Paging Dogears

[billyz]

Dogears,
I have always enjoyed the clips of your playing. I have been trying to ascertain which Dumble circuit I would most enjoy ( just one). Which is your favorite Dumble amp ? Circuit? which mods to said circuit?

I realize I may be asking for your trade secret sauce recipe. I am not saying I would copy it either, just for reference. I am quite interested in building a dumble style amp for myself. I am certain It will not be an exact clone either as I plan to use most of my available parts ( CDE green caps, Kimber wire polystryene caps etc).

Question #2. What is the main tonal difference with the Precision PS as opposed to the more fenderesque one of #124 ?

Question #3. Does the high plate circuit mostly feature more gain/distortion, than the low plate classic? Are the cleans as clean as a low plate version?

I really want beautiful sustaining cleans ala Larry Carlton as well as the smooth overdrive of Robben ford.

BTW, I will mostly use Gibson style guitars, Humbuckers and 24 3/4" scale neck. But a tele is also in the occasional mix.

Of course everyones responses will be much appreciated.

[TheHandsomeOrk]

I'd like to know the the answer to #2 as well.

I do prefer the cleans on a nonHRM low plate 50W that I built for a friend ages ago. With a 70s les paul playing above the 12th fret it sounded chimey like a harp (harpo marx kind of harp) simply beautiful cleans. Hard to believe it was a guitar I was hearing. The OD channel needs tweaking ( I will get to it oneday). My personal high plate I have a love/hate relationship with but I think the problem is mostly me.

If you like cleans my vote is for the low plate.

[dogears]

LOL.... I have no idea the difference on #2. I have amps with both and like both.

I do love the Ojai though. I think it a must have circuit if you like the Ford tones. Look at the Ojai layout thread. I prefer Sylvania STR 387/415 tubes in the output and Mullards/Bugle Boys in the preamp. Telefunken PI. Matched. Set trimmer to taste. Bias around 33/34ma.

Here is Dave Henderson's newest clip using his Ojai.
http://soundcloud.com/davidhenderson/dusk-street

I find the high plates to have more of a clean OD thing. They clip later and with less harmonics I believe, but have more gain. A little fuller and darker tone too.

[Structo]

It's funny the power supply came up as a topic.

I've been doing a lot of reading about (dare I say it?) Hi Fi amps.
I would love to have a couple mono blocks some day and a nice turn table.

Anyway, they place a great deal of importance on the power supply.
Particularly the filter caps on the power tubes.
And to some extent the preamp tubes.
They feel the filter caps can and do affect the sound of the amp.

Not only for ripple clean power but but for the general tone or clarity of the amp.
If you have ever dabbled or read about Hi Fi, they really like a flat toned or transparent amp with absolutely no distortion.
In other words, they want to hear the recording as it was intended without adding coloration to the tone.
That is it in the purist form.
So things like Dielectric Absorption (DA), Dissipation Factor (DF) ESR, etc.
all play an important role in Hi Fi power supply design.

But guitar amps as we know are a completely different animal.
What we do in these amps would surely make an audiophile cringe and shudder.
We like the harmonics and overtones and distortion.
But it's ironic because they will listen to recordings of said tube amps.

Anyway, long story short, the filter caps do affect tone, performance and regulation of the amp.

I haven't tried the precision power supply but just by looking at it, it would seem it would provide much better filtering so lower noise would result.
On paper it looks like it would work very well.
But, along with better filtering, sometimes that can lead to a more sterile tone and affect sustain of the notes.
Yet I haven't heard anybody here complain about that supply hurting their tone or sustain.

Take #183 for example.
It has two 330uF caps in series for the plate voltage.
That is 165uF total.

#124 used two 300uF for a 150uF total.
It uses 20uF for each node.

#183 uses two 47uF in series for each node.
That is 22.5uF for each node.

But having two in series doubles the voltage rating and I'm sure it helps other factors as well.

It would be interesting to take two amps each having the different supply and measure noise at idle to see how much better the filtering is on the precision supply.

[67plexi]

Billyz. Tony pointed me to the #124 low plate 100 watt ODS. Quad 6l6gc.
It is a great amp still blows me away if you want more gain use a Zen drive or a ts-808
I used polystyrene caps on the bright switch and snubbers on V-2 smooth.
If you can find a donor amp Fender twin or showman 1960s-1970s for the Iron.
Caution the Dumble amp building is addicting it won’t be just one.
Voltages to get the D-sound B+465v, V-1 a,b 190-200v V-2 a,b 200-210v V-3 300-310v
The PI V-3 you want to put a balanced section 12ax7 also use mil-spec 1% 1 watt resistors
On the preamp board. Sprague q-line, IRC, Mepco, Blyschlag, Philips.
Jason has nice boards it will save you time. http://www.agbamplifiers.com/
The cheap Sprague 6ps work just fine.

Take care, Steve.

[billyz]

LOL.... I have no idea the difference on #2. I have amps with both and like both.

I do love the Ojai though. I think it a must have circuit if you like the Ford tones. Look at the Ojai layout thread. I prefer Sylvania STR 387/415 tubes in the output and Mullards/Bugle Boys in the preamp. Telefunken PI. Matched. Set trimmer to taste. Bias around 33/34ma.


I find the high plates to have more of a clean OD thing. They clip later and with less harmonics I believe, but have more gain. A little fuller and darker tone too.

Thank you mr Dogears.
I have to concur with your tube choices, excellant in almost any circuit.

Is the Ojai layout the robben ford #102 ? I do not find a specific one labled "ojai" . I assuming because RF is located in Ojai, that it is his amp.
Much appreciated.

billy z

[billyz]

Billyz. Tony pointed me to the #124 low plate 100 watt ODS. Quad 6l6gc.
It is a great amp still blows me away if you want more gain use a Zen drive or a ts-808
I used polystyrene caps on the bright switch and snubbers on V-2 smooth.
If you can find a donor amp Fender twin or showman 1960s-1970s for the Iron.
Caution the Dumble amp building is addicting it won’t be just one.
Voltages to get the D-sound B+465v, V-1 a,b 190-200v V-2 a,b 200-210v V-3 300-310v
The PI V-3 you want to put a balanced section 12ax7 also use mil-spec 1% 1 watt resistors
On the preamp board. Sprague q-line, IRC, Mepco, Blyschlag, Philips.
Jason has nice boards it will save you time. http://www.agbamplifiers.com/
The cheap Sprague 6ps work just fine.

Take care, Steve.

Plexi Man,

I lived in AK for many years, was in Juneau only once though, Rained sideways for a week straight.
I always use matched PI tubes, Military JAN usually. I have so many Green CDE caps that is probably what I will use and Poly styrene pf values. I will ordered some high end resistors though as I only have AB or Stackpole CC's in my draws. I think I have a Blackface Twin OT in a box somewhere. And maybe a Musicman PT. But I would rather have a multi-tap OT.
Tony pointed me to the #124 as well, is that the Ojai ?

[billyz]

It's funny the power supply came up as a topic.

I've been doing a lot of reading about (dare I say it?) Hi Fi amps.
I would love to have a couple mono blocks some day and a nice turn table.

Anyway, they place a great deal of importance on the power supply.
Particularly the filter caps on the power tubes.
And to some extent the preamp tubes.
They feel the filter caps can and do affect the sound of the amp.

Not only for ripple clean power but but for the general tone or clarity of the amp.
If you have ever dabbled or read about Hi Fi, they really like a flat toned or transparent amp with absolutely no distortion.
In other words, they want to hear the recording as it was intended without adding coloration to the tone.
That is it in the purist form.
So things like Dielectric Absorption (DA), Dissipation Factor (DF) ESR, etc.
all play an important role in Hi Fi power supply design.

But guitar amps as we know are a completely different animal.
What we do in these amps would surely make an audiophile cringe and shudder.
We like the harmonics and overtones and distortion.
But it's ironic because they will listen to recordings of said tube amps.

Anyway, long story short, the filter caps do affect tone, performance and regulation of the amp.

I haven't tried the precision power supply but just by looking at it, it would seem it would provide much better filtering so lower noise would result.
On paper it looks like it would work very well.
But, along with better filtering, sometimes that can lead to a more sterile tone and affect sustain of the notes.
Yet I haven't heard anybody here complain about that supply hurting their tone or sustain.

Take #183 for example.
It has two 330uF caps in series for the plate voltage.
That is 165uF total.

#124 used two 300uF for a 150uF total.
It uses 20uF for each node.

#183 uses two 47uF in series for each node.
That is 22.5uF for each node.

But having two in series doubles the voltage rating and I'm sure it helps other factors as well.

It would be interesting to take two amps each having the different supply and measure noise at idle to see how much better the filtering is on the precision supply.

Structo,
I am a tube Hifi guy and do hear the difference a Well designed PS makes.I don't find a well regulated one makes for a sterile sounding amp either, better note definition and detail though and more depth of tone. And yes, a saggy one is part of the sound of many amps.

[dogears]

Billy, yeah, the #102 stuff.

[billyz]

Scott, You are cool. Hope we meet someday.
Billy Z

[Structo]

Billy, I meant on a guitar amp that a too stiff or over filtered supply can be detrimental.
On Hi Fi stuff, the sky is the limit.

My latest 100w ODS leans heavily towards #102 and I like it a lot.