How can I get my ODS to be more "on the edge of out of control"?

[jcsifu]

every track on here was recorded with a telecaster of some kind and my #102.



https://www.marcuscliffe.com/music


if you listen at 2:46 on track 6 I put a spell on you, you can hear the amp starting to take off






M

I like the arrangement and mix. What mics did you use? Great tone, I would have guessed it was a semi-hollow at first listen. I'm looking forward to trying out a teli for myself now. Maybe that will get me out of my boredom with myself.

Amp was #102, speaker EVM 12 in the closed ported cab. Mic'd with a 1960 Neumann U67.
Clean guitar is a telecaster with P90 neck
Gtr solo is this gtr

marcus- bound tele.jpeg


you were spot on with semi-hollow


because of the Covid situation and not working I had to sell the U67 recently



M

I've never had a chance to go through a real U67, just a reissue. I usually fight to have them put a SM57 channel in too, but noses get turned up sometimes. I like that kind of combo for a full sound and great definition that can be mixed at the board. Sorry to hear about your loss...things always come and go it seems. I have bought the same gear more than once on several occasions, including a certain model jazz box I have bought and sold 3 different times in the last 10 years. Sometimes I come out ahead, sometimes not. I don't seem to jive with EVM speakers, I want to, but my playing doesn't sound right. If I use G12-65 or any close relative I sound good. But then I haven't been able to go through v30's with a marshall, which is what most guys playing harder sets like. I must have some odd dynamics in my hands...

[jcsifu]

No, I haven’t. Have you tried reducing the global feedback, such as increasing the feedback resistor or increasing the presence cap?

I have not. I have a "raw" labeled pot on the back of my super reverb that was there when I got it. That pot increases the resistance of the GF. What value would you suggest trying in the 102? What do you think would happen if I go too low with the filter caps? Just noisey? Mushy bottom end?

AFAIR The Feedback City amp had 100uF on the plates 20uF on the remaining nodes, no NFB on V1 and the standard 102 Presence circuit with 2.2 uF cap. Using some basic testing methods I concluded the feedback was generated mostly in the output section, although I am sure the resonant frequency or onset was generated in V1 (and the tonestack) so IMO one caused the other. The OD and boost just made it more intense!...Don't ask me how?

BTW. I could plug in an external preamp in the loop and the thing would still want to feedback..Output Section
Tony

Really...? Are you saying other ODS type preamps or other non-ODS types?

[jcsifu]

I have a "raw" labeled pot on the back of my super reverb that was there when I got it. That pot increases the resistance of the GF. What value would you suggest trying in the 102? What do you think would happen if I go too low with the filter caps? Just noisey? Mushy bottom end?

I would think that increasing the FB resistor (adding a pot) up to 5x its current value would be enough to see what reduced GNFB could bring. The global FB wire is the most likely candidate for creating positive feedback in the power stage, since the output signal is in phase with the PI's input grid. The loose bottom end that comes with decreasing the power stage filters is probably not desirable, so personally I wouldn't be too eager to try that.

One of the best days of my life was in a large fast venue with a dimed VibroKing. The sound and feel was so magical and made me so thoughtless that everything I played came from the heart and soul. I will always chase that night. As far as the filters go I guess I was thinking that the feel of the amp might go in that direction. I agree though, loose low end is not good to my ears either so maybe I'll put a pot in the feedback section and see what that does with the value range your suggesting first. I have a pot on hand but would need to order some caps.

[jcsifu]

This is one of my fav modes when doing ODS builds. I almost always install a pot for GNFB and then dial it to taste!

G

What do you find makes that mod work so well for you? What volume are you usually at when it sounds best to you? Humbuckers or single coils?

[talbany]

Hello Tony --

Through both long ancient series of posts again with curiosity yesterday, the "feedback" and also "build". Forgotten about that brief clone war.

Noted from the photos what appeared to be 100uF plates, then 20uF+20uF+40uF+20uF. That last one tucked in up in the corner behind the FET. Differences across the photo at top of the "feedback" chain and those in the "build" thread. However consistent values. Perhaps different amps? Unconvinced this was the difference that made a difference in any case. Couldn't see a nice detailed photo showing power stage -- PI components and lead dress. Any thoughts and potential for other photos that provide another closer peek?

Best .. Ian

Hello Ian
Yes you are absolutely right I completely forgot about the 40 on V2 So that amp did have it. I just went through and searched for more shots of that amp and no luck. My Macbook died shortly after I built that amp and all the shots I had were I am pretty sure lost when that computer died unfortunately taking those shots with it

As far the NFB on V1 goes this is IMO a personal taste thing. Some players prefer the slightly flatter more compressed sound it brings others do not.For me it depends on which model ODS it is and how I run the amp and what mode I am in..I actually prefer the FB in when in OD at higher volumes and with Humbuckers and not in when at low volumes on the clean channel and or with pedals I like it off. I always recommend putting it on a switch.

As far as adjusting the amount of GNFB here is a method I use to find the perfect amount of GNFB on that specific amp..
You can take say a 5k or 10K B pot and wire it as a variable resistor put it on the back next to the speaker out.Run your wire from the + tip connection that feeds the GNFB resistor through the pot in series with the GNFB resistor. You can now decrease the amount of GNFB feeding that resistor . This gives you less NFB to help open the amp up. With the pot turned all the way back basically bypasses it so you will have a stock Dumble approved presence control if you want to take it completely out of circuit.With this mod you can now control both the frequency response and amount of signal sent to the presence circuit. Just remember though as you add resistance you effectively lifting the presence control out of circuit limiting the range of your presence pot on the front. I have this control on my Musicman amp and find I generally like less GNFB at low volumes and more at gig volumes.This is also a great way to tweak the amp to find the right amount of GNFB for that amp or tubes and output transformer and load for your personal taste.
Another words install the pot play the amp find the perfect value (where the amp wants to feedback) measure the resistance across the pot theirs your perfect value GNFB resistor for that amp at the volume you normally run,now pull the pot and install the new resistor. If you want the variability use the stock Dumble value resistor leave the pot on the back and tweak it as needed..

Tony

[Guy77]

Hi JC. Tony has described the mod perfectly in his post above ( thanks Tony ) and I use it exactly as he has described it.
It works great for all types of pickups. I also tend to use less GNFB (greater value resistor or pot setting) at lower volumes and more at higher volumes as he also mentioned.

Cheers

Guy

[JD0x0]

IMO there's many factors, but one of the big ones seems to be having enough mids dialed in. More mids tends to increase the frequencies where most guitar's resonant frequencies sit. This helps get the feedback-y flippy quality as the guitar will want to feedback more with those frequencies pushed. I've found my Lab Series L5 preamp does it really well because it has an active parametric EQ, so you can dial in the resonant frequency, then jack it way up. Of course there's many other factors. I have some amps that'll do it at nearly 'clean' gain levels. https://www.dropbox.com/45a85669-8008-4 ... e1a1ee8f0c

Well tuned amps, such as the Bludos seem to be able to do it at bedroom type levels, too.

https://www.youtube.com/watch?v=41c6ItoPi8g

I can't seem to access the drop box link you posted but would like to. Just curious, what mid frequency do you boost on the Lab Series? Did you do a kit or did you buy one of the limited number of complete pedals?

Thanks for the heads up on the link. I think I posted the wrong URL. Should be working now.

I built a kit from Musikding, using the AION boards. I think the frequency can vary based on guitars, but I usually find 650-800hz tends to be the sweet spot for most. IIRC it was a trick I originally learned from Zappa. He'd apparently use his active preamps to boost the resonant frequency of his guitars to get them to feedback more easily. I suspect that's what he's doing to get the feedback he did on tracks like Filthy Habits https://youtu.be/5ugJrB2jYm0

[talbany]

IMO there's many factors, but one of the big ones seems to be having enough mids dialed in. More mids tends to increase the frequencies where most guitar's resonant frequencies sit. This helps get the feedback-y flippy quality as the guitar will want to feedback more with those frequencies pushed. I've found my Lab Series L5 preamp does it really well because it has an active parametric EQ, so you can dial in the resonant frequency, then jack it way up. Of course there's many other factors. I have some amps that'll do it at nearly 'clean' gain levels. https://www.dropbox.com/45a85669-8008-4 ... e1a1ee8f0c

Well tuned amps, such as the Bludos seem to be able to do it at bedroom type levels, too.

https://www.youtube.com/watch?v=41c6ItoPi8g

I can't seem to access the drop box link you posted but would like to. Just curious, what mid frequency do you boost on the Lab Series? Did you do a kit or did you buy one of the limited number of complete pedals?

Thanks for the heads up on the link. I think I posted the wrong URL. Should be working now.

I built a kit from Musikding, using the AION boards. I think the frequency can vary based on guitars, but I usually find 650-800hz tends to be the sweet spot for most. IIRC it was a trick I originally learned from Zappa. He'd apparently use his active preamps to boost the resonant frequency of his guitars to get them to feedback more easily. I suspect that's what he's doing to get the feedback he did on tracks like Filthy Habits https://youtu.be/5ugJrB2jYm0

Michael Schenker and Tom Sholtz did something similar I believe the device they used was called a wah wah pedal..Find the resonant frequency and the onset of feedback for that room and leave it cocked at that frequency all night. Throw in some Stereo Chorus and you get the Boston/Rockman sound

Tony

[jcsifu]

I can't seem to access the drop box link you posted but would like to. Just curious, what mid frequency do you boost on the Lab Series? Did you do a kit or did you buy one of the limited number of complete pedals?

Thanks for the heads up on the link. I think I posted the wrong URL. Should be working now.

I built a kit from Musikding, using the AION boards. I think the frequency can vary based on guitars, but I usually find 650-800hz tends to be the sweet spot for most. IIRC it was a trick I originally learned from Zappa. He'd apparently use his active preamps to boost the resonant frequency of his guitars to get them to feedback more easily. I suspect that's what he's doing to get the feedback he did on tracks like Filthy Habits https://youtu.be/5ugJrB2jYm0

Michael Schenker and Tom Sholtz did something similar I believe the device they used was called a wah wah pedal..Find the resonant frequency and the onset of feedback for that room and leave it cocked at that frequency all night. Throw in some Stereo Chorus and you get the Boston/Rockman sound

Tony

Ha! the Wah...wait... ...is that true...

Oh man...Rockman brings back memories of younger years of quiet practice at 2 in the morning. I had one of the soloist versions also. Not my tone, but good memories.

[jcsifu]

IMO there's many factors, but one of the big ones seems to be having enough mids dialed in. More mids tends to increase the frequencies where most guitar's resonant frequencies sit. This helps get the feedback-y flippy quality as the guitar will want to feedback more with those frequencies pushed. I've found my Lab Series L5 preamp does it really well because it has an active parametric EQ, so you can dial in the resonant frequency, then jack it way up. Of course there's many other factors. I have some amps that'll do it at nearly 'clean' gain levels. https://www.dropbox.com/45a85669-8008-4 ... e1a1ee8f0c

Well tuned amps, such as the Bludos seem to be able to do it at bedroom type levels, too.

https://www.youtube.com/watch?v=41c6ItoPi8g

I can't seem to access the drop box link you posted but would like to. Just curious, what mid frequency do you boost on the Lab Series? Did you do a kit or did you buy one of the limited number of complete pedals?

Thanks for the heads up on the link. I think I posted the wrong URL. Should be working now.

I built a kit from Musikding, using the AION boards. I think the frequency can vary based on guitars, but I usually find 650-800hz tends to be the sweet spot for most. IIRC it was a trick I originally learned from Zappa. He'd apparently use his active preamps to boost the resonant frequency of his guitars to get them to feedback more easily. I suspect that's what he's doing to get the feedback he did on tracks like Filthy Habits https://youtu.be/5ugJrB2jYm0

Nice! Always good to learn from others. Never met Frank but I bet you had some interesting conversations . I haven't done a pedal in a few years, I think I might have follow suit with you. I have a few odd blank boxes that might fit the bill, one that I was going to do a 4 switch foot pedal with would prob be cool looking. It has wooden sides and is a slanted top metal case.

[jcsifu]

Hi JC. Tony has described the mod perfectly in his post above ( thanks Tony ) and I use it exactly as he has described it.
It works great for all types of pickups. I also tend to use less GNFB (greater value resistor or pot setting) at lower volumes and more at higher volumes as he also mentioned.

Cheers

Guy

Hey Guy!
Thanks for verifying what you used and your observations of what settings you found worked. What made you gravitate towards higher FB at higher volume? Did it get too wooly? Did it give you a different feel to the amp?

[Guy77]

Hi JC. Tony has described the mod perfectly in his post above ( thanks Tony ) and I use it exactly as he has described it.
It works great for all types of pickups. I also tend to use less GNFB (greater value resistor or pot setting) at lower volumes and more at higher volumes as he also mentioned.

Cheers

Guy

Hey Guy!
Thanks for verifying what you used and your observations of what settings you found worked. What made you gravitate towards higher FB at higher volume? Did it get too wooly? Did it give you a different feel to the amp?

Hi JC. At higher volume it would breakup sooner when there was very little negative FB and increasing the negative feedback would tighten things up and I liked that. Yes you could also say it got a little too wooly.

Cheers!

Guy

[erwin_ve]

I have a "raw" labeled pot on the back of my super reverb that was there when I got it. That pot increases the resistance of the GF. What value would you suggest trying in the 102? What do you think would happen if I go too low with the filter caps? Just noisey? Mushy bottom end?

The global FB wire is the most likely candidate for creating positive feedback in the power stage, since the output signal is in phase with the PI's input grid.

#124 GNF (orange)wire:

[jcsifu]

I have a "raw" labeled pot on the back of my super reverb that was there when I got it. That pot increases the resistance of the GF. What value would you suggest trying in the 102? What do you think would happen if I go too low with the filter caps? Just noisey? Mushy bottom end?

The global FB wire is the most likely candidate for creating positive feedback in the power stage, since the output signal is in phase with the PI's input grid.

#124 GNF (orange)wire:

Oh....I didn't think to take a look, I believe I now understand. I appreciate the hint Erwin.

[martin manning]

#124 GNF (orange)wire:

That's the grid that gets the FB signal, so if anything running the FB wire close to it provides a little additional NFB.