Help Debugging TS808/LPB 1 Clone Builds

Started by pork ruckus, May 25, 2019, 10:15:56 PM

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pork ruckus

Hey I'm wondering if anyone out there could give me a hand troubleshooting a few issues I'm having with a recent dual pedal build. I've listed all that comes to mind so far below. I'm suspicious this issue may be stemming from the Transistor substitution I made and wanted to see if anyone has ever encountered this issue or knows of a direction I could be pointed in.

Thanks!
Aidan

1.Name of the project: Tonepad El Griton and El Boost-o
2.http://tonepad.com/getFile.asp?id=68
   http://tonepad.com/getFile.asp?id=81
3.Etched the Tonepad PCBs myself, added 2 seperate perfboards: one to put two caps together as a substitution for the tone control and the other for the Asymmetrical/Symmetrical switch on the El Griton. I also used a perf board for star grounding.
4.El Griton:
Substituted 220nf cap connected to middle leg of tone pot for a 183nf cap (150nf + 33nf in parallel)
Added Asymmetrical/Symmetrical clipping switch using spst and 1n914's
   El Boost-o:
Substitututed 2n5485 in Millenium bypass section for 2n5457( I checked the pin out and it is correct.)
Note:
These two pedals are connected via a 3pdt toggle switch for order switching


6.The light for the overdrive turns on and off with the switch but the effect is barely audible unless the Level pot for the boost is turned up. This happens whether the boost is on or off, though, the level is a lot louder when the boost is on. There also seems to be a hump in volume at about 80-90% of the boost's pot sweep.

The boost light is off whether the effect is on or off but the light will come on and get brighter with stronger picking, almost like a VU Meter.

If the boost is before the overdrive the tone of the unit is a lot darker.

VOLTAGES

LPB

Q1 (2N5088)
E: 0.15V
B: 0.75V
C: 5.13V

Mil. By. (2N5457)
D:9.36V
S:0.27V
G:0.00V

D1
C:9.36V
A:0.00V

TS 808

Q1 (2N3904)
E:3.55V
B:3.98V
C:9.36V

Q2 (2N3904)
E:3.56V
B:3.99
C:9.36

IC1: (4558)
1: 4.65V
2: 4.67V
3: 4.65V
4: 0.00V
5: 4.65V
6: 4.65V
7: 4.65V
8: 9.36V

On both boards
9V Bus: 9.36V
Gnd: 0.00V


Here's the diagram for the wiring I used:


pork ruckus

Just updating on this post, I ended up taking out the Millennium bypass and wiring the lpb to a 3pdt switch. The lights are working properly and the TS 808 sounds great.  unfortunately, I'm getting a lot of ugly distorted noise from the lpb (when engaged) throughout the sweep unless it's cranked, in other words when the level pot is maxed out the boost is pretty clean otherwise it's garbled.

Could this be the result of a damaged pot or transistor?

Voltages at Q1 of LPB are:
E: 0.15V
B: 0.75V
C: 5.22V

Side note, the wiring diagram I posted is almost certainly wrong so ignore that!

lukeferg

While I am certainly no expert I'd be looking for solder bridges or other issues before pointing the finger at pots or transistors. You transistor voltages look ok so it's probably fine.

One thought, the 390R resistor from the emitter. Check to see if you've accidentally put a 390k in there instead.

pork ruckus

Thanks for the reply Luke! I probably should've mentioned in my original post that the first thing I did was look for solder bridges and wiring mistakes. I assumed after checking for human error that it might be a faulty component. I don't know what to expect in terms of voltages for the transistor but upon further reading and listening I think this boost is just inherently grittier than I was hoping for. It sounds great when the OD and Boost are engaged but I'd like to be able to boost my clean tone without colouring the tone  too much. I think I'm going to try my hands at a Micro Amp, if anyone has suggestions for a boost that plays well with Tube Screamer I'm all ears, in the meantime I'll peruse the forum for what people have recommended.

Thanks,
Aidan

lukeferg

No worries, truth be told, I never really gelled with the LPB1 either.
Try a Super Hard On or the AMZ mosfet boost. Both these are much cleaner, the AMZ is as transparent as it gets. They give you more of what you've got and if put before the tubescreamer will kick the TS into more saturation.
They're also useful when used after a drive pedal to give a volume boost rather than more distortion.