Recommend a circuit. Please.

Started by harmonic, June 03, 2011, 09:11:20 AM

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harmonic

Hi all!

I've been asked by a friend if I'd build a pedal for his situation. The sound he wants is something to liven up the clean channel of his amp. When he wants to kick up the 'dirt', he'll switch to the other channel of the amp, but he wants the clean channel sounding a little move 'lively'. He's got an Epiphone Dot (double humbucker, or is it P90s?). I've interpreted this all to mean that he's looking for a boost pedal that gives a little bit of 'sparkle' or 'chime' (or some other, fairly useless, subjective term) or possibly an overdrive pedal that can be subtle. It's mostly open chords he's playing, and it's a lot of strumming (rather than fancy picking).

Can any of you fine people point me in the direction of something that fits the bill?

Thanks so much!

h.

petemoore

I've been asked by a friend if I'd build a pedal for his situation.
  What is the situation ?
  The sound he wants is something to liven up the clean channel of his amp..
  What is the amp ? What is the speaker ? "Liven" will probably take on a clearer definition after trying something on it, I would start with a Jfet Stratoblaster/studying the Fetzer Valve.
   When he wants to kick up the 'dirt', he'll switch to the other channel of the amp, but he wants the clean channel sounding a little move 'lively'.
  Whatever is put before both of course will effect both channels, sometimes clean boost [perhaps leaning toward the treble side] will help out the dirt channel also. That's another ball of waxy string I work around by simply staying with the clean channel and dirt that up various ways...unless the dirt channel just happens to be right, it was for AJ last night, we discussed this, all the other times it wasn't, either too harsh, too this or too that.  I prefer to add 9VDC to my epidermis, it doesn't mind that, mucking about with re-tweeking expensive and dangerous equipment is something...Mr. amp tailor did and amp designers followed with 'this amp sound for you too'...which may [or ime more often may not] fit the PU's, boosted or otherwise.
   He's got an Epiphone Dot (double humbucker, or is it P90s?).
  Different pickups may require changing the wax in the stringball.
  I've interpreted this all to mean that he's looking for a boost pedal that gives a little bit of 'sparkle' or 'chime' (or some other, fairly useless, subjective term) or possibly an overdrive pedal that can be subtle. It's mostly open chords he's playing, and it's a lot of strumming (rather than fancy picking).
  If expecting a different character to clean-sparkle rythms/leads, I've found the '1rst position' Jfet [fed by PU's] works very much like a tube, just barely distorting but boosting puts that sound on 'it' if it is otherwise pristine clean [very nice] or drives the next slightly distort-thing [speaker ? If a tube output is distorting the drive increase is quite welcome.
  To put it bluntly, boost will not make a speaker or solid state output exceed it's limitations. While speaker compression/distortion can be desirable, SS output clipping is to be avoided.
  Can any of you fine people point me in the direction of something that fits the bill?
  Please excuse or dismiss the adjectives, used as quick reference.
  7:
  Jfet, smooth, sparkly, ~tubey [Fetzer read recommended].
  CMOS, smooth, and ~distortion from output tube-ey [prepare for study].
  Mosfet, Clean ~sparkly, as easy as biasing a Mosfet.
  Bipolar, Clean-ish, LPB wires up/fires up.
  Opamp, Clean, ton of gain if you like, same here, but requires Vbias.
  Tube, Clean, but the 1rst position might as well be a Jfet or something, considering the power supply and any convenience requirements.
  Ge, Dirty-ish character, finicky, a whole subset of requirements with these devices.
  LM386, has some rougher dirt, wires up to a <15v supply, = high output quickly.
   All can be made to distort more, or less, they all distort differently, I'd suggest the smooth/sparkly options as starting point.
  Probably more than 1/2 of 'general boost' questions have specific application which may or may not include copious amounts of 'downstream distortion' when pushed by a boosted signal.
  Copious amounts of distortion Vs. very little distortion contributed is comparing two very different sounds. What is downstream has much to 'say' about what it is being fed.
   Thanks so much!

h.
Convention creates following, following creates convention.

ayayay!

#2
If it's not much gain/volume increase he's looking for, I'd recommend a Tillman Preamp.  Very low parts, super easy to build.  If he does want a little grit, you can increase the large cap to ground.  Should give things a little depth and character.  There's no pot on the output, so I'd recommend a 50k.  Or 100k to keep things on the bright side.  Search the forum for it.  I'm sure there's layouts galore.  Renegadrian comes to mind. 

If it were me, I'd just build an Orange Squeezer and that would be that, but I don't think that fits your guys bill since he's doing a lot of strumming on a hollowbody. 

http://www.till.com/articles/GuitarPreamp/
The people who work for a living are now outnumbered by those who vote for a living.

harmonic

Thanks for the input so far guys!

His amp is a solid state preamp, so I don't want a volume (signal) boost necessarily as I don't think the amp will take it too well. The sound I'm imagining is not fizzy and not a fuzz. 'Sparkle' is really the best way I can describe it.

The Tillman looks interesting and I'll bread board it — thanks for that!

Any other ideas out there?

Hides-His-Eyes

The absolute first step is an SHO pedal (similar to the Mosfet Boost and improved upon with the "crackle not OK") which will provide a massive impedance to the guitar and stop absolutely any treble suck that might already be going on. This is sometimes interpreted as a more "lively" sound rather than just boosting frequencies, although that's what it's doing; just not in a typical filter way.

harmonic

Yeah, a buffer circuit, right? (What does 'SHO' stand for?) I wondered about that and thought it might interfere with what ever boost/overdrive circuit might come next, knowing some don't like a buffer in front. I guess it all depends which circuits is chosen in the end?

egasimus

^ sho = super hard on

How about something different, say, the Woody acoustic simulator?

Hides-His-Eyes

Quote from: harmonic on June 04, 2011, 06:25:29 AM
Yeah, a buffer circuit, right? (What does 'SHO' stand for?) I wondered about that and thought it might interfere with what ever boost/overdrive circuit might come next, knowing some don't like a buffer in front. I guess it all depends which circuits is chosen in the end?

there are a handful of vintage fuzzes that respond poorly to buffers before them (and the clones thereof) but almost any boost or overdrive will not mind at all.

CynicalMan


harmonic

Hi all,

I breadboarded the Tillman. Definitely a nice, noise-free, capable buffer. Does add any 'sparkle' though.

The Crank looks like a lot of fun — I think that's next!

Any other suggestions?

Thanks!
h.

sault

Try changing the biasing on the Tillman... by changing the bias you'll be introducing some gain and 2nd order harmonics.... that might do the trick. That's essentially what the Fetzer valve is all about - using a jfet with a lower Vp and purposely biasing to get more gain.

Take a look at the Shaka Braddha IV... notice that 470k || 470k voltage divider right in front of the Jfet? That cuts the signal down so you won't get as much saturation.

http://diystompboxes.com/pedals/shakahv.jpg

So if the Tillman is getting you close, then maybe tweaking the bias a little and/or putting a voltage divider in front of it might do the trick.


Sault

CynicalMan

Try using a 4.7M or 10M resistor instead of the 3M resistor. Also try playing with the bias.

ThunderShowers

#12
If you want, i could draw up the (new) schematics for my tube drive. It takes 9-volt adaptors, and but it does have a voltage pump. the best way to describe it as it stands is "A bloody tube amp in a box."
http://www.sendspace.com/file/7opk6m for audio demo; Excuse my terrible playing: my fingers are covered in cuts from work.

Edit: in review, I am terrrible today, on both playing and settings.

Also note, that's straight into a POS M-Audio "Fast track"

CynicalMan

Quote from: sault on June 04, 2011, 09:11:06 PM
Take a look at the Shaka Braddha IV... notice that 470k || 470k voltage divider right in front of the Jfet? That cuts the signal down so you won't get as much saturation.

http://diystompboxes.com/pedals/shakahv.jpg

A 470k in parallel with a 1M? Must be an error. Anyway, I'm don't think a voltage divider on the input will be necessary. With one FET there isn't that much distortion unless you go into gating.

sault

QuoteA 470k in parallel with a 1M? Must be an error.


Huh, looks like you're right. I bet that .01 cap should be there...

harmonic

Having reread what I've posted and the replies,, I think I haven't been clear on what I'm looking for.

When I've said sparkle or chime, I haven't meant a boost of treble, but some overdrive that sounds like sparkle or chime. So, a booster will give more volume, and some of them are a treble boost, but I'm looking for a circuit that creates a sweet sparkle over the whole signal.

Any ideas for that?

Thanks again! :-)

ayayay!

Sparkle Boost?  Search for Andrew Carell / Dragonfly.  It's kinda like a Tillman, with much more output and a noticeable amount of grit.

Or, you can put a 22uF instead of the 10uF on that Tillman and see if that gets closer.

http://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=1855&g2_serialNumber=2
The people who work for a living are now outnumbered by those who vote for a living.

waltk

To "liven up" without adding treble or distortion, you might try a Little Angel with the chorus turned all the way down.  That leaves you with a doubler that is kind of subtle.  It's a cool effect that's hard to detect until you A-B it.

EATyourGuitar

I just built an sho and it did exactly the sound you described on my solid state practice amp. the input impedance of the SHO is probably higher than my crappy SS amp. also, the amp is being fed an active signal now. totally gave it clarity and a bit chimey when playing up high. I would say the sho nails the sound.
WWW.EATYOURGUITAR.COM <---- MY DIY STUFF

markeebee

+1 on using the Little Angel in double tracking mode, sounds brighter and thicker. Is it possible to be both?

Also, I'd really recommend the Aussiemart compressor for janglers.  It's an easy-peasy build, and it sounds like you've taken a blanket off your amp, if you know what I mean.   Also has a lot of boost if you need it.  Not a great compressor, but a nice 'livener'.

http://www.diystompboxes.com/smfforum/index.php?topic=81761.0