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Solid State Amplifiers => Amplifier Discussion => Topic started by: AllThorUp on November 12, 2022, 02:23:08 AM

Title: I have a question regarding this schematic - Pignose Amp
Post by: AllThorUp on November 12, 2022, 02:23:08 AM
Hi I have this Pignose 30/60 amp and I was looking at the schematic and also the circuit board and was wondering if anyone could tell me what the purpose of LED1 and LED2 are in this circuit? On my amp's PCB they are labeled but not populated.. I'm just curious about them is all. Thanks
 Pignose_30-60_schem.pdf
Title: Re: I have a question regarding this schematic - Pignose Amp
Post by: Tassieviking on November 12, 2022, 09:04:06 AM
To me they look like clipping diodes, stick some sockets in the holes and then you can experiment with led's diodes etc.
If you get a row of SIP sockets you can break them off individually and solder them in.

They might also work as a signal limiter so the signal after this stage stays below a certain level, the led's would start conducting at a certain voltage and thus limit the voltage going to C9 and C10.
Title: Re: I have a question regarding this schematic - Pignose Amp
Post by: joecool85 on November 12, 2022, 09:24:42 PM
Quote from: Tassieviking on November 12, 2022, 09:04:06 AMTo me they look like clipping diodes, stick some sockets in the holes and then you can experiment with led's diodes etc.
If you get a row of SIP sockets you can break them off individually and solder them in.

They might also work as a signal limiter so the signal after this stage stays below a certain level, the led's would start conducting at a certain voltage and thus limit the voltage going to C9 and C10.

I'm going with clipping diodes.  They were left out because the Pignose 30 is a bass amp and, generally speaking, people don't like distortion in their bass amps.  You could throw the diodes in (though I do recommend using sockets as suggested above) and see if you like it.
Title: Re: I have a question regarding this schematic - Pignose Amp
Post by: Loudthud on November 13, 2022, 04:06:42 AM
It would be a cool place to try one (and only one) of those bi-color LEDs that are one color with one polarity and a different color if you reverse polarity.
Title: Re: I have a question regarding this schematic - Pignose Amp
Post by: AllThorUp on November 22, 2022, 04:08:03 AM
Quote from: joecool85 on November 12, 2022, 09:24:42 PM
Quote from: Tassieviking on November 12, 2022, 09:04:06 AMTo me they look like clipping diodes, stick some sockets in the holes and then you can experiment with led's diodes etc.
If you get a row of SIP sockets you can break them off individually and solder them in.

They might also work as a signal limiter so the signal after this stage stays below a certain level, the led's would start conducting at a certain voltage and thus limit the voltage going to C9 and C10.

I'm going with clipping diodes.  They were left out because the Pignose 30 is a bass amp and, generally speaking, people don't like distortion in their bass amps.  You could throw the diodes in (though I do recommend using sockets as suggested above) and see if you like it.

Actually this amp is a pignose 30/60 which is different from the 30, which is a bass amp. this one, however, is a small combo amp made for guitar that I repaired and turned into just a head unit because the speaker and enclosure were thrashed.