Hwy 89 tweaks

[m-theory]

Ok, so I took the Hwy 89 out for a spin last night, and found a few things about it in a live setting that need tweaking, and I'm not sure where to go with this. 

First, it definitely needs a 100k pot for output...it's got just absurd output, to the point where it oscillates at a certain point. 

Secondly, it seems very heavy in the mids dept...almost %^&*ed wah middy.  I like a bit of a mid bump for leads, but not quite this much. 

Finally, whether the gain is cranked or a bit turned down, the guitar volume rolled back a bit will produce an absolutely beautifully articulate, open sound..."bell-like," as the layout verbiage says.  Very nice.  However, with the guitar volume pegged, that beautiful tone disappears and becomes a muddy, compressed fuzz tone.  I love a good fuzz, but it's really not what I'm looking for with this circuit.  I also love the amount of gain that it has when the gain is maxed and the guitar volume is pegged, but I want that beautiful, open tone that the circuit has with the guitar volume rolled back a hair, but with the gain that it has with the volume pegged.

Am I dreaming of something that isn't possible with this circuit? 

Here's the thing...I run my amps hot...I love a classic, cranked plexi tone, and all of my amps are set up to cop that tone.  I ride my guitar volume to go from "cleanish" to gainy, and when I play a solo, I usually step on a mosfet boost.  However, there are times when I want more gain yet, which is why I've built the 89.  I had previously tried a couple of different fuzzes (love the gain...didn't like the compression) and modified TS build with LED clippers (not gainy enough), as well as a BSIAB.  Nothing is quite where I want it to be.

I'm basically looking for something along the lines of what the mosfet does, but with more gain.  I want gainy, but with sharp attack...articulate detail, note separation, etc.  I KNOW it can be done, but I just haven't quite gotten there yet. 

So, can I get there with the 89, with some tweaking?  I absolutely LOVE the way it sounds with the guitar volume rolled back, except for that heavy mid bump.  If I could somehow get the gain from that thing that it has with the guitar volume pegged, but with the "bell-like" clarity of it with the guitar volume down a bit, and knock some of the mids down, that would very likely be what I'm looking for.  Any suggestions? 

Thanks.

[DougH]

I wasn't sure where all the "gainy" comments were coming from wrt this circuit, but I will say it was originally intended to be used with a clean amp. With a dirty amp, all bets are off- it may sound great and be what you want or it may not, but it was intended to produce a bluesy overdrive with a clean amp and passive pickups.

The mid-hump and the nice cleanup comes from the low input impedance of the first stage. You may be able to decrease the mid hump (increase treble) by scaling the base resistors of the first stage higher and raising Zin- but as you do it will lose the ability to clean up with the guitar volume. You could also try tweaking the low pass filter on the output to pass more highs to reduce the mid hump. This will give you more treble (lose the mid hump) and won't affect the cleanup- but it may introduce harshness too.

All you can do is play with it- everything is a tradeoff.

[jakehop]

I must say, this excellent piece of circuitry acts very different to the choice of transistors chosen by the builder. I seem to like transistors with hFE 300-350 for humbuckers and single coils. It cut's down on the max gain available though, so if I am building one strictly for single coils, I'll use 5089's.

Hope this helps.

Kind regards, Jake

[m-theory]

I suppose pretty much all dirt boxes are designed with a clean amp in mind as a base, and that would certainly make sense.  This circuit does have a lot of gain on tap though, whether through a clean or dirty amp.  Not recto distortion, of course, but definitely beyond what I would typically call "overdrive." 

I like it a lot, gain-wise, but this compressing effect is something that I'd really like to dial out, if possible.  I listened to your clip, Doug, and I heard it there as well.  With the guitar volume between about 8-max, the circuit acts as if it's loading the signal.  Instead of that beautifully articulate, crisp, clear attack that you get with it anywhere below about 8, you get a compressed signal that borders on fuzz tone, imo.

That's what I want to address before anything, really.  If I can get that choking effect out, I may find that the mid bump is right where it needs to be.  It seems that much of what gets lost during this loading effect with guitar volume maxed is the high end. 

What are some useable subs for this particular transistor, that would be a bit lower in gain?  Or, is there a resistor value somewhere that could be raised, in order to shave a bit of the signal off somewhere, to minimize or eliminate this loading effect? 

[nokaster]

i like this circuit a lot with 2N2222's
lower gain than the 5089's, less fuzzy when cranked.
i'm gonna build me another one with all the right component values.
the first one had some subs, because they were all i had.
this time it'll be exactly like dough intended and i'm gonna try a bunch of different transistors in there.
i don't want to change anything else, although a lower value volume pot might be a good idea...

i'll be trying these:
2N5089
2N2222
2N2369
2N3904
bc107
bc239
and i've got some 337, 338, 547, 548, 549's as well
maybe the odd C9013's i got in my futurlec value pack will sound incredible in here... :-)

i'm about ready to start building and i'll report back with my findings when it's done!

i'm still looking for a good source for germanium NPN transistors in europe by the way...
those might sound interesting in this circuit as well...

[Caferacernoc]

I think playing around with lower gain trannies, 2N2222 and/or
2N3904, plus opening up the treble cut at the end of the circuit should get you what you want.

[m-theory]

I do hope you're right on that, because I REALLY want this to be "the one."  As for opening up the treble cut, would you be referring to C8 or C13? 

[slacker]

I don't know if it will work with this circuit but to get the sound you get with the guitar volume rolled down a bit try putting a pot in series with the input like the Axis Face smooth control.

[DougH]

What are some useable subs for this particular transistor, that would be a bit lower in gain?  Or, is there a resistor value somewhere that could be raised, in order to shave a bit of the signal off somewhere, to minimize or eliminate this loading effect?

I addressed that in my post above.

[m-theory]

I'm going to try some transistor swaps first, to see what happens.  I did socket them, so that'll be a snap.  I'm thinking that I might even find that just replacing one to a lower gain device might solve the issue.  I don't think it's going to take much, really.  Through about 80% of the guitar volume range, the circuit is gorgeous.  It's that final 20% that seems to push it over the edge, to my ears. 

I don't know if it will work with this circuit but to get the sound you get with the guitar volume rolled down a bit try putting a pot in series with the input like the Axis Face smooth control.

You're right...that might indeed work as well.  If I can't find a transistor combo that floats my boat, I'll give that a shot. 

[nokaster]

i've finished the board already.
all 40 components and jumpers soldered, all 12 cuts done.
hopefully tomorrow i'll feel like drilling the BB and doing all the off board wiring.

i want to know how this one sounds!
my previous one had all ceramic caps (multilayer and normal)
this time all caps are mylars, except for the 680nf, which is a wima.
and like i said before... are values are as per schematic. even the volume pot. 

if i finish the box and the off board wiring, the transistor test can start.

i can't help but wonder how this circuit will sound with a woodrow clone in front of it...
anyone have both at hand?
maybe the woodrow will push the highway in muff territory?

i must say i like the woodrow in front of a green ringer. makes for a very nice octave booster.
and you have a lot of control over the woodrow with the volume of the guitar.
so you can lower the guitar's volume to get more ringer, or turn up the volume for nasty octafuzzy noise.

[Caferacernoc]

I do hope you're right on that, because I REALLY want this to be "the one."  As for opening up the treble cut, would you be referring to C8 or C13? 

C12 and C13. Cut them in half for a start.