Dear all,
I've been using Peavey 158 Rage until now. I remembered when I have it for maybe 10-12 years ago. Now I wanted to make something mods on to it.
I believe there'll be someone posted about good news and challenging idea with this cheap amps.
Just to make it become more interested. I realized that Peavey Rage 158 are transtube series with bad Distortion channel (sounds like a crap), and without tone control, but it has good equalization, mid, bass, treb, and two options(modern and vintage) which this one more useable than distortion channel.
I planned to create smoother od channel on it in order change the bad distortion channel, and try to implement baxandal tone control for it.
Please anyone, try to stimulate and give any suggestion perhaps. I'm will be thankful if there anyone help
Cheers all
I am confused, you said it does not have good tone control but it has a good EQ... Are those not the same.
This is a transistor amp on a PCB. While there are some things you could do, with out great knowledge of the parts involved a detailed schematic, you most likely will not be happy with any changes other than some minor cap resistor to change the tone quality or to increase or lower gain.
I would scrap the electrons and build a nice new amp, saving the cost of cabinet and chassis.
http://www.freeinfosociety.com/electronics/schemview.php?id=643
The speaker is probably most of your sound in the distortion, they did not put great speakers in these machines, as they cost less than a good speaker for the whole amp.
Since I am not sure the sound you want to get, that is best I can do.
Quote from: iccaros on April 17, 2012, 11:56:50 AM
I am confused, you said it does not have good tone control but it has a good EQ... Are those not the same.
This is a transistor amp on a PCB. While there are some things you could do, with out great knowledge of the parts involved a detailed schematic, you most likely will not be happy with any changes other than some minor cap resistor to change the tone quality or to increase or lower gain.
I would scrap the electrons and build a nice new amp, saving the cost of cabinet and chassis.
http://www.freeinfosociety.com/electronics/schemview.php?id=643
The speaker is probably most of your sound in the distortion, they did not put great speakers in these machines, as they cost less than a good speaker for the whole amp.
Since I am not sure the sound you want to get, that is best I can do.
Hmm, yeah probably I need learn again about difference between EQ and tone control. I want to make it clear, okay if the problem is EQ, okay I revised my post, I will say EQ also like a crap.
Some of them said that change nearly resistor to 1M will make the distortion sounds better, but I forget the place of that resistor, or maybe some value. I just remembered "change to 1M" thats all.
and again Yes iccaros , you're right about the speakers. I just try to make this cheap amp to get maximized. I believe there will be something to try on.
Well, I guess I will spend my saturday to breadboarding my old cheap amp.. Maybe I can combine it with some of TS overdrive sound, if i can do that. I just need to trace back the schematic that you gave to me,
Thanks in advance iccaros. I really appreciated your comment and correction
Cheers
i,ve got a peavey special 150 that is pretty similar...
i can translate what i did for your schem.
basically the dist chanel was way too hot for me, at 2 it was too dirty for me, and too middy as well.
reading wgtp's 'thick presence' mod its in the gallery in wgtp's folder it seems it used to be a pull thick controll,but in some amps it is hard wired in... :-\
c19 changed the 2,2uf to 1uf.
r15 changed 100 to 470 ohm.
r10 removed and replaced with a full tonestack...
(http://dl.dropbox.com/u/28004258/peaveyeqmod.bmp)
this is a bit overboard, adding a 3 knob tonestack to an amp...but it really sounds good and marshally now, low gain i can bump up the mids for fat low gain breakup, or crank up the gain and turn down the mids for a scooped high gain sound - still has plenty of gain...
i found wgtp's mod here...
http://www.aronnelson.com/gallery/main.php/v/WGTP/SuperSatMods.jpg.html (http://www.aronnelson.com/gallery/main.php/v/WGTP/SuperSatMods.jpg.html)
definately an improvement!! i basically just went a bit further with the tonestack thing...
The Rage sticks a 2+2 set of clipping diodes on the output of U1B. The HF rolloff of U1B is set by C7/R7 at just under 3.4khz. While that sounds nice and round/unharsh, the fact that the clipping diodes come after the output introduces fizz and harsher elements that will require the sort of EQ adjustments that might take away from the sound.
I'll suggest resituating the diodes from where they are now (going to ground) to going in the feedback path of U1B, Tube Screamer style. That ought to, in theory, make the over drive smoother sounding.
Given nuisance of taking them out, I'll suggest simply cutting the trace that connects them to ground, and placing a 2+2 set in parallel with the copper-side traces/pads for R7. That way, you can easily reverse it if you don't like the way it sounds.
I realized my 158 rage, doesn't have 4558 op amps, based on the schematic
take a look on my 158 board
(http://farm6.staticflickr.com/5231/7091028269_34049bc0f1_z.jpg) (http://www.flickr.com/photos/75813062@N05/7091028269/)
IMG_0637 (http://www.flickr.com/photos/75813062@N05/7091028269/) by DIY Parts + PCB Center (http://www.flickr.com/people/75813062@N05/), on Flickr
(http://farm8.staticflickr.com/7245/6944956948_8e59974b66_z.jpg) (http://www.flickr.com/photos/75813062@N05/6944956948/)
IMG_0636 (http://www.flickr.com/photos/75813062@N05/6944956948/) by DIY Parts + PCB Center (http://www.flickr.com/people/75813062@N05/), on Flickr
(http://farm8.staticflickr.com/7194/7091030257_2c63ee7200_z.jpg) (http://www.flickr.com/photos/75813062@N05/7091030257/)
IMG_0639 (http://www.flickr.com/photos/75813062@N05/7091030257/) by DIY Parts + PCB Center (http://www.flickr.com/people/75813062@N05/), on Flickr
I need to know where should I do mods in this version ?
(http://farm6.staticflickr.com/5336/7091032409_9906274075_z.jpg) (http://www.flickr.com/photos/75813062@N05/7091032409/)
IMG_0638 (http://www.flickr.com/photos/75813062@N05/7091032409/) by DIY Parts + PCB Center (http://www.flickr.com/people/75813062@N05/), on Flickr
supposed use multilayer ceramic caps
Also I've found http://www.youtube.com/watch?v=E2RhnnRglWA, but maybe he did Quackzed mentioned schematic (Supersat mods)
I will try the Quackzed schematic tomorrow
Thank you for both of you (Mark and Quackzed), you've been so generous for helping me to figure it out
Cheers all
It doesn't seem to have much of anything, now that we see it. Does it actually work? It looks like the chips have been removed.
Quote from: Mark Hammer on April 18, 2012, 03:28:57 PM
It doesn't seem to have much of anything, now that we see it. Does it actually work? It looks like the chips have been removed.
Yes this one works, but, I haven't tried the mod. I think mine 158 is the original version (without IC), does anyone have any idea to do mods with this old amp ? Probably resistor and caps value swap, or something else ?
Cheers
I'm seeing 4 transistors and what I assume is the TDA2040. Is there another board underneath?
Quote from: Mark Hammer on April 19, 2012, 09:07:30 AM
I'm seeing 4 transistors and what I assume is the TDA2040. Is there another board underneath?
I'm not sure Mark, but I'll take a look closely, and No there isn't another board underneath. Any idea ?
Okay, after another hard look at the posted pics, I see six transistors, not four. That still doesn't seem like enough to do the job. Are there more than 6?
From schematics I have seen the Supersat is a variety of circuits. The latter TransTube versions use discrete transistors (not FETS) in a design I can't begin understand. ;)