EH LPB

[uki]

Hey guys !

I'm working on this small boost but no go... 

Is this schematic good working ? Also I don't have the 2n5088 , using c945 atm can this be the problem ?   


Thanks

[sluckey]

Schematic looks OK. That C945 should work if you connect it correctly. Be careful. It has a different pin arrangement from the 2N5088.

[uki]

Schematic looks OK. That C945 should work if you connect it correctly. Be careful. It has a different pin arrangement from the 2N5088.

Thanks sluckey , I did check the pins , I got some others here gonna try different ones too.

Here is a simpler schematic to compare: http://fuzzcentral.ssguitar.com/schematics/lpbschem.gif

[uki]

I've tried so far C945, BC548, BC549, 2N2222, BCY59 ... but so far all I get is radio.
What is wrong ?!  

Hey I got it, some ground was disconnected !!

[Ritchie200]

Uki, you may want to check out the Linear Pro Boost+ thread a ways down in this section.  Jojo could help you out on this as he has spent HOURS on this design.

Jim

[uki]

Oh hey Ritchie !

Thanks for the hint, I got the pedal almost done, the footswitch just arrived today, and now i can complete it !!
Also I've found a small box laying around for housing!

The 2 transistors(the ones I have) that work the best is BC945 and BCY59 this one is strong does some distortion at high level almost like a fuzz.

I got few more pics!!

[uki]

Now that it is finished it isn't working...
Already have tried several things,checked all connections, wires, I've checked the circuit itself several times, replaced the electrolytic cap, replaced the transistor, checked for shorts, nothing... the signal dies when the switch is pressed it only work in bypass mode.

 

[jojokeo]

Transistor is in backwards as Sluckey mentioned to check earlier. The original transistor used one of two tranny's with the 2n5088 being one of them. This circuit is highly dependent on the tranny used and the hFE of it. See data sheet below:

[uki]

Yay got it , it is working !!!  Thanks man !!!  I was miss reading the datasheet picture, the pic shows the transistor from the botton I was reading it like it was the top...     confusing transistor..

 

It sounds good !!

Many thanks !!

[alerich]

Good job. Glad you got it working. This is my old EH LPB-1 with the plug in 1/4" connector form the late 1970's.

[uki]

Good job. Glad you got it working. This is my old EH LPB-1 with the plug in 1/4" connector form the late 1970's.

Wow nice !! The original one, it is a nice pedal to overdrive the amp !!

[Ed_Chambley]

Good job. Glad you got it working. This is my old EH LPB-1 with the plug in 1/4" connector form the late 1970's.

Very cool you still have it.

[jojokeo]

I have that exact LPB-1 also from the 70's and used it as the basis for my Pro Boost design: It continues to sound amazing and complements everything that goes into it...http://el34world.com/Forum/index.php?topic=19969.msg216249#msg216249
 
I have a hard time letting cool old stuff go. I still have my original Maestro Fuzz Tone too.

[smackoj]

Here are a couple of the designs I have tried and they all work great. I am a big fan of using Jfets for booster pedals. They have a ton of "quiet" gain in a very small package. I keep J201 and MPF102 around my shop because they are so consistent and powerful.