Getting a smoother OD

[martin manning]

I said Twin Reverb thinking that we were talking about a 100W, and Mr dB corrected me. I've edited my post to include both options.

[philbard]

I said Twin Reverb thinking that we were talking about a 100W, and Mr dB corrected me. I've edited my post to include both options.

Thanks for the info Martin...

[philbard]

An update on the last few weeks tinkering with the OTS 50 (ala #102)…

First of all, thanks to all of the forum folks who have chimed in on this, and particularly to CW and Jelle for the components I’ve gotten from them. The amp is certainly smoothing out, and the OD channel in particular. Some of it has been progressive and I suspect is related to break in as has been suggested. I play predominantly Humbucker and Mini Humbucker guitars and get that this may be a factor in my decisions to either use or reject the various mods I’ve tried. Here is a list of some of the things I’ve done. Even though its only been a short time it feels like a very long journey. I hear you chuckling out there.

- Installed EV-12L speaker. Increased clarity and brilliance.
- Added a Dumbleator, this probably made the biggest difference in the OD as I can get the Volume and Master Volume up into their midranges and the overall sound is smoother and more dimensional.
- A large number of Roederstein Draloric’s on the main board.
- MK3’s on the cathodes, Piher on the OD trimmer
- Removed the Dales and installed Draloric’s on the grids
- Changed snubbers from 330pf to 250pf. Removed some of the harshness from the overdrive’s top end
- As per Tony’s 102/183 removed the LNFB. I like what it did to the OD channel but not to the clean so will put it back in with an external switch to govern.
- Also from Tony, switched the treble cap from a 330pf to an NTE 470pf ceramic.
- Swapped the OD Level and Drive pots out from 100K to 250K. This darkened the OD tone but came at the cost of what I perceived as smoothness and sustain, so went back to 100K’s on both.

I spent a couple weeks rolling preamp tubes. I bought a range of modern 12AX7’s from JJ, TAD, Sovtek, Tungsol and Mullard, and also some NOS RCA’s (1950’s and 60’s), Jan’s and GE’s, which of course cost more than just chump change. Although I could hear differences with all of the NOS, I came to the conclusion that the differences they produced were in my case fairly minor and not in step with the increased cost. In some cases the sound from the modern tubes was indistinguishable from the NOS’s. I tried very hard to be objective about this, indeed I wanted the NOS’s to perform a lot better, but in the end had to admit that some of the modern ones were awfully good. Certainly I noticed a warmer, sometimes creamier quality from the older ones, but it wasn’t exclusive to them. V1 is currently a TAD ECC83-CZ that has very lively midtones and the PI is a Sovtek. I suspect I will continue to test in this area. Gutshot below….

[talbany]

Lookin good!

- A large number of Roederstein Draloric’s on the main board.

For me these changes improves clarity, harshness , overall balance and noticeably smooths out the amp.

- Removed the Dales and installed Draloric’s on the grids

- Also from Tony, switched the treble cap from a 330pf to an NTE 470pf ceramic.

IMO The Treble cap is one of the most, if not the most important tone cap in the amp!

- Changed snubbers from 330pf to 250pf. Removed some of the harshness from the overdrive’s top end

250 is the general consensus from myself and many others I know, 220 is next.

- As per Tony’s 102/183 removed the LNFB. I like what it did to the OD channel but not to the clean so will put it back in with an external switch to govern.

Welcome to the crowd

- Swapped the OD Level and Drive pots out from 100K to 250K. This darkened the OD tone but came at the cost of what I perceived as smoothness and sustain, so went back to 100K’s on both.

I agree changing both out the 250K can add in too much low end. This gives the OD that cool sounding low end saw tooth growl but can kill some sustain. A good compromise would be 100k on drive and 250k on OD level. For me this is a good mod for those that play at low vol levels, especially if it's a low plate loaded single coils
Tony

[philbard]

Lookin good!
I agree changing both out the 250K can add in too much low end. This gives the OD that cool sounding low end saw tooth growl but can kill some sustain. A good compromise would be 100k on drive and 250k on OD level. For me this is a good mod for those that play at low vol levels, especially if it's a low plate loaded single coils
Tony

Thanks for the tip in your earlier post about the 102/183. I tried the 250K in both positions a week or so ago and then in just the Level spot, this morning I decided to give it another look and decided to with 250K there. So, yes, good compromise even with my high plate and humbuckers, subtle difference but there nonetheless.

[talbany]

Lookin good!
I agree changing both out the 250K can add in too much low end. This gives the OD that cool sounding low end saw tooth growl but can kill some sustain. A good compromise would be 100k on drive and 250k on OD level. For me this is a good mod for those that play at low vol levels, especially if it's a low plate loaded single coils
Tony

Thanks for the tip in your earlier post about the 102/183. I tried the 250K in both positions a week or so ago and then in just the Level spot, this morning I decided to give it another look and decided to with 250K there. So, yes, good compromise even with my high plate and humbuckers, subtle difference but there nonetheless.

The larger the pot earlier on in the OD circuit (trigger,drive,level.master,) the greater the low end content due to the following voltage amplifiers.. IMO you really have to watch your parts selection with the dual 250 setup otherwise the OD can lose clarity, get muddy and go loose real quick..
183 with humbuckers?
Thats quite a bit of low end but due to the MK3's/NTE's ( a few other parts) and Skyliner the mids are clear and smooth (2 dimensional) IMO.. Sounds good though if you like low end!!

BTW. A long time ago i actually recommended the 250K on both and most disagreed and said it was not standard fare .......Then 183 showed up

Glad it worked out!

Tony

[philbard]

Thats quite a bit of low end but due to the MK3's/NTE's ( a few other parts) and Skyliner the mids are clear and smooth (2 dimensional) IMO.. Sounds good though if you like low end!!

BTW. A long time ago i actually recommended the 250K on both and most disagreed and said it was not standard fare .......Then 183 showed up

Tony

Tony,

Is that an actual Dumble or a clone Matt is playing? It sounds fantastic, I don't mind the bottom end and would be happy to get that quality of tone out of mine. Wondering if on top of this I need to think about moving up to a 100 watt model.

[talbany]

Thats quite a bit of low end but due to the MK3's/NTE's ( a few other parts) and Skyliner the mids are clear and smooth (2 dimensional) IMO.. Sounds good though if you like low end!!

BTW. A long time ago i actually recommended the 250K on both and most disagreed and said it was not standard fare .......Then 183 showed up

Tony

Tony,

Is that an actual Dumble or a clone Matt is playing? It sounds fantastic, I don't mind the bottom end and would be happy to get that quality of tone out of mine. Wondering if on top of this I need to think about moving up to a 100 watt model.

Phil
That's 183 in the clip I posted..Yes a rather large part of the overall sound from an ODS is generated in the higher power/higher current, high filtered output section IMO.The amp stays tighter longer, has more authority (punch)along with increased touch sensitivity, higher responsive attack time along with an overall deeper throat (if that makes sense) 100w also tend to want to bloom,sustain and even feedback easier/longer.
Mo Current!!


Given all that low end 183 has the 100w output section is in a way a must just to keep things from going too loose on you especially at higher volume levels..This is of course just my opinion..i know many builders here who have built 50w versions and like em

BTW..Here is a 183 circuit w/<Music Man Iron I built a long time ago..Please excuse the playing..You can also hear all the low end this thing has using dual 250's fairly similar sounding to 183..
https://www.youtube.com/watch?v=ycsYz5RLH34

Tony

[philbard]

That's 183 in the clip I posted..Yes a rather large part of the overall sound from an ODS is generated in the higher power/higher current, high filtered output section IMO.The amp stays tighter longer, has more authority (punch)along with increased touch sensitivity, higher responsive attack time along with an overall deeper throat (if that makes sense) 100w also tend to want to bloom,sustain and even feedback easier/longer.
Mo Current!!


Given all that low end 183 has the 100w output section is in a way a must just to keep things from going too loose on you especially at higher volume levels..This is of course just my opinion..i know many builders here who have built 50w versions and like em

BTW..Here is a 183 circuit w/<Music Man Iron I built a long time ago..Please excuse the playing..You can also hear all the low end this thing has using dual 250's fairly similar sounding to 183..
https://www.youtube.com/watch?v=ycsYz5RLH34

Tony

Tony,

Makes sense about the 100w circuit and I'm planning to try it. I'm preparing to build a couple more Dumble's, this time from scratch, already have chassis's from Taylor. Question is whether to do the mod to my 50 watt or just go with it in a new build. Its taken me some time to explore sourcing, and I'm part way there but still have a ways to go before I'm clear about what to get and where to get it. This is why I went with the kit the first time around, I wanted to have an understanding of what a Dumble build was like first, even if it might not be dialed quite the way I'd eventually want it, at least I'd have a sense of it with one under my belt. This has proven to be the case already, and I know more about what is involved with these amps even though I'm still new to them. I know if I want to convert my 50 I need tubes and sockets and a small handful of components, the big things are the transformers, and I'm trying to figure out which ones to get and how I'll be able to adapt the PT if I put it in the 50.

Thanks for the clip, no need to apologize for your guitar work, sounds great. The thing I'm really struck by is the smoothness of the high end, and of course the lovely grind of the mids and bottom. I'm closer on that part with the mods I've done but still don't have that velvety quality to the highs, mine are still slightly harsh unless I back the tone pot on the guitar way down. I get that its a fine balance, I'll just continue to work at it and hopefully get closer as I go. BTW, ran through the NOS preamp tubes I have again today, the award goes to the 1951 RCA 12AX7 Blackplate in the V1 spot. Great bottom end... Cheers.

[talbany]

That's 183 in the clip I posted..Yes a rather large part of the overall sound from an ODS is generated in the higher power/higher current, high filtered output section IMO.The amp stays tighter longer, has more authority (punch)along with increased touch sensitivity, higher responsive attack time along with an overall deeper throat (if that makes sense) 100w also tend to want to bloom,sustain and even feedback easier/longer.
Mo Current!!


Given all that low end 183 has the 100w output section is in a way a must just to keep things from going too loose on you especially at higher volume levels..This is of course just my opinion..i know many builders here who have built 50w versions and like em

BTW..Here is a 183 circuit w/<Music Man Iron I built a long time ago..Please excuse the playing..You can also hear all the low end this thing has using dual 250's fairly similar sounding to 183..
https://www.youtube.com/watch?v=ycsYz5RLH34

Tony

Tony,

Makes sense about the 100w circuit and I'm planning to try it. I'm preparing to build a couple more Dumble's, this time from scratch, already have chassis's from Taylor. Question is whether to do the mod to my 50 watt or just go with it in a new build. Its taken me some time to explore sourcing, and I'm part way there but still have a ways to go before I'm clear about what to get and where to get it. This is why I went with the kit the first time around, I wanted to have an understanding of what a Dumble build was like first, even if it might not be dialed quite the way I'd eventually want it, at least I'd have a sense of it with one under my belt. This has proven to be the case already, and I know more about what is involved with these amps even though I'm still new to them. I know if I want to convert my 50 I need tubes and sockets and a small handful of components, the big things are the transformers, and I'm trying to figure out which ones to get and how I'll be able to adapt the PT if I put it in the 50.

Thanks for the clip, no need to apologize for your guitar work, sounds great. The thing I'm really struck by is the smoothness of the high end, and of course the lovely grind of the mids and bottom. I'm closer on that part with the mods I've done but still don't have that velvety quality to the highs, mine are still slightly harsh unless I back the tone pot on the guitar way down. I get that its a fine balance, I'll just continue to work at it and hopefully get closer as I go. BTW, ran through the NOS preamp tubes I have again today, the award goes to the 1951 RCA 12AX7 Blackplate in the V1 spot. Great bottom end... Cheers.

Cool!..You are a lot further along than I was when I was new to building these amps.Out of all the amps I've built these are by far the most difficult to get right IMO. There are very few replicas out there that I've played (I've played many) that really grabbed my attention and said "I have to have this amp" This may sound arrogant but it's how I feel.I'ts been only recently that I've been able to build an ODS without having something about it that bothered me or was not what I expected, 15 years later..My point is it's a constant evolving process and with the help of many people here I would have never have got this far without the Garage So keep at it try different part combos and enjoy the process

If it were me I would leave the 50 a 50 and make the next one a 100. I am sure your going to find something you like about the 50..Take your time and collect all the parts you want for the 100 and any good set of off the shelf Twin/Showman Iron should do the trick!
BTW. I love the old Black Plates. I have one in V1 of my Music Man Low Plate. A wonderful tube fur sure. Congrats!
Best of Luck!

Tony

[ChopSauce]

As the knowledge sums on this forum, the builds seem to refine ...

One question I have been willing to ask for several days now, that I can't help but asking:

- if I'm right Draloric are NOS resistors, so what would be suitable replacements to the Dale(s), amongst modern ones?

[norburybrook]

As the knowledge sums on this forum, the builds seem to refine ...

One question I have been willing to ask for several days now, that I can't help but asking:

- if I'm right Draloric are NOS resistors, so what would be suitable replacements to the Dale(s), amongst modern ones?

I made a #183 and used these lovely metal film TE Connectivity / Holsworthy Black resistors amp sounded great. I sold it to a friend who's a great player and has used it extensively for the last 3 years.

https://www.mouser.co.uk/ProductDetail/ ... CE-dQ-IFmE


M

[ChopSauce]

Thanks!

[talbany]

As the knowledge sums on this forum, the builds seem to refine ...

One question I have been willing to ask for several days now, that I can't help but asking:

- if I'm right Draloric are NOS resistors, so what would be suitable replacements to the Dale(s), amongst modern ones?

Here is a list of all the resistors I have tried and liked and recommend. They each have their own subtle nuances but are musical sounding resistors IMO..As to which one of these you like ???

Carbon
Iskra 1/2 or 1 watt (my fave)
1/2 watt Phiers/ Beyschlag
Q-Lines/LCA 0617's
Allen Bradley 1/2 watt
Philips 70's https://reverb.com/item/30266987-10-x-p ... rs-100k-1w or https://reverb.com/item/2498419-20x-nos ... ock-1970-s

Metal Film
NOS Dales
NTE HW's or Diamond labels
Roederstein MK'3 1/2 watt
Mepco/Electra
KOA Speer (honorable mention)


I have not tried many of the new stock resistors as I have not yet had any recommended to me and this is a question I ask constantly!..(It took me over 6 months of ebay scouring to collect all the resistors on my last 2 amps )
BTW. I have not tried the Dralorics Jelle sells yet?, however ,I know people who have and like them!
BTW-2 A lot of popular builders use KOA Speer Carbon film's.. I am not a big fan?

Tony

[philbard]

Here is a list of all the resistors I have tried and liked and recommend. They each have their own subtle nuances but are musical sounding resistors IMO..As to which one of these you like ???

Carbon
Iskra 1/2 or 1 watt (my fave)
1/2 watt Phiers/ Beyschlag
Q-Lines/LCA 0617's
Allen Bradley 1/2 watt
Philips 70's https://reverb.com/item/30266987-10-x-p ... rs-100k-1w or https://reverb.com/item/2498419-20x-nos ... ock-1970-s

Metal Film
NOS Dales
NTE HW's or Diamond labels
Roederstein MK'3 1/2 watt
Mepco/Electra
KOA Speer (honorable mention)


I have not tried many of the new stock resistors as I have not yet had any recommended to me and this is a question I ask constantly!..(It took me over 6 months of ebay scouring to collect all the resistors on my last 2 amps )
BTW. I have not tried the Dralorics Jelle sells yet?, however ,I know people who have and like them!
BTW-2 A lot of popular builders use KOA Speer Carbon film's.. I am not a big fan?

Tony

Just getting back online, we had 3 ice storms in a row in Portland and have been without power for 3 days now. Camped out at a friend's whom we trust has been quarantining religiously. Our bedroom was 46 degrees this morning, yikes...

Thanks for the list. I've seen you mention Iskra's, and some of the others are familiar. Charlie sent me some Allen Bradleys, but as I put them in at the same time as the Draloric's I'm unable to tell what they contributed. I also have been leaning towards waiting for the new builds to go 100 watt. Probably it will take a similar number of months to source the parts, but I'm less impatient now that I have a functioning Dumble to play in the meantime. That is, when we get power again.