gaussmarkov: diy fx

11 Responses to “Thor”

1. GCollier said:
   

   Any thoughts on using the THOR as a solid state preamp. If this were done could you simply incorporate tone controls before the opamp?

   Thanks!

   Posted 17.12.2007 at 8:26 am

2. gaussmarkov said:
   

   If I were going to add additional tone controls, I would try a passive tone stack after the final op-amp and use the available op-amp in the TL072 in a recovery stage before the output.

   How does that sound?

   Posted 17.12.2007 at 9:51 am

3. GCollier said:
   

   Sounds reasonable…

   I’ll see what I can do with my existing Thor. I built it a while ago using the layout at Runoffgroove. Too bad because I could have simply modified your Eagle layout and added the tone stack. I might just add an active EQ after it and see how it sounds.

   Do you suppose there would be an advantage converting this to run on a split supply?

   Posted 18.12.2007 at 1:04 pm

4. gaussmarkov said:
   

   Perhaps, but I don’t know what the advantage would be.

   Posted 19.12.2007 at 1:02 am

5. GCollier said:
   

   I took your eagle file and modified it to use the 2nd half of the opamp as an active 3 band tone control with a swithc to bypass it…built it and it sounds great. Just one issue…the gain control doesn’t seem to do much of anything regardless of how I bias the thing. Could this be an issue from running at a higher voltage (~13.5V). I double checked the pot wiring and continuity in the wiring…any suggestions?

   thanks for the nice layout

   Posted 04.03.2008 at 6:00 am

6. gaussmarkov said:
   

   Hi!

   I’m glad to hear that you have made the Thor layout “your own.”

   My quick reaction is that, yes, the supply voltage can make a difference and that you could try a lower supply to check that theory. To really diagnose the problem, one needs to know the voltage readings on all of the transistors’ pins when the input is grounded.

   If you post on Aron’s forum about this, please let me know with a pm (personal message) and I will try to help there.

   All the best, Paul

   Posted 04.03.2008 at 6:47 am

7. GCollier said:
   

   Just an update to let you know that I managed to solve my issues. I initially dropped the voltage down to 9V but still had the same issues with the gain…in the end it turned out to be a bad pot! Sounds fantastic, the active tone control is a BIG help.

   Thanks for providing such a great layout to modify…so many sites just provide PDF files, the Eagle files are very useful!

   Posted 12.04.2008 at 7:14 am

8. gaussmarkov said:
   

   GCollier,

   thanks very much for following up! it helps us all. are you going to post your version somewhere? i would be pleased to put it up here.

   and i am pleased that you are benefiting from the eagle files. that is one of my goals.

   all the best, paul

   Posted 12.04.2008 at 8:27 am

9. thomarz said:
   

   Hi,
   I’ve just finished my second version of the Thor, this time with the pcb layout of this site. The first one was the one from ROG. Still both cause the same problem. Playing it in front of clean solid state amp at higher gain setting, you get some oszillating sound like a bezerk synthesizer. Sounds really funny but it’s not quite what I was after.
   I’ve sucessfully built some other pedals but this one is really making me go crazy. Would be nice, if I could get some help here.
   regards
   Thomas

   Posted 13.04.2008 at 3:59 am

10. gaussmarkov said:
    

    Thomas,

    It probably isn’t the solid state amp. I suggest you start debugging by listening to each stage of the circuit with an audio probe.

    All the best, Paul

    Posted 13.04.2008 at 6:47 am

11. gaussmarkov: diy fx » G. Collier’s RunOffGroove Thor said:
    

    […] part on gaussmarkov.net projects. George Collier took the Thor circuit from runoffgroove.com, the Eagle files from gaussmarkov.net, and put in his own 3 band active tone control. Here’s a gut shot of his build.  If you view […]

    Posted 30.05.2008 at 8:08 am

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