EF86 driving an ODS style tonestack?

[roberto]

You need to change the values of the tonestack because the response of the eq, if the source impedance is lower, will be less effective (flatter).
You need to use a simulator, save the eq response at different settings, lower input impedance, modify the values to get the same response.

With a standard eq, it is an easy job on TSC.

As for the input configuration, you can test the other configuration I posted and see what you prefer.

[Lynxtrap]

OK, thanks.
I'm starting to think I should scrap this whole idea with a pentode and CF and work with something I know instead, like two halves of a 12AX7...

[roberto]

Before giving up, play with this one:
https://www.guitarscience.net/tsc/marshall.htm

[Lynxtrap]

Before giving up, play with this one:
https://www.guitarscience.net/tsc/marshall.htm

Whoa, that was a surprise! Going by the curves one could think that the Dumble stack is one of the worst ever The mid pot seems virtually useless. Yet that is not how I experience it. I find it much better than for instance the Fender TS.

But altering RIN, I don't see much change in the response except overall gain?

Thanks for that link! Many more models than in the TSC software.

[Lynxtrap]

Before giving up, play with this one:
https://www.guitarscience.net/tsc/marshall.htm

Which particular Dumble TS is modelled in the calculator?
There are some differences compared to the ones I've worked with, where for instance C4 is out of the circuit in Rock mode.

[martin manning]

https://www.guitarscience.net/tsc/dumbl ... V_pot=LogA
There are two options in a pull-down under Dumble in the top menu bar where you select the stack, Rock or Jazz.

[Lynxtrap]

https://www.guitarscience.net/tsc/dumbl ... V_pot=LogA
There are two options in a pull-down under Dumble in the top menu bar where you select the stack, Rock or Jazz.

Yes, I know, but the names of the parts should be the same in both modes.
I was mostly curious of which of the different ODS circuits/amps/versions it models.

One difference to what I've worked with previously is C4, the one between the treble pot and ground in Jazz mode. Switching to Rock mode in the TSC, C4 sits across the Bass pot where it seems to affect low mids.
Isn't that cap disconnected in Rock mode in, for instance, the Ford Skyliner version (0.005 in the schematic)? Or have I got something wrong?

TSC Rock mode.jpg

Ford Skyliner.jpg

[martin manning]

...the names of the parts should be the same in both modes...

True, It would have been much better to make C7 the Jazz cap (which is out of the circuit in Rock mode), and kept all the other numbers the same. That is what was done with R4, the 100k that gets switched in from the bass wiper to the treble wiper in Jazz mode.

[Lynxtrap]

...the names of the parts should be the same in both modes...

True, It would have been much better to make C7 the Jazz cap (which is out of the circuit in Rock mode), and kept all the other numbers the same. That is what was done with R4, the 100k that gets switched in from the bass wiper to the treble wiper in Jazz mode.

OK thanks, I think I get it now. Didn't realize that there was a C7.
C4 is the same as the 0.001 around the bass pot in the skyliner.
That cap has not been included in the D-style tonestacks I've worked with, so I guess that added to the confusion.

So, is the TS in the calculator basically a skyliner?

[TUBEDUDE]

OK, thanks.
I'm starting to think I should scrap this whole idea with a pentode and CF and work with something I know instead, like two halves of a 12AX7...

Substituting with a 12DW7 (ECC832) you get a 12AX7 half with a 12AU7, which can be used for a.lower source impedance.

[martin manning]

So, is the TS in the calculator basically a skyliner?

Yes.