Dedicated harp amp
Ok, so I have considered using my guitar Amps for harp but none of them sound great and by the time I’ve paid out to get one of them modded up for harp, with no guaranteed results for good tone, I think it wise to buy a dedicated harp amp, but which one?
i plan to gig eventually and so want an amp which will do this. I am thinking HarpGear hp50?
or at a more affordable level lone wolf harptrain 40?
advice is very much welcomed.
Yes I have but he has only reviewed small amps and a few mid sized. I was thinking more of 4x10” cabs
I think I’ll go for the lone wolf harp train 40
Just remember that any 4x10 cab is going to be loud, and unless you're playing in a large venue you may not get as much use out of it as you'd like. The Lone Wolf is 40 Watts, so that's not incredibly powerful, and it uses gain switching to improve the grit at lower volumes.
You can actually do this on any amp and it's a fairly simple mod. I've been putting a voicing switch on many of my non-vintage amps and a couple that I purpose-built. The mod is pretty straight-forward. You would place a two- or three-way switch on the cathode of the first stage of the preamp tube with a couple of cap selections -- usually none, 25uF, and .47uF. I've seen some also use a 1uF and .68uF in place of the .47uF cap, too, for an even different and more agressive voicing on that side of the switch. The circuit looks like this:
As an example, here is a Princeton amp schematic with the area you are working with highlighted. Most classic amp preamp tube stages have this configuration:
So with a three-way switch as above, you could choose no cap (straight across the 1.5K resistor) for a clean -- VERY clean -- sound, .47uF, or 25uF (for most modern amps, 25uF is the default cap for the preamp cathode). The voicing for this circuit has been described as "Blackface-style shimmer and twang, to fat tweedy raunch, to bright plexi-like crunch". So it's like having three amps in one. I really love using this on my amps, and it definitely gives you some dirt options at lower volumes.
I would bet that the Lone Wolf has something like this going on. You could modify your Blues Jr. with such a circuit, too (I wouldn't touch the Selmer).
Thanks for your advice. The cheapest and most sensible option sounds like modding the jnr.
It certainly can't hurt to try. And at 10 bucks it's a whole lot cheaper than a $495 head plus a $390 4x10 cab.
It might even turn the Jr. into a decent amp, who knows? And at 15 Watts, it'll be a little more of a crowd and club manager pleaser for smaller venues, and you can always mic it into the PA for larger crowds.
I haven't tried this mod on a Jr., so I'd be interested to hear how you think it sounds when you do.
You'll only need three parts for this. They can be ordered from Mouser. You can repurpose the existing 25uF cap if you can unsolder it without damage. The components you'd need would be:
- (1) Toggle Switch SPDT ON-OFF-ON P/N 633-M201304
- (1) .47uF 100VDC 150M Mallory Capacitor P/N 539-150474K100DC
- (1) 25uF 150VDC Vishay/Sprague Electrolytic Capacitor P/N TVA1411-E3
Personally, I'd disconnect the entire Fat switch circuit and replace it with the above. You could leave the Fat circuit on the board and reconnect it if you found you liked it better. You'd also need to find a place to drill and mount the switch.
A word of caution: AMP VOLTAGES CAN KILL YOU!!! Make certain you are comfortable working inside the amp and that you know how to discharge the filter capacitors before mucking around with the circuit. One should also familiarize themselves with the inner workings of the preamp circuit to ensure you understand how the circuit functions and what the changes to it will do. A good resource for this is a book by a fellow redcoat Merlin Blencowe titled "Designing Tube Preamps for Guitar and Bass". You can find his excellent and informative website at:
And a good introductory chapter to tube theory and operation at:
http://www.valvewizard.co.uk/Common_Gain_Stage.pdf
Also remember, messing around with your amp circuit if you aren't fully familiar with how it functions can cause it to fail. Unless you are already properly trained, please learn more about what you're doing than my little thumbnail sketch here. Keep in mind that there are amp techs out there who can help you with this if you want some assistance.
Scorny, a little more detail about modding the Blues Jr. above.
You can find the schematic for the Blues Jr. here:
https://schematicheaven.net/fenderamps/blues_jr.pdf
If you look at that schematic, the Fat switch portion of the circuit is here highlighted in red:
To try the voicing switch mod, I would cut the trace on the PCB between the R4 and C3 connection and between R4 and the Q1 JFET connection. I would leave the entire circuit in place on the board so that you could reconnect the traces and go back to the original Fat switch configuration if you find the mod isn't what you want. You would connect your switch mod to the top of R4 between it and pin 8 of V1-B. If you like the mod, a good place to mount the switch would be where the current Fat footswitch jack is located on the underside of the chassis on the back of the amp (you would remove the jack of course). You may have to drill the hole a little larger to accomodate the .450" diameter switch bushing.
Again, I have not yet tried this on a Blues Jr., but I can't see why it wouldn't work. You should have a qualified amp tech review this and comment further before starting. Also, I just want to reiterate my cautions above and also be aware that this would definitely void any existing warranties on the amp.
Good luck with this! Let me know if you do it how you like it.
My god you know your onions. i reLly appreciate your comments and advice. I will let the tech guy that I found do the modding, he’s going to put a lead out point on it so that I can connect it to the pa and use the amp as a monitor which is useful. He has modded around 50 of these now. He is a harp player and I guess also knows what he’s doing.
his link is
I am not electrical savvy to attempt it myself as I would prefer to live longer than the 51 yrs I have so far clocked up.
ill certainly look at the links you gave me as it’s always useful to know how and why something works .
cheers
Living longer is always a good thing! LOL!
I didn't know much about this stuff either, but back in the day, when I took my amp to my tech he would always tell me: "I can get it back to you in a month." To which I would reply: "You do know we have a big show next week, right???" Then he would bitch me out and tell me I wouldn't need my amps repaired so often if I didn't kick and abuse them so much. From there the conversation generally went downhill and I decided if I wanted it done, I'd have to do it myself. Now it's become a bit of a hobby, and I've even begun building some boutique amps for my friends. And yes, I've had a few hair-raising moments from touching the wrong part of the inside of an amp. If you survive, it'll make you pretty squirrelly for a while for sure.
Good luck with your amp search and mod experience. Glad I could help!
Have you reviewed Davids section on Amp reviews in the equipment section?