Friedman Dirty Shirley thoughts.
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Re: Friedman Dirty Shirley thoughts.
10k in 2nd stage,with the switch you parallel a 4,7k or 3,3k and .68uF
Inviato dal mio Redmi 4X utilizzando Tapatalk
Inviato dal mio Redmi 4X utilizzando Tapatalk
Re: Friedman Dirty Shirley thoughts.
Thanks! I was just playing around with a DS mini at a shop today. The 10K alone must be the middle position then, lowest overall gain structure but cold clipping.
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Bryan
Bryan
Re: Friedman Dirty Shirley thoughts.
From memory second tube stage cathode : 10k for clean mode, 3k3 // for the first gain mode then add a 470n for the 2nd gain mode (similar to non switch mode).
I remember aiming for 2k7 for mine to mimic the original Shirley mode.
But on the mini Shirley info I got (not sure of its accuracy) still 10k fixed but either 47k or 2k7/680n (470n cathode caps for the Shirley, 680n for the mini)
Last edited by mojotom on Sat Sep 23, 2017 12:39 am, edited 1 time in total.
Re: Friedman Dirty Shirley thoughts.
That's it. The switch is quite noisy as there is a significant change in DC voltage.
Yours Sincerely
Mark Abbott
Mark Abbott
Re: Friedman Dirty Shirley thoughts.
The implementation of the voltage divider at the master volume is interesting. I think it is different values for mini versus regular but probably the same idea......probably part of the reason the first PI resistor is dropped to 470K. Trying to wrap my head around the science of what is happening there if anyone already knows. It seems to help keep the overall gain/tone steady as the volume is increased or decreased (at least on a mini).
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Bryan
Bryan
Re: Friedman Dirty Shirley thoughts.
I can be too curious sometimes. Here are some voltages readings from a DS Mini. Sizable PT on this.
Wall Voltage 119.1-119.6 (was creeping up during measurements)
Heaters - about 6.25 VAC
Gain switch on highest setting
V1
1 - 154.6
3 - 1.44
6 - 202.4
8 - 1.736
V2
1 - 168.1
3 - .879
6 - 274.2
7 - 168.2
8 - 169.2
V3
1 - 204.2
2 - 36.1
3 - 52.84
6 - 192.4
7 - 34.43
8 - 52.90
V4
3 - 11.39
7 - 353.1
9 - 346.9
V5
3 - 11.40
7 - 353.5
9 - 347.3
Wall Voltage 119.1-119.6 (was creeping up during measurements)
Heaters - about 6.25 VAC
Gain switch on highest setting
V1
1 - 154.6
3 - 1.44
6 - 202.4
8 - 1.736
V2
1 - 168.1
3 - .879
6 - 274.2
7 - 168.2
8 - 169.2
V3
1 - 204.2
2 - 36.1
3 - 52.84
6 - 192.4
7 - 34.43
8 - 52.90
V4
3 - 11.39
7 - 353.1
9 - 346.9
V5
3 - 11.40
7 - 353.5
9 - 347.3
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Bryan
Bryan
Re: Friedman Dirty Shirley thoughts.
Looks good. Who's effects loop is it?
Yours Sincerely
Mark Abbott
Mark Abbott
Re: Friedman Dirty Shirley thoughts.
That's very nice looking. You can easily remove and replace all the components from the top of the PCB...except the radial caps...
I build and repair tube amps. http://amps.monkeymatic.com
Re: Friedman Dirty Shirley thoughts.
early version of the Dirty Shirley Mini
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Re: Friedman Dirty Shirley thoughts.
sonicmojo wrote: ↑Wed Sep 27, 2017 7:35 am I can be too curious sometimes. Here are some voltages readings from a DS Mini. Sizable PT on this.
Wall Voltage 119.1-119.6 (was creeping up during measurements)
Heaters - about 6.25 VAC
Gain switch on highest setting
V1
1 - 154.6
3 - 1.44
6 - 202.4
8 - 1.736
V2
1 - 168.1
3 - .879
6 - 274.2
7 - 168.2
8 - 169.2
V3
1 - 204.2
2 - 36.1
3 - 52.84
6 - 192.4
7 - 34.43
8 - 52.90
V4
3 - 11.39
7 - 353.1
9 - 346.9
V5
3 - 11.40
7 - 353.5
9 - 347.3
The mini is a bit different, 680n cathode caps and a "balanced" PI (not 470k/1M).
Could you confirm if you still got the amp the value of the master pot sonicmojo ?
Should be A100k
Re: Friedman Dirty Shirley thoughts.
Will there be any clips forthcoming from these builds?
Yours Sincerely
Mark Abbott
Mark Abbott
Re: Friedman Dirty Shirley thoughts.
I couldn't see the values on the alpha pots and the amp is returned. Sorry.
I was curious about how these sound and feel as I'm still experimenting with and comparing my recent 18 watt high gain Marshall style build to other amps. For what it is, the DS Mini is a well thought out and decent sounding amp. I think some values of pots, voltage dividers, etc were chosen to user proof it a bit.
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Bryan
Bryan
Re: Friedman Dirty Shirley thoughts.
What is the circuit for the high gain Marshall style amp?recent 18 watt high gain Marshall style build
Yours Sincerely
Mark Abbott
Mark Abbott
Re: Friedman Dirty Shirley thoughts.
In the 18W amp that I recently transformed from another circuit, I started pretty close to the standard Marshall master volume scheme like this from Rob Robinette but I used a .001 first stage coupling cap so my amp is fairly bright, even without any bright cap on the first volume. In my case I had an extra triode so I paralleled the last stage before the cathode follower with a shared 50K plate resistor and two separate 1.6K/25uf cathodes. Been tweaking values and voltages a bit since but really kind of close the the traditional chain, as is the DS (for the most part). As I've been adding some of the extra voltage dividers around the volume pots, like the DS, the range of possible gain tightened up a whole lot.
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Bryan
Bryan