Transistors for highway 89, are 2N5088 OK?

[svstee]

I built the Highway 89 from this layout

but used 2N5088's instead of 2N5089 transistors, because than was all I had. When I tried it out (using an unregulated cheapo power supply) I got horrible noise that made the pedal unplayable, although everything worked fine. Would the transistor swap make that big of a difference with a good power supply?

[oldrocker]

Well if the PS is unregulated then that's the problem.  Since the 5089 would be higher gain I doubt if changing them would matter.  I used 5088's in mine and made a power supply from the instructions from tonepad.com.  It is super quiet.

[svstee]

Aren't 2N5089 just low noise 2N5088's? I'll get my good PS back later today and check it out. You made a Highway 89 with the 5088's then? Did you try any other transistors? Mine sounds like it has quite a bit of gain on tap, I was thinking about trying metal can 2N2222's to tame it a bit.

[Ben N]

I believe that 2N5088 is higher current, slightly lower gain.

[oldrocker]

I originally used 3904's with good results.  It might've been slightly noisier so I switched to the 5088's.  I guess you could experiment with other trannies.  I was wanting to make it with more gain on tap but didn't have any higher gain transistors on hand to try. 

[svstee]

Well, I useda regulated PS and that took care of the noise. Found another problem, though. I used a 250K log pot for volume (i didn't have a 500k) and it ain't cutting it. Volume goes up (?) when pot is at far left and right of rotation, works normally in the middle half of the range. Can I just use a different pot with a resistor in series, or will that make it too linear to be workable?

[oliphaunt]

Double check the wiring on that pot.  My guess is it's wired wrong, and the value isn't making that much of a difference.

[svstee]

Checked it, pot is wired right, but not sure if pot is defective, that has happened to me before. I'll go check that. Should a 250ka be close enough?

[svstee]

Anyone? What can I do to fix this?

[svstee]

I just put a 220K resistor between lugs 2 and 3, no luck. All it did was reduce effectiveness of volume pot, didn't lower the level at all, or fix the issue of having unusably loud volume at both ends of the pot's rotation. What else can I do here?

[petemoore]

  Value of pot shouldn't matter.
  One outside lug connected to ground...?
  When the wiper is turned to that end of the rotation it too should read ground, and all signal would be shunted there.

[~arph]

oh and rename to highway '88   

[petemoore]

  The Old's Delta was great for the east-west highway trips.
  I have a box with the Old's's old ''88'' emblem on it, shouldn't be too hard to find one of those.
 

[~arph]

Like this?

[petemoore]

  Nope, that's actually in better shape than my 'script' logo, also very nice.
  Not sure which is higher output...

[~arph]

There is a '89 script logo too... 

[svstee]

Well, got it all working, I had missed the ground plane with lug 3... oh well, it sounds great now!