DAM Red Rooster clone- weird input cap!

[claytushaywood]

So i built a vero version of the DAM red rooster from the layout at tagboardfx.  Got a germ from smallbear and biased it up to 6.66v, just like the dude at DAM says he does.  Now it sounds great- quiet super fat germanium boost, but I'm not getting enough treble... or not as much as i'd like with the range knob all the way to the treble side.  and i'm getting a lot more bass than i'd ever need, but i guess thats besides the point.  I see the range pot mixes between the 5n and 2u2 cap.  So first I tried to put the 5n cap on a switch so I could try some lower values for more treble.  I put a 2n2 on one side and couldnt hardly tell a difference, then I put a 1n cap (measured it and everything) and I'm getting LESS (not super obvious, but it sounds like that to me) treble when the 1n cap is in place.  I've checked the switch continuity with my multimeter a dozen times because I was absolutely sure that would not be the correct response to a lower value cap!  I even tried replacing the 2u2 with a 1u just in case I was getting 2u2 mixed with the treble caps.  am i just wrong about this input cap?!

thanks for any ideas!
here's the layout

http://tagboardeffects.blogspot.com/2011/11/dam-red-rooster-vero-layout.html][url]http://tagboardeffects.blogspot.com/2011/11/dam-red-rooster-vero-layout.html[/url]

[claytushaywood]

so ive tried all sorts of values... including 560pf, 10n, 22n, 2.2n, 1n.  and i definitely got more treble with 4.7n than 560pf!  and i got slightly more treble with 10n... but less treble with 22n!

is this just the design of the circuit?  maybe something going on with my pot or the 10n output cap?

and i did convert this to use a PNP transistor... reversed the polarized caps and all that (but i am using a non polar 1uf cap in place of the 2u2 for the one input cap)

[Quackzed]

make sure the larger cap is the one with the 100k variable resistance pot between it and the input jack,lug3 and the small cap is lug1,2 and is directly connected to the input jack. one way goes from 5n to 2u2plus5n the wrong way will go from 2u2 to 2u2plus5n and thats not much change.

[claytushaywood]

i'm definitely getting a treble boost.  not getting just a muddy bass boost of 2u2 (which i changed to 1uf because 2u2 was just unuseable).  i'm just not getting enough treble and I cant get anymore out of it, i swear its the weirdest thing ever.  I get a rotation of treble to bass on the range knob but I just cant get it any brighter! could my pot be not getting me fully counter clockwise... like could it be still mixing the 1uf (2u2) with my treble cap when its fully counter clockwise?  the 100k pot is measuring at 0.6 ohms when its fully counter clockwise- could this be it?

[claytushaywood]

make sure the larger cap is the one with the 100k variable resistance pot between it and the input jack,lug3 and the small cap is lug1,2 and is directly connected to the input jack. one way goes from 5n to 2u2plus5n the wrong way will go from 2u2 to 2u2plus5n and thats not much change.

and yeh the pot is connected correctly.  i just went and measured a bunch of 100k pots and removed the 100k pot from the circuit and they're all measuring about 3.6ohms when fully counter clockwise.  Is it just the design of this circuit that doesnt allow me to get much more treble?

its crazy because I'm using a strat with some custom switching and it doesnt have enough treble (though it is very trebley, with that rangemaster almost parametric eq honk sound) with the bridge pickup, but when I put bridge and middle in series it's seriously not cutting it

[Pojo]

This circuit looks like it has a rather low input impedance (68k I think?). Try putting a buffer in front of it and see if your treble comes back.

Using small input caps doesn't actually give you *more* treble, just cuts more bass from the input. But then when the signal is boosted the net result is a brighter, thinner tone. Unless of course your pick ups are loaded down which I'm suspecting is happening. So if you have a buffered bypass pedal like any old Boss pedal, I'd try that in front of your circuit just to see if it helps. Then build a buffer into your pedal if you like the result.

[Arcane Analog]

There is nothing wrong with the circuit itself - it is very common - without the buffer idea.

There has to be an error somewhere. also, as noted, the arrangement simply filters bass - it does not boost treble. There should be a significant difference between the extreme ends of the pot rotation.

If lug 3 has the 2.2uF cap and lugs 1&2 have the 4n7 cap and it is wired correctly and you still have little difference in rotation I would suggest the pot value is wrong. A 1K-10K pot will sound towards the bass end of things. Measure your pot rotation.

[davent]

Have you tried it with just the 4n7 for the input cap, get the pot and other cap right out of the circuit like in the original Rangemaster. What happens then?

[claytushaywood]

okay!  got one more idea... maybe

maybe i have it misbiased because of the confusion switching this NPN layout to PNP.  When I measure the bias off the collector of the transistor would I go from collector to the power supply's ground?  or because its now PNP would I go to the power supplies 9v?  Lets make it power supply so I dont confuse -9v vs +ve

Because I'm getting 6.75v to the power supplies ground and 2.2v to the 9v lug of my dc jack... know what i'm sayin?

[claytushaywood]

There is nothing wrong with the circuit itself - it is very common - without the buffer idea.

There has to be an error somewhere. also, as noted, the arrangement simply filters bass - it does not boost treble. There should be a significant difference between the extreme ends of the pot rotation.

If lug 3 has the 2.2uF cap and lugs 1&2 have the 4n7 cap and it is wired correctly and you still have little difference in rotation I would suggest the pot value is wrong. A 1K-10K pot will sound towards the bass end of things. Measure your pot rotation.

pot has been removed and measured at 3.6 ohms to 98k
and as i've said there IS a significant difference throughout the pots rotation, i never said there was not a significant difference.  that is not the problem.  It is just not nearly as bright as other rangemasters i have built or played and i cannot adjust how bright it gets (or how much bass is cut, do i really have to explain that every time I wanna say its not bright enough)  With other rangemaster builds ive had- a 1n cap is SUPER bright.  shoot, 4n7 is really bright, but with this one its not.

i thought the point of the rangemaster was to load your pickups directly and a buffer in front would ruin this effect

[Arcane Analog]

(or how much bass is cut, do i really have to explain that every time I wanna say its not bright enough)

I guess not. Good luck fixing it.  

[claytushaywood]

This circuit looks like it has a rather low input impedance (68k I think?). Try putting a buffer in front of it and see if your treble comes back.

Using small input caps doesn't actually give you *more* treble, just cuts more bass from the input. But then when the signal is boosted the net result is a brighter, thinner tone. Unless of course your pick ups are loaded down which I'm suspecting is happening. So if you have a buffered bypass pedal like any old Boss pedal, I'd try that in front of your circuit just to see if it helps. Then build a buffer into your pedal if you like the result.

So i tried plugging in a buffer before the pedal and I'm definitely getting more 'brilliance' like its sparklier and clearer, i think this may be the answer.  I'm gonna see if I can hear the difference between different caps for the 4n7 now- because its still not really piercing enough like a rangemaster should be

[Arcane Analog]

So i tried plugging in a buffer before the pedal and I'm definitely getting more 'brilliance' like its sparklier and clearer, i think this may be the answer.  I'm gonna see if I can hear the difference between different caps for the 4n7 now- because its still not really piercing enough like a rangemaster should be

Seems to me the original design got along fine without a buffer - or do the originals not sound how a Rangemaster should?  

If it does not sound right you have an error somewhere or a bad part.

[Pojo]

I've never used/built/breathed same air as a Rangemaster (not that I wouldn't, just never got around to it) so I'm less than qualified to give any recommendations based on how they're supposed to sound or behave. Was just making a recommendation based on the symptoms.

I found the schematic for the circuit here:
http://revolutiondeux.blogspot.co.uk/2012/03/dallas-rangemaster-dam-red-rooster.html

Looks like there's some tips from R.G. there for tuning the circuit which may be helpful.

[claytushaywood]

its weird... it sounds great

can anyone answer my biasing question... when i measure off the collector to the dc jacks ground lug i get 6.66v.... but i converted the board to use a PNP germanium.  so i was wondering if i should actually be measuring to my dc jacks 9v lug.  i'm talking actual lugs just to be sure i'm not confusing ground and 9v after converting to PNP.  but its measuring 2.2v to the actual 9v off the dc jack.

i really cant imagine having a bad component with how good it sounds.

when i put a buffer in front of it i definitely got more brilliance and sparkle out of the pedal... it sounds great without the buffer and with the buffer in front.  but there is definitely an obvious different.

I dont know what component could be bad with how good its sounding.  and the range pot does have a nice transistion from treble to bass.  anyone got any ideas what component might be bad?

[Arcane Analog]

It sounds to me like the pedal is working fine. Perhaps the pedal is not the problem.

[claytushaywood]

i'm starting to think its just the circuit doesnt get as bright as a rangemaster... ive heard all sorts of different demoes of the actual units and they all sound different.

http://www.youtube.com/watch?v=ywqi2nWzJq8

mine gets brighter and darker (a lot bassier) than this one, ive heard a lot of reviews that say they cant use a lot of the clockwise part of the range knob because its so damn boomy. i really dont see why this circuit wont get as bright as a rangemaster. but i'm a newb

[skrunk]

its weird... it sounds great

can anyone answer my biasing question... when i measure off the collector to the dc jacks ground lug i get 6.66v.... but i converted the board to use a PNP germanium.  so i was wondering if i should actually be measuring to my dc jacks 9v lug.  i'm talking actual lugs just to be sure i'm not confusing ground and 9v after converting to PNP.  but its measuring 2.2v to the actual 9v off the dc jack.

to measure the voltage...
DMM's red probe to the collector,
DMM's black probe to ground.
you should get a negative reading (eg. -6.6v) as it's a positive ground circuit.

also, don't obsess about the 6.66v reading, just bias it to where you think it sounds good yourself, then take a note of the voltage.
Dave just gets a kick out of the satanic reference of 666.
anywhere between -6.5 to -7v will probably sound fine depending on the transistor.
even if you bias it at 6.66v, it won't stay that way for long given germaniums sensitivity to temperature changes or the draining of a battery, which will both alter the collector voltage anyway.

[Quackzed]

you might also try tracing out the circuit you built, one piece at a time, what connects to what, no cheating!, and THEN compare it to the schem. often you see what you expect and assume things are connected that aren't etc... if you draw out your build as it is, you may find something is connected differently that you thought. thought you may be right, it just may be that its correct, just bassier than you expect, though a smaller cap than the 4n7 should give you less bass than with a 4n7...
something to try.