Lovetone - Brown Source  [traced]

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Postby gus » 06 Oct 2007, 21:40

Tone control is a BM type control with switchable parts.

Funny posts here. First like a few effects the BS works well with some players and guitars and amps and speakers. Think of it as a buffered IC based RM with a cool tone control at the end.

Some effects I think of as more as an added gain stage for an amp than as an effect.
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Postby Jim777 » 06 Oct 2007, 23:04

If I have this right the 470n cap and 220 ohm R will start cutting bass from 1.5 khz. The treble cut at max gain will be from 185hz :shock:
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Postby DougH » 07 Oct 2007, 13:29

Jim777 wrote:If I have this right the 470n cap and 220 ohm R will start cutting bass from 1.5 khz. The treble cut at max gain will be from 185hz :shock:


Thanks, finally someone willing to do some work.

Your HPF calculation is off by a decimal point. It's a 15kHz HPF and 185Hz LPF.

So what affect is this going to have?

Anyone have an idea?
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Postby Jim777 » 07 Oct 2007, 18:33

Tried it again and still got 1.5khz. I'm assuming 470n is the correct value? On Analogguru's schem he has 47n which gives 15khz. What I think it will do is give max gain half way between the two at approx 650hz falling off at 6db/octave either side. However, because the cut is quite severe it's going to reduce gain a fair bit. Max gain from that clipping stage looks like around 120 but actual gain will be alot less.
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Postby Bernardduur » 08 Oct 2007, 14:53

Just build this little thing and is sound pretty nice; can't really test it out as my switch is popping but when that is cured the thing will do just fine

The only downside I can hear now is that it has a lot of low end / bass which muddies up my sound..... now I need to crank my treble control
'No more....... loud music.......'
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Postby DougH » 09 Oct 2007, 16:10

Jim777 wrote:Tried it again and still got 1.5khz. I'm assuming 470n is the correct value? On Analogguru's schem he has 47n which gives 15khz. What I think it will do is give max gain half way between the two at approx 650hz falling off at 6db/octave either side. However, because the cut is quite severe it's going to reduce gain a fair bit. Max gain from that clipping stage looks like around 120 but actual gain will be alot less.


You are right. I accidently used the 47n value which I believe was a typo (and sounded terrible IIRC).

Yes the full passband gain of this thing should be 26k/220 = 118 if the HPF and LPF were designed "correctly". The actual gain will be a lot less due to the HPF/LPF curves crisscrossing and attenuating the signal from the potential maxium passband gain.

When I was experimenting with it on the breadboard, I redesigned it at one point with the HPF Fc < LPF Fc and to have approximately the same actual gain and freq response. It sounded different. The BS tuning sounded "warmer". IIRC, when I ran some sims, the shape of the freq curves between the 2 types of tuning were different. I don't remember all the details.

I don't know if this was a happy accident as the result of sloppy design, or if it was completely intentional from the beginning. It does make a nice "amp input stage" as Gus mentioned, similar to the way a Rangemaster works. You can get some nice sounds out of it. My only complaint is I've had difficulty dialing it in for both my neck and bridge pickups. When I dial it in to sound good with the bridge pickup, it can sound a little muddy with the neck pickup, etc.
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Postby MoreCowbell » 09 Oct 2007, 18:12

DougH wrote: My only complaint is I've had difficulty dialing it in for both my neck and bridge pickups. When I dial it in to sound good with the bridge pickup, it can sound a little muddy with the neck pickup, etc.



Make the high pass filter values switchable by footswitch...that way you can just stomp it when you change pickups. :)
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Postby DougH » 09 Oct 2007, 21:19

Yeah, I don't like switches, other than the bypass and my pickup selector... :D
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Postby MoreCowbell » 09 Oct 2007, 21:48

DougH wrote:Yeah, I don't like switches, other than the bypass and my pickup selector... :D



I like simplicity too (you've seen my circuits :) ) ...but i don't mind an extra stomper so long as its "useful". :D
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Postby Jim777 » 09 Oct 2007, 23:16

It would be interesting to know why it was designed like this. The other odd thing is the very low input impedance at 220 ohms. Maybe it was designed 'by ear'.
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Postby DougH » 11 Oct 2007, 14:07

Jim777 wrote:It would be interesting to know why it was designed like this. The other odd thing is the very low input impedance at 220 ohms. Maybe it was designed 'by ear'.


The 26k/220 sets the passband gain of the inverting op amp stage. Of course, that doesn't completely apply here since the passband is attenuated by the filter tuning.

Low Zin is really not that significant since the input is buffered. Not really sure why they used an inverting amplifier stage instead of non-inverting here though. The TL072 is high Zin and will not load a guitar pickup. (I "fixed" this in the ToneSource.) An inverting amplifier usually has a low Zin which requires a buffer, and if the series resistor is too high it will produce a lot of noise. In general, using an inverting amplifier as an input stage is a poor design choice IMO. With a high Zin FET op amp like a TL072, with a properly designed non-inv stage, there is no need for any additional buffering.

Speaking of the buffer- it's poorly designed too, with those big 1.2M resistors on the base. 1.2M from Vcc to base starves the base of current and will pull the base voltage down pretty low (<<4.5v). This may not be significant with a 100m-1v guitar signal but I'm not sure what the point is. Maybe it's a cheezy way of raising Zin (why not use a JFET buffer instead?). Maybe they claim the low bias of the base creates some "mojo" effect (doubtful, with a weak guitar signal). For an unnecessary piece of the circuit, it doesn't appear to be designed right either, IMO.

Anyway, these are just some of the problems I've found with this design. I still wonder if there's a method to the madness or if they just fell backassward into something that happened to sound good. It does sound pretty good, and the BMP tone control switching is a nice touch. But I'm not following the plot as far any coherent, thought-out design work is concerned. Looks like it is from the "keep adding parts until it sounds good" school of design, to me, which is unfortunately the process many pedal "booteekers" and "tone gurus" seem to follow...
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Re: Lovetone - Brown Source

Postby ryanuk » 21 Oct 2009, 20:09

Been tasked by a buddy to put a "brown source" clone together.

THere seems to be a lot of debate on this forum (and others) regarding the validity of the schematics. DOes anyone have some shots of the pcb tracks that they can post??

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Re: Lovetone - Brown Source

Postby DougH » 22 Oct 2009, 14:16

ryanuk wrote:Been tasked by a buddy to put a "brown source" clone together.

THere seems to be a lot of debate on this forum (and others) regarding the validity of the schematics. DOes anyone have some shots of the pcb tracks that they can post??

RyUK


At this point I assume the traced schematics are all correct, as they have been pretty consistent.

The question of whether it is a competent electronic design is another story. One of the issues I will always have with this is taking the output off of the "-" pin of the second op amp stage instead of the output pin. There is no reason to do that. This makes that op amp stage completely unnecessary as it will have no effect on the signal. It reinforces my opinion that this is a sloppy design that was easter-egged until it sounded good.
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Re: Lovetone - Brown Source

Postby sonicvi » 22 Oct 2009, 15:40

DougH wrote:
ryanuk wrote:Been tasked by a buddy to put a "brown source" clone together.

THere seems to be a lot of debate on this forum (and others) regarding the validity of the schematics. DOes anyone have some shots of the pcb tracks that they can post??

RyUK


At this point I assume the traced schematics are all correct, as they have been pretty consistent.

The question of whether it is a competent electronic design is another story. One of the issues I will always have with this is taking the output off of the "-" pin of the second op amp stage instead of the output pin. There is no reason to do that. This makes that op amp stage completely unnecessary as it will have no effect on the signal. It reinforces my opinion that this is a sloppy design that was easter-egged until it sounded good.


as long as it sounds good...
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Re: Lovetone - Brown Source

Postby ryanuk » 22 Oct 2009, 22:32

DougH wrote:
ryanuk wrote:Been tasked by a buddy to put a "brown source" clone together.

THere seems to be a lot of debate on this forum (and others) regarding the validity of the schematics. DOes anyone have some shots of the pcb tracks that they can post??

RyUK


At this point I assume the traced schematics are all correct, as they have been pretty consistent.

The question of whether it is a competent electronic design is another story. One of the issues I will always have with this is taking the output off of the "-" pin of the second op amp stage instead of the output pin. There is no reason to do that. This makes that op amp stage completely unnecessary as it will have no effect on the signal. It reinforces my opinion that this is a sloppy design that was easter-egged until it sounded good.


DougH - Cant comment on the sound - never tried one!! Although samples are interesting. This build is for a pal who refuses to pay the VERY HIGH market prices.

I've crossed referenced the schems (linked within this thread) and have found inconsistencies within the tone switching circuit and with the final op amp stage. The values are more/less consistent through. A good pic of the traces would help - that way I could create my own schem and layout - I would share of course!!!

The is a gut shot on ebay at the mo - but resolution is too poor.

Can anybody help me out?
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Re: Lovetone - Brown Source

Postby John Lyons » 23 Oct 2009, 15:11

Do a search over at DIYstompboxes.com All this has been gone over.
The sound clip on lovetone's site is through a distorted amp.
The real brown source is not anywhere near as distorted.
The BS is a booster with a little grit, nothing more as the clip
would lead you to believe.
When I built it I was highly dissapointed.
Build doug's Tone Source.
It works better... you can find it over there as well (gallery).
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Re: Lovetone - Brown Source

Postby sonicvi » 23 Oct 2009, 15:29

John Lyons wrote:When I built it I was highly dissapointed.


Same here, low gain, not much volume boost. For what it does there are a lot better pedals to build.
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Re: Lovetone - Brown Source

Postby ryanuk » 23 Oct 2009, 19:20

thanks to John Lyons and sonicvi,

I appreciate your thoughts and opinions but my bud is dead keen on a brown source.

I scoured DIYstompboxes for alternative schems, layouts and pics - no joy.

I may be at a dead end if I cant verify any of the schems :(

Well - if anyone has any pics then great - please post them if you read this!! If not then I'll suggest he identifies something similar.
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Re: Lovetone - Brown Source

Postby DougH » 26 Oct 2009, 16:19

One of the guys who traced it at diystomp swore up and down it was 100% accurate. There were pics of the pcb and etc at the time. You'll have to search the threads over there and decide for yourself. Whatever "variation" you build is going to be fairly similar with the others, except for the "twank" setting I added to mine that was a sub for the "bypass" setting.

I just build stuff to suit myself. If it sounds good and I like it I'm done. I don't have much interest in building duplicates or clones of stuff. So I can't help you much more with the "accuracy". I look at the BS like a Rangemaster with a fancy tone control. Through a distorted amp or an amp that breaks up easily with a little push, it sounds good and the tone control is a lot of fun. Through a clean amp it's pretty ho-hum. Like John, I believe the BS clips at the Lovetone site are through a distorted amp. They have to be. Because it just doesn't sound like that by itself. (IIRC that clip also has a wah which confuses the issue even more.)
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Re: Lovetone - Brown Source

Postby ryanuk » 26 Oct 2009, 17:06

DougH wrote:One of the guys who traced it at diystomp swore up and down it was 100% accurate. There were pics of the pcb and etc at the time. You'll have to search the threads over there and decide for yourself.


Yeah - I have the PCB and schematic for the version which is generally considered correct. Interesting that there are 2 variations of this schmematic - the author made a change to the tone circuit.

For info - I now have detailled pics of the brown source PCB. I confirm that the latter schematic is correct. However, this still doesnt help me out with the values which differ to the schematics produced by Analogguru and yourself, DougH. I guess where differences lie I'll go with the majority or socket those caps and try different values.

DougH wrote:I just build stuff to suit myself. If it sounds good and I like it I'm done. I don't have much interest in building duplicates or clones of stuff. So I can't help you much more with the "accuracy". I look at the BS like a Rangemaster with a fancy tone control. Through a distorted amp or an amp that breaks up easily with a little push, it sounds good and the tone control is a lot of fun. Through a clean amp it's pretty ho-hum. Like John, I believe the BS clips at the Lovetone site are through a distorted amp. They have to be. Because it just doesn't sound like that by itself. (IIRC that clip also has a wah which confuses the issue even more.)


I agree - normally I build stuff that suits what I want musically. A lot of projects dont capture my interest especially as many pedals appear to be closely based upon others.
However this build is for a good pal who wants a brown source. No comment on sound cause I've never played one, but he has played one and loves it. I heard that you either love or hate the brown source. I guess I'll find out soon enough.
When i spoke of sound samples - I didnt mean the one the lovetone site which I have not heard until today. I agree that particular clip, the brown source is driving an overdriven amp. Yes, there is a wah sound also which I attribute to a meatball.
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