#153539  by MattMan
 Sat Aug 20, 2016 9:33 am
Hi Folks,

After the recent exchange in the Garage Sale forum on envelope filters (forum/viewtopic.php?f=334&t=18095#p153540), I took Dr. Waldo's advice to change out the R32 resistor in my Q-Tron 1997 Silver Box from 47k to 68k.

I made three comparison tone tests for your review. Please let me know your preference. All were made with middle pup (single tap), TPC-1, Twin, MC2100, K120. SM57.

All three tests contain the same sequence of songs: Catfish John, Estimated, Shakedown.

1. Q-Tron Pre Mod: 0:00 Catfish John, 2:28 Estimated, 6:00 Shakedown


2. Q-Tron Post Mod: 0:00 Catfish John, 1:54 Estimated, 5:20 Shakedown


3. Mu-Tron III: 0:00 Catfish John, 2:24 Estimated, 5:50 Shakedown
hippieguy1954 liked this
 #153545  by PurpleTrails
 Sat Aug 20, 2016 12:56 pm
The mod really gave the Q-tron better tone, but the Mu-tron seemed to respond more dynamically, particularly in the Shakedown, and seemed to have a little more low end content in the solo at the end, if that makes sense.

Also, it sounded like you were a little more inspired playing the Mu-tron. Just seemed like you were having more fun, which translated into your playing having a little more feeling to it. I know that happens with me when my rig is sounding just right. :cool:
 #153599  by Jedstein
 Tue Aug 23, 2016 8:32 am
This is a great demo -- thanks, Matt. The Waldo mod for the Q makes a noticeable difference. And -- yeah -- the mutron sounded the best (to my ears), but that modded Q sounds damn good!
 #153601  by rugger
 Tue Aug 23, 2016 9:21 am
Love your setup. I wish I had a dedicated space with all my stuff ready to go.

I have to wait for my wife to head out of town and then I take over the bedroom. Incidentally, she just got on a plane this morning! :cool:

john in san diego
 #153605  by Tennessee Jedi
 Tue Aug 23, 2016 4:50 pm
MattMan wrote:Hi Folks,

change out the R32 resistor in my Q-Tron 1997 Silver Box from 47k to 68k.
Thanks for doing the demo
Can you tell if this is the Q tron in question ?
I want to do it to mine
Image
 #153606  by MattMan
 Tue Aug 23, 2016 4:58 pm
Yup. That's it. Start by ordering a few 68Kohms metal film resistors (1 watt, 5%) from Mouser electronics (they're terribly expensive--$0.19 each). Then replace the resistor at R32 with the new 68k resistor. That's all there is to it.
 #153723  by TRG
 Wed Aug 31, 2016 10:54 am
MattMan wrote:Yup. That's it. Start by ordering a few 68Kohms metal film resistors (1 watt, 5%) from Mouser electronics (they're terribly expensive--$0.19 each). Then replace the resistor at R32 with the new 68k resistor. That's all there is to it.
Thanks for the demo! I think the modded Q-Tron sounds real good! I actually tried it to mine last night and while initially it sounds better, it also introduced some type of distortion...it doesn't happen with every note, but every once in while a single hard plucked note will come out as distorted/splat sounding. My soldering skills are rookie at best, but figure I'd give it a try anyway. I'm wondering if maybe I got the incorrect resistor?

I'm using a 68Kohms Vishay Metal Film Resistor - through hole. 1 watt, 5 %

Do you happen to know if that is the correct resistor? Just trying to determine if I used the incorrect resistor, or my shoddy soldering skills could be to blame :lol:
 #153726  by waldo041
 Wed Aug 31, 2016 3:09 pm
That resistor is probably a little bigger than the others but it is the correct value. If you have not already, try reflowing the solder. Make sure you do not pinch any of the wires under the potentiometers when you put it back together, or break them performing the mod.

~waldo
 #153729  by TRG
 Thu Sep 01, 2016 4:17 am
waldo041 wrote:That resistor is probably a little bigger than the others but it is the correct value. If you have not already, try reflowing the solder. Make sure you do not pinch any of the wires under the potentiometers when you put it back together, or break them performing the mod.

~waldo
Cool - I'll try that. Appreciate the response - thanks!
 #153732  by tatittle
 Thu Sep 01, 2016 12:26 pm
Hey now! I knew there would end up being a good reason to keep my older big box Q and sell the smaller new version (instead). Ill never sell my Mutron if I have any choice in the matter, it needs some maintanence though fortunately the normal setting sounds good its the Dancin' setting that drifting etc. may be straying the tone a bit.

Many thanks Waldo and for the thread. Ive been busy the last year havent checked in much, but glad I did today.