Very old pignose 7-100

[larwood.amps]

Hello, please let me introduce myself, ( where have i heard that line before ).

My name is Larry, nickname Larwood, and I'm here on this site not only to try and share info whenever i can about my hobby of building Valve/Tube Amps, but also to get help on the mysterious world of Stomp boxes, and my once Trusty go anywhere with me, Pig nose.

Now as hard as i scour this wonderful,weird,web, I cannot find a schematic out there anywhere, can anyone help? The one way i would suggest if we cant find one, is for me to post a small drawing if its allowed, of the resistor that burned to a frazzle before my eyes as a techie tried to show me where to connect an adapter, instead of running it on batteries.
Of course this part used to look like a resistor, but now resembled a small sample of my wives cooking, burnt, black as your hat and no way of ID'ing it.

Now this all happened 12years or so ago,and the old old Pignose has been laying in the back of my workshop since then.If we could establish the age and place of manufacture which i believe to be L.A,
with a Serial No of 28315
and a Model No of 7-100,
PCB No 104/032/041.

I may get another chance to hear the wonderful tone of a piece of equipment trying it's best to operate as the six 1.5v batteries start to flag or sag or go flat, whatever, but that tone I've missed it.

I can tell you that it's the largest resistor or whatever it is (Diode maybe?) on top of the PCB as soon as you take the black metal shield away.

I do HOPE that this problem will soon be a thing of the past and Piggy will be singing away again,and then we can start talking stomp box lingo and the questions that arise from the cloneing and patent issues that always seem to rear their ugly heads if some person comes up with a cracking pedal and immediately gets jumped on.
All that for next time eh.

Appreciate your help in advance.

Larwood.:)

[Enzo]

Hi, welcome to the forum.

Did you contact Pignose and ask if they could provide the schematic?

[teemuk]

Here's a schematic for some post 1986 models. I believe there have been several revisions of this amp so not all component values may apply. You need to do a little bit of detective work to find out how accurate this diagram actually is. For example, I heard rumors that newer Pignose 7-100's just have a IC-based power amp section and no longer use transformer coupling (I haven't opened up a new Pignose to verify this, though). That would mean the circuit would be entirely different. Anyway, let's hope this diagram helps.

[larwood.amps]

Hi, welcome to the forum.

Did you contact Pignose and ask if they could provide the schematic?

Hi Enzo,

I just took it for granted that they ( pig nose ) would not release the schematic into the public domain, this is the info i had picked up from searches on other AMP & EFFECT SITES, while searching for info to repair my JEN Mr Crybaby, that still needs to be done as well. Pignose have schematics posted for their foot pedal effect "The Detonator" and i believe the G40 Amplifier, but the general concensus was no 7-100 schematic,s existed.
But i suppose i,ll have nothing to lose by trying them direct. I do have a schematic to look at that has been posted by a member, and see if that tallies up with other components on the board, if all works well i'll save that schematic for future reference for myself and other members.
Thanks.

Larwood.

[Rob Mercure]

Wow, just looked at the schemo that Teemuk provided and the only thing that comes to mind is "transistor radio." The amp is almost the exact audio section from the first "6 transistor" Japanese radios of the late 1950s - early 1960s.

Rob

[larwood.amps]

Wow, just looked at the schemo that Teemuk provided and the only thing that comes to mind is "transistor radio." The amp is almost the exact audio section from the first "6 transistor" Japanese radios of the late 1950s - early 1960s.

Rob

Hi Rob,
Time to hold the hands up here i think, never been a tranny lover until late, actually when it was time to try to sort out the Cry Baby, I dont want to get into any for and against type of forum polls, but i must lay my cards on the table here, but i quite literally, sleep, eat & drink tubes/valves. So i am going to find myself on one of Leslie West's Sleigh Rides here, and i think i'm going to enjoy the curve. I will accept any help and or criticism,if anybody thinks i,m starting to run off track, I do have a nice 1963 BUSH Transistor in the workshop that usedto belong to my Father, so time to open her up and go to school i think.

Larwood

[52 Bill]

The original ones I remember, used a pre-made circuit board that was also sold at places like Allied and Lafayette. They had a metal cover that also served as the heatsink for the output transistors.

And as Teemuk's schematic shows, these were japanese 2SB germanium transistors. That leads me to believe that the schematic is in fact for pre 1984 versions. The ones I see now-a-days have silicon TO-220 outputs.

I have not yet seen any IC versions, but I wouldn't be surprised if they have moved on to a LM386 version.

[Dave Curtis, dB AudioTech]

Here's the one I have.

[larwood.amps]

Here's the one I have.

Hi Dave,
I thought it about time i pulled the Pignose off the shelf and remove the shield protecting the circuit, that done I've unclipped the transistors from off the power & output transformer shield to see if we can throw a bit more light on the date of the circuit board,

They are :- B324(G)

And the two on the board are :-B172(A) & B175(B)

I also ran a search on the names that 52 Bill threw into the mix, my eyes have been well and truly opened, Lafayette closed down 1970, and the site
www.childhoodradios.com really blew me away, especially the link to the Lafayette Radio Club.

Hope this helps.

Larwood:confused:

[larwood.amps]

Just replying to my own post here, the transistor set up is exactly the same as Dave's schematic so i'll just start chasing it down to see if other values are the same on the board. Things, i feel are starting to look good. :D

[Enzo]

Asian transistor types have numbers that start with "2S", just as American types start with "2N." The asian transistor makers generally leave off the 2S as understood. Thus B324 is really 2SB324, and so on. If you look at Dave's schematic with that in mind, you will find your transistors are the same ones listed in that schematic.

[larwood.amps]

Asian transistor types have numbers that start with "2S", just as American types start with "2N." The asian transistor makers generally leave off the 2S as understood. Thus B324 is really 2SB324, and so on. If you look at Dave's schematic with that in mind, you will find your transistors are the same ones listed in that schematic.

Hi Enzo,
Thanks for the info regarding the 2S & 2N Prefix's, that is one for the note book in this late lesson in life about Solid State components.
I had in fact just spotted my oversight just as my post hit the Ether, and as you can see, i sort of sent myself a post to show what can happen if you don't analyze a drawing before shooting off onto the stage in the proceedings. I also received an Email from Howard@ Pignose this morning, with the component list echoing Dave's Schematic.
So it seems as between you all you have solved the date issue, Howard seems to think it's Post 86 by the schematic that was Emailed to me, i can only ask would you all tend to be in agreement with that?
Now the only thing is to build up a component by component circuit board, and hopefully by process of elimination that burnt out resistor, will show itself. Then after we have installed anew one on the board, i will have to find out what was the real cause of the burn out, somehow i just cant see it being an adapter, even if the polarity had been reversed, with enough steam in it to burn out what appeared in size to be possibly a 2W resistor.
But things are looking up and hopefully this Little Piggy should be singing before much longer.

Larwood.

[Enzo]

Which part it is? What other parts does each end connect to?

Then after we have installed anew one on the board, i will have to find out what was the real cause of the burn out, somehow i just cant see it being an adapter, even if the polarity had been reversed,

Excuse me? I can think of no faster way to burn out parts on a little board than reverse polarity power. The transistors don't like it, nor do those electrolytic caps. And tantalum caps have almost no tolerance for it, if you have any in there.

222ma from a 9v source makes 2 watts. Chances are your adaptor can handle at least that much.

Educating my customers as to power adaptor selection and use is one of the most common lectures I serve up.

[larwood.amps]

Enzo, we're going back some 12-15Yr's here and much of what i remember was my Pignose going up in smoke.

Now this techie with the adapter just turned up at a jam we were having at a friends house, and the batteries in the amp were running low, also giving off that beautiful distortion as they do so. He takes out this adapter and set it for 9v, as for the rest of the specs, i haven't a clue , it was one of those modern at the time multi voltage, i think Ross adapter's, and plugged it in.

Nothing happened at all, even left it connected as he swung the case open to pull the batteries, at the same time the amp just started to smoke, he pulled the plug , but alas to late.

Now i don't know if you've ever seen the plate where you plug an adapter into on a Pig nose, but it's just a standard 3.5mm jack socket without ref to any form of polarity, in fact, all it does say is 9v-adapter.Also this guy roadied for a couple of bands that i knew of, so the last thing on my mind was to question what the **** had he just done. Needless to say that was the end of my jamming session, and the one good thing that came out of it ,I never let him within 10 meter's of my kit, and i ask him now all these years later, has he managed to kill any Pigs lately.

Now as i said in one of my other posts, i am going to pull the circuit board and put all the specs, around the offending Resister down on a piece of paper and hopefully we should find the value that way.

Now if what you have pointed out in your post is likely to have happened, i am going to have a seriously sick amp regarding the other parts on the board, and the outlook maybe to anticipate and get ready to replace all components on the board.

Enzo i cant thank you enough in helping me to get my feet wet, so to speak in my speed course into solid state circuitry, and my ignorance of the power situation is unforgivable, but all these lessons learned now will provide well for the future. I have some specification figures from that factory schematic here and i,ll just type them below

SOURCE = 9V dc
OPEN LOOP = 15MV
MAX CURRENT = 400MA
INPUT IMPEDANCE = 50K

As I've pointed out this is for a 7-100R, POST 1986

[Enzo]

Adaptors are in no way generic or universal, though many people assume they are... like your buddy.

Most gear nowdays is labeled for just what power it needs. But when Pignose made the amp, it was assumed you would use the Pignose power adaptor. We know now from the schematic what it needs to be, but if you use the proper Pignose item, then you don't NEED to know what it spits out, all you need know is that it is the right one for the job.

Not all makers get this for that matter. I remember some little MIDI acessory many years ago that came through the shop. They had tried the wrong adaptor and blown it up. In the repair game, this is not a rare type repair. Little Boss effects pedals for example will blow up the little protective zener diode if polarity is backwards or AC is applied. So I called the company that made the thing to ask what parts commonly fried when reverse power was applied. I also wondered to them why did they not add a protective diode for just that reason. They responded, "Oh no, only use our adaptor." Yes, I know that I replied, but when some nut uses the wrong kind, what typically blows up? "Oh no, don't use the wrong kind." Took me a while to get through to them that regardless of what we all are SUPPOSED to do, not everyone does it, and wrong power adaptor is something they should expect to happen to their products. And while there is no guarantee, many products have a fairly predictable failure mode under those circumstances.

We are always glad when things work out around here, thanks the other guys for the schematics and insights as well.

[larwood.amps]

As i have already mentioned in a previous post, i have quite literally been blown away by this foray into solid state circuitry.
I cant thank you all enough for all the suggestions and schematics, it only leaves me to apply the brain to the technology and letting you all know the outcome.
Once again thanks to everybody.

Larwood.

[Borg54]

Larwood, if you get that pig up and flying again. There is a really cheap and easy mod for the Pignose. Almost everyone that I know has fallen in love with the thing at 1/2 battery life. The same Tone can be achieved with the wall-wart PS by taking and wrapping the dc cable around a ferrite core. Just keep wrapping until you have the tone that you?re after. The mojo is in the turns, I don't question why and how some things seem to work, they just do. Have Fun

Doug

[larwood.amps]

Thanks Doug,
I'll definitely try that, i have even thought of having an onboard wart so's there would always be a permanent power supply.
But at this moment in time i have arrived at the conclusion that the resistor that burnt out is the bleed resistor between the two 324 transistors, 1R-1W Carbon. Now i cant say that is the correct resistor , because although all the other resistors are original ( white insulation paint on the legs ) only 11 of the 18 resistors tie up with the schematic. I've searched the case for more clues as to the age, and where the 9v input is , is a stamped date, that looks very much like 14 APR 1978. Now the other schematic that was posted by Teemuk, shows an 8.2R resistor in the bleed off..
But most of all , until I've located the transistors i wont be going ahead with the rebuild in case there was a backwash of damage to the other components before the resistor burnt out.
As i said in other posts I'll keep everybody up with the progress as i go along. Because along with all the help I've received from the Forum WE CAN'T FAIL CAN WE.:D

[Cagey]

. There is a really cheap and easy mod for the Pignose. Almost everyone that I know has fallen in love with the thing at 1/2 battery life. The same Tone can be achieved with the wall-wart PS by taking and wrapping the dc cable around a ferrite core. Just keep wrapping until you have the tone that you?re after. The mojo is in the turns, I don't question why and how some things seem to work, they just do. Have Fun

Doug

Noob translation request: "wall-wart PS" - the AC adaptor? Ferrite core - a magnet or just iron? Thanks.

[Cagey]

Noob translation request: "wall-wart PS" - the AC adaptor? Ferrite core - a magnet or just iron? Thanks.

OK figured out the WW. I haven't seen this mentioned anywhere else. Does anyone else have another reference to this trick?

I found a "Dying battery simulator" - another way to achieve the same effect?

http://beavisaudio.com/Projects/DBS/