Ou7shined Posted February 28, 2014 Share Posted February 28, 2014 (edited) Hi all. I've been given a single pup Pangborn with dodgy 'tronics to work on. The owner has made one or two home "improvements" in it's time. Chiefly the Vol pot, which does absolutely nothing now. He also partially installed an LED for the active circuit. It was a horrible mess and I've spent all day tracing, re-soldering, removing extraneous wires and replacing old corroded ones) and still can't figure out what's wrong. My poor finger tips are now scorched from soldering and de-soldering in the tiny space for the controls and I'm pretty fed up. The big old preamp is still wrapped up old school style in it's original masking tape and copper foil. So I'd rather only crack it open as a last resort - although tracing the circuit would be much more finite if I did. Below is my diagram of how it was originally presented to me (once I'd removed all the dross). I hope I've made everything clear enough. To the best of his knowledge this is how it was before he started modding it too. Although he can't be certain of the pot value that he removed. I've tried a 500k B and a 10k pot in case it was a bit fishy like an EMG circuit but nothing helps. Note : The centre control is stacked - both pots are fixed and adjust simultaneously. What I thought was a 50k treble pot in the diagram actually turns out to be more like a 100 when measured. The controls are vol>bass>treb in active mode (bass and treb seem to work to an extent) and I presume that it should then become vol>tone in passive mode (with the treble pot now out of the circuit) but obviously it doesn't function in this state. The pup bypasses the vol pot which itself bypasses the tone and the lone connection to the tone pot (if that's what it is) seems pointless. Any suggestions guys? Many thanks in advance. Edited February 28, 2014 by Ou7shined Quote Link to comment Share on other sites More sharing options...
Musky Posted February 28, 2014 Share Posted February 28, 2014 (edited) I've got a Pangborn circuit in one of my basses. Push/Pull on one of the volume controls, phantom power. Seem to remember that there was a stacked pot in there and the circuit board was enclosed in something or other. I'm a bit busy this weekend but I'll see if I can have a poke around and let you know what I find. Edit: There used to be a Pangborn group on Yahoo. Common comment was that the electronics could be a bit unreliable. Edited February 28, 2014 by Musky Quote Link to comment Share on other sites More sharing options...
Ou7shined Posted February 28, 2014 Author Share Posted February 28, 2014 [quote name='Musky' timestamp='1393616723' post='2382717'] I've got a Pangborn circuit in one of my basses. Push/Pull on one of the volume controls, phantom power. Seem to remember that there was a stacked pot in there and the circuit board was enclosed in something or other. I'm a bit busy this weekend but I'll see if I can have a poke around and let you know what I find. [/quote] Aw man that would be awesome thanks. No push/pull in this one though.... just scratchy barely functioning crap. [quote name='Musky' timestamp='1393616723' post='2382717'] Edit: There used to be a Pangborn group on Yahoo. Common comment was that the electronics could be a bit unreliable. [/quote] From what I have here I can well believe it. It sounds lovely plugged in ... you just can't change anything. Quote Link to comment Share on other sites More sharing options...
Musky Posted March 3, 2014 Share Posted March 3, 2014 As you can see, it's a minor rats nest in there. It's probably best if you just let me know exactly what you need, but the treble and bass pots are both 100k (I imagine the 'L' after the '100k' means they're log) and the square pot is 500k (push/pull switch for active/passive). Presumably the second volume pot is the same value but I can't read it due to the positioning of the circuit board. Quote Link to comment Share on other sites More sharing options...
Ou7shined Posted March 4, 2014 Author Share Posted March 4, 2014 Hey thanks ever so much for taking the time to post this. From what I can see, it looks a little different to the one I have here. He might have used similar techniques to wire them up though. I wonder if you could knock up a rough sketch of how everything is connected in your circuit? I might be able to get a better idea of where he was coming from and replicate it in this one here. Quote Link to comment Share on other sites More sharing options...
GeeCee Posted March 5, 2014 Share Posted March 5, 2014 Is the bass a Chieftain or a Warlord model? I believe Nick Smith (doctor_of_the_bass on BC) has a single P/U Chieftain with B/T active circuit. Why don't you send him a PM. He may be able to help you. Quote Link to comment Share on other sites More sharing options...
Ou7shined Posted March 5, 2014 Author Share Posted March 5, 2014 I think it's a Warlord. Although I can't find one that looks quite like it online. It's a very basic single bucker version. I'll put a pic up tomorrow. Cheers for the tip. I'll see what he has to say. Quote Link to comment Share on other sites More sharing options...
Musky Posted March 5, 2014 Share Posted March 5, 2014 [quote name='Ou7shined' timestamp='1393928023' post='2385813'] Hey thanks ever so much for taking the time to post this. From what I can see, it looks a little different to the one I have here. He might have used similar techniques to wire them up though. I wonder if you could knock up a rough sketch of how everything is connected in your circuit? I might be able to get a better idea of where he was coming from and replicate it in this one here. [/quote] I'll give it a crack, though a whole bunch of those wires seem to disappear into the preamp. I'll take a poke about and let you know what I find. Quote Link to comment Share on other sites More sharing options...
Kiwi Posted March 5, 2014 Share Posted March 5, 2014 I have a graphite necked Panger too, unfortunately it's with Jon Shuker waiting to be finished. I thought the circuit in mine sounded pretty good, all things considered. But it did seem to be built in someone's garage somewhere. The main thing to be careful about is frying the preamp chip. Easily done if there's a short circuit. Quote Link to comment Share on other sites More sharing options...
scojack Posted March 5, 2014 Share Posted March 5, 2014 (edited) My Pangborn had a pretty awful circuit too. I know AP hated paying a lot of money for electronics and a lot were made for him by someone he met in Radio Shack one day! Mines had a home made cicuit built on vari-board (i think it's called) lovely wee red LED on the pickup selector which was at the time pretty fecking fancy! (We are going a long way back here lol) Anyhoo i eventually gave up on it and would just run the bass passively tbh, it eventually just died anyway....... Not much help though m8 but thought id share the AP experience... Id love to see this bass Edited March 5, 2014 by scojack Quote Link to comment Share on other sites More sharing options...
Ou7shined Posted March 5, 2014 Author Share Posted March 5, 2014 Here's the bass in question. Quote Link to comment Share on other sites More sharing options...
Ou7shined Posted March 5, 2014 Author Share Posted March 5, 2014 [quote name='Musky' timestamp='1393985071' post='2386679'] I'll give it a crack, though a whole bunch of those wires seem to disappear into the preamp. I'll take a poke about and let you know what I find. [/quote] Cheers again mate. Just draw what you see I should be able to second guess the wires coming from the pre. Quote Link to comment Share on other sites More sharing options...
Ou7shined Posted March 5, 2014 Author Share Posted March 5, 2014 [quote name='Kiwi' timestamp='1394010353' post='2386772'] .... I thought the circuit in mine sounded pretty good, all things considered. But it did seem to be built in someone's garage somewhere. The main thing to be careful about is frying the preamp chip. Easily done if there's a short circuit. [/quote] Yup same here jerry-built in appearance but sounds great.... despite there being no real control over it at the moment. My greatest fear is that the chip (or some other part of the pre) has already expired. Quote Link to comment Share on other sites More sharing options...
Ou7shined Posted March 5, 2014 Author Share Posted March 5, 2014 [quote name='scojack' timestamp='1394015677' post='2386858'] .... I know AP hated paying a lot of money for electronics and a lot were made for him by someone he met in Radio Shack one day! Mines had a home made cicuit built on vari-board (i think it's called) .... [/quote] That would explain a lot. I suspect the one I have here will be a similar construction under the layers of copper shielding and masking tape. Quote Link to comment Share on other sites More sharing options...
Kiwi Posted March 5, 2014 Share Posted March 5, 2014 If the preamp (Op-amp) chip is accessible (rather than covered by epoxy), they're cheap as chips to extract and replace if you can find a supplier. I replaced the one in my Jaydee circuit a number of times before going to a Bart circuit. Quote Link to comment Share on other sites More sharing options...
scojack Posted March 5, 2014 Share Posted March 5, 2014 Yup that's a Warlord ....takes me back. Lovely lovely Basses to handle and play though ..despite the dodgy lectrics. I should never ever have sold mine Quote Link to comment Share on other sites More sharing options...
Ou7shined Posted March 13, 2014 Author Share Posted March 13, 2014 Just a quick update. A couple of Pangborn buffs advised me to do as they did and rip out the dodgy original pre and replace with something better. So after discussing our options (the restrictive size of the control cavity being a factor) the owner and I decided to go for an Aguilar pre. That out of the way, I decided to dissect the original Pangborn preamp. Those of a nervous disposition please look away.... Trust me the picture makes it look much better than it actually is. Real amateur hour stuff. How it was felt appropriate to put work of this quality out in a finished instrument is beyond me. Quote Link to comment Share on other sites More sharing options...
MoonBassAlpha Posted March 16, 2014 Share Posted March 16, 2014 That's pretty shocking for what would have been an expensive bass when new. BTW the trade name for that stuff is VERO board, generic name is strip board. Quote Link to comment Share on other sites More sharing options...
Ou7shined Posted March 16, 2014 Author Share Posted March 16, 2014 [quote name='MoonBassAlpha' timestamp='1394992596' post='2397502'] That's pretty shocking for what would have been an expensive bass when new. [b]BTW the trade name for that stuff is VERO board, generic name is strip board[/b]. [/quote] Yup I've used it many times. But I've not made a mess like that since I first started making my own projects way back in the 80s. Quote Link to comment Share on other sites More sharing options...
Musky Posted March 17, 2014 Share Posted March 17, 2014 I take it you probably don't want me to do that layout diagram then? I did actually get halfway through it, thought I'd finish it off the next day but in the intervening period managed to sever a nerve in my right index finger. Which kind of put a damper on anything that involved using a pen. Quote Link to comment Share on other sites More sharing options...
Ou7shined Posted March 17, 2014 Author Share Posted March 17, 2014 (edited) [quote name='Musky' timestamp='1395014499' post='2397847'] I take it you probably don't want me to do that layout diagram then? I did actually get halfway through it, thought I'd finish it off the next day but in the intervening period managed to sever a nerve in my right index finger. Which kind of put a damper on anything that involved using a pen. [/quote] Good god man no. You get yourself better first... if its at all fixable. The last thing any of us bass players needs is nerve damaged fingers (a constant fear of mine in my day to day work). Maybe once you're all better you can update the thread with your circuit for future Pangborn users in a similar predicament. Edited March 17, 2014 by Ou7shined Quote Link to comment Share on other sites More sharing options...
.gif.9ad672bb8b84505709f76b39c8c256ec.gif)
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.