tube power amp

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anselm

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I am looking for a guitar power amp. I like the marshall el34 100/100, but it is way overpriced. I am wondering what the alternatives are. Any suggestions?

thanks
 
Mesa has their version as well. It isn't any cheaper.

Tube power amps are going to be expensive. All the money is in the power supply for the power section of a guitar amp. You are buying two independent power sections of a guitar amp.
 
You can still pick up Ampeg V4 heads, 100 watt all tube, for under three hundred dollars if you look around. The only problem with them is they don't have a master volume control and you can possibly injure or kill yourself with them. They are the best head I ever got. Ask Johnny Winter or Keith Richards :eek:
 
The other problem with the V4's is that they are all getting really old. All the caps dry out and there are 150 tubes in that thing. Some of them aren't very easy to find any more.
 
Farview said:
The other problem with the V4's is that they are all getting really old. All the caps dry out and there are 150 tubes in that thing. Some of them aren't very easy to find any more.
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sovtek now puts out the 7027a power tubes so they are no longer difficult to find. I think some other companies are making them also. The rest are just standard tubes.
 
It's the 6K11 and the 12dw7 that were always hard to get. A 7027A was just a military spec 6L6.

When I was looking for them, the internet wasn't what it is today. I'm sure it's easier to get the tubes now. I gave up trying to resurect my old V4 a few years back. It would have needed a complete rebuild.
 
Farview said:
It's the 6K11 and the 12dw7 that were always hard to get. A 7027A was just a military spec 6L6.

When I was looking for them, the internet wasn't what it is today. I'm sure it's easier to get the tubes now. I gave up trying to resurect my old V4 a few years back. It would have needed a complete rebuild.
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7027a,s are not military spec 6L6. They don't have the same biasing etc. Try swithing them out and see what happens to your amp.

6K11-http://thetubestore.com/nos-6k11.html $17.95

12DW7-http://search.store.yahoo.com/cgi-bin/nsearch?unique=ac58d&catalog=thetubestore&et=466acc95&basket=b%3D5C3a42bfd1016c3d466ac58dea4f2d242bfd12f11d14a06c2431db9610b60cafc%26l%3D%26s%3DG0XBE51yhgKJSuOaeUgMJnzkC4U-

$12.95

First place I looked, all very available.

I have owned three V4s and two VT22s and 6l6's cannot be substituted for the 7027a's without changing out bias resistors and resetting the bias.


unleash the beast

"For under $5.00 one can unleash the beast in a V-4 or VT-22 amp by adding a master volume control in a very convenient location (R21 and R23 get replaced with a 100K pot and 10K resistor connected to the wiper arm).

7027 tubes are rare and expensive, however, for under $3.00 one can modify these amps to accept 6550 or EL 34 tubes. The screen resistors are changed from 470 ohms. 1 watt to 1K 5 watts. If using EL 34 tubes, pin 1 has to be jumpered to pin 8. For 6550, R50 has to be changed to 82K. R49 sets the bias level. The plate resistors (R39, R40, R45, R46) are 10 ohms, so 0.4 volts =40 mA. When checking this voltage, the safest way to do it is to connect and disconnect the meter with the power off and capacitors discharged. (Modification taken from the Aspen-Pittman Tube Amp Book, with exception of biasing method). The recommended plate current for EL 34 and 6550 in most applications is 40-45 mA (then again, B+ is less than 450 volts). In the case of this amp with EL34's I would personally bias the power tubes around 30 mA. I received email from a person who tried 32 mA with EL 34's with no ill effects. I also read somewhere that EL34's should dissipate 15-18 watts at idle (the math for 545 volts of B+ equates to 30 mA of plate current).

Additional note on Ampeg V4- a 6L6GC has identical characteristics to a 7027, except for that specs call for 500VDC max plate voltage. I ran a quad in a Fender Dual Showman that had the transformers changed (the owner didn't want to put the proper set in, so I had to make the amp work). It had 540VDC at the plates (the power transformer was 780VCT) so I set the idle current at 30mA per tube (-60VDC at the grids of the power tubes). You could drop in 6L6GC's to a V-4, but beware!!"
 
I blew it, You're right, 6550's. It was a long time ago, like I said there was no internet at the time. You would have to go to a TV repair shop (when it was worth it to repair a TV) and try to order these things. The last time I retubed it was a year or two after they stopped making US tubes.

You still can't go to GC or Sam Ash and expect to find half the tubes you need for that thing.
 
Power tube substitutions:

* 6BQ5/EL84 (miniature pentode with pinout 9CV)

6267 7189 EF86
6BQ5 7189A EL84
6BQ5WA 7320 N709
6P15 E84L Z729

* 6L6 (beam power tube with pinout 7AC)

6L6(many suffixes) 7581(A)
5881 WT6
5932 EL37

* EL34/6CA7 (power pentode with pinout 8ET)

EL34 12E13
6CA7 KT77
7D11 KT88

* 6550 (power pentode with pinout 7S)

6550[A] 7027A#
7D11 KT88
12E13

http://home.alltel.net/vintage/tubefaq.htm

haven't gone through the whole site but it looks very good.
 
Farview said:
I blew it, You're right, 6550's. It was a long time ago, like I said there was no internet at the time. You would have to go to a TV repair shop (when it was worth it to repair a TV) and try to order these things. The last time I retubed it was a year or two after they stopped making US tubes.

You still can't go to GC or Sam Ash and expect to find half the tubes you need for that thing.
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Isn't the internet great, you can find all this info and shit in minutes have it delivered to your door and be on your way.

All I can say are my VT22s and V4s just kicked ass. They are to big and heavy for me and now at 55 I just don't need that kind of volume anymore. I never played better sounding amps and that includes Marshalls, Fenders etc. I have never really tried Mesas so I can't say, or any of the newer amps. But for the old days they were the cats meow and I am a big Johnny Winter fan and that is his sound.
 
My VT-40 and V-2 are great and not quite as loud though they still can be used as welding machines LOL!

They are heavy as shit but I'm gonna start using that V-2 head some in the near future ..... best sounding amp ever and it's the only one that has a mastervolume.
 
Farview said:
It's the 6K11 and the 12dw7 that were always hard to get. A 7027A was just a military spec 6L6.

When I was looking for them, the internet wasn't what it is today. I'm sure it's easier to get the tubes now. I gave up trying to resurect my old V4 a few years back. It would have needed a complete rebuild.
Click to expand...

If you still have it, send it to anselm and he can rebuild it for alot less than a new head.
 
dragonworks said:
If you still have it, send it to anselm and he can rebuild it for alot less than a new head.
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I got rid of it a long time ago. The thing stopped working around 1990 and I kept it (moving it through 3 apartments and 4 houses) until 2002. I bought it in 1982.
 
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