ODS 102 with 2x KT88s and built-in Dumbleator

[bcmatt]

I'd like to convert another Traynor YGL-3a that I have to a #102 High-Plate Skyliner.

It's already been modded a bit to take a couple KT88s. This is it currently:

20240504_140745.jpg

YGL with KT88 screen VVR.jpg

I'm first trying to theorize what a built-in Dumbleator in a #102 would look like and I pasted together this:

102 with Dumbleator Theorized.jpg

I haven't tested that schematic to see if it would work well, but I'm theorizing as well, how I would adapt that to fit my current YGL power section, and came up with this so far:

YGL 102 KT88.jpg

I haven't figured out yet how much more the filtering and dropping resisters ought to be tweaked....
Any thoughts would be appreciated.

EDIT: I already bumped up the filtering for B+3 and increased the resister slightly to closer reflect the YGL since it has less filtering earlier. I reuploaded that last schematic wit the changes

[GAStan]

bcmatt I did a very similar build, if I were to put together a schematic of my build it would look nearly identical to what you pieced together.

On mine the switch to select or bypass the Dumbleator is actually a relay. I did this mainly to avoid long signal wire runs to a switch. Where I was able to mount the relay actually didn't add much if any wire length. In this Pic you can see the standard PAB & OD relays, the relay closest to the filter caps is for the Dumbleator.

20240315_121814.jpg

If you have any questions don't hesitate.

Best of luck with your build, I'm really interested in what you come up with.

Edit: PS-the chassis hasn't been put in a cabinet yet, if you want better pics of anything in particular let me know and I'll get them for you.

[bcmatt]

bcmatt I did a very similar build, if I were to put together a schematic of my build it would look nearly identical to what you pieced together.

On mine the switch to select or bypass the Dumbleator is actually a relay. I did this mainly to avoid long signal wire runs to a switch. Where I was able to mount the relay actually didn't add much if any wire length. In this Pic you can see the standard PAB & OD relays, the relay closest to the filter caps is for the Dumbleator.

20240315_121814.jpg

If you have any questions don't hesitate.

Best of luck with your build, I'm really interested in what you come up with.

Edit: PS-the chassis hasn't been put in a cabinet yet, if you want better pics of anything in particular let me know and I'll get them for you.

Thanks Glenn! That's very generous. Looking back at where I scoured ideas from, your thread definitely was a primary source of information. Your reference images in your first post definitely helped me figure out what I might be able to try. That schematic of the Super Reverb Conversion that you found is what I'm using for the Dumbleator in/out switch and connecting to B+2. I actually haven't been able to find any other schematics at all for how anyone has incorporated a built-in Dumbleator. So, if you had to make any changes to that, I'd love to hear.
Do you think you would ever switch in and out the Dumbleator mid-song, or is your use of the relay there exclusively for shorter wire runs? (I actually would like to incorporate the relays in this amp, but hope to convert the circuit first without them and add them later... but I hadn't considered making one for the loop switch too.
I'm going to figure out a layout next, so I'll definitely study what you did and see how I might adapt for my situation. Right now I am actually thinking I would try to put the controls on the front panel of the amp, while keeping the jacks on the back... but I haven't started that configuration stage yet. I've decided to more thoroughly document my plans schematic and layout-wise this time before building. When I did my Traynor to SSS conversion with my other YGL amp, I would get turned around a lot because of the different way I had to configure my layout compared to the MHartman layout I was following. I think it will go smoother this time if I put my particular translations down on paper first.
I do have the luxury of way more space than you had... which I'm relieved about. I'm more torn about where to leave space for planning ahead for relays.

Where did you get your relay boards from?

[Stephen1966]

... I actually haven't been able to find any other schematics at all for how anyone has incorporated a built-in Dumbleator. ...

I've used the dumbleator in both my Skyliner and the Delta amps I've documented here. The cap values are a little different than standard for modified filtering but the basics are very similar. They don't have relay switching but that can be easily designed in.

Check out the Delta (183) for the mature circuit.

https://ampgarage.com/forum/viewtopic.php?f=4&t=35724

I found a picture of it in place. DME caps are great and save space.

IMG_20230129_135702.jpg

[GAStan]

Not sure if I'd ever need to switch it in or out mid-song, great question to consider if it's worth putting on a pedal.

The relay was used primarily to keep the wire runs shorter. My goal was to keep it as close to 102 as possible when the Dumbleator was not in use. The possibility of putting it on a pedal switch came up later.

These particular boards came from Erwin_ve, a fellow member or this board from Europe. I've also used some similar ones from Taylor at Amplified Nation. Mojotone also sells some good ones but currently are out of them. I believe there are other sources but cannot recall any at the moment.

[bcmatt]

I've used the dumbleator in both my Skyliner and the Delta amps I've documented here. The cap values are a little different than standard for modified filtering but the basics are very similar. They don't have relay switching but that can be easily designed in.

Check out the Delta (183) for the mature circuit.

https://ampgarage.com/forum/viewtopic.php?f=4&t=35724

I found a picture of it in place. DME caps are great and save space.


IMG_20230129_135702.jpg

Cool! Thanks for chiming in. I'm exploring around in that thread of yours now. So perhaps you addressed this, but I see you have 4 jacks for your loop. Looking at your schematic, it appears you are giving a passive and an active loop option. Have you found that you ever use the passive loop?
I'm perhaps a little confused as I think about this... but does that also give you the option for another amp to use the Dumbleator in this amp?
When you say "modified filtering", what do you mean by that? Is something specifically your amp required?

[bcmatt]

Not sure if I'd ever need to switch it in or out mid-song, great question to consider if it's worth putting on a pedal.

The relay was used primarily to keep the wire runs shorter. My goal was to keep it as close to 102 as possible when the Dumbleator was not in use. The possibility of putting it on a pedal switch came up later.

These particular boards came from Erwin_ve, a fellow member or this board from Europe. I've also used some similar ones from Taylor at Amplified Nation. Mojotone also sells some good ones but currently are out of them. I believe there are other sources but cannot recall any at the moment.

ok, cool. Thanks. Good to know.

[bcmatt]

I'm just playing with my panel layout options in Paint based on the actual front and back panels and what sorts of holes they have.
I'm not sure, but maybe something like this:

CHASSIS.jpg

I want to build it without relays first, but I do want to make it possible to add OD and PAB relays later...

[Stephen1966]

...
Cool! Thanks for chiming in. I'm exploring around in that thread of yours now. So perhaps you addressed this, but I see you have 4 jacks for your loop. Looking at your schematic, it appears you are giving a passive and an active loop option. Have you found that you ever use the passive loop?
I'm perhaps a little confused as I think about this... but does that also give you the option for another amp to use the Dumbleator in this amp?
When you say "modified filtering", what do you mean by that? Is something specifically your amp required?

Actually, during biasing the passive RET jack in bypass mode can be used to inject a signal straight into the PI and on to the power section. That's a way I've used it. The passive jacks are there so that you can SEND a raw unfiltered line out before processing it and returning it via the passive RET. My circuit is designed so that when the jacks are inserted in the passive side the active side is switched out. You can't have both passive and active loops in operation in this design. It's a relatively straightforward design problem of switching to make it so the passive jacks act as INPUT and OUT for a seperate amp though that would probably make it the world's least useful, least portable and most expensive tube effects loop next to a genuine Dumbleator which is probably the least useful, least portable and most expensive tube effects loop compared to any other commercially available loop you aren't afraid of losing, breaking, having stolen or breathing on. From this point on in electronics, just easier to assume the answer to all your questions is (somehow) 'yes'

One design change I will make to the loop design in the Delta in the future is to exchange the passive Switchcraft 12A jack for a Switchcraft 11. That way I can hook a line up between the Delta and any other amp for daisy-chaining amps in series.

I went into some depth regarding the filtering changes here:
https://ampgarage.com/forum/viewtopic.p ... 83#p444383

One thing that has started to irk me about the design is (what would normally be) the .47uF coupling cap coming off the cathode. If that cap fails, you could have around 30V hitting your pedals. A class Y capacitor, might be a tad unfashionable but it could save your pedals if a standard cap were to fail short.

[bcmatt]

Actually, during biasing the passive RET jack in bypass mode can be used to inject a signal straight into the PI and on to the power section. That's a way I've used it. The passive jacks are there so that you can SEND a raw unfiltered line out before processing it and returning it via the passive RET. My circuit is designed so that when the jacks are inserted in the passive side the active side is switched out. You can't have both passive and active loops in operation in this design. It's a relatively straightforward design problem of switching to make it so the passive jacks act as INPUT and OUT for a seperate amp though that would probably make it the world's least useful, least portable and most expensive tube effects loop next to a genuine Dumbleator which is probably the least useful, least portable and most expensive tube effects loop compared to any other commercially available loop you aren't afraid of losing, breaking, having stolen or breathing on. From this point on in electronics, just easier to assume the answer to all your questions is (somehow) 'yes'

One design change I will make to the loop design in the Delta in the future is to exchange the passive Switchcraft 12A jack for a Switchcraft 11. That way I can hook a line up between the Delta and any other amp for daisy-chaining amps in series.

I went into some depth regarding the filtering changes here:
https://ampgarage.com/forum/viewtopic.p ... 83#p444383

One thing that has started to irk me about the design is (what would normally be) the .47uF coupling cap coming off the cathode. If that cap fails, you could have around 30V hitting your pedals. A class Y capacitor, might be a tad unfashionable but it could save your pedals if a standard cap were to fail short.

OK, thanks. Some things to think about. I'll see if I can get a class Y cap for that spot.
I'll consider whether I ought to have that passive jack option. I may be ok with the just the switch that takes the the dumbleator out of the circuit... but that passive input might be handy for the PI balance process.
I'm going to read that thread thoroughly and make decisions about the exact Dumbleator circuit version I will try. I do like what I'm hearing about going with the 25k pot...
I'm also trying to decide about having either a parallel switch option of that mesa-style parallel blend pot.

I'm going to keep refining the vision to get down on paper exactly what I'm going to try....

[bcmatt]

I'm leaning toward drawing out the full vision and going for the whole build at once, instead of the trial steps. (so I will do a more full conversion of the filtering, including add the choke). So I'm still refining that vision.

I'm currently experimenting what it would look like to add reverb to the current design. I am trying to figure out how to have it compromise the 102 OD circuit the least. I assume I would need to at least increase the size of the grid stopper on the reverb driver tube so that it doesn't rob all the signal going to the dry/OD circuit:

YGL 102 KT88 with Reverb.png

I would still need to sort out the B+ supply and filtering, but I am wondering about the send and return points for the Reverb. I was thinking I would have both between the Dumbleator and the PI, but I see maybe the advantage of taking the reverb send early like as in the SSS #002.


It just occurred to me I should look at #005 for Reverb implementation because I believe it deletes the return blending tube...

[bcmatt]

Yup, I keep changing my mind. I'm thinking I'd like to build it leaving space for a classic Fender 2-tube reverb before the loop. Sort of a future expansion idea after I've played the regular 102 circuit and can judge properly if the reverb circuit compromises anything by being added.

May 11.jpg

I'm going to look at the D-Later now and tweak that part of the schematic to what I want to actually build.
I'm thinking I'd also like to add Martin's FET relay and drive control. I'll add it to the schematic, but again, I think I'll save the FET circuit and all the relay switching for the second stage of the build and just put on front panel switches for now while leaving space for where the relay boards would go.

[Stephen1966]

Yup, I keep changing my mind. I'm thinking I'd like to build it leaving space for a classic Fender 2-tube reverb before the loop. Sort of a future expansion idea after I've played the regular 102 circuit and can judge properly if the reverb circuit compromises anything by being added.
May 11.jpg

I'm going to look at the D-Later now and tweak that part of the schematic to what I want to actually build.
I'm thinking I'd also like to add Martin's FET relay and drive control. I'll add it to the schematic, but again, I think I'll save the FET circuit and all the relay switching for the second stage of the build and just put on front panel switches for now while leaving space for where the relay boards would go.

Yeah, man! Who are you building this amp for? You really don't need to do what anyone else did, myself included - do what makes YOU happy. Big thumbs up. Mind you I would definitely sort out the relay situation first. In a standard D-style chassis, there isn't a ton of space and installing them after the main circuit would be next to impossible without undoing several other major parts of the circuit. Even if I had the space though, I would still sort it out first. Looking forward to your updates.

[bcmatt]

Yeah, man! Who are you building this amp for? You really don't need to do what anyone else did, myself included - do what makes YOU happy. Big thumbs up. Mind you I would definitely sort out the relay situation first. In a standard D-style chassis, there isn't a ton of space and installing them after the main circuit would be next to impossible without undoing several other major parts of the circuit. Even if I had the space though, I would still sort it out first. Looking forward to your updates.

It's definitely for me. This particular Traynor was my first ever guitar amp I ever played. I do have several friends and acquaintances that play my amps too (I'm always trying to help people find their ideal tone). So, in the end it is still nice if they are user-friendly and not too confusing. I appreciate them looking nice and making sense but the time I'm finished messing with them, but this is not the sort of thing I'm trying to please a "customer" with. I don't need special-made faceplates or powder-coated chassis. I'll probably flip the thin aluminum faceplates over, shine them up and label things with a Dymo sticker printer like I did with my other YGL-3a that I converted to an SSS:

20240508_225139.jpg

That said, I will take your advice on the relays and make sure they are at least fully planned out before I break out the soldering iron and start my modding/building.

[bcmatt]

After doing a bunch more suggested reading on the Loop, Stephen, I lifted your circuit from your 183 build. In the interest of not drilling too many more holes or installing parts that I think won't get used, I removed the the line/instrument switch as well as the jacks for the passive loop. I'm thinking I will probably put the Series/parallel switch and the Loop IN/Out switch on the back panel with the send and return jacks, but put the three control pots on the front panel.

May 13.jpg

Next I will take look at the FET input and relays switching circuits.