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Vintage threads from the first ten years

SansAmp Noise

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1/23/2000 5:44 PM
Brad	SansAmp Noise Have a GT2. Works well and sounds good in Tweed settings. But pretty noisy in British and California settings. Any tricks to attenuate the noise in this? This is through all amps and direct, and with single-coil or HB's. Thanks. Brad

1/25/2000 8:01 AM
Kursad Kurt	What do you mean by "direct"? Direct into a power amp?

1/25/2000 1:32 PM

Basically, it gets a lot of buzz when in Brit or Cal settings, even going direct into mixer. I took the thing apart (they don't make it easy) and checked out all diodes, resistors, connections, etc. I wondered if there was some sort of adjustment pot(s), but there wasn't. There IS an 8-pin surface mount IC that they removed all ID from, and a big square rubber covered thing, with no marking. It's basically useless in Brit or Cal settings, and I have heard that some get noisy, and some aren't. Just wondering if anyone has a cure. Almost sounds like a bad ground, but I checked all the traces, and everything (as far as I could tell) seemed fine.
Brad

1/25/2000 3:42 PM

Brad,

Turn the volume on your guitar off when in those two settings and listen for the buzz level. If you no longer hear noise, your pickups are sending the noise through to the GT-2. Are you sitting in front of your computer monitor with your guitar? More and more people are discovering that computer based recording systems and electric guitars don't like to be near each other.

There is a huge amount of gain in those two modes, actually more than people need. Set the gain to where it feels comfortable, then back it off two notches. You will probably notice that there is still enough drive. There is hiss in those two modes, but there should not be any buzz without a pickup present. When your guitar is connected (and more so if you use single coils) you will hear hum in the high gain modes. Try hooking up a guitar with P90's to a high gain amp and listen to the noise. The hum is louder than the notes when your not playing. The two things to look for are power supply hum, and proximity to devices such as monitors, and transformers. If you find that you still have trouble, you should just contact me at work:
john@tech21nyc.com

1/25/2000 6:16 PM
Frank Clarke	The surface mount chip is a HEF4013BT dual D-type flip-flop. Presumably for switching purposes. The noise is not from the guitar or computer monitors, it is from the GT2. The key parts are epoxied, so selling it would be the best option. Pity.

1/25/2000 6:24 PM
Frank Clarke	The HEF4013BT is 14-pin, sorry. The 8 pin is 072c, pin 1 in the top right hand corner. It seems to be a dual opamp.

1/26/2000 1:49 AM

Re: SansAmp Noise - Mods!

Try a 5.6nF cap from ground to the leftmost lug of the High pot. This reduces some of the hiss without affecting the tone. I'm using a 12" speaker, and the PCB out of the box to test this.

A 5.6nF cap from ground to pin 2 (inverting I think) of the 8-pin opamp gives you a treble boost on the british and california, but not on the tweed. So maybe an inductor to pin 2 would cut treble on the british and california.

The lowest noise setting seems to be a V-shape on the switches.

You have tried the in-between settings on the 3-way switches?

My GT-2 hadn't been working for a while, turns out I broke the 9v adapter plug taking the PCB out of the box. Another for R.G's dirty tricks list. Along with the double-sided PCB.

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