I've got a Fender Champion II 25 which at 12 pounds is a good match to my 67 years. It does an excellent job simulating a Fender Deluxe Reverb clean and slightly overdriven. It probably excels at other things, but that is what I use it for. In some situations, I would like to connect it to a PA without losing the speaker output. The headphone output sounds very good into my JBL IRXBT108 but mutes the speaker. Unlike the previous generation Fender Champions that have a differential class D output, the Champion II has an old-fashioned class AB output with one side grounded (looks like an unmarked clone of the discontinued TI LM1875). I think I can get away without a transformer. I've found this on the Internet and might try it:
Seems it is a -27 dB pad with a -3dB@1.4kHz single pole low pass filter, if I did the arithmetic right. When I read free Fender Deluxe Reverb cabinet IRs into Audacity and check the spectrum with a rectangular window function it does not look much like a single pole low pass, though 1.4 kHz might not be wrong. I'm not certain how much of that junk is the short snippet and that window, but it seems any other window function would clobber the IR's main tap. When I try a Blackman window a simple low pass filter does not look that far out of place.
The passive cabinet simulating Friedman "Amp No Mo" DI has a potted can which no doubt obscures their secret sauce. Buying a $99 DI for a $129 amp is just too crazy for me. Any ideas for something more sophisticated than the above, but still passive? There seems to be a rich selection of Chinese branded inexpensive active DI's with "cabinet simulation" in their bullet list of claims, but sticking with something passive appeals to me and I'm not a shredding connoisseur of high-end high-gain tube amps.
Thanks!
Jon
Seems it is a -27 dB pad with a -3dB@1.4kHz single pole low pass filter, if I did the arithmetic right. When I read free Fender Deluxe Reverb cabinet IRs into Audacity and check the spectrum with a rectangular window function it does not look much like a single pole low pass, though 1.4 kHz might not be wrong. I'm not certain how much of that junk is the short snippet and that window, but it seems any other window function would clobber the IR's main tap. When I try a Blackman window a simple low pass filter does not look that far out of place.
The passive cabinet simulating Friedman "Amp No Mo" DI has a potted can which no doubt obscures their secret sauce. Buying a $99 DI for a $129 amp is just too crazy for me. Any ideas for something more sophisticated than the above, but still passive? There seems to be a rich selection of Chinese branded inexpensive active DI's with "cabinet simulation" in their bullet list of claims, but sticking with something passive appeals to me and I'm not a shredding connoisseur of high-end high-gain tube amps.
Thanks!
Jon
Basically yes as far as cabinet emulation it is just some sort of EQ.
Usually just rolling off the top end is all that is needed.
For a very simplified passive pad, for speaker level to line.
It is a simple passive filter. With distortion the roll off is likely much more desired.
Just clean tone not as much as a issue. Or a higher filter.
Another classic DI / Preamp was the Sansamp which had opamp cabinet emulation.
Same thing basic EQ or high pass filter with a little Q to emulative the bass peak or common guitar speakers.
The again a higher order filter to roll off highs for distortion. Then a notch filter to emulate the typical
3k dip that many guitar speakers have. They have used all pass filters as well to emulate a microphone being
on or off axis. Wouldn't call it a gimmick, but often not completely necessary. Just a bunch of filters.
Most the important is the high end roll of so distortion doesnt sound awful on the mains,
Of course now it is full on FFT emulation, which they sample many real speakers and whatever response curve
they have is emulated at every frequency. Or much like the older direct effects pedals had many more presets
using different filters. And a cool name for the preset like bassman 4x10 or tweed 1x12 blah blah just filters.
The passive 1 pole filter in your design is set at around whatever it is. Being 1 pole to have enough cutoff
at around 5k to make distortion sizzle sound ok. So being 1 pole the filter would be set at around 800 Hz
to 1.2 kHz to make 5k actuated enough. Being a simple 1 pole filter.
With clean tone could be opened up a little. as with the opamp emulators they can use 2 pole or 3 pole
filters .More easily so the cutoff is sharper and the filter more open, then brick walls that sizzle at 5k
I would assume it is possible the Duncan magic can is just a 2 pole or 3 pole passive filter.
It is just harder to make higher pole filters with passive components.
Instead of using a 800 Hz to 1.5 kHz 1 pole filter. Is likely a 3 to 5k 2 pole or 3 pole filter.
Again same thing getting a sharp cutoff for high frequency for the sizzle and noise of typical guitar distortion.
Since speakers have natural roll off. He might have added a notch filter to emulate a mid dip or the classic
2 to 3k dip that many guitar speakers have. Some like it some dont. changes the sound of the distortion.
Usually just rolling off the top end is all that is needed.
For a very simplified passive pad, for speaker level to line.
It is a simple passive filter. With distortion the roll off is likely much more desired.
Just clean tone not as much as a issue. Or a higher filter.
Another classic DI / Preamp was the Sansamp which had opamp cabinet emulation.
Same thing basic EQ or high pass filter with a little Q to emulative the bass peak or common guitar speakers.
The again a higher order filter to roll off highs for distortion. Then a notch filter to emulate the typical
3k dip that many guitar speakers have. They have used all pass filters as well to emulate a microphone being
on or off axis. Wouldn't call it a gimmick, but often not completely necessary. Just a bunch of filters.
Most the important is the high end roll of so distortion doesnt sound awful on the mains,
Of course now it is full on FFT emulation, which they sample many real speakers and whatever response curve
they have is emulated at every frequency. Or much like the older direct effects pedals had many more presets
using different filters. And a cool name for the preset like bassman 4x10 or tweed 1x12 blah blah just filters.
The passive 1 pole filter in your design is set at around whatever it is. Being 1 pole to have enough cutoff
at around 5k to make distortion sizzle sound ok. So being 1 pole the filter would be set at around 800 Hz
to 1.2 kHz to make 5k actuated enough. Being a simple 1 pole filter.
With clean tone could be opened up a little. as with the opamp emulators they can use 2 pole or 3 pole
filters .More easily so the cutoff is sharper and the filter more open, then brick walls that sizzle at 5k
I would assume it is possible the Duncan magic can is just a 2 pole or 3 pole passive filter.
It is just harder to make higher pole filters with passive components.
Instead of using a 800 Hz to 1.5 kHz 1 pole filter. Is likely a 3 to 5k 2 pole or 3 pole filter.
Again same thing getting a sharp cutoff for high frequency for the sizzle and noise of typical guitar distortion.
Since speakers have natural roll off. He might have added a notch filter to emulate a mid dip or the classic
2 to 3k dip that many guitar speakers have. Some like it some dont. changes the sound of the distortion.