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Looking for tube advice [message #9509] Mon, 30 January 2006 17:42 Go to next message
blades976 is currently offline  blades976
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Registered: May 2009
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The tube preamp section in the Hartke 3500 basshead we are using is hissing pretty bad. The hiss goes away when the tube channel is turned down (we normally like it about half way up) but then the bottom end drops out (for us anyway). I'm just wondering if anybody knows a good replacement tube to get. I believe the preamp uses a 12AX7. I've done a few searches and the name Sovtech seems to come up a bunch.

Thanks

John

Re: Looking for tube advice [message #9510 is a reply to message #9509] Mon, 30 January 2006 20:54 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18292
Registered: January 2001
Illuminati (33rd Degree)

Check with Aki at BOI Audioworks. He has a bunch of 'em and they're inexpensive so you can try a few and see which ones you like. I like Светлана (Winged "C" Svetlana) and Electro-Harmonix, but there are plenty of other good brands to try too.


Re: Looking for tube advice [message #9511 is a reply to message #9510] Tue, 31 January 2006 14:45 Go to previous messageGo to next message
blades976 is currently offline  blades976
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Thanks Wayne. There sure are a bunch of choices out there; right now I have my eye on an Electro-Harmonix tube.

John



Re: Looking for tube advice [message #9512 is a reply to message #9511] Tue, 31 January 2006 17:08 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18292
Registered: January 2001
Illuminati (33rd Degree)

I have a bunch of EH tubes too, and I really like them. Don't forget about Aki - He's a sponsor of ART, has good quality parts at reasonable prices and is and a real good guy. I've bought several tubes from him and many of them were matched. They measured spot on every time.


Re: Looking for tube advice [message #9513 is a reply to message #9509] Wed, 01 February 2006 12:09 Go to previous messageGo to next message
Shane is currently offline  Shane
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Registered: May 2009
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Ditto what Wayne said, as it's good to buy from sponsors. On another note, I've had very good luck and sound from JJ tubes I've gotten at Eurotubes for my Peavey 5150 and Fender Vibrochamp. They were much better sounding than the Sovteks that came in the Peavey, especially in the preamp section.

Re: Looking for tube advice [message #9514 is a reply to message #9512] Fri, 03 February 2006 19:11 Go to previous messageGo to next message
blades976 is currently offline  blades976
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Registered: May 2009
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I will be buying an EH tube from Aki in a couple of days, in the mean time I've picked up a groove tube 128X7C (gotta get the amp up and running ASAFP), I bought it because the plate structure looks kewl compared to the other offerings. Will be cool to compare it to an EH tube.

John

Re: Looking for tube advice [message #9518 is a reply to message #9514] Sat, 04 February 2006 13:10 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18292
Registered: January 2001
Illuminati (33rd Degree)

Let us know how they sound, differences, etc.


AMP FREAKS OUT [message #9522 is a reply to message #9518] Sun, 05 February 2006 22:24 Go to previous messageGo to next message
blades976 is currently offline  blades976
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Registered: May 2009
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Well the new tube was great yesterday when I replaced it. We played it for about 15 minutes at a moderate volume just to make sure the thing works. It did and sounded nice and clean.

Well today we fired it up and the bass amp worked great for about 45 minutes then just totally went to shit. Horrible distortion (VERY loud crackling and grating noises) kicks in when the amp is pushed to anything beyond quite operation. I'll try and replace the old tube tomorrow to see if maybe I got a bad tube. I hope the output section of the amp didn't get shorted out. The distortion comes out in the amps speaker level outputs and the balanced XLR as well. At first the distortion was heard as faint crackling in the PA then within 10 minutes the damn thing went nuclear and had to get turned off.

The old tube is a plain old Groove Tubes 12AX7. Could this malfunction be from not having the amp re-biased? I understand that the tube can wear a bit quicker but an hours worth of playing? I bought the tube from a local guitar store, but I honestly don't think the tubes where individually tested there.

I hope this doesn't get expensive

John

Re: AMP FREAKS OUT [message #9523 is a reply to message #9522] Mon, 06 February 2006 07:15 Go to previous messageGo to next message
Damir is currently offline  Damir
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Registered: May 2009
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Two possibilities - or you got bad tube, or something in the amp "around" it (coupling cap, socket contact...) is damaged. Try it again with 100% good tube, and if it`s not the tube - you need the tech.
P.S. you don`t need to "rebias" 12AX7 preamp tube.

Re: AMP FREAKS OUT [message #9529 is a reply to message #9523] Tue, 07 February 2006 23:15 Go to previous messageGo to previous message
blades976 is currently offline  blades976
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Registered: May 2009
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Ran the amp tonight with the old tube in it. No problems except for the excess hiss that made me buy a new tube to begin with. I guess I'll try and order another tube and see if I get better results.

John

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