Taming bass notes on 5E7 Bandmaster

[POWDOG]

Hi folks. I built a 5E7 Tweed Bandmaster for a jazz guitar player. He loves it but says that the bass notes over power the high notes. He is plugging into the Low input on the Normal channel and has the Bass all the way up. The three bass strings overpower the three high strings. He wants me to tweak the amp so all strings have the same volume or presence. Any ideas? The amp is stock with 0.02 and 0.1 uF coupling caps and the bank of 16uF filter caps. I sure appreciate any help on where to start. Thanks.

[martin manning]

What about his guitar? Is the pickup height (base-treble) set correctly?

[POWDOG]

Pretty sure he has it set right. Experienced player, been playing same guitar thru a couple other amps.

[JazzGuitarGimp]

I don't understand. One the one hand, you say he's an experienced player, and on the other hand, he has the bass controll all the way up, and he's complaining about too much bass? Couldn't he simply turn the bass control down, or am I missing something?

[mr_hankey]

Those 25uF cathode bypass caps are too big in most cases. Try putting in one or two 5uF or 10uFs.

[Roe]

Hi folks. I built a 5E7 Tweed Bandmaster for a jazz guitar player. He loves it but says that the bass notes over power the high notes. He is plugging into the Low input on the Normal channel and has the Bass all the way up. The three bass strings overpower the three high strings. He wants me to tweak the amp so all strings have the same volume or presence. Any ideas? The amp is stock with 0.02 and 0.1 uF coupling caps and the bank of 16uF filter caps. I sure appreciate any help on where to start. Thanks.

1 turn down the bass
2 use the bright channel with bright caps ala marshall
3 reduce coupling caps after v1 to 6n8 and 22-33nf in PI. reduce PI input cap to 1nf like a BF fender

[skeezbo]

He is concerned about the tonal balance, not the farty looseness in the bass that these amps often have, right? Is his guitar a hollowbody with only a neck pickup? Those are pretty boomy anyway.
I remember the jazz guys from Berklee (I worked at a music shop around the corner); they would always start at 10 on the bass when dialing in the twin reverbs and Polytone mini brutes. It seemed strange, but they got the sound they wanted, and it sounded right once they got it. Those amps are very different, of course, from your customer's 5e7.
If you can't get the owner to simply back off the bass, try a large grid stop resistor on the inverter (this tightened up the bass considerably on my tweed super which has the same inverter). Another choice might be a smaller bypass cap on the first gain stage.
In my opinion, the 5e7 is a great blues amp. Are you facing a never-ending battle to try to make it fit the jazz player's needs?
Good luck!
Skeez

[billyz]

Replace the PI entrance coupling cap with a 500pf .

[POWDOG]

My player is associated with the Berkley School (San Francisco, not Boston) and plays a pretty exotic solid body guitar with the slanted frets. And it is the balance of the high and low strings he's interested in. I have a pair of alnico Webers in the amp, and it doesnt have the usual flabby farty problems. And I agree that the Bright channel Hi input with the Volume up really does scream bluesy rock and roll, but overall its not really gainy. Thats the reason that I put this particular amp in front of a jazz guy. With it biased dead center and a 12AY7 in V1, it has a nice amount of clean headroom, not at all like the Tweed Supers and Pros I've built before. Do you remember the value of the PI grid stopper you used on your Super? I really dont think it will take a whole lot of tweaking to make my guy happy. Thanks alot guys for the help.

[alvarezh]

The first thing I do with some players is educate them a little on amp design. Most players think that tone stacks are all the same because the controls operate in the same manner.

I have a friend of mine that loves the mid frequencies, therefore to any amp he plugs into he zeroes the treble and the bass controls and places the mid on 5 or 6. That could work fairly well on a scooped mid tone stack, but they are not all scooped (Dumble skyline stack).They learn to use that setting on an amp and they think it's going to work on all.

SKEEZBO: The looser sound on the bass is probably mostly the result of such a low filtering on the PS.

Try to educate the player before worming up the gun.

All the best.

[billyz]

I have a Jazz guy who is also from the Berkley school he has a masters in Music education and plays the big box jazz guitars. plays Twins and Polytones.

Like I said the entrance cap to the pi should be changed to 500pf .

[skeezbo]

POWDOG,
I started with a 500k grid stopper. I liked it but thought the amp began sounding a little too much like my long tailed pair Fenders. I tried 100k, but that didn't seem to do enough, so I went up another 100K.
My amp has some other mods: no negative feedback and a TMB tone stack, so your mileage may vary. I think you can safely go as high as 1M if that takes you where you need to go.
Skeezbo

[Firestorm]

Those are tough tone controls to dial in for jazz. The bass control is a mid/treble cut; the treble control is high pass at one end and high cut at the other, but the pass frequencies look like they skew high so probably won't help balance the sound except in higher registers. You could try what Billy said and cut the overall bass, which your guy may or may not like; you could try boosting the treble cap from 250p to 500p to pass more mids. Or do the obvious thing and have him put a graphic eq pedal in front of the amp.

[skeezbo]

I think firestorm has it: the tone stack! I called it up on the Duncan Tone Stack Calculator. The bass does need to be on 10 to simulate a standard graphic sweep, and the treble has a significant boost between 8.5 and 10. I think this is the problem: the mid dip is very steep and is centered on 1k, an octave higher than a twin reverb. This would make the low mids seem very pronounced. This boosted range is probably an octave higher than the fundamentals of the E and A strings open, but it would be more pronounced as you work up the neck. A 500p treble cap in place of the 250p (as firestorm suggested)slides the dip down into tweed bassman territory, a 1n looks more like the blkface dip which would lessen the perceived boost on the wound strings.
Even modded, the stack has very little control, however. The bass needs to stay on 10; the treble looks too bright at 10 but off below 7. I would try one of those treble cap swaps and see if it takes you in the right direction. An increase in the bass cap deepens the mid dip, too. 10n in place of the 5n seems like as much as you could want.
You might get lucky with these swaps, but If your customer wants tone controls that really work, you may need a more modern tonestack.
Skeezbop

[POWDOG]

Thanks guys. This really helps a lot. Short of building a different tone stack, I'm pretty sure this will get me into nirvana territory. I really appreciate all of your expertise.