another 7pro down.... - Page 2

B-string · #21 12-19-2012, 06:29 PM

Any variant of a 12AX7 will be fine, also ECC83 or 7025

will33 · #22 12-19-2012, 06:29 PM

For testing purposes, I'd just pick up something cheap that's available locally and known to work....probably a groovetube or sovtek.

After the amp is up and running, you can then proceed to empty your wallet chasing tone....keep the working cheapy as a spare.

JimmyM · #23 12-19-2012, 06:32 PM

Actually, forget the last letters. As long as it's a 12ax7, you're fine.

Stone Soup · #24 12-19-2012, 06:43 PM

The Sovtek 12ax7WA is a very common, inexpensive, reliable and often used preamp tube.

nubs · #25 12-19-2012, 06:50 PM

just purchased a mullard from GC for about 20 bucks, went through them because of the Snowpocalypse or snowmaggedon they are predicting in the next few days to come, i'll make my UPS buddy deal with the elements thanks for your help guys.....i hope this is all thats wrong, sound legit

B-string · #26 12-19-2012, 07:00 PM

A Mullard for $20 will be a reissue (new production) but will be fine. Old stock Mullard run $100 and up

See if you get more volume by plugging your bass straight into the effects return? That will let you know the power amp is okay and the trouble is in the preamp stage.

nubs · #27 12-19-2012, 07:42 PM

Quote:

Originally Posted by B-string

A Mullard for $20 will be a reissue (new production) but will be fine. Old stock Mullard run $500 and up

See if you get more volume by plugging your bass straight into the effects return? That will let you know the power amp is okay and the trouble is in the preamp stage.

bass plugged into the effects return give me allot more volume. maybe not as much normal, but tons more than before. looks like its the pre-amp okay so now i got a replacement tube on the way. i'm hoping the mullard will fit the bill.

B-string · #28 12-19-2012, 07:46 PM

Yes that is a very promising sign. It will not be as loud because the preamp which increases instrument voltage level as well as tone shaping is bypassed.

vin*tone · #29 12-19-2012, 09:53 PM

Quote:

Originally Posted by JimmyM

An electrical dummy can easily replace the tube. Unbolt the lid, open it up, pop the old tube out, po the new one in, replace lid. Try Will's idea first, though...it's free.

Does this void Ampeg's warrantee? Sounds like that might come in handy right about now.

Personally I would recommend leaving the case firmly screwed up tight.

JimmyM · #30 12-19-2012, 09:59 PM

Replacing tubes absolutely does NOT void the warranty. However, there is a 90 day warranty on tubes if you want to be a schnorrer about it

Downunderwonder · #31 12-19-2012, 10:25 PM

If more people claimed on failed tubes they might put some better ones in there in future.

JimmyM · #32 12-19-2012, 11:46 PM

Quote:

Originally Posted by Downunderwonder

If more people claimed on failed tubes they might put some better ones in there in future.

Good luck with that one, bro

SBrown · #33 12-20-2012, 10:22 PM

I hope its the tube, my C00 fried the circuit board. My authorized tech contacted Ampeg, they determined it wasn't repairable, and authorized a replacement. It took 3 months to get the new amp, but its better than the one I had before. I cant explain why, it just seems like it has more headroom. Anyway, Ampeg took care of me, even though it took a while. A large part of the delay was probably due to the local tech not showing up for days at a time

. My symptoms were different than yours, my amp shut down in the middle of a song, and never powered back up. BTW, the svt 7 pro they sent back was also a C00, but I suspect it has the updated circuit board, and it promptly unseated the replacement amp I had purchased in the meantime. I'm happy with the support I got from Ampeg.

B-string · #34 12-20-2012, 10:26 PM

Quote:

Originally Posted by SBrown

I hope its the tube, my C00 fried the circuit board. My authorized tech contacted Ampeg, they determined it wasn't repairable, and authorized a replacement. It took 3 months to get the new amp, but its better than the one I had before. I cant explain why, it just seems like it has more headroom. Anyway, Ampeg took care of me, even though it took a while. A large part of the delay was probably due to the local tech not showing up for days at a time

. My symptoms were different than yours, my amp shut down in the middle of a song, and never powered back up. BTW, the svt 7 pro they sent back was also a C00, but I suspect it has the updated circuit board, and it promptly unseated the replacement amp I had purchased in the meantime. I'm happy with the support I got from Ampeg.

That is why I asked the OP to plug into the effects return. That indicated to me the poweramp (main board) was okay

JimmyM · #35 12-20-2012, 11:07 PM

The vast majority of the time, if something goes wrong with a hybrid, it's a tube or effects loop corroding. Stuff happens, though, so I'm glad the folks at Ampeg took care of you, even if your tech is a little flaky

nubs · #36 12-26-2012, 09:18 AM

update: it was the pre amp tube and my SVT7pro is up and rockin. thank a bunch for your advice guys!

will33 · #37 12-26-2012, 10:41 AM

Yay.

Always a good idea to check the easiest, simplest, cheapest stuff first. Plenty of people have thought their amp was crapping out on them when what was needed was to replace the battery in an active bass. Total cost what...$3?

B-string · #38 12-26-2012, 10:52 AM

Quote:

Originally Posted by nubs

update: it was the pre amp tube and my SVT7pro is up and rockin. thank a bunch for your advice guys!

AWESOME!

JimmyM · #39 12-26-2012, 10:56 AM

Whammo! Look at me call it! BAM!!!

Have fun with it, bro!

Jim C · #40 12-26-2012, 12:19 PM

Good news!
Always great when the 1 user replaceable part is the culprit no matter wht the device.