in there don't worry, they're not entirely needed, but if you want or are worried, run a healthy bead of silicon across the top of the two caps. Take a look at my old thread, unless the caps look swollen or have electrolyte seeping out they probably aren't bad, also if they are bad it would be more hummy than normal, although they may have been on their way out when you got the head. I'll put a link to my old thread after I get done writing this.

Later on,

-Nick

edit-a-rino:http://www.rig-talk.com/forum/viewtopic.php?f=14&t=33961
 
Thanks Nick,

OK, this can be something different. I've noticed ch2 is weird too, it is not as fuzzy as channel 3, but it's definitely not alright. I didn't have much time to check things today, but I will do some testing & see what's what.

Edit: Nick, I've just noticed you had weird noise on Ch2 also, just like me. Seems pretty similar. I'll make a clip today or tomorrow & take the amp out of the cabinet & see if I can see anything visually wrong inside. I believe this may have something to do with overheating.
 
OK, here is an mp3, condenser a few FT away. Channel 1, then ch2 -, +, - & then around 1:05 you can hear channel 3. Channel 2 gain is at 9:00, in minus position it should be clean. I flipped the amp & I couldn't see anything visually wrong with my naked eye. I'll take some pictures & post them soon.
 

Attachments

NBARTS_HELP.jpg


This cap is bad, it has leaking electrolyte, I need a better picture with better lighting for the other two. A chinese manufacturer stole an incomplete electrolyte formula and flooded the market with bad caps a few years back, they're still being weeded from the market, more than likely this is the case. Computers got hit really bad with the defunct caps. As far as the mp3 it sounds similar but a little worse than what mine sounded like, more than likely a settings thing. Did the bass roll off some? If it did then this is most likely your problem. Anyway it goes you definitely have to replace the one cap, you will notice some sort of improvement even if it isn't your cure, definitely less hum. Need better pics of the other caps.

Later on dude,

-Nick

Edit: By the way, definitely NOT a heating issue, the Herbert boards are too well built for that.

Edit 2.0:
closeupoftwincaps-1.jpg


Here's the two caps I need a better pic of and in the pic you can see a bad cap and a good cap, there shouldn't be expanding goo/foam coming out of the lead area.
 
Nbarts22.jpg


Nbarts21.jpg


Replace.

Yes, that's the ones.

Later on,

-Nick
 
Peter Diezel":2rw25fx9 said:
Any news ?
Click to expand...

I've placed an order for caps today, I'll have them probably in the beginning of the next week. I'll keep posted.
 
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