Final build diagram with all changes

[Mark]

Dear Scott

What mods do you recommend for the D'Lite?

Perhaps this is a good thread to post them all at one time, rather than have to search the breadth of the forum for every little snippet.

I dare say you don't see the D'Lite as being in a 100 watt Dumbles league, but that's okay. I'd love to know what someone with your experience thinks what works best in these amps?

[dogears]

Hi Mark,

I have a 100 watt D'lite Bluesmaster here. It is definately in a 10 watt Dumble's league

I'll see about some type of mod list. But, basically do not deviate from what Dumble did. No bass mod (keep stack like Dumbole did it), no grounded presence pot, minimum 50 watter w/ big iron, choke or 330ohm resistor, etc....

Dear Scott

What mods do you recommend for the D'Lite?

Perhaps this is a good thread to post them all at one time, rather than have to search the breadth of the forum for every little snippet.

I dare say you don't see the D'Lite as being in a 100 watt Dumbles league, but that's okay. I'd love to know what someone with your experience thinks what works best in these amps?

[Mark]

The Bass mod is a strange one, the amp started off without it, and the it came about, and now I have read a few threads against it?

The grounded presence pot does reduce the value of the resistor from 390 ohms to 326 ohms. I'm not sure if that is audible, but let me know what you've encountered.

[dogears]

Mark, the bass pot needs to have the 1st and 2nd lugs connected, via relay, when in normal mode. This connection is broken with PAB on. The practice of not connecting them was an error. It ruins the tone of the amp IMO (unless you are looking for that one specific thin tone and nothing else) and I have played them that way. If the amp is too bassy, then you should try reducing bass via one of the several tried and true ways. Not by messing up the the stack operation. So, for me, bass mod is not the right term. The incorrect way would be the mod. Connected is the correct way. There is no middle ground or gray area. Wire the stack the way Dumble did. There are no valid arguments for doing anything different. As I said, if you want to reduce bass content, you can reduce the CL2 coupler, lower plate loads, change bypass caps, etc.....

Also, the grounded presence pot has a large effect. Reducing the tail not only decreases NFB, it also changes the operation point of the presence circuit and alters its effectiveness.

The Bass mod is a strange one, the amp started off without it, and the it came about, and now I have read a few threads against it?

The grounded presence pot does reduce the value of the resistor from 390 ohms to 326 ohms. I'm not sure if that is audible, but let me know what you've encountered.

[Mark]

Dear Scott

Thanks for your reply, very helpful.

I was curious as to how the bass mod came into existence, I agree a horrible thin tone isn't much fun.

I did think the presence control didn't do too much. Though I didn't think the effect would be all that great, I stand corrected. Thanks.

I will have to implement that change.

Thanks again for all your help.

[dogears]

The bass mod was a mistake on the build as Norm pointed out in another thread. Gil and Billy Yates pointed it out. In addition, I commented about the amps weak bottom and how I did not dig it much after playing it NAMM two years ago. Subsequently, Norm pointed out that there was a problem with how he wired the stack. I could tell there was something wrong without knowing. As a switching option, the "mod" is not a bad idea. As long as it doen't compromise the regular stack operation. The PAB needs to have the lug connection broken.

Don't get me wrong. There is a decent tone in the amp after mod too. If you use neck pickup and only in certain instances. It is just that you can't use the bridge and it gets rid of all the classic Dumble tones.

Dear Scott

Thanks for your reply, very helpful.

I was curious as to how the bass mod came into existence, I agree a horrible thin tone isn't much fun.

I did think the presence control didn't do too much. Though I didn't think the effect would be all that great, I stand corrected. Thanks.

I will have to implement that change.

Thanks again for all your help.

[Tdale]

When you say that the outer ears are connected, do you mean connected with a cap, like in the hybrid-a schematic?

I'm not sure what we're talking about with the grounding of the presence pot. The schematic shows that the resistor and cap should be grounded, but what ear is not supposed to be grounded, the one on the "top" or "bottom" in the schematic?

Tommy

[Structo]

On the D'Lite the first lug of the presence pot is taken to the ground buss wire.
Where as on the Dumble it is grounded through the 1uf cap and 390R resistor.

[dogears]

Right. And that was a mistake.

Do it the Dumble way. You can alter the size of the feedback resistor and/or the presence cap size if you want different effects. Grounding the presence pot is a mistake.

Sorry to be obnoxious with this stuff, but this is the Dumble forum and that presence ctrl wiring was an error. Whether Norm and Moss liked the end result or not. It was an admitted mistake.

On the D'Lite the first lug of the presence pot is taken to the ground buss wire.
Where as on the Dumble it is grounded through the 1uf cap and 390R resistor.

[Mark]

Dear Scott

I don't think there is any harm in pointing out areas where there can be improvement. That's positive criticism.

I think the PAB circuit falling into the same catagory, though I may well be wrong, but looking at the circuit as Scott points when using the PAB circuit the top end of the pot breaks connection with the bottom end of the treble pot. The wiper of the bass pot should also breaks with the top of the bass pot.

where as the D'Lite only breaks connection between the the bass and treble pot. I assume this was done by Dumble to disable the effect of the bass pot and give maximum output. Though it may well be said by Norm and Moss that simply breaking the bass/treble connection gives a boost in level while presenting less of a tone shift from the original tone. Also to be considered, if you have the bass pot pretty much up full you won't hear a difference anyway.

The other thing I notice is that there are 47pF caps across the master volume control on Dumble amps but these aren't present on the D'Lite. Is this because they aren't necessary or is it deemed that this a personal sort of thing most users would do in time anyway?

[jelle]

It really depends on whether you run an external Dumbleator. If you do, and with 6 or 8 foot cables, 47pf is really good....

Dear Scott

The other thing I notice is that there are 47pF caps across the master volume control on Dumble amps but these aren't present on the D'Lite. Is this because they aren't necessary or is it deemed that this a personal sort of thing most users would do in time anyway?

If you don't mind me commenting on this one....

IMHO the bright caps across the master is something that needs to be done on an amp by amp basis...some need it some don't. Some need 10 or 20pF. 47pF can be a bit much.....

Just tweak 'till good!

[angelodp]

If the Bass pot is connected, 1&2 lugs through a switch and toggled manually, will the tone stack be re-constituted to the Dumble way, along with the other points you made Dogears.

[dogears]

True. And there are Dlites like that. However, in PAB mode, the lugs need to be broken. So it is best to use the relay to do it. I'd only suggest the toggle if the relay overides the toggle in PAB mode.

If the Bass pot is connected, 1&2 lugs through a switch and toggled manually, will the tone stack be re-constituted to the Dumble way, along with the other points you made Dogears.

[angelodp]

could you please diagram what the correct wiring is for the presence pot. I understand that the 3rd lug should not be grounded and that the resistor cap combo should be grounded, but they are all linked??

[benoit]

could you please diagram what the correct wiring is for the presence pot. I understand that the 3rd lug should not be grounded and that the resistor cap combo should be grounded, but they are all linked??

If you take a look at the ODS101 schematic, for example, I'm pretty sure you can do just like that except make sure the bottom of the pot is not connected to anything.