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Topic: 73 fender twin needs new tubes help me |
Larry Schubert
From:
Orcutt, CA, USA
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Posted 12 Jan 2002 3:06 am |
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| I have a 73 fender twin reverb that needs new tubes. The problem is that the tubes don't have the number on them just clean glass. Witch looks kinda cool if you take the time to take off the tube covers and look behinde your amp. This how ever dose nothing to help my perdicament(did I spell that right?) All the tubes are way past due for a changeing every thing is nice a fuzzy all the time. Can any one give me the numbers for tubes thanks! |
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Jack Stoner
From:
Kansas City, MO
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Posted 12 Jan 2002 4:12 am
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Look at the tubes closely. Sometimes the markings will fade away but if you blow your breath on them it will give you enough to read what they are.
I thought there was a tube placement label on the side of the amp. Check to see if the tag is still there. It also says what chassis it is, e.g. AB768 or whatever.
From memory the first two are 12AX7's. And of course the power tubes are 6L6GC's. |
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Jon Light
From:
Saugerties, NY
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Posted 12 Jan 2002 5:29 am
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As you look at the rear of the amp, from right (the side wall) to left (the center) the 6 preamp tubes are:
1)12AX7A/7025
2)12AX7A/7025
3)12AT7
4)12AX7(A)7025
5)12AX7
6)12AT7
The 4 power tubes are 6L6GC.
I'm unsure of the difference between 12AX7 and 12AX7A. And there are many variants of the 6L6's. If you talk with a good dealer or tech you will get his idea of what the best tube is. In the end you have to trust someone. My rule of thumb is that if he says 'such and such just plain sucks" he is probably not a useful source of practical advice. He just loves the sound of his opinions.
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Larry Schubert
From:
Orcutt, CA, USA
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Posted 12 Jan 2002 11:02 am
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| Thank you all for your help. MY amp is a ltlle less mysterious but still cooler than heck. |
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Bruce Derr
From:
Lee, New Hampshire, USA
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Posted 13 Jan 2002 9:19 pm
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The 12AX7A/7025 is a low-noise version of the 12AX7. I believe the difference is in the way the filament (heater) is constructed. I don't know if new production 12AX7A's have this characteristic, however.
When replacing the 6L6s, be sure to use the 6L6GC, as opposed to the 6L6GB, which doesn't have a sufficiently high voltage rating for the Twin. The Svetlana (sp?) 6L6s seem to be highly regarded these days. But another option is to get American-made NOS (new old stock) tubes, which are still available but can be expensive. Here's a web site with NOS tubes for sale, and some interesting articles. http://users.erols.com/bluestat/
If your amp is fuzzy it may have problem other than weak tubes. Might be worth having a tech check it out, especially for an amp that old. At the very least, he'll set the bias for your new power tubes, which is something that should be done. |
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Brian Wetzstein
From:
Billings, MT, USA
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Posted 14 Jan 2002 2:24 am
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hi larry. in addition to replacing your tubes, have a tech check your capacitors. most caps only have a recommended life span of 10 years. after that they could fail and harm other things in your amp. it is good preventative stuff for your vintage amp.
good luck!
brian |
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Danny Hullihen
From:
Harrison, Michigan
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Posted 14 Jan 2002 4:47 am
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| Larry. As a suggestion, if you're considering using Sovtek Tubes, you might want to consider their 12AX7WB for some of the preamp tubes, and the Electro Harmonix 6L6GC for your power tubes. You can order these in matched sets. |
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Frank Venters
From:
Peru,In,USA
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Posted 14 Jan 2002 10:59 am
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| I bought a whole set of tubes for my 71 Fender Twin at www.tubesandmore.com and they have a lot of parts for Fender amps. I paid approx. $105.00 for the whole set of tubes. |
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Jon Light
From:
Saugerties, NY
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