What makes Dumble style amp sound better?

[chikov]

I know it is a very broad question, but I just finished building Ceriatone version of ODS and can not get enough of the tone that ooooses out of it. I began to wonder, I have Fender Jr amp (the green PCB one) and 1958 Magnatone troubadour that I restored. They sound nice but smaller, less dimetional, if you would... not as juicy and creamy... What is it? Bigger transformers? Just more wattage (mine is 100W)? People will be asking me, so I am looking for some kind of answer, if any of you could help...
Thanks.

[sepulchre]

There's no one thing you can point to and say, "It sounds so good because of . . . ". It's the whole design, particularly of the preamp section. HAD is brilliant in his design work and meticulously tweaks his amps until he gets the sound he wants. So the clones sound very good, well most that I've heard anyway. Not like the originals, mind you, but very good nonetheless. A read of the Dumble Discussion and Dumble Files sections would help you understand, I think.

[Kassie]

1. Seasoned Iron,
2. Lead dress around v1, v2 (anodes and kathodes together to create negative and positive feedback. Powertube grid wires to v3 close together for negative feedback).
3.Solid Copper wire. (Debate on sound, but imho als more of a vibration/stability factor, tight to chassis so added capacitance) The epoxy glue might be a stabalizing factor too at the powersupply caps, preamp section. As well as the thick twisted filaments, and the tie wrapped PT primaries. Electrical wires tend to vibrate, AC wires tend to extend their field when they vibrate. (I notice a difference in sound when the bare chassis is on top of my speaker cab, or when the chassis is in the amp head thereby reducing vibrations).
4. Certain Cap tolerances, Potentiometer tolerances (275K presents a different load then 220K, but both can be rated at 250K).
5. The natural aging of components. 124 sounds a tad different in 2014 then it did when it was freshly built.
6. Another trick is 4 ohm OT secondary setting into an 8 ohm speaker.
7. The particular Dumble Cab is a tonefactor as well.
8. Use of particular coax cable with added pf capacitance.
9. The chassis (anodized aluminium), aluminium is a faster conductor than steel
10. Dumbleator can be a major tone contributing factor (102 is built specifically for the use of a dumbleator, Robben uses a longer send shielded cable thereby adding capacitance).
11. Correct cap orientation (outside foil).

And there may be more details which I am unaware off.

[bluesfendermanblues]

Component choice (Orange Drop 6PS, resistors, pots, cables, tubes, OT iron)
Component values all around
Tone stacks
Phase Inverter (values, voltages and balance between anodes)
Lead dress and placement of anode and cathode wiring anound preamp
Ground scheme
tubes
anode voltages
Low bias (around 50%, instead of the typically 70% of Fenders and Marshalls)
Dumbleator loop (and cable length and type to/from the loop)
Speaker cabinets and choice of speaker units

The list is long and even with atttention to the above, there is still the X-factor, being extensive tweaking of the individual amp.

GREAT EARS and taste is, I believe the secret ingrediens that HAD and other master builder (chefs, artists etc) have in spades. The rest of us can build copies, but since we dont have masters ear and skills, we wont be able to really nail it.

[vibratoking]

The things listed basically consist of everything. That's not much help, although it gives you everything to think about. With all due respect, some of the things listed have little or nothing to do with the "sound".

[xtian]

Previous posters detail some very fine-grained things, but miss the big one, hinted at already: the preamp gain staging. HAD's preamp stages are set for max compression and sustain. Compare Ra/Rk values with Fender or Marshall.

[matt h]

(deleted)

[xtian]

I disagree that the preamp gain stages are designed for maximum compression and sustain and will point to the same Rk/Ra values as evidence.

I made an assumption, without merit. I'm definitely interested in what those values do for the preamp.

[talbany]

Design
Component choice
Lead dress
Attention to detail on every connection
Good ears/Good understanding of how each circuit/component functions and
Knows exactly how he wants it to sound
Stout 100 watt output section

Tony

[matt h]

(deleted)

[katopan]

Thanks matth. I did the same with my 18 Watt when questions about what was happening came up and posted it on 18Watt.com years ago back in 2009.

Test the waveforms. Blueprint the static *and* dynamic behaviour of the amp. Don't make assumptions about what it will show. Then amp secrets reveal themselves. Takes some simple test equipment, a bit of time and lots of passion.

[chikov]

Wow, even though a lot of this info is over my head (not for a long though), I got a taste of what it takes to get to the best tones in industry. I will keep rereading your posts ( I even printed some), but my question is , what does "Lead dress" mean?

[norburybrook]

Wow, even though a lot of this info is over my head (not for a long though), I got a taste of what it takes to get to the best tones in industry. I will keep rereading your posts ( I even printed some), but my question is , what does "Lead dress" mean?

Quick, let me jump in here, as a novice at all this I find myself being able to answer a question!


Lead dress is the actual physical positioning of your wiring. So things like twisting together your heater wires, making sure certain wires cross at right angles , making sure certain wires stay away from other wires/components etc all affect the end result.



MC

[Davidg]

Lead Dress is basically how you wire the amp. There are certain "rules" that must be followed and you must learn them if u ever hope to build a working amplifier circuit.It is how the wires are ran, where they are placed or not placed . I could go through them but most are really just guidelines and are open to interpretation.Main thing is grid wires and a filament or heater wiring, transformer placement, and grounding .Not much info but I hope it puts u on the right track.

[jcsifu]

1. Seasoned Iron,
2. Lead dress around v1, v2 (anodes and kathodes together to create negative and positive feedback. Powertube grid wires to v3 close together for negative feedback).
3.Solid Copper wire. (Debate on sound, but imho als more of a vibration/stability factor, tight to chassis so added capacitance) The epoxy glue might be a stabalizing factor too at the powersupply caps, preamp section. As well as the thick twisted filaments, and the tie wrapped PT primaries. Electrical wires tend to vibrate, AC wires tend to extend their field when they vibrate. (I notice a difference in sound when the bare chassis is on top of my speaker cab, or when the chassis is in the amp head thereby reducing vibrations).
4. Certain Cap tolerances, Potentiometer tolerances (275K presents a different load then 220K, but both can be rated at 250K).
5. The natural aging of components. 124 sounds a tad different in 2014 then it did when it was freshly built.
6. Another trick is 4 ohm OT secondary setting into an 8 ohm speaker.
7. The particular Dumble Cab is a tonefactor as well.
8. Use of particular coax cable with added pf capacitance.
9. The chassis (anodized aluminium), aluminium is a faster conductor than steel
10. Dumbleator can be a major tone contributing factor (102 is built specifically for the use of a dumbleator, Robben uses a longer send shielded cable thereby adding capacitance).
11. Correct cap orientation (outside foil).

And there may be more details which I am unaware off.

Nice list bro! This would be a great starting point for anyone.

Kassie,
How seasoned is seasoned enough for your taste? 60's Schumacher?