Hello Roly,
     I have four 12" speakers. I want to put two into the Crate. One into a cabinet I am going to build as a combo for the RMS amp I modified, and I also have a Newcomb PA I converted into an amplifier. On an output plug in the back there are outputs for a 4, 8, or 16 ohm speaker. So I can finally put all of that together. It will be nice to have all of that junk organized into cabinets so at least it can all be stacked instead of laying all over the place.
     I have been really studying that Fender Squier 15 amp schematic. It is starting to make sense. It is a little easier now as the leads coming out of the triangles are part of a rectangular IC and all of the leads represent the numbers of the pins. I also see that there are kind of like loops going out and back into to a line that goes kind of straight through the circuit. The loops mold the sound with pots,caps, diodes, and a lot of resistors. The RC circuits make sense to me because they are in tube amps.
     It makes more sense now, but then I look at the Crate schematic, and that one still blows me
away. Anyway its getting a little better.
      I'll check out that meter. I think it cost about $25.00. I am going to have to buy a better one it
doesn't read high enough to go much further if I continue working on things that have higher voltage.
      Thanks for all your input. 

Hello,
      That being the case could I replace the 6" ones with the 12"s. I used the meter on the 12"s to come to the conclusion they were 8ohm, they came from an organ. The ones in the amp are stamped on the back 4ohms.                                                                                                                                              I hate to ask so many stupid questions on here. I was able to do some modifications to a Magnavox
record player and convert it to an amp, also a Newcomb PA system converted to an amp. With tube stuff it
is visible on both sides and it seems it is easier to grasp the idea of a path through it all. With solid state it is hard to know where anything goes or what it does, as there is a whole lot of stuff going everywhere all at once.
      I built an Inductance adapter, Capacitance adapter, and a Gauss meter adapter to try to learn about
solid state electronics, however they were kits and it was like a paint by number set.
      There is one amplifier repair shop in this area. While the guy does a remarkable job repairing things, He
told me, He only knows how to diagnose and repair problems, He told me He doesn't know what will happen if you do any modifications to any given circuit.
       I have some electrical books that were used for military training. The library has a limited number of books on things about audio electronics. I learned a great deal about tube amps from a few books by Gerald Weber. 
       So I am trying to learn how to do things but it seems to take forever. Thank You again.

Hello,
       The reason for the two different designations is because when I was going to contact Loud, it was my understanding they would want the serial number. On the front of the amp GX40-C is silk screened, As I was
looking on the label on the back for the serial number it has GX-40C+. I was going off what it said on the front of the amp. Up until that time, I had no idea there was a discrepancy involving two numbers. Or even two
different models. Sorry if that caused a lot of problems.
        I am searching now for information involving speakers. The two in the Crate are 6" they are listed as 4ohm, but read 5.5 and 5.3. The two 12"s are 5.7 and 7.4 so I am trying to find out if that is close enough.
        I really appreciate your time and effort, Thank you very much.   

Hello,
      Yes you are right. I can see that is why they require anyone requesting their schematics to waive the company of responsibility. It's just a little frustrating. Also it is 25 years old. I will just keep watching the forums, maybe someone will make a repair on that part of the circuit. Thanks for your explanation.

Hello,
       I took chassis out and there are at least 25 or 30 diodes on it, none of them are opposite each other so I think I will just leave well enough alone. Without a proper schematic I would have no idea where to start.       
       Everything functions, I only paid $20.00 for it because the electrical input socket was shot, and someone had dropped it or something fell against the knobs and broke the circuit board. I just melted the solder back together, adding more as needed. Good to go. I would hate to meddle with it and ruin it being stupid.
       So I guess if Eric Clapton ever decides to come over, he will have to bring his own amp if he can't make
do with one of the 15 watt ones. However I am quite sure before that ever happens, I'll probably have it up
and running.
        Thank each and every one of you for your interest and effort, it was not for the lack of trying this did
not work. It was lack of information being available. I am going to send some emails to service departments
of a lot of major company's and inquire as to why they do not include a schematic in their owners manuals.
It probably won't make any difference but someone has to start somewhere
         Thanks again!!!!!!!                                       

Hello Guy's,
      Dr Gonz 78. I copied the 2-G40 schematics you put in your post. I think it will help as the should be at
least similar. I have the one you told me about online.
    Roly,
      I am just going to have to take it apart. Only way to go.
    teemuk,
      Thanks for your drawing, that may help me to know what I am looking for when I get inside.

    I tried to call Loud Technologies yesterday and stayed on hold for a while. I just gave up on the phone. I found an email address and emailed them. I got the reply this morning. They only have the one sheet. and
there is no way to copy it any better. So that's just the way it is. Anyway I will just jump in.
       So this will likely be me later today.   :grr   :grr   :grr   :grr   :grr

Hello Roly,
       OK, The GX40-C has no LED's. But that's all right I will pull it apart and look at it. At that time I may be able to see a pair of diodes close to the volume control.
        I tried to call Loud today but they put me on hold. I will try again tomorrow. I will ask them if they can do something about the resolution of the schematic. I will also inquire about getting both pages. I am sure
that they may not be aware they are only sending one page.

Hello Roly,
       I can maybe make out, 4 and 5. I am going to check it out. Thank you !!!!

Hello,
      Sorry you went to the trouble to post that schematic, but I don't think its the one. The one I have is on a now defunct computer. I cannot post it, however I can tell you it is the GX-40DSP / It was drawn on
11/04/92. Also on the bottom it says, page 2 of 2. I was trying to get a better view of the clipper circuit.
      Thank you. I guess I will leave that one stock, at least until I learn more about electronics. If you saw the thread about the Fender Squier 15, it really opened my eyes to how much better an amp could sound with so few changes. I thought the Crate could be improved on slightly with changes to the clipper circuit as well. Without the schematic for the preamp stage I am hesitant to go in changing things willy nilly.
       I guess you can see the beating Crate amps take on some of the other forums. I have a hard time something that sold so well could be considered so sorry by so many people. Anyway thanks again.
                                                                   
                                                                     
         

Hello,
      Does anyone have a readable schematic of a Crate GX40-C amp, with the preamp laid out. I have one that Loud let me download but it is not clear enough to read the values of anything. I know it is an amp of
the previous owners, and that is probably all they have in their data base.

Hello,
      I think you are right about this. I have a lame schematic for the GX40-C. I cannot read any of the values, and it doesn't seem to have the preamp on it so I guess I will hold off on that until I can find a better schematic. Anyway two out of three ain't bad.

Hello Roly,
      Last night I added a diode to the RMS-200. I put it into the cabinet with the 12" speaker, same results.
Instant full rich sound. It is unbelievable.
      I have a Crate GX40-C, it contains two amps and I think I see the same type circuit in both, coming off of the IC's. It is comprised of two diodes a resistor and a capacitor. I am wondering if I can achieve the same effect with that one ? Anyway I will have to remove it from the cabinet to see if it has the same configuration. The schematic from Loud Technologies is not very good. The lettering is not plain when it is magnified. I'll have to search around and see if I can come up with a better one.
       Any suggestions would be greatly appreciated.Thank you in advance.
                                                                   
       

Hello,
      Yes, The second harmonic has the effect of the technique musicians sometimes use recording several takes of the same song and blending them to come up with a harmony using more than one of them. I am
in awe how simple it was.
       Now on to the next project. I have another small amp RMS-200, I was trying to find a schematic to  no avail ! TO MY SURPRISE right in the middle of the board was the same little circuit, two IN4148 diodes and a 2.7K resistor. That is very encouraging because I just happen to have four more 12" speakers and a few of the Schottky diodes. It seems to get better and better. Now it seems some my hoarded up junk is not so useless after all.
        So I am on my way to adventure, in the words of the Terminator (ALL BE BACH) !!!!!!!!
                                                               8|

   

Hello,

  Thank you J M Fahey for your input and advice concerning my amplifier modification. It worked out great.

                                                                    :dbtu:

Hello,

      Thank you Enzo for your input and advice concerning my amplifier modification. It worked out great.

                                                                    :dbtu: