Gradual/fast switch

Express, Liverpool, Rocket, Dirty Little Monster, etc.

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tictac
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Re: Gradual/fast switch

Post by tictac »

That's my drawing.... I put that circuit into a Train-wreckish type of amp I built years ago. I came up with that design due to paranoia involving the thought of HV DC on a mini toggle switch with a metal toggle mechanism on it, which I would have to touch....

Another thing you can do with that arrangement is connect the unused triode on V2 to one of those caps. Now you can switch between two tiodes with diffrent flavors of plate resistor, cathode resistor combos. you could tie both outputs to the PI input or have a common plate resistor for both triodes.... If V2 was a 12DW7 you could have some interesting fast-high gain, gradual-low gain things going on....

TT
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norburybrook
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Re: Gradual/fast switch

Post by norburybrook »

Mark wrote: Sat Nov 18, 2017 12:13 pm How did the fast/slow switch work out?

Do you use it much?

I imagine the amp sounds quite different between fast and slow.

Mark,

I quite like the amp on the slow switch it has less gain and has more bottom end/fuller. I'm not sure which capacitors I have on the fast slow and that's probabaly the reason for more bottom end in the slow.

ON fast the amp is I amagine full 'Express' and the bottom end roll off suits the higher gain.

I'd be interested to see what a Komet 60 HD would sound like as they say..and I quote;

The Touch Response switch allows a choice between a fast, or a gradual response to one’s picking dynamics and guitar’s volume control settings. Players who prefer clean tones can run the full range of dynamics without breaking into unwanted distortion—you choose the response and feel you want, making this amplifier capable of playing every style of music.

My express doesn't give me 'full range of dynamics without breaking into distortion' I always break into distortion....


What are the Main differences between the express and the Komet that would do this?



Marcus
Mark
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Re: Gradual/fast switch

Post by Mark »

It does sound like a good mod to put into an Express clones. Other than the fast/gradual switch the option is to use a 12AY7. The switch seems to be a better quicker option. The addition bass response does sound great in an Express amp. I was surprised how well the bass control works with the larger capacitor.

I wonder how the purists feel about this mod?

Any gutshots on how you implemented the fast/gradual switch?
Yours Sincerely

Mark Abbott
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Ledvedder5150
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Re: Gradual/fast switch

Post by Ledvedder5150 »

Old thread, but I'm interested in implementing this. If anyone has any more info, it would be very helpful.
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Reeltarded
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Re: Gradual/fast switch

Post by Reeltarded »

Split plate load

https://ampgarage.com/forum/viewtopic.php?t=1202

I don't like it because simpler and better things approach what it does without having a cosmic microwave background detector connected with a tiny switch to B+.

My amps have a lot of features. Not this one. :)
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Ledvedder5150
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Re: Gradual/fast switch

Post by Ledvedder5150 »

Reeltarded wrote: Thu Jan 19, 2023 4:34 pm Split plate load

https://ampgarage.com/forum/viewtopic.php?t=1202

I don't like it because simpler and better things approach what it does without having a cosmic microwave background detector connected with a tiny switch to B+.

My amps have a lot of features. Not this one. :)
What simpler things do what it does?
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Re: Gradual/fast switch

Post by guitarmike2107 »

Don't fit a tiny switch to B+ ever - If you do switch between different coupling caps so there is no DC voltage on the switch.

This mod works fine to tame the amp a bit and you can play with the resistor values to get it where you want it.

Check out the Pete Thorn Komet demo he did years ago with fast and slow switches so you can see how it works.
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Reeltarded
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Re: Gradual/fast switch

Post by Reeltarded »

Literally a gain control and bright caps with a tonestack and my attitude. The gradual setting is almost as useless as a pentode with a triode switch.

There is always interstage mixer magic. Splitting the mixers on a 2 pole 6 position switch with another switch to defeat either side and another to engage peaks or snubbers.

I would rather select the plate that sounds great.
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Mark
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Re: Gradual/fast switch

Post by Mark »

The amp is capable of more bass response. You can lower the gain and open up the bass response. That might add a different dimension to the Express.
Yours Sincerely

Mark Abbott
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Ledvedder5150
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Re: Gradual/fast switch

Post by Ledvedder5150 »

Can anyone share some pics or a layout of how they implemented this? I'm thinking of doing it with a push pull pot, so I don't have to drill another hole in my chassis.
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Reeltarded
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Re: Gradual/fast switch

Post by Reeltarded »

Signatures have a 255 character limit that I could abuse, but I am not Cecil B. DeMille.
Mark
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Re: Gradual/fast switch

Post by Mark »

There is a lot of good info in that link.
Yours Sincerely

Mark Abbott
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Reeltarded
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Re: Gradual/fast switch

Post by Reeltarded »

Mark wrote: Fri Jan 20, 2023 6:25 am
There is a lot of good info in that link.

If you'll notice in split load conversations the most discussed thing is the Faraday coil and the second most is never using the split switch. :D

It is better to choose your favorite plate load and approach tone shaping in other places. If you picked 100k and wanted to chop envelope you could use your least favorite side of the bright switch, sub in a 2 pole switch with a 25p cap to ground instead of wiper and moderate the volume by an infantecimal amount. Add +10-15% para coupler on the other pole and do blind tests with friends who think they can tell the difference.

Changes made to this part of the circut are completely negated on a change of instrument, even if 'identical'. Most of us have dark ones and bright ones? Probably.
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Reeltarded
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Re: Gradual/fast switch

Post by Reeltarded »

Ledvedder5150 wrote: Fri Jan 20, 2023 2:02 am Can anyone share some pics or a layout of how they implemented this? I'm thinking of doing it with a push pull pot, so I don't have to drill another hole in my chassis.

You do not want to extend high gain signal across your amp onto a pull pot. There is a reason this whole idea is switched as close to the plate junction as possible and a plethora of details as to why it is a terrible idea. Anything that inducts and is dictated by the design is creating fields and fields interacting with other fields does magically weird things that were dictated by the design.

We are trying to make massive sustain with minimal parts. That is good magic. Bad magic tempts the opposite. You can make your amp sound like you use tape wound strings.. by design, accidently.

Thub thub shsssssssshhhhhhhhhhhhhhhh
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Mark
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Re: Gradual/fast switch

Post by Mark »

quote=Reeltarded post_id=448453 time=1674224535 user_id=6156]
Mark wrote: Fri Jan 20, 2023 6:25 am
There is a lot of good info in that link.

If you'll notice in split load conversations the most discussed thing is the Faraday coil and the second most is never using the split switch. :D
I really didn’t understand the reason for the wire wrapped around the split load wiring when shielded cable could be used. I don’t understand the reference to Faraday coil. What do you mean?

https://youtu.be/Hh58afwzHfA[
Yours Sincerely

Mark Abbott
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