Brown Source comparison through two differnt amps.

[John Lyons]

I made a couple sound clips of the Brown source I made through two different amps. The differences are pretty stark!

Amp #1 Fender bassman converted to marshall type preamp. Slightly distorted.
http://www.mrdwab.com/john/BrownSourcemarshall.mp3


Amp#2 Fender Twin Reverb set very clean.
http://www.mrdwab.com/john/BrownsourseTwinR.mp3
The picking chords at the end of the clip demonstrates the fizzle on top of soft picked notes.

Les Paul Copy HB set to bridge.
Through my strat it sounds good as well. (with the marshall that is)

Yikes!

I tried a  50KB  pot in place of 25kB. Didn't get any more noticable gain but made the circuit motorboat. I added more power supply filtering but that didn't do anything. Must be another problem. Any Ideas? Maybe I'll just go back to the 25k pot.

Here the PDF of the PCB and shcematic from Nelson
http://www.esnips.com/web/nelsonsOtherStuff

John

[John Lyons]

No one?
Bumpsky!

[burnt fingers]

Sounds about right to me.  I borrowed my friends cheese source a few months back and that's what it sounded like pretty much.

I rather liked it for good ol' crunchy rock stuff.

SCott

[MartyMart]

That sounds about the same as mine, on one particular setting of the cap switch
and tone pot.
There's a lot more "beefier" tones available though !
One setting with tone pot set to full bass can motorboat on mine also, but it's
only one EXTREME setting
I also have a 50k gain pot, so backing off slightly cures that problem, probably worth
me putting a 47k r across 1 & 3 to halve it ..... but IMO it's not a great circuit, I had
to reconnect jacks/batt clip and vol pot just to hear it again !!!  ( stolen ! )

MM.

[John Lyons]

After building this I was under whelmed on the whole.
I normally play through a blackface Fender Twin Reverb which is a very clean and full amp.
The Brown Source sounds a bit grainy and doesn't have much boost or gain with a totally clean amp.
I tried it through my marshall style homebrew amp and it sounds much better.
The amp has mainly over driven tones with very little true clean tones.
The brown source pushes out gain and compliments this amp much better.



I built this one into a 125 year old piece of American Chestnut salvaged from a farm house.

Here are a couple more clips.
http://www.mrdwab.com/john/Lovetonesolo.mp3

http://www/mrdwab.com/john/lovetonemaxgain.mp3

Mods etc: The only really deviation from the schematic I did is to cut a trace and connect the output cap directly to Pin 1 of the opamp.
I cut the trace on the board from pin 2 and put in a jumper on the bottom of the board from the negative pin of the 4.7uf output cap to pin 1 of the IC.
I tried to raise the 25K gain pot to 50K but I got low end motorboating and no real increase in gain.

All in all I would recommend this only for pushing a mild overdriven tube amp or along with another overdrive,fuzz or booster.
For use alone with a clean amp it's not very good.

[Doug_H]

That's a nice looking pedal, John. I like the sound of it too, esp through the dirty amp. Sounds very "woody" (no pun intended, seriously). I did some sims and I agree that taking the output off the output pin makes more sense than off the junction of the 22k/3.9k. It shouldn't change the sound much, if any, and you should get about 15db more of gain. Gus has been talking about this one for years; I should give it a try on the breadboard.

[MartyMart]

Nice box John ( still have one to drill ! )
For some reason, I had mine wired correctly from  the output pin, so have always had
a decent boost from it.
I scrapped it and stole the parts for an Ibanez 855OD !
Perhaps I'll give it another go, as I have a PCB now and mine was a bit of a "Frankenstein" mess
after all my "fiddling" !

MM,

[John Lyons]

Ok, get this...

I usually record with a Shure SM57, EV RE20 or a SM58 into a tube mic preamp to a Pro standalone CD recorder. For some reason the CD recorder is having problems so I have been using the Mic Preamp straight into the computer through a USB converter. Well I was thinking that it sounded off and just confifrmed that the USB input I have been using is way off!!

I played a CD through the connection and there was no bass or high end sparkle!!!!!! No wonder the Brown sourse samples sounded a bit dull and not a lot of low end. I'll have to re record those now so you can hear them the way they really sound through the amp.
The amps actuall sound is much fuller and crisp.

Here's a clip I just cobbled up a good soundcard http://www.mrdwab.com/john/BrownSourcegood.mp3

[Doug_H]

Wow, that sounds really great, John! I will definitely have to try this one.

The first few clips I recorded sounded horrible because I had something set up wrong on the soundcard (a "mic" vs. "line" thing IIRC). Amazing what a difference it makes when you get it all working.

Oh, I almost forgot to mention...

If you are looking for more gain out of this thing, play with the 470n cap on the "-" input of the first op amp stage. That inverting gain stg is very sensitive to that cap value and increasing it will increase the overall gain in the lower mid freqs. Now, it may turn it into a fuzz box, but it's probably worth investigating. You could revoice it for more highs by using a smaller cap in the feedback loop too.

EDIT: I just tried this in the sim and it looks pretty good- try a 4.7u in place of the 470n input cap and a 6.8n in place of the 33n in the feedback loop. This should give you roughly a 15db boost over the whole freq spectrum. It may introduce other stuff into the distortion and not sound as good but it gives you an idea to play with if you want more gain.

[John Lyons]

Doug
When I was trying somethings a couple weeks ago I did try to change out the .47 cap for a smaller value and the gain went away. I didn't think to increase the value but it does make sence, just didn't think of it. (One schematic called for a .047 so that was my initial inspiration to try somethig different)
Good observations. The .03 in the feedback loop is quite a moster as far they usually go. That value should really be digging into the highs and mids as well. I'll try these things and see what I come up with. There is a little grittyness to the sound but a small cap here or there would probably knock that down a bit, maybe a matter or diode choice? I tried LEDs and Jfets but with that .03 cap in the loop it really cuts a lot out from the clipping section.

By the way, thanks for the kind words on the box Doug and Marty. I spend a lot of time on them.

John

[Doug_H]

The .03 in the feedback loop is quite a moster as far they usually go. That value should really be digging into the highs and mids as well.

It does seem big however remember that a tube screamer has that big honking .22u shunting from the op amp output to ground (or Vr) and it sounds right. There are so many variables...

I'll try these things and see what I come up with. There is a little grittyness to the sound but a small cap here or there would probably knock that down a bit, maybe a matter or diode choice?

If it sounds too harsh, try increasing the .033u shunt on the output first.

By the way, thanks for the kind words on the box Doug and Marty. I spend a lot of time on them.

Your boxes look great!

[John Lyons]

Doug

Which .03 are you refering to?
The cap on the selector to ground from the level control?
That's only active for the two middle spot on the selector switch... Although that would be good to have the option with the selector...

If I jumper pins 1 and 3 without that 22K will this give me more level? Seems I have to dime the level control with a slightly distorted amp. I could try a 100k pot and see If I get anything more.

[Doug_H]

Doug

Which .03 are you refering to?
The cap on the selector to ground from the level control?

That's the one.

If I jumper pins 1 and 3 without that 22K will this give me more level? Seems I have to dime the level control with a slightly distorted amp. I could try a 100k pot and see If I get anything more.

Make the 22k larger or the 3.9k smaller for more gain from the output stage.

http://www.tpub.com/content/neets/14180/css/14180_112.htm

Check the next page too for the gain equation for a non-inverting amplifier.

The inverting amplifier (like the brown source 1st stg) is covered a few pages back in the tutorial.

[John Lyons]

oh, ok. I wasn't looking at that as a voltage divider but it sure is, a divider in the feedback loop that is, less resistance = less gain for that 22K ...

[Doug_H]

I tried this on the breadboard yesterday and here's a few observations:

Overall I think the loveclone schematic sounds pretty decent. .47u for the input into the gain stage sounds good. With .047 there was no gain (and it attenuated) and 4.7u sounded flubby.

The 220/.033u LPF on the output doesn't do anything and serves no purpose that I can see. Fc is around 21khz, out of the audio range. It's not needed to kill oscillation either esp since the 1st stage inverts the signal. So that's the first thing I would omit.

The .033u in the feedback loop of the 1st stg is very high and adds an "old school honk" to the sound, which I suspect was intentional. If you lower that you can get more harmonics. I tried it with .01u and .0068u. If your amp is forgiving this might be a worthwhile simple mod. I tried this with a trainwreck liverpool derived prototype I have on the bench which is a very pedal-friendly amp and this sounded good. With my octal fatness, which is not as pedal friendly, it was kind of "edgey". Both amps were set clean. I suppose you could compensate by putting a useful LPF on the output but I didn't mess with that.

Re. the rotary switch (from bottom to top on the loveclone schem): The "bypass" postion sounded good. Lots of gain as you can hear it driving the output stage. The 2nd position that puts the 33n in parallel with the other 33n in the tone control made a negligible effect on the sound. Didn't hear much use for that. The 3rd position which puts the 220n in parallel sounds good as it adds more bass and keeps it from getting thin when you turn the tone to the treble side. The 4th position was a good basic kind of overdrive sound. One thing I noticed with pos'n 2 and 4 is that if you lowered the tone control to the bass side you got a lot more gain out of the circuit.

When I first wired this up I made a mistake and put the 220n in parallel with the other 33n (the shunt) in the tone control. This gives it a real "Keith Richards" sound, very midrangey and sweet, esp with the tone set to 50% or lower. It makes a real nice rhythm sound. This sounded real useful to me so I would wire the 2nd pos'n for that instead. I would also use the bottom pole for switching the feedback resistor in the 1st stg from 33n to 10n for this setting, instead of the useless LPF. This gives it a nice chime.

Taking the output off pin 1 of the output stg gives a good boost and if you set the tone control to the treble side in pos'n 3 or 4 it makes a nice treble booster.

This is what I would do with it. I've got a box and rotary switch that would work and I may build this up with some odds & ends parts I have lying around. It's not a high gain screamer, but you can get a lot of different sounds out of it if you play with the controls enough.

[MartyMart]

Doug, thanks for those observations ... MUCH appreciated and will inspire me to rebuild
one ... and get it right this time !
I have a PCB ( thanks Paul ) so it will be much "neater"

Marty.

[Eric H]

The "bypass" postion sounded good.

I already have a couple pedals that have that position covered.

-Eric

[Doug_H]

I already have a couple pedals that have that position covered.

-Eric

Hehe! Yeah, but is it "true"?

FWIW I made a typo in my previous post:

One thing I noticed with pos'n 2 and 4 is that if you lowered the tone control to the bass side you got a lot more gain out of the circuit.

That's supposed to be "pos'n 3 and 4".

[Doug_H]

One more thing...

You don't need the input buffer. Just convert the 1st op amp stg from an inverting amplifier to a non-inverting amplifier and throw away the buffer. I don't see an advantage to inverting the signal in this circuit, esp since it is not high gain and prone to oscillation. I tried this last night on the breadboard with a tl072 and it works fine.

[Doug_H]

After building this I was under whelmed on the whole.
I normally play through a blackface Fender Twin Reverb which is a very clean and full amp.
The Brown Source sounds a bit grainy and doesn't have much boost or gain with a totally clean amp.
I tried it through my marshall style homebrew amp and it sounds much better.
The amp has mainly over driven tones with very little true clean tones.
The brown source pushes out gain and compliments this amp much better.

I think it helps to remember this (from the Lovetone site):

"Three classic ways to use the Brown Source with a guitar are for snap crackle and "pop" into a clean amp, dripping fat into a cooking amp and controlled feedback with singing harmonics into a driven amp."

So it sounds like yours is probably right on target, John.

I'm almost finished with my little twist on this circuit. Should have the box drilled tonight. I'll try to upload schem, pics, and maybe a clip or two when finished. BTW, the sound of mine on the breadboard pretty much agrees with the Lovetone description too. Sounds very good when the amp's got some dirt of its own.