try lowering the supply voltage to 9Volts, 12 volts is the max supply voltage for most LM386 chips , it is possible that you have a bad wire or solder joint, or speaker, however I would lower the supply voltage 1st. 9 volt batteries are cheap.

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Bob Rissi (Risson Amps) and Kaufman work at fender around the same time , if my memormy is correct. This makes it real hard to say who designed what. I have heard that the Solid State Champ was Rissi's , but to be honest the only thing of his I know much about are the tube amps he has done and the  Rickenbacker Transonic(I still have 1 of these). Rissi possible  designed  most of the Rick solid state amps the design is very simular in all of them. The tube amps he has done the guitar amps sound like Marshall clones and the Bass Amps sound like Ampeg clone IMHO.

     The modelling question I really can't give you any insight on , I just don't work on them , if you wanyt it to sound like a Fender, Marshall, Mesa , buy those amps.

      The Hughs & Kettner , what happened was they started selling trash, I have made thousands for dollars repairing there design errors(keep'em coming H & K).

   out of time I have to get back to work for now , I will continue when I can.

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lol-ok I'll see wht I can dig up, The Risson, I have worked on 1 but it was the tube unit nothing unusual really. I"ll let you know what I find in my dusty old file cabnets , and what I can remeber about these units.

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Quote from: gbono on October 27, 2008, 09:33:45 PM

QuoteIf you want to get down to it  with  electronic history son I can go there , I have my degree and time in as well.

Okay, I'm waiting for the history lesson...............

What amp do your want to know about , lmao-if I can remeber anything about it I'm more that willing to share the info.

It was a GENERAL history , in the first place , and for your info teemuk ALL TUBE AMP CIRCUITS are designed around the western electric design considering the fact the built the first tube usable for audio amplification(and every other circuit that has followed since is based on it as well. If you want to get down to it  with  electronic history son I can go there , I have my degree and time in as well. that was just something I found online we all know about how accurate the facts you find online are.

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well Dan I'm not using a simulator , I using a paper and pencil and over 20 years of working with tubes.

Sounds like a plan armstrom, lets us know how it works out.

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Quote from: danV on October 26, 2008, 06:40:42 PM
I'm not sure wether on the schematic it says 50nF or 50uF (I guess it's 50u, since it's for bass and the requency response must go very low). In any case it'll give a gain of roughly 60-65 for guitar frequencies.

About the voltage divider in the Real McTube, it really depends on what kind of amplification you use after the pre. If it's a tube power amp, large signals are going to be OK. On the other hand, if the power amp is solid state, or you use the circuit as a pedal (like the Real McTube), you have got to limit the voltage swing to prevent clipping.

The gain of the first stage is 62.5 , if you add clipping diodes it will clip all the time. the type of driver and power stage (solid state or tube) is not important , if you place a cap between stages and and a dropping resistor( 47k or so) in the circuit this will drop the voltage (if needed) to your driver stage.

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If I remember correctly (I calculated it some months ago), voltage gain for tubes without the bypass caps are around 20, and you may still need the voltage divider network (maybe with another ratio). Sound was also a bit different. I'll check if I can still find the calculations, computer simulations and samples.

Quote from: blinkdude182 on October 26, 2008, 09:10:18 PM
what do you fellas know about the tech 21 trademark 60? i heard it once again on youtube only and it sounded nice but has anyone ever played it?

lol-many times , did some mods on 1 yesterday. they are good amps, not what I would use but I play blues and jazz.

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I found this while cruising the web this morning.


History of the Guitar Amp:

As with the Electric Guitar the origins of the guitar amp aren't really known. The first guitar amp was probably a hi-fi or pa amplifier. The transistor hadn't yet been invented. Rickenbacker and Gibson started making guitar amps in the late 30's. Gibson had a model that was meant to be sold with the ES-150 which was their first hollowbody electric. This was in 1937 where it appeared in the Gibson catalogue. Rickenbacker is known to have manufactured their first electric guitar in 1932 but there is no mention of an amplifier to go with it. When they and Gibson started manufacturing amps they were based on the current amps used in radio and hi-fi amps.

Fender got in to the act in the mid 40's (1945) with the company was still called K&F Manufacturing. They were also very simple amps and didn't have any controls (volume or tone). You used the guitar's volume and tone controls. It wasn't until after the aliens landed at Roswell J (1947) that Fender introduced their first amp. It still didn't have any volume, and tone controls. It was the Model 26 which used a 6V6 and Jensen speakers. The transformer was actually mounted onto the speaker rather than inside the amp housing. The first guitar amp with a volume control was the Fender Champion 600. These amps where beginner's amps (similar to the Champ Amp of today) and used a single 6V6 output tube. Also in 1947 Fender introduced the Dual Pro which had two channels and two volume controls (one for each channel) and a single tone control. These amps where used for the pedal and lap steel guitars as well as hollow and solid body electrics.

In the early 50's Gibson introduced the Les Paul Amp which used the 6L6 output tubes. It was also of a similar designed to that of the Fender which was based upon the RCA tube application manual. The demand for louder amps came around this time as well. Fender responded with the Tweed Series of amps and most notably the Fender Bassman. These amps had more tone controls (treble, middle, and bass) as well as a Presence control and found the use of the now very popular 12AX7 and 12AY7 preamp tubes. These tubes allowed the amps to have more tone variation than any amp. With the Tweed amps you found one of the first uses of 'Vibrato' (modulating pitch changes) and 'Tremolo' (modulating volume changes). Each of these functions further advanced the sound of guitar amps.

Vox introduced the AC15 in 1956 which was the first amp to use a class 'A' design. The Fender and Gibson amps all where class 'B'. The Vox amps even though only had 15 watts or so where loud and sounded great when turned up (distortion). They became the amp of choice for England guitarist mainly because Fender amps cost too much. The Beatles for instance used Vox Amps quite extensively. Some of the more important Vox amps are the AC30, AC50, as well as the AC100. The number was the amount of watts the amps put out. There was one great Vox amp called the Vox AC30TB. The TB meant Top Boost which it had because of the addition of an extra tube.

The 1960's found the guitar amp in even more demand with the start of Rock-n-Roll. Fender introduced there famous BlackFaced amps. These amps were known for their great tone and reliability. These amps are the first Fenders where the controls of the amp are on the front panel instead of the top panel. The Fender Tweeds, Gibsons, and Vox amps all had their controls mounted on the top of the amps so the guitarist could clearly see the amp settings. This change to move the control knobs to the front of panel probably came from the amps being louder. With the amp being louder caused the guitarist to be located further away from the amp. This meant that they couldn't see the controls if they were on top of the amp. So they got moved to the front. From what I can find out is the Fender VibroVerb was the first amp to have a spring reverb. Gibson had around the same time as this something called a Maestro EchoPlex. The EchoPlex was the first tape delay system that used a ¼ inch tape to record the guitar and then delay it and then play it back. This could be used to create a not so convincing reverb effect.

I would change that first bypass cap on the cathode of V1 to a 1Uf polorized and the bypass cap on V2 to the same , this will yeild a higher gain(not distortion but gain(will have a slightly higher volume)).

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try the Marshall MG, Valvestat, or Peavey 6505+ .

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Yes this is 100 watt bass head, but need tons more info bro.


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Wow , I have seen a Power Sonic years and years, I think it was a Bass amp (not really sure). If mot mistakin It had 2 15 inch speakers old alinco's. However one of the older guys here says that back in the day they made bass, guitar and PA's. Good luck bro

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That's what were here for, bro  :tu:

If the amp has an effects loop check and see if you get signal come from there if so the preamp is fine it is in the driver or power amp stage. Blown fuses can be caused by a many different problems.

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