Dumbleator Tweaks, Settings, etc. to Retain Dynamics?

[ayan]

Hi guys,

Recently I did a couple of gigs in which they provided a "decent" backline, so I decided to invest a little $ and put a delay on my pedalboard so that I wouldn't have too dry a sound when using a backline. My board had In/Out buffers (homebrew), a compressor, a Zendrive, a Crybaby, a "Blue Magic" (homebrew), an EB volume pedal and a Boss tuner. I've added a TC Flashback which, with the possibility of editing your own custom patch via Tone Print, has proven to be a very valuable addition. This little set up works really well and putting it in from on my own amps highlights the "limitations" of using a Dumbleator in terms of loss of dynamics. Running overdrive and delay via the pedalboard sounds good and is pretty "bouncy." Also, putting the volume pedal right before the amp's input acts as an overall master volume, and not a gain control, and that comes in really handy. I really like these results and can see why maybe guys like RF and LC have moved in this direction.

On the flip side of the coin, the overdrive sound of the amp itself is what got me on this Dumble quest path 15 years ago, and I think that is the "ultimate" lead sound when things are dialed in just right. Of course, being able to achieve that depends on a number of factors and sometimes the planets just don't line up at a gig and we struggle with the amp a bit. Nevertheless, I would like to see if there is a way to have, when using the Dumbleator, some of those dynamics we hear when not using the loop. I'll state that, to me, using the delay from the pedalboard and the overdrive from the amp is simply not an option... I don't care for that sound.

I'd like to see if you guys have any ideas in this area. I'll list the things that I don't think have worked out so well for me:

1. Having a bright cap on the amp's master volume control (for non HRM amps where there is a single overall master) is a pain. If I dial it where it adds chime to the clean, the overdrive will be harsh; if I dial it where the overdrive is smooth the clean will be too boring. I have tried 20, 30, 47 and 68pF and nothing sounds good to me. Has anyone tried something more radical, like some Marshall's have? One big con to having a brightness cap around the master is that if one decides to not use the loop, the amp will be way too bright as the master settings will be lower in that case.

2. Bright switch on the Dumbleator's send. This is a huge cap, 1,000pF over a 250K pot, and while it sounds good at low (i.e., not gig) volumes (I turn up the Send control to get the brightness I want and then turn down my FX input level to prevent overdriving the FX unit), it seems to never sound good at gigging volumes. Has anyone tried different brightness caps here?

3. Bright switch on the Dumbleator's return level. This is a smaller cap (270 pF) and while it can work OK sometimes, by the time I get the rig up to gigging volume, the effect of this cap is negligible.

Somehow I think items 1., 2. and 3. above are not a solution that would work for me. I wonder if rather than trying to make up for loss dynamics in one spot, one could implement a more "distributed" solution. Has anyone tried using small caps in various places, for example a 30pF cap on the amp's preamp volume control, permanently wired there and maybe a 15pF on the master? And some smaller permanent caps on the Dumbleator send and return pots? Lastly, perhaps trying to fine tune the loop brightness network in 124 (220K resistor // 250 pF cap) and maybe using 470K // 500pF, etc.? I have never toyed with that myself and what I like about this is that the "fix" is only implemented when needed, since the network is out of the picture when there is nothing plugged into the loop.

I realize a solution to this problem may be adding the "bright cap on clean only" capability via relay, but I am curious about finding a more "organic" approach...which may or may not exist. Also, while some people have success using parallel loops, I think they are hard to dial in and limit the type of FX that can go in a loop since they get along with time-based FX but not compressors, EQs, etc.

I hope you can share some of your experiences in this area.

Thanks,

Gil

[jelle]

Axe the lnfb on the return stage and let me know if that increased dynamics for you. Jelle

[ayan]

Axe the lnfb on the return stage and let me know if that increased dynamics for you. Jelle

Oh yeah, and that one can easily be put on a switch. Will try it, thanks.

G.

[dobbhill]

Gil:
I can't get brite caps dialed in right. Ever. If I get lucky and nail it at home, when I gig, all bets are off. This includes brite caps on the volume, master, and d'lator controls. I guess I don't have the patience to twiddle that much. I just want to play. I get more mileage out of my presence control; seems to give me more consistent results. But, I like the sound of my amp and speakers without brite added. My go-to speakers are somewhat brite: Altec 417C and the stock eminence in my Demeter cab....
My question to you would be: what's missing that sends you looking for a brite cap?
Trying to help....
D

[ayan]

BTW, I get a lot more milage out of the presence control as well. What's lacking when using the loop is the "quickness" of the response of the clean channel when nothing is plugged in the loop, for example. I can sort of fix that via bright caps for the clean sound when I use the loop, but then the OD goes out the window. So I guess in my post I was wondering, among other things, if there would be bright cap values along the signal path that would "liven up" the clean sound without making the OD harsh. I realize the answer is probably "no."

I need to try pulling V1B loop, as Jelle says. That may be a good thing.

Gil

Gil:
I can't get brite caps dialed in right. Ever. If I get lucky and nail it at home, when I gig, all bets are off. This includes brite caps on the volume, master, and d'lator controls. I guess I don't have the patience to twiddle that much. I just want to play. I get more mileage out of my presence control; seems to give me more consistent results. But, I like the sound of my amp and speakers without brite added. My go-to speakers are somewhat brite: Altec 417C and the stock eminence in my Demeter cab....
My question to you would be: what's missing that sends you looking for a brite cap?
Trying to help....
D

[aflynt]

I've found with the #102 circuit, balancing out the 68pF master cap with about 200-250pF to ground on the loop send and a high amp master setting (I do 560k in series and 470k to ground on the master voltage divider) is just right. I just entirely ditch the master pot in favor of fixed resistors since IMHO the loop return really IS the master when you're running a D'Lator.

Still, I get your point about the clean being a bit squished and slow. I kind of like that feel though, especially for clean leads. I never use an OD pedal and put the volume pedal in the loop to get a foot-enabled master. Delay / Reverb go after the volume pedal right before the loop return.

-Aaron

[JazzGuitarGimp]

Ayan,

I have a feeling you've already answered your own question. As I was reading your original post, and before I got to the last paragraph, my thought was (as you mentioned in the last paragraph) to add a relay the triggers with your OD relay, and switch-in a different bright cap for the OD.

Bright caps are tricky business by their very nature. As has already been mentioned, the position of the volume control its associated with will have a significant bearing on just how much "brightness" you get out of it. If you've heard of the Fletcher-Munson curves, you'll instantly know why the bright switch came about to begin with. It's just not the perfect solution in ALL situations. Perhaps two other alternatives are:

- Use a relay, triggered by the OD switch, to switch in a second treble pot for the OD channel.

- Implement a bright switch that isn't interdependent on the position of the volume control.

All the best,
Lou

[wjdunham]

Gil, have you tried an OD HF taper control. Not the perfect solution, but simple and does allow some control over the frequency balance between channels. I went with small bright caps on the master (47pf) and loop pots (somewhere between 100pf and 200pf if I recall). I did not want to make any radical changes to the basic topology or add more relays and found the taper to work well enough even with it being before all the bright caps.
Bill

[10thTx]

There may not be anything real useful that I'm sharing?

I like a 12AV7 or 12AY7 in mine. I don't like the LNFB. I have put that on a switch before but found I never switched it in so left it out on the on board D'Lators.

Some other values obviously have been changed to match what I wanted out of the amp. And I added a smoothing cap that turned out to be useful to me.

On the first two D'Lators I did (which were out board), I found I never changed the setting on the return 250k pot. So I measured what it was set at and use an 82k & then just have the send pot and level pot for adjustments.

with respect, 10thtx

[ayan]

Yes, I was a strong advocate of the HF taper for a long time. Later, I changed my mind about the effect it has on the tone because I felt it takes away some of the really good stuff. But I agree that it does work, all in all.

I tried a few things this morning -- although I've not yet tried nuking the LNFB on the D-lator -- and the closest I can get to the sound I like is using the bright switch on the D-lator send, the one with the .001uF cap and the 250K pot turned way up. However, that has proven to be a very delicate balancing act in the past.

Cheers,

Gil

Gil, have you tried an OD HF taper control. Not the perfect solution, but simple and does allow some control over the frequency balance between channels. I went with small bright caps on the master (47pf) and loop pots (somewhere between 100pf and 200pf if I recall). I did not want to make any radical changes to the basic topology or add more relays and found the taper to work well enough even with it being before all the bright caps.
Bill

[ayan]

Very interesting. Looking at the schematic, I wonder how much crunch you are able to get from the "clean" channel? It would seem like quite a lot!

Thanks for sharing,

Gil

There may not be anything real useful that I'm sharing?

I like a 12AV7 or 12AY7 in mine. I don't like the LNFB. I have put that on a switch before but found I never switched it in so left it out on the on board D'Lators.

Some other values obviously have been changed to match what I wanted out of the amp. And I added a smoothing cap that turned out to be useful to me.

On the first two D'Lators I did (which were out board), I found I never changed the setting on the return 250k pot. So I measured what it was set at and use an 82k & then just have the send pot and level pot for adjustments.

with respect, 10thtx

[stelligan]

Parallel loops and sometimes small value bright caps on the d-lator return work for me.

[img::]http://static.musiciansfriend.com/deriv ... 28_top.jpg[/img]

I am soon to be trying this instead/also: https://tubeamparchive.com/viewtopic.php?t=21205

[DonMoose]

Um - does a double-d'lator sound too stupid an idea?

The first one has a relay in the middle that skips or inserts the actual loop, the second drives and buffers the loop.

[markusw]

Gil, have you tried lowering the 220k grid resistor of the Dumbleator's recovery stage as suggested by Gary a while ago?
https://tubeamparchive.com/viewtopic.ph ... 220k#37211

I went down to 10k and although it's more subtle than the Dumbleator's bright caps it definitely helped to restore some brightness.

What tube do you use in your Dumbleator? A bright tube like a short plate Holland Valvo/Philips ECC83 might help too.

Regards,

Markus

[bluesfendermanblues]

I've found with the #102 circuit, balancing out the 68pF master cap with about 200-250pF to ground on the loop send and a high amp master setting (I do 560k in series and 470k to ground on the master voltage divider) is just right. I just entirely ditch the master pot in favor of fixed resistors since IMHO the loop return really IS the master when you're running a D'Lator.

Still, I get your point about the clean being a bit squished and slow. I kind of like that feel though, especially for clean leads. I never use an OD pedal and put the volume pedal in the loop to get a foot-enabled master. Delay / Reverb go after the volume pedal right before the loop return.

-Aaron

@Aron,
I tried the above mentioned cap values - on both a #102 and a #183 with builtin loop - but, found that I like a (560k/470K) fixed master without any caps (200pf-250pf + 68p).

The 200p-250p cap dulls down the signal and (just like a cable would) and the 68p retrieves the brightness, but I feel its a little more alive without the caps.

@Gil,
And in order to get a good balance between clean and OD, I found a 150p across the (250k) OD master in my #183, is all it takes. IMO you should not hear a tonal difference between the clean and the OD.

I will try Jelle's tip regarding switching out the LNFB for increased dynamics, but I would expect more low end, removing the LNFB.