Lovetone Brown Source

[Torchy]

Need a reliable schematic for this - especially the 3p4w switch.
Anyone ?

[cd]

Try a search with the addition of posts under my user name, me and someone else (whose name escapes me at the moment) decoded the proper switch wiring.  I even simulated the whole thing and it worked perfectly.  If I can dig up the corrected schem I'll post it, it should be floating around though since i posted it on imageshack.

[cd]

Nevermind, I found the file:

[bruce bennett]

I have those 3P4T switches By Lorlin.

If you need some.

[markusw]

I even simulated the whole thing and it worked perfectly.

I also did a simulation in LTspice but the drive pot did not appear to "work" unless I included a modification proposed by a guy in the german forum


:?:  :?:

Maybe I did something wrong with the simulations. However, it might be worth a try.

Markus

Edit:  also the second opamp does not have any influence on the waveform, also it does not alter the gain (if my simulations are correct). Any ideas what it is supposed to do?

[Torchy]

Thanks guys - lots to play around with

[cd]

I even simulated the whole thing and it worked perfectly.

I also did a simulation in LTspice but the drive pot did not appear to "work" unless I included a modification proposed by a guy in the german forum
:?:  :?:

Maybe I did something wrong with the simulations. However, it might be worth a try.

Markus

Edit:  also the second opamp does not have any influence on the waveform, also it does not alter the gain (if my simulations are correct). Any ideas what it is supposed to do?

Try it with the schem I posted above, I can't find the thread anymore but we picked apart the switch over a couple of days, so I know the switch is wired correctly.  The 2nd opamp just buffers the tone control, no gain necessary.  

I have to re-install Multisim, once I do that I'll simulate it and repost the waveform stuff.

[markusw]

With the tone switch everything seems make sense, it`s quite similar to the BC tone control. If the second opamp is supposed to be a output buffer then the simulations should be OK with this. However, I just can get the drive pot to "work" if I add the correction proposed by analogguru.

Would be great if you could post the waveforms.  

Markus

[cd]

However, I just can get the drive pot to "work" if I add the correction proposed by analogguru.

Would be great if you could post the waveforms.  

Markus

Yeah, there's a a reason for that - with the "mod" you've posted above, it's actually bypassing the gain control completely  No wonder the gain control doesn't work!

[markusw]

Yeah, there's a a reason for that - with the "mod" you've posted above, it's actually bypassing the gain control completely  No wonder the gain control doesn't work!

:? Confusion:  I meant the tone control pot does'nt work if i use the original drawing, it works pretty as supposed with with the mod included.

Markus

[ESPguitar]

What do this "thing" do???

:?

Robin

[cd]

Distortion pedal.  Sounds at www.lovetone.com.

[analogguru]

@cd
maybe you like to control the wiring of the switch again ?



analogguru

[cd]

With the tone switch everything seems make sense, it`s quite similar to the BC tone control. If the second opamp is supposed to be a output buffer then the simulations should be OK with this. However, I just can get the drive pot to "work" if I add the correction proposed by analogguru.

Would be great if you could post the waveforms.  

Markus

Here's the simulated waveform.  This is with the tone control in the middle with the switch in the "regular" (BMP style) position.  Left is max gain, right is minimum gain.

[RickL]

Great timing on this thread for me. I just finished up a Brown Source and I've been pulling my hair out trying to get it to work.

I just did the suggested mods to the gain and tone controls and it works better than it did but I still think there's a problem. The gain control now has an effect but I need to have the volume and gain maxed to get just over unity volume. I hear little if any tone changes when the tone switch is rotated and the tone pot doesn't seem to do anything in the first position and acts like a volume control in the other three positions.

I have a paper copy of a hand drawn schematic that I downloaded from somewhere (marked with G.S. [Gus Smiley?]) that shows yet another variation of the gain wiring. It has the 0.033uF cap connected between the output and inverting input of the opamp and the gain pot wired across the diodes. The tone switch wiring is the same as the unmodded schematic posted above and the 3.9k resistor from one lug of the tone pot going to ground instead of Vb.

I built it according to the later schematic assuming it corrected the hand drawn version. Maybe I was wrong.

At this point it sounds nothing like the clips on the posted site.

[Joep]

Hi Analogguru,

Do you have more pics available...I'd love to trace this one out.....

Bye,

Joep

[analogguru]

So....:

1.) I have only this picture, which I found on ebay....
Then I have the hand-drawn-schematic, and the other one and....a little bit of knowledge....

2.) We had a long discussion in the german forum about this, and I mentioned, how i supose it should be...it seems that reading is more complicated than looking pictures, so here is what i wrote in added to the picture:

http://forum.musikding.de/attachements/Lovetone_BrownSource_edit2.gif

3.) I could trace the Schematic, but not verify the component values

4.) The routing of the PCB-Layout is in my opinion something what is not allowed to mention here...
For this reason and that I only have the material mentioned above, I can not verifiy my suggestions...in the picture it looks that the output-buffer is really like shown...even when it would not make sense...
I believe, that the BrownSource should be like shown in the last schematic.

5.) I can say for sure that Schematic - NOT THE COMPONENT VALUES ! -of the input buffer, the first OP-Amp the Tone-control and the tone-switch is valid...

6.) But even the component values seem to be correct
the 33n of the firsr stage is for my feelings a bit high, maybe only 3n3...are you DIY ?..TRY !!!

7.) The poti in my corrected version IS across the diodes also the capacitor

8.) if you want to understand how the first Op-Amp is working, you can find an explanation with pictures here:
http://forum.musikding.de/yabbse/index.php?board=8;action=display;threadid=1711;start=165

9.) The Tone-Control should work properly as shown, corner frequency is about 1khz

10.) Output cap 3n3 seems to be a little bit low, maybe 33n....are you DIY ? ....TRY !

11.) I only used this (crazy) schematic to show the necessary changes.
When I will find some time and have a good mood, then i will draw a more readable schematic...

analogguru

[mikeb]

Oh no, not again!

I have two pictures (one from on top of the PCB, one below) and a PCB layout that was traced from an original unit a few years back. I know I have sent these items to some other people before, but if someone else wants them (who is contributing towards getting the schematic right) send me an email (not PM, *email) to mikeb at prophecysound dot com. It should provide another opinion, at the very least!

Mike

[mikeb]

Ok, I've emailed the files to the people that contacted me, so no more requests now thanks. Hopefully this will let it be 'finished'.

Mike

[analogguru]

@mikeb
many thanks for the pictures !

for the reason, that nobody pays me for my work, and I even don´t get only two minutes of a perfect self-played .mp3 of my hot-loved "stool pigeon",

- a guitar primer video you can find here:
http://www.kidcreole.com/Pages/avframe.html

...THIS WILL BE MY LAST WORDS TO THE LOVETONE BROWN SOURCE SCHEMATIC:

http://forum.musikding.de/attachements/Lovetone_BrownSource.gif

and it doesn´t mind me, how exact it is like the original or not, cause my version is a working distortion with tone-control and everything....

Happy soldering...

Maybe somebody can make a sound-comparision to the original one...


analogguru