New 183 build

[Stephen1966]

Here's another question for you. Imagine if you will, your 183 included an onboard Dumbleator. Would you consider putting it on a relay driven footswitch?

[WhopperPlate]

Here's another question for you. Imagine if you will, your 183 included an onboard Dumbleator. Would you consider putting it on a relay driven footswitch?

I would consider

[Stephen1966]

Here's another question for you. Imagine if you will, your 183 included an onboard Dumbleator. Would you consider putting it on a relay driven footswitch?

I would consider

Hmm... thinking about the logistics of this, I'm not sure it would be needed. Running a single effect - maybe. Running a pedal board though... and given the (mostly) transparent nature of the dumbleator, there wouldn't be much sonic benefit to switching it in or out during a gig. Switching is possible electrically, but unlikely to be used in practice. Mucking around at home or in the studio is one thing, but on stage, you are really either not going to use it all, or have it on for the entire duration of the gig driving any back end effects which are each with their own switches in and out anyway.

Note to self: just because you can do something, doesn't mean you should

[jazzbass]

Stephen1966 wrote

"By the way ... you might want to review the way you talk to Mr. Andrew Fuchs. He's from New Jersey, you know: wink:"

Hi Stefano, I don't remember what I said about Mr. Andrew Fuchs but if I said something wrong I apologize, I have great respect for those like him who have been able to build their own path in the music industry.

Charlie wrote

"As other very knowledgeable members have already stated, the layout and main attire are indispensable for research. Probably the most important. You can use the most common branded parts and make something spectacular while respecting only these principles."

Hi Charlie, I started building amplifiers trying to reproduce the Traiwreck Express. Unfortunately or fortunately I have experienced firsthand what the correct lead dress means with hundreds of hours spent to obtain a sound as close as possible to that made by Ken Fisher who used a minimal approach where even the wires were not only a necessary component. but fundamental of the construction.
I would like a chapter of H. Dumble's project discussions to develop this topic that many, including myself, often take for granted.

Charlie wrote
"Dumble creatively assembled the available parts to produce amplifiers that ideally would achieve his and the artist's goals.
This fundamental philosophy of the Dumble approach to amplifier construction is more or less evident in the historical record of his evolving work.
Charlie "

I totally agree 100%

a hug.
Franco

[WhopperPlate]

Here's another question for you. Imagine if you will, your 183 included an onboard Dumbleator. Would you consider putting it on a relay driven footswitch?

I would consider

Hmm... thinking about the logistics of this, I'm not sure it would be needed. Running a single effect - maybe. Running a pedal board though... and given the (mostly) transparent nature of the dumbleator, there wouldn't be much sonic benefit to switching it in or out during a gig. Switching is possible electrically, but unlikely to be used in practice. Mucking around at home or in the studio is one thing, but on stage, you are really either not going to use it all, or have it on for the entire duration of the gig driving any back end effects which are each with their own switches in and out anyway.

Note to self: just because you can do something, doesn't mean you should

And that’s why I have only considered .

With that stated the versatility of a dumbleator isn’t simply with effects. You could theoretically utilize it as some sort of volume or gain boost. Treat it like a compressor . No effects at all.


Depending on the features of the chosen dimbleator type circuit , it’s possible to easily dial in a secondary tone and kick it on.

“Mostly transparent”…except we all know it’s not

if you are using it as a lineout or parallel effects loop it can also serve as an easy on off switch, especially if you have rack effects that do not have their own foot switch . Really depends on what and how you interface with the rest of your rig.

Imagination is the limit.

[Stephen1966]

With that stated the versatility of a dumbleator isn’t simply with effects. You could theoretically utilize it as some sort of volume or gain boost. Treat it like a compressor . No effects at all.

Yeah! That's really the beauty of it with a modified (25k) send pot. And gain and boost are available with it too. I've already nixed the idea for now so I will live with it for a while and if I feel it calls for these kind of extra dimensions, I will reconsider the footswitch idea. Easy to implement and I can plan for it in the layout. Mostly transparent, sure! It is pretty close to invisible with the 250k send pot though. Not entirely, and not unpleasantly, but not enough to make a difference for that drunken girl dancing in front of the stage.

[Stephen1966]

I'm derailing my own thread

Dumble talk here:

[WhopperPlate]

I watched that recently . Taylor does a great job of keeping it simple and humble .

[bepone]

As other very knowledgeable members have already stated consistently , layout and lead dress are imperative to the search . Arguably most important. You can use the most common brand parts and make something spectacular with adherence to these principles alone . Brushing this aside is not advised .

this permanent problem in amp building, "lead dress".. can be avoided? if we put more space between the stages, ie. we space out preamp tubes more, like from 5 cm between the centers we can put 7 cm, it will be more space to put down the wires and reduce interaction..

[Stephen1966]

As other very knowledgeable members have already stated consistently , layout and lead dress are imperative to the search . Arguably most important. You can use the most common brand parts and make something spectacular with adherence to these principles alone . Brushing this aside is not advised .

this permanent problem in amp building, "lead dress".. can be avoided? if we put more space between the stages, ie. we space out preamp tubes more, like from 5 cm between the centers we can put 7 cm, it will be more space to put down the wires and reduce interaction..

Sure! This is an interesting thought experiment but it probably wouldn't work in practice. Take tube sockets. If you have seven of them in a line and each is 5cm apart, if you keep them in a line and increase the distance to (for argument's sake) 7.5cm, you are going to end up needing a chassis half as long again. So your 19" chassis, now becomes 19 + (19/2) = 28 1/2". You are going to need a bigger car I know I shouldn't be mixing metric with imperial, but you probably shouldn't be doing this either.

Fact is we have to build these amps within a whole bunch of physical constraints, and in my admittedly limited understanding, lead dress is part of those. And sure, while some leads are better kept away from others because of the cancelling effects of inverse phase relationships, there are others which actually benefit (or at least don't detract) from sharing a space close to each other.

Take the plate and cathode wires of a typical dual triode.

ODS_124049.jpg

On the OD tube from the 124 here, notice how the grid wires (GRN) float or are encapsulated in coax, how the plates (BLU) have been kept on opposite sides of the socket but how the cathodes (YEL) have been tightly pressed together with the plate on the second stage side of the tube. It's a pattern he repeated in this image, in the dress for the clean tube as well. In each case, one of those cathode wires (the one that wraps around the back to reach the opposite side) is out of phase with its neighboring plate and cathode wire. But this is the side from which the amplified signal emerges, and so it can be argued that any phase cancellation is mitigated by this arrangement.

That's simply just good phase management, but what about the idea that it's not just about separating the wires with inverse phase relationships, but that by placing them next to or near to other, you can exploit the phase difference for a special kind of augmenting effect?

What happens with the signal and the tone when we tie the cathodes together across a tube?

[erwin_ve]

Actually the plate of v1a is in phase with the cathode of v1b. Same with v2a and v2b. Positive feedback.

[Stephen1966]

Actually the plate of v1a is in phase with the cathode of v1b. Same with v2a and v2b. Positive feedback.

Agreed. But the cathode of V1a with the cathode of V1b are they also in phase? They aren't physically tied together, (that is, they are designed as ordinary - anode follower - inverting gain stages) and induction is a relatively small force, but even small changes in the cathode affect big changes at the plate. I'm also thinking what happens in a LTP where the [PI] cathodes are tied together in the tail - the biasing effect it produces.

[Edit: I see what you are saying about the phase relationship of the plate wire in this arrangement - agreed. And apologies it was a poor use of words in my post. I was just thinking about the effect of the cathodes together... but you're right, there is also the effect it has on the signal in the plate as well.]

[bepone]

positive feedback is good! negative is a problem

[Stephen1966]

positive feedback is good! negative is a problem

We can take it further, by asking ourselves, if it is only about positive feedback and it is good, why doesn't he apply to both stages? Why only the outgoing stage?

[bepone]

positive feedback is good! negative is a problem

We can take it further, by asking ourselves, if it is only about positive feedback and it is good, why doesn't he apply to both stages? Why only the outgoing stage?

on the picture it is on both stages, and also i see on many D pictures repeatable detail - from speaker wires to PI second plate, so on all 3 stages?