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You guys are pros..help me with my Classic 30


Rampdog

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I recentally bought a Peavey Classic 30 amp and the previous owner put a Marshall Wolverine model WH-80-16 speaker in it. My tube configuration is 3 12AX7-A Tubes and 4 6BQ5 EL-84 Tubes. I know the amp is rated for a 30 Watt speaker but I'm finding that it's breaking up a touch at lower volumes in my drive channel. The clean channel is fine. Is it the speaker, tubes, or both that is doing this? I've heard a Classic 30 before and it had a tighter sound than I'm getting from this one. Should I put a 30 Watt speaker back in? Also, and it could be my imagination, I notice the batteries in my pedals are running down faster than they should. (Yes, I do unplug them when I'm done) HELP!!!!

Thanks guys.

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Uh, maybe I'm missing something, but the drive channel is supposed to break up - it has higher gain for the purpose of breaking up; that should be preamp distortion. If your clean channel doesn't break up at a certain SPL level and eq content, but the drive channel does, that's an indication that its preamp distortion. Speakers break up at different levels, I'd say a 30 watt amp (tube amps I think are traditionally rated at clean output, and can put out much more than that) will very likely reach speaker breakup before it will reach power tube breakup, depending of course on the speaker. My theory is that a 15 watt amp, like with 2)EL84's will pretty much saturate most guitar speakers - driving them at least close to their max SPL output.

 

When you crank the clean channel up to where you start hearing some breakup, that's either the speaker and/or the power tubes. If you plug it in to a 4x14 cab or even add a single 12" extension cab, and the breakup disappears at that volume, it was the speaker. With plenty of speakers connected - like 2 or more, turn it up some more, now, when you now hear breakup, that's probably the power tubes.

 

I don't know any place to test tubes (yeah, I remember when super markets had 'em !), but from what I understand, they don't do a real good job of testing anyway - they aren't put under a real-world load. The best way I know without paying a tech is to have some spares (which you should have anyway...), swap 'em out, if it sounds better, there was something wrong with the old one(s).

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I think your issue may be with the 1st pre-amp tube. Modern 12AX7's are pretty dirty and have fairly high gain. You might try substituting a 12AT7 or a 5751 for that first tube (I like the 5751's). Either of these should give you a lot more clean headroom.
"It's better to wear out than to rust out!"
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MCHEN... Will the 5751 tube give me a tighter distortion? That's really the only way I know how to phrase it. Right now it sounds on the sloppy side, if that makes sense to you. Excuse my ignorance but I've never played around with changing tubes so I appreciate all the tips I can get. I'm not that knowledgable when it comes to customizing amps and I didn't know you could mix tubes.

Thanks for the help...

Billy

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Rampdog,

 

You can pretty well exchange a 12AX7, 12AT7, 12AU7, 12AY7 or 5751 for each other. A 12AT7 and a 5751 have about 70% of the gain of a 12AX7 and a 12AU7 about 50% of the 12AX7.

 

Stevie Ray Vaughn used 5751's for his 1st pre-amp tube (V1). Because the tube dosen't have quite as much gain, you can crank the preamp up higher before it starts to breakup. To my ears, the 5751 has a "creamier/smoother" overdrive when you push it. Most 12AX7's sound harsh to me when overdriven.

 

The current Sovtek 5751's are pretty good and you can get one for about $10. Try the Tube Depot (www.tubedepot.com). I've been running a Westinghouse NOS (new old stock) 5751 as the V1 on all of my tube amps and you wouldn't believe the difference!

 

Part of the fun of a tube amp is messing with the tube combinations!

 

Have fun and I hope this helps.

"It's better to wear out than to rust out!"
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Mchen...I'm ordering the Sovtek 5751...I really hope this does the trick and I thank you for taking the time to reply to me. I also wish you a happy birthday. We were both born in the same month and year and we're still around. I wish you the best and will let you know how the tube works out. One last stupid question. Which is my first pre-amp tube? Sorry but I'm new to this tube thing.

Billy

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Rampdog,

 

Thanks for the B-Day wishes. Sometimes it's tough to be 25 in a 53 year old body!

 

Generally, the 1st pre-amp tube is the one furthest from the power tubes. Looking at the back of the amp, if your power tubes are on the left (4 - EL84's for your Classic 30, I believe), then your 1st pre-amp tube is the closest to the right side of the amp.

 

Let me know how it sounds with the change.

"It's better to wear out than to rust out!"
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Rampdog,

 

I took a look at the back of a Classic 30. Indeed, the 4 power tubes are kind of left-center. The 1st preamp tube is the one all of the way to the right.

"It's better to wear out than to rust out!"
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"You guys are pros..."

 

Why, yes - yes, we are pros...

 

I'm afraid I can't help much; my advice would be to jack up the Classic 30 and put a Fender Deluxe under it :D . Not a big fan of Peavey amps, unfortunately. But it sounds like others are getting you on the right track and who knows? the kinds of mods people are suggesting might make the Classic 30 a little more pleasing to my ears. That's be great, because I'm a big fan of Peavey, well-built, AMERICAN-built products.

 

Let us know how you get on.

 

 

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