I'm new to the harmonica, but I've been playing for a few months and would like to start playing amplified.
I've got a Peavey Classic 20 amp that I used to use for my guitar, but am going to try out as a harp amp. It needs new tubes though, and I'm wondering if there are tubes that I should get that might be more conducive to harp amplification. A few different websites I've read discuss tube options, but they are all geared toward guitar.
Does anybody have any thoughts? Are there other ways that might make the amp more harp-friendly?
Last Edited by PM42 on Jun 02, 2013 2:48 PM
You'll find all kinds of info if you do a search with something like "tubes harp (harmonica) amplifiers". I'm no tech guy but basically pre-amp tube swaps for harp are very popular and common. Most guitar amps use a 12AX7 in V1, that is the tube farthest to the left as you look at the amp from behind. To make the amp more harp friendly swapping out that tube for a 12AT7, 12Ay7, or 12au7 reduces the gain and helps with reducing feedback from the harp mic.
It's easy to find info on the web as to how much gain is reduced by each of these tubes. Do the research and educate yourself. Then experiment and find out what works for your amp, mic, and what you're trying to accomplish. Also be aware that different brands of tubes will sound different even of the same type. I'm a big fan of New Old Stock (NOS) vintage tubes from RCA, Amprex and Telefunken. Contemporary tubes don't do it for me so much with the exception of JJs.
Tube swaps are not a silver bullet but it's where everybody starts. ---------- LSC
As much of a Peavey fan that I am, the sad truth is that it can be very difficult to get a Peavey amp to an ideal configuration for harp. The Classic series tends to be very clean sounding by nature. The only Classic I've had good results with in its stock form is the Delta Blues...but there ARE ways to coax them into being pretty decent harp amps once you learn your way around them.
In terms of replacement tubes for it, you might as well just get the original value tubes. I believe it uses a pair of 12AX7's and a pair of EL84's, similar to the Fender Pro Junior. As LSC pointed out, you could try something like a 12AY7 or a 5751 in the first preamp socket to reduce gain a bit if you find it too harsh with AX7's. The Classic 20 has a boost switch. Steer clear of it. Just the like the dreaded "FAT" switch on the Fender Blues Junior, it'll send the gain through the roof and put you on a train for Feedback City.
In terms of tube brands, I agree with LSC. NOS tubes are the best you can get. But they tend to be pricey. You prolly wouldn't go wrong with a set of Peavey tubes for it and keep it as original as possible. Peavey tubes are just rebadged JJ's, which are good quality.
Getting a favorable harp tone out of it will be your biggest challenge. Your technique is a key factor. What kind of mic do you use?....how's your cupping?....do you pucker or tongue block?....etc. You might consider an effect pedal to condition the signal first. Check out the Lone Wolf Blues Company pedals. They're golden, and they are a fine remedy fo a lot of amps with less than desirable harp capabilities.
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Hawkeye Kane
Last Edited by HawkeyeKane on Jun 03, 2013 10:25 AM
Minor correction - V1 is usually closest to the side of the amp - it is connected to the input jack. I prefer lowering the gain by swapping out V2 (and V3 if its there) FIRST - leave a 12AX7 in V1. And to make an appreciable difference you can certainly go down even further - I would recommend a 12AU7. At least that way you'll really be able to tell the difference and you can go up from there if you don't like it. But you will..... Remember, lowering the gain doesn't reduce maximum available power - it simply adds more "gas pedal travel" - making the amp easier to control and allowing you to approach closer to the feedback threshold without getting bitten. ---------- ---------- /Greg
Modding high gain guitar amps for harp is always a compromise. But I think it is worth a try. Start with reducing the gain by swapping tubes, as has already been mentioned. If that gets the amp going in the right direction then a speaker swap might get you even closer to your goal.
Tinkering with amps is fun, and you will learn a lot about what makes a good harp amp. But be ready to abandon the project early if it does not show promise. You can waste a lot of money doing this.
Remember, first you have to know what to listen for. It is hard for new players because you often don't have a frame of reference. Have you ever played through a "good" harp amp that you can compare it to? That will help a lot.
Most of the Peavey's sound awful for harp, switch all the tubes you want. That said, I was convinced enough to buy one of my own and I have all of $150 in it -and it's as loud as most 4-10"s. Peavey VK12
I've also got a Fender Princeton Plus 112, which is a solid state. I just assumed the tube amp would be a better harp option, but maybe not? Any thoughts on the usefulness of the Fender for harp?
I suppose I should just fire them both up and see which sounds better.
I've never heard harp through a Princeton 112 before. But it could have its uses. There are a few Fender solid states that many find pretty decent for harp. The smaller Frontmans, the Mustang modellers, and the Rivera-era Yale Reverb to name a few. Give it a whirl, mess around with the settings, let us know what happens! ----------
@LSC: No. On Fender amps, the tube designated is closest to the side of the amp. V1 refers to the "first tube in the signal chain." Because the input jacks are usually mounted at at one end of the chassis, and the signal goes straight from there to V1, V1 is most likely going to be the outside tube on any amp. ---------- ---------- /Greg
