Tonebender MkII Attack pot question

[elpucho]

Hi,

I've just finished building a Tonebender MkII Professional using the vero layout from the Gallery (I followed the SolaSound schematic, but changed the  R4 470 resistor for a 1k2, and also changed the R3 100K to a 47K, as suggested on Fuzz Central) and I'm not entirely sure it's functioning properly.  The "problem" I think I have is that the Attack pot doesn't seem to take much of the fuzz off when it is set as low as possible.  The pedal is sounding good, but I'm not sure if the attack pot should have more effect, when it is set at 1 there is still a lot of fuzz there (Maybe that is the way the Tonebenber sounds?)

I have measured my transistor voltages as follows:

   Battery - 9.1v

   Q1 - C8.6v  B0.07v E0.00v
   Q2 - C0.66v B0.13v E0.00v
   Q3 - C4.52v B0.66v E0.53v

The odd thing I found after experimenting was that if I reverse the pinout of Q1 (Hitachi 2SB77 - I am currently assuming that the triangle marker on the transistor is indicating Collector) the Attack pot seems to work a lot better, but the voltages all go a bit wrong, and the pedal doesn't sound as good as it does now.  I used a matched set from Small Bear.

I tried replacing the 1K Attack pot with a 2k (I used the 1k pot with a resistor across it, changing it to a 2k) to see if it helped, but the fuzz still seems very strong even with the Attack pot set as low as possible.

As I said, I'm not entirely sure if this is the way the pedal should sound as I have never had a Tonebender before.

This is the layout I used.

http://aronnelson.com/gallery/Richard-Boop-RLBJR65/MarshallSupaFuzz



Thanks in advance for any advice you can offer me.

PS - Great site, I can't thank everyone enough for all the info I've gained since I started reading here.

[lacto]

Adding resistors in parallel, as in putting a resistor across a pot (which acts as a variable resistor) makes the value smaller not larger.
There is no way to make a pot value larger only smaller with that method , i.e. 1K pot with 1K resistor across the lugs equals approx. 500ohms, not 2K.

[elpucho]

Oops, that was my mistake.....I meant to type that I replaced the original 1K pot with a 4k7 pot which had been modifed down to a 2k pot. 

[tcobretti]

I built my TB from the GGG schem, and it is still pretty fuzzy when the knob is down all the way.  However, it certainly gets kazoo fuzzy toward the end of the knob travel, so it sounds like something may be wrong.  Initially my pedal was oscillating like crazy in the last third of the attack knob, but I put a cap across the battery that fixed that problem.   I highly recomend trying out the the PN2369A in the Tone Bender.  Recently I read the Fuzz Central article about using PN2369A trannys because they have similar numbers to the germanium trannys in the original, so I tried those in all three positions.  The pedal went from being cool to being great and is now quite possibly my favorite fuzz.

[elpucho]

I'm not sure I'm any further forward.  The only way I can get the Attack pot to take a lot of the fuzz away is to reverse the pinout on Q1, but I'm sure that's not the answer as when I do that the Q1 Base reads 0.00volts when I do that.

The thing is I love the sound of the pedal, but I can't figure out why it is so fuzzy at low settings (Unless I'm an idiot and that's the way it should sound!).

If anyone can have a look over my voltage readings above, or answer the question of how much fuzz should be on a TB MKII at low settings I'd be really grateful.

If all else fails I'll have to upload a recording of the pedal at low and high setting to see if that is how it should sound.  You really don't wanna hear that, trust me. 


Thanks for the advice so far guys.

[elpucho]

Quick update........I found out that the Q1 pinout is fine the way I have it.

I'm still struggling with attack pot problem.  If anyone has any idea how can I sort this out I'd be really grateful.

Basically I'm not sure if my pot is working OK, as it seems to be very fuzzy even at a low setting.  Anyone have any idea what I can measure just to double check everyting is wired properly?

Thanks

Edit - I'm going to try a rebuild tomorrow of this one, I checked out everything on this one as far as I could, perhaps using a different layout and see how that sounds.

In the meantime, remember folks I'm still looking for an idea of how it should sound with the attack pot turned down, or if there is anyway I can figure out this one.

[yeeshkul]

I have the same trouble. I just wander if TB should be behaving this way - the attack pot does not take much of the fuzz sound away..

[elpucho]

I think it's just the way this pedal is, the Attack pot doesn't take roll off a lot of the fuzz, so even at it's lowest setting the pedal is still pretty "fuzzy".

You could try adding a pot straight after the input to act as a kind of pre-gain/cleanup.  That's what I did and it adds a bit more versatility to the pedal.  It's really easy to do, just connect the input from the input jack into lug 3 of the pot, then connect lug 2 to the input on the board.  I think I used a 250k pot.

I hope that helps.

[yeeshkul]

You could try adding a pot straight after the input to act as a kind of pre-gain/cleanup. 

Yes i have done it (but i am using 50k i guess) - i made FF/TB pedal where you can switch between FF and TB and they both play great . I just was not sure abou the Attack.
anyway - thanks man

[m-theory]

Not that I've ever had previous experience with this fuzz, but I built the GGG version as well, and found the attack knob to have nothing whatsoever to do with the amount of fuzz, but rather seems to control the, well, the attack.  When it's all the way down, notes sort of run together a bit, and when it's all the way up, there is a clearer definition between notes.  Either way, the pedal is fuzzy as hell. 

I will say though, that through a clean amp and with my Lester on the neck pickup, it sounds VERY Clapton-esque, so I have every reason to believe that the circuit is correct. 

[mac]

The attack pot is "symbolic". It just decreases the amount of fuzz a little. That's the reason some people like to build FF/TB without the drive pot and use the guitar volume.
I not sure but a long time ago I remember to have biased q1 as a buffer like aron's the rocket. The pot worked much better this way.. or not?

mac

[yeeshkul]

I guess i am satisfied now  . That's what i wanted to hear hehehe. I love this forum.

[mac]

You could try adding a pot straight after the input to act as a kind of pre-gain/cleanup.  That's what I did and it adds a bit more versatility to the pedal.  It's really easy to do, just connect the input from the input jack into lug 3 of the pot, then connect lug 2 to the input on the board.  I think I used a 250k pot.

My FFs have  a 100K log pot at the input. It is more useful than the drive pot, IMHO. It lets you put a wah in front or use HB without tone sucking.

mac