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The Newcomer's Forum / Re: CRATE GFX-20 doesn't work, just makes humming noise when powered up
« on: May 07, 2020, 11:04:59 AM »
Is the hum affected by the volume/gain controls or is it there all the time. And is it LOUD.
News:
Boards have been ordered for prototyping SSG-AMP-1. Stay tuned!
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Amplifier Discussion / Re: TIP147 TO-218 equivalent for Fender Performer 1000
« on: April 27, 2020, 02:14:16 PM »
Did you remember to isolate the transistor tab from the heatsink?
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Amplifier Discussion / Re: Poll: Official SSGuitar amp kit - preamp, or small battery amp?
« on: April 23, 2020, 03:45:52 PM »
The Artec amp uses this IC although they rate it at 2.5w. The Electro Harmonix EHX 5MM Guitar Power Amplifier also uses this Chip.
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Amplifier Discussion / Re: Poll: Official SSGuitar amp kit - preamp, or small battery amp?
« on: April 23, 2020, 03:34:55 PM »
Can I suggest NJM2073 bridged with JFET buffer a la Ruby or noisy cricket. NJM2073 gain is some 44dB or x158 approx. Probably enough gain for a big muff tone control after the buffer. NJM2073 will give some 2 watts into 16 ohms and about 1.5w in 8 ohms. Almost forgot - off 9v.
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Guitar News / Re: Nutube is the word of the day at NAMM - Vox and Korg Nutube pedals
« on: January 11, 2020, 03:25:58 PM »
As far as I can see these Nu-tubes are just a gimmick. You dont get a lot of gain from them so they are not going to have much effect to the signal. Snake oil 
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Amplifier Discussion / Z-MATCHER 100W IMPEDANCE MATCHER
« on: September 13, 2019, 05:42:51 AM »
Does anyone here use this device, any comments and does anyone know what is inside? It looks small to house a 100w transformer.
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Amplifier Discussion / Re: What Op Amp for 20W+ Busking Amp?
« on: August 08, 2019, 05:36:53 AM »
Check out the OEP30w amplifier this will give you 17w into 2x8 ohm speakers in parallel at 12v. Class d bridged amplifier, you wont hear the difference between 17 and 20w. All over ebay at about $2
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Amplifier Discussion / Re: Fuse or resistor?
« on: June 19, 2019, 05:10:50 AM »
The resistor within a circle /oval is the symbol for a thermistor, and is part of the temperature compensation for the bias network. It should - but is not always - be mounted on the heatsink for the output transistors. Unfortunately there is no value given for it.
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Schematics and Layouts / Re: Operational Amplifier in Marshall 5010 scheme
« on: March 17, 2019, 04:17:08 PM »
It doesnt really matter. Any dual op amp eg TL072, NE5532, JRC4558 etc will work.
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Amplifier Discussion / Re: Help with Gallien-Krueger 200GT guitar amp
« on: March 02, 2019, 07:01:46 AM »
Probably something simple like a dry joint or a duff pot
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Amplifier Discussion / Re: Polytone 102 Tremolo
« on: January 24, 2019, 02:37:54 PM »
The symbol is the Greek letter Lamda which indicates the resistor is light dependent. The resistor in a circle above R53 must be a light source (48v lamp?). This is coupled optically to R16 which is a Light dependant resistor.
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Amplifier Discussion / Re: OK to run Marshall Lead 12 into 4 ohm load?
« on: November 26, 2018, 06:15:00 AM »
The output transistors are ok with the higher power, but the heatsinks are a little small.
All I can suggest is try it and see how hot it gets. If you cannot hold your fingers on the heatsinks for a couple of seconds then they're too hot.
All I can suggest is try it and see how hot it gets. If you cannot hold your fingers on the heatsinks for a couple of seconds then they're too hot.
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Amplifier Discussion / Re: SWR 550X Bass Amp Trouble
« on: September 21, 2018, 06:21:57 AM »
The first thing I would do is to check the output for DC. To me it sounds like one of the output transistors has failed.
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Amplifier Discussion / Re: Need Help Repairing Pyle Guitar Amp after short circuit--only hums & pilot lite
« on: August 21, 2018, 02:23:10 PM »
You will have blown the power amplifier by connecting the external amplifier. It will be an IC or discrete transistor device. A photo will show which. If an IC it will probably easier to replace if you are competant to do that - can solder properly etc. A Transistor amp will be more complicated. If you are not sure it would be better to take it to a tech.