Thor w/o the bass boost?

[Mr. G.]

I've been wanting to build a Thor for some time now, but I don't really think that I need the bass boost section.  What would I need to do to build it without the bass boost section? 

I drew up a schematic, leaving out what I thought should be left out, but I'm sure I've done it wrong . 

Here's a link to the schematic I drew:  http://i2.photobucket.com/albums/y50/PRSplaya/DIY/Thor_nobassboost.png

Could somebody give me a hand and explain to me how I should do this?

[petemoore]

  Hard to tell wherat the bass boost whas.
  The only thing I'm wondering about is the resistor R-15 toward the end of the circuit, going to Vr, and I'm only wondering because I haven't seen 'that one' before.
  But it looks like it should work AFAICsee. The transistors may need to be sorted I think, 5k is a small variable resistor for biasing Jfets, 20k might not bias some Jfets.
  Anyway all the DC blocking caps and power supply look ok [I only looked for a short while] for 2 gain stages before a Mu Amp...looks like everything need to 'work is there.

[Mr. G.]

Thanks.  I drew the schematic from the one posted on the ROG site:  http://www.runoffgroove.com/thor.html

[petemoore]

  Eliminate the Opamp and it's peripherals, keep the volume control...
  Take the output from the Mu Amps output capacitor [100n], put that into the volume control.
 

[Mr. G.]

So, in my schematic, should I eliminate everything after C9 (minus the level pot), or leave it like it is?  I'm not sure which 100n cap you're talking about... C9 or C14?

[Mr. G.]

Is this what it should look like?  http://i2.photobucket.com/albums/y50/PRSplaya/DIY/Thor_nobassboost_schematic.png

[Ripthorn]

That schematic you just posted looks good to me.  I would put it on the breadboard to be sure, though.

[Mr. G.]

I plan to try it on the breadboard, but I REALLY suck at using a breadboard.  Only reason I can do layouts, is because Eagle shows where the connections need to go while layout out the components. 

[petemoore]

  http://www.runoffgroove.com/fetzervalve.html
  Getting Jfets biased and sounding great is easier when the 'fitting is done using sockets and variable resistance.
  The Mu Amp is self biasing.

[solderman]

Hi
I think your last schematic will work altough I think you will lose more than just the bass boost. I have seen schematics of the Thor where the 33k to GND is supped for a 100K pot and the switch is omitted. in the stock schematic the switch used is a "bass killer" if i have read it correct. I think you should breadboard the original and put in a switch to jump the Op-amp part to your schematic and hear if you like it.

I can really recommend this one I have built 3 of them, one in a 1590A enclosure, where i excluded the bright switch (always on) for space saving reasons. I rellay like the "deep breathing" sound you can get from it. On low gain settings it acts like a great treble booster. The bright switch has no effect on gain settings over 50%. The bass switch works over all gain settings.

//Solderman 

 

[Mr. G.]

I just built it on the breadboard, and I am very unimpressed.  I'm not sure if I did something wrong, or what, but it really doesn't sound anything like any of the clips I've heard of it.

Here's the breadboard layout that I made:  http://i2.photobucket.com/albums/y50/PRSplaya/DIY/THOR_breadboard.png

See anything wrong with it?

Yes, I know some think it's silly to make a layout for a breadboard, but that's just how I like to do it.   

[solderman]

I just built it on the breadboard, and I am very unimpressed.  I'm not sure if I did something wrong, or what, but it really doesn't sound anything like any of the clips I've heard of it.

See anything wrong with it?

Hi Eric
As i wrought earlier, to Skip the Op-amp will probably change the overall sound and not just the bass part. Try to build it stock and mod the components around the inverted in and out on the op-amp

//Solderman 

[Mr. G.]

I would if I had a TL071 or other single opamps, but unfortunately I don't.  That's pretty much the whole reason I wanted to try to build it without that section.   

[solderman]

I would if I had a TL071 or other single opamps, but unfortunately I don't.  That's pretty much the whole reason I wanted to try to build it without that section.   

Ok
If you have a double try with half a TL072 or some thing like it or buy one. This effect is really worth it.   

//Solderman

[Ripthorn]

It is worth it, though I have noticed with mine there is plenty of noise and at max volume and gain, I only barely match the input signal in level.  But it does have a great sound.