D'lite customer build

leleduke · Post by **leleduke** » Fri Jul 17, 2009 2:43 am

Here are a few pic's of the D'lite I'm building for a forum member.

[IMG

766]http://i5.photobucket.com/albums/y167/l ... 0_4015.jpg[/img]
[IMG

766]http://i5.photobucket.com/albums/y167/l ... 0_4026.jpg[/img]
[IMG

766]http://i5.photobucket.com/albums/y167/l ... 0_4018.jpg[/img]

dogears · Post by **dogears** » Fri Jul 17, 2009 12:52 pm

Nice....

Remember, the presence pot does not ground to the buss. Looks like yours might?

leleduke · Post by **leleduke** » Fri Jul 17, 2009 1:07 pm

dogears wrote:Nice....

Remember, the presence pot does not ground to the buss. Looks like yours might?

On the d'lite it does.

http://www.brownnote.net/shared/images/ ... %20Mod.bmp

bigmik · Post by **bigmik** » Fri Jul 17, 2009 1:36 pm

leleduke wrote:
dogears wrote:Nice....

Remember, the presence pot does not ground to the buss. Looks like yours might?
On the d'lite it does.

http://www.brownnote.net/shared/images/ ... %20Mod.bmp

but the d-lites way is wrong, as mr. dogears would say

dogears · Post by **dogears** » Fri Jul 17, 2009 2:42 pm

Yes, the schematic is wrong. Use it at your own peril. However, why on earth would you take the time and effort to build a Dumble clone and incorporate a mistake that was just that, a mistake. It does effect the presence circuit and NFB.

I am friends with Moss and Norm, and at risk of pissing them off, I was told it was an oversight and not intentional. They really should post a clarification ont he matter. It just confuses the issue leaving a bad error out there with no correction.

I also believe that all current Brownnotes use the correct presence wiring. Maybe Moss or Norm can chime in.

Bottomline, this is the Dumble forum and not the Brown Note forum. I would not jump in like this if it were the Brown Note forum, but it is not. We discuss Dumbles and Dumble circuits here. That presence is clearly a mistake.

Structo · Post by **Structo** » Fri Jul 17, 2009 5:10 pm

I know we have discussed this a lot but there seems to be two ways that the Dumble Presence control has been drawn.
Which is the correct way or do they do the same thing electrically?

dogears · Post by **dogears** » Fri Jul 17, 2009 6:46 pm

Same thing. As long as the pot is not grounded directly, all is good.

leleduke · Post by **leleduke** » Fri Jul 17, 2009 8:01 pm

From the BN site:

--------------------------------------------------------------------------------

People will argue this point, but it's really not 'best' to wire it Dumble style.

You can go either way, for the D'Lite in particular it I'd say stick with the way it's shown.

It will sound different, Dumble style is the correct way for a Dumble or straight up clone, but the D'Lite departs from a clone with it's lower powered output stage and the corresponding feedback circuit.

If you go straight D style you'll be changing the feedback ratio, and may or may not like it.

With a 390R resistor parallel with a 2K pot your total PI tail resistance is 326R...this works with the 6.2K feedback resistor off the 4 Ohm tap to open up the response of the D'Lite.

I forget the exact ratio this equates to, but if you go D style you may prefer a 4.7K feedback resistor.

dogears · Post by **dogears** » Fri Jul 17, 2009 8:10 pm

Problem is that parallel grounding the pot changes the effect of the presence as you sweep the pot. It changes the presence circuit breakpoint. I am not referring to the choice of tail resistor or feedback resistor, I refer to the grounding of the pot. It is wrong. Plain and simple. Changing the feedback resistor is a great way to fine tune things and I have zero issue with deviating from the circuit. However, the grounding of the pot lug was a mistake. I was told it was a mistake. It confuses things, especially since many follow the Dlite layout for their D clones. Do the presence the Dumble way and then adjust that feedback resistor, ie 4.7K or 6.8K or even a trimmer to get the desired result. If you want to open up the "tone" more, then do not ground the pot and increase the feedback resistor even higher! Try an 8.2k or so. You can also change the 1uf cap to something larger or smaller to get the presence breakpoint right. Pointi sto keep the circuit standardized, and while the effect of the mistake may be a happy accident, wiring correctly with the appropriate values makes more sense.

I understand the reluctance to admit the mistake as that opens a can of worms...

leleduke wrote:From the BN site:

--------------------------------------------------------------------------------

People will argue this point, but it's really not 'best' to wire it Dumble style.

You can go either way, for the D'Lite in particular it I'd say stick with the way it's shown.

It will sound different, Dumble style is the correct way for a Dumble or straight up clone, but the D'Lite departs from a clone with it's lower powered output stage and the corresponding feedback circuit.

If you go straight D style you'll be changing the feedback ratio, and may or may not like it.

With a 390R resistor parallel with a 2K pot your total PI tail resistance is 326R...this works with the 6.2K feedback resistor off the 4 Ohm tap to open up the response of the D'Lite.

I forget the exact ratio this equates to, but if you go D style you may prefer a 4.7K feedback resistor.

Structo · Post by **Structo** » Fri Jul 17, 2009 10:30 pm

The issue I see is that the D'Lite was conceived as a 6V6 amp.
I don't think there are any 2 x 6V6 ODS's.

I understand BN's intent and think it was to improve the performance of the 22 watt version, but the amp is capable of running the 6V6 or 6L6 and other high power pentodes as well.

When I ordered my D'Lite it was with the intention of running 6L6 power tubes.
So I don't really care if the presence control was designed for the 6V6, I wanted a 6L6 amp.

The two tubes have entirely different tonal characteristics so it is understandable that a guy that wants it as a 6L6 amp would build it more towards what a true Dumble is.

If the amp is built with the intention of leaving it as a 6V6 amp then by all means follow the BN specs and layout.

After Scott informed me of the error, I immediately changed it to the way he shows and have left it as such since it was built.

BTW, I believe the way BN wired their presence is more typical for a Marshall amp, with the pot grounded to the buss.

ayan · Post by **ayan** » Fri Jul 17, 2009 10:34 pm

dogears wrote:Problem is that parallel grounding the pot changes the effect of the presence as you sweep the pot.
{snip}

This is not even open for argument, as far as I'm concerned. Scott is right... anyone can just draw the schematic corresponding to the layout posted above and see that it is NOT the same way Dumble did it. Will it sound better the other way? It is a possibility, of course, but it will not be what was meant to go with Dumbles.

Gil

dogears · Post by **dogears** » Fri Jul 17, 2009 10:46 pm

Gil, thanks!

When I discussed this with Norm, he told me it was an accident and that he then tweaked the feedback resistor up to 6.8K to further open the tone. That sounded good so that is what they went with. After the fact, the ground issue was pointed out. They thought it sounded good so they left it. Probably to not open a can of worms since many amps were already built/shipped. I bet all the newer amps from Brown Note do not have the presence wired like the early Dlites.

Problem is that people are blindly following the layout as if it was engineered in. It was not. It was an honest mistake. I make mistakes all the time too. No biggie. No slags. I think in the interest of "getting it right", which is what this forum is here for, the circuit should corrected to reflect the way it was originally designed. I think in the interest of reducing confusion and aiding the enthusiast community, the layout should be updated. But that is just me.....

Here is a question, is there any other amp ever that has the presence pot grounded on the third lug, in parallel with the tail resistor and presence cap? None I can find......

ayan wrote:
dogears wrote:Problem is that parallel grounding the pot changes the effect of the presence as you sweep the pot.
{snip}
This is not even open for argument, as far as I'm concerned. Scott is right... anyone can just draw the schematic corresponding to the layout posted above and see that it is NOT the same way Dumble did it. Will it sound better the other way? It is a possibility, of course, but it will not be what was meant to go with Dumbles.

Gil

Sonny ReVerb · Post by **Sonny ReVerb** » Fri Jul 17, 2009 11:33 pm

Here's Norm's post explaining the presence pot wiring:

https://tubeamparchive.com/viewtopic.php?p=44436#44436

talbany · Post by **talbany** » Sat Jul 18, 2009 4:22 am

This is not even open for argument, as far as I'm concerned. Scott is right... anyone can just draw the schematic corresponding to the layout posted above and see that it is NOT the same way Dumble did it. Will it sound better the other way? It is a possibility, of course, but it will not be what was meant to go with Dumbles.

I remember wiring up a few amps using the D-Lite presence discussed..Got lazy figured Id mount it on the pot.. Several things I noticed right off was it had hardly any range to it.(.4 ohm tap)
You couldn't really get the amp to open up.. Also on a few I was even getting some DC on the pot... Could have been a bad cap..So to answer your question no they don't sound good or function like a normal presence!! Too me..

Tony VVT

leleduke · Post by **leleduke** » Sat Jul 18, 2009 1:34 pm

So all I need to do is snip the ground from the left lug leaving the 1UF and the 390R grounded to buss and replace the 6K2 with a 4K7 ?

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