Where best to post about diff between Fender and Dumble?

[imo1]

I'm definitely going to give that a try with the tonestack, and I will also put the V1 neg feedback on a switch.
I'm going out of town for a gig, so won't be back for a week, but will tinker with this when Im back. I have a good deal of downtime until March and then I'm pretty busy touring

[martin manning]

I'm definitely going to give that a try with the tonestack, and I will also put the V1 neg feedback on a switch.

Great, it will be very interesting to hear about what you find. The effect of the jumper will vary somewhat over the range of settings, so I think it would be best, at least initially, to fix the TMB positions at noon, and listen for the effect of the scoop as is it appears in the tone stack plots above, A/B fashion. To do that, use a short clip lead rather than soldering a jumper in, or better yet temporarily solder in a switch. The pots are isolated from high voltage, so there is no issue there. I've found rapid A/B switching to be the best or even the only way to compare listening test results, even better with a helper to make the change out of your sight.

[WhopperPlate]

I've found rapid A/B switching to be the best or even the only way to compare listening test results, even better with a helper to make the change out of your sight.

You have helpers? What a privileged luxury

Not exactly applicable in this context , but when it comes to quickly testing and hearing differences between specific components, a pair of alligator clips in line with a guitar and cable into the input of any amp can be very informative.

Easy to set up switches if you must, but also stupid quick to just clip and un clip components . The effect may not be as drastic for whatever circuit position that part is going to occupy , but it’s an effective means to understand how it will be coloring the signal .

Even try this with your electrolytic capacitors… I have found the sonic characteristics of each are imparted within the whole amplifier , and this is a quick way to get a glimpse of the results of what would generally be a long winded process of rebuilding a power supply with different caps .

As I already alluded in a previous post ; don’t take my word for it, try it yourself

[martin manning]

...and this is a quick way to get a glimpse of the results of what would generally be a long winded process of rebuilding a power supply with different caps.

More than that, after a few seconds the memory of the sound fades, and the ability to go back and forth really highlights the difference. Whether or not it's significant, or if nudging a control knob would do the same thing, is another question ;^)

IMO the best helper is a really good player, where I can make the A/B change, and we can trade opinions on it.

[WhopperPlate]

...and this is a quick way to get a glimpse of the results of what would generally be a long winded process of rebuilding a power supply with different caps.

More than that, after a few seconds the memory of the sound fades, and the ability to go back and forth really highlights the difference. Whether or not it's significant, or if nudging a control knob would do the same thing, is another question ;^)

IMO the best helper is a really good player, where I can make the A/B change, and we can trade opinions on it.

Everyone can suffer illusions of psychoacoustics , and I have been my own victim of hearing differences where there absolutely weren’t any (like turning up the bass on an unused channel lol ) but this is where repetition comes into play.

I have literally sat for hours on end , days on end, analyzing and comparing components in this manner , and the longer you do it the more nuance you will notice . Same argument as earlier : develop the ear and you will notice and hear more . Apply these findings to the entire amplifier and you can shape the sound with far more confident predictability.

Also same argument as earlier: memory fades at different rates for each individual. Mozart could walk into a church , listen to the music , and go home and write it down from memory .

Rick Beato talks about his friend Aydin Esen , amazing piano virtuoso, and how when they were in school together he could be writing out a piece of music by ear from memory after the piece was already over.

That fish from “Finding Nemo” can’t remember 10 seconds ago.

It’s not beyond us to exceed our limited expectations , regardless of any assumed improbabilities, but I will grant that the fish should probably get a helper and wire up some switches

[WhopperPlate]

IMO the best helper is a really good player, where I can make the A/B change, and we can trade opinions on it.

This scenario is truly effective , but then again I don’t get to feel the difference under my own fingers , which to me is more than half the equation with electric guitar

Relative example: I remember back in the day playing with lots if bands that used mesa dual rectifiers. They got great live tones that I was impressed by , and when the opportunity to get one used from a friend came along I jumped at the opportunity.

However, under my fingers it felt stiff and brittle and without any forgiving characteristics. In recordings it was great sounding , under my fingers I was fighting a battle .

A good hack : When I listen to a player , I pay the most attention to their face and whether or not they are smiling. If they are having fun that’s probably the best sign .

[imo1]

Man, back from the weekend. What a fantastic night. I'm a little biased, being an Austin player, but just love the style and substance of all the cats a generation before me. I played with Terry Allen, taking the spot that Charlie Sexton normally does(he's out with Elvis Costello). Lloyd Maines was playing steel, and I was doing my best to channel my inner Jesse Taylor. I don't know if any of yall are hip to this scene, but man, i think its some of the coolest stuff.

Anyway, back home, gonna open the amp up tomorrow and try a couple of these things. Just to confirm..@martinmanning

just taking the low side of bass post to high of middle.. Don't need to dissconnect anything..

I'll try this and also the shorting of the feedback V1 on a switch.

I've been thinking about it. Matt Schofield and I aren't totally the same, but he definitely seems to dig in a lot of the same territory that I do, and his amp uses dual rectifiers, which I'm sure make a difference in note bloom, especially when you hit a note hard, which is a huge part of blues based player(as opposed to the more rock style that many of the ODS cats have). I wonder how close I can get with a power sag resistor?

[martin manning]

Just to confirm..@martinmanning just taking the low side of bass post to high of middle.. Don't need to dissconnect anything..

Yes. I think the best way to listen for it is as described above, setting the controls at noon and clipping/unclipping (or whatever) that jumper. Sounds like you had a great time. No doubt the audience can sense that and join right in.

[imo1]

Thanks Martin. Have you messed around with emulating rectifier tubes?

I’d also love to hear from anyone some more thought on implementation of different cathode caps. I’ve read and re-read Merlin’s book on preamps and feel like I understand the tech side pretty well, but I’m finding there is a pretty big gap between that and implementation of build in a musical way. I don’t want to tear my board up on this build as it’s tour worthy

[imo1]

I suppose I will be the person to answer the posted question:

“Where to best post about diff between Fender and Dumble?”

Answer:

The Dumble sub forum of the ampgarage…nudge nudge

I've found, after building a number of Dumble based designs, that I love the general design, but for my type of playing, there are pieces of Fender sound that I really miss. In a perfect world, most players that are going for similar sounds as mine are mixing Dumble or Dumble style amps with Fender amps. There is a cool "funkiness" that just comes out of Fender amps that for bluesy players is so fundamental. The Dumble(SSS type) and a lot of the Two Rock stuff has so much more power in the low end, which is amazing, but kind of tend to be a bit clacky if you are using them by themselves, and I find in my own playing, that it makes a lot of that funky rhythm/lead playing (Hendrix/SRV) not work as well.

Thoughts?

Ian

I have the opinion that most cloned circuits out there generally either have too much clack and quack , or too little. The temperamental nature of the whole recipe demands careful adjustment, and if you aren’t careful you can over compensate with band aid circuit value adjustments. A lot of this boils down to component materials and their inherent characteristics, and when you use the typical cathode bypass values of 5uf across the board through the preamp this really becomes sketchy. Easy way to smear and blur that line is to raise those values back up to fender territory , definitely will tame the clack and return some “cool funkiness” .

Another thing is the typical 820R 24k LTPI compresses and evens the response of the power amp unfavorably for a classic feeling response imo. The earlier generation amps, the ones that don’t get cloned as much , often have that classic fender values 470R 22k and that is another wide turn back into “cool funkiness”

I would be interested to hear more thoughts on how you think the cathode cap changes affect the tone and feel. I don't have an easy way to substitute in my current amp without tearing up the board.. I know what they do technically in terms of frequency, but I'd love to hear more thoughts about tone shaping..How would a cathode cap, for instance, affect tone as opposed to a coupling cap..?

[WhopperPlate]

I would be interested to hear more thoughts on how you think the cathode cap changes affect the tone and feel. I don't have an easy way to substitute in my current amp without tearing up the board.. I know what they do technically in terms of frequency, but I'd love to hear more thoughts about tone shaping..How would a cathode cap, for instance, affect tone as opposed to a coupling cap..?

If you simply can’t bare ripping apart your board , try this : alligator clip small value caps ,like 1 uf , paralleled over the already installed caps . Listen and see what you hear . Try several brands and composition caps .

No substitute for experience. Trying to explain and compare how one thing affects another thing compared to how another thing effects everything is just regurgitation of a million previous posts on the amp garage that can be found with a search engine.

Long story short : everything effects everything. how much is negligible is dependent on how much you perceive, but even the biggest skeptic will at least agree coupling caps and cathode bypass caps are relatively quite significant.

[martin manning]

There are also component substitution boxes, like this: https://www.tedweber.com/amptechtools/p ... ion-boxes/

[imo1]

It would be cool to have some of the sub boxes.

I’ll try the tone stack first, as well as the feedback defeat. For some reason I didn’t put this in this build, and I tend to like the 1st stage without it.

Regarding cathode bypass caps, I’ve messed with that before a bit and the difference was subtle to me. I know this is a much bigger deal with higher gain amps. @whopperplate, I am very aware of the difference the caps” values make, especially coupling. I actively switch those around in my builds. What I was hoping to hear was some thought on experience with cathode bypass, as I haven’t messed with that as much and most of my thought on it is theoretical, based on frequency shifting.

As I said in the last post, before I got into building myself, I was always surprised by the lack of technical knowledge that most of my favorite builders and techs had. They knew the circuits and what they did on a much more intuitive level, whereas some of the more technical minded people tended to struggle with amp designs. Merlin repeatedly talks about how many of the early designers(fender, Marshall, etc) made huge design “errors” and these are what many of us love about the amps.

To me, the greatest achievements are made with good players working with builders who know the circuits. I think one of the coolest things that Dumble did was really listen to the players play and try to sculpt his choices with those in mind. The two Austin guitarists that I knew deeply both integrated their dumbles into their rigs. In EJ’s case, most of his tone and playing came from his Marshall set up, with his clean tone being his stereo twins. The Dumble was his “crunch” rhythm, and was used more sporadically. Stevie’s best tones were using his Dumble mixed with fender amps, and it was the mix that gave him his tone. The Dumble by itself was pretty tight sounding. I know the internet says that Stevie played Jackson’s dumbleland on the first record, but richard(Stevie’s engineer) told me that it was a mix of that and a couple of fender amps, which is in line with what he always used. John Mayer has basically been on a quest to try to get Stevie’s sound for years. He gets good tone, but it’s not what I’m looking for. I do think both he and two rock benefited from working so closely together and I know that two rock having access to John’s dumbles had a lot to do with a lot of the development of their designs

[WhopperPlate]

Regarding cathode bypass caps, I’ve messed with that before a bit and the difference was subtle to me. I know this is a much bigger deal with higher gain amps. @whopperplate, I am very aware of the difference the caps” values make, especially coupling. I actively switch those around in my builds. What I was hoping to hear was some thought on experience with cathode bypass, as I haven’t messed with that as much and most of my thought on it is theoretical, based on frequency shifting.

As I already mentioned , 5uf across the board tightens bass response . For reference , far less extreme than a Marshall bright channel with .68 bypassing each cathode and . Here’s a quick and dirty calculator to give you more understanding.

https://www.ampbooks.com/mobile/amplifi ... alculator/

[martin manning]

Have you messed around with emulating rectifier tubes?

I haven't, but take a close look at the rectifier emulator on the Weber component sub box page. You can see that it just adds a resistance, and the ohm values they suggest using are on the selector markings.