Thanks for those vids! Ive been hanging out for such a comparison for several years.
Out of those, both sound great, but I don't think I need both and Im very happy to run with my VM
Unwinding an inductor coil: 1mH to 0.9mH
Nothing better to do on a Saturday morning, so I decided to unwind an air-cored inductor.
The 8 Ohm version of the M2 attenuator calls for a 0.9mH inductor. But many standard ranges only offer 0.82mH or 1.0mH. To be honest, its not really critical, a...
I still have one and I like it very much. But they are notorious for heat-related issues that build up over time, and they are hard to work on. Mines from 2005 and needed a serious do-over a few years ago, and now it's got some new issues. A given 401 could be more than 20 years old. I don't...
I looked up that SVT! it's a BEAST! If you want to attenuate because of better tone up high, all the design theory should work but built with Stage 1 like an industrial substation. Speakon connectors instead of jacks, thick gauge for the coil and uprated resistors, probably divided in multiples...
hi @KIL0 and welcome to our thread.
For the HRD, if you need a 16 Ohm load, you can build a 16 Ohm M2 and use it with either a 16 or 8 cab, or in principle, an 8 Ohm Torpedo. But when I looked up HRD's specs, It looked to have an 8 Ohm output rather than 16Ohm?, also ok with two cabs for a 4...
Hi Gene, these new units look really good - great work!. Im proud of them too!
Getting to a place where we have such a well executed and proven design continues to be a great ride. I really enjoy the collaboration and none of us would be here on our own!
Onward!
hi @PelliX , I can pick up the question about the Webers.
With a good circuit model of a full speaker, we can model most passive attenuators in Spice. Here's my Weber Mini-mass analysis:
On the schematic at the bottom, a full speaker is modelled, and at the top the mini-mass driving a...
ok sounds fine. No issue with steel for the screws for other than the coil and you have that covered.
Can you check resistance of the fan as measured by a meter?
Looks like a great bit of product design and production engineering!
What's your coil-mounting arrangement? Any space to offset it a few mm up off the base?
Also, since you've got a credible looking fan, shall we try to take the next step with developing an amp-driven self-powered...
It's hard to find some comparisons like this. Origin, VM and also SV20 although different are to some extent all designed to 'scratch the same itch' for 'vintage-y tone. Most people wouldn't have access to more than one in that ballpark. I do love my VM combo though. I can recommend it as a...
Hi @Gene Ballzz , that looks really great! (I think I'd keep wanting to turn it over to admire the grills!)
And I see it's getting the neat 8-16 tweak on the output with the 39ohm. I'll get a schematic diagram to show that.
Our designs use switched stages, for a few reasons:
Passive attenuator designs based on pots or Lpads may or may not sound good enough or acceptable, but as you note, there typically is indeed some tonal difference across the dial. In the basic examples it sucks! But M2 and its related...
Hj @Gene Ballzz Here's the double version, described in post #1731 on page 87
There's a couple of ways to do this, depending whether each half is an 8 or a 16 ohm circuit.(8 ohm halves shown here) It's also possible to do 4, 8 and 16 out of two 8 ohm circuits, but switches with the right...
hi @colchar , all good advice posted above!
If you can identify an amp output impedance that will work across the amps that you have or might like, then you can build an M2 for that, and the attenuator can let you run either 8 or 16 Ohm cabs safely, and with good tone. If you like heads, I think...
In principal you feed a rectifier circuit, that feeds a dc fan. Search online for rhe Marshall Powerbrake circuit. But in practice it would take ecoeriment to get the right values and components that work for you. So I wouldn't launch right into it yet.
hi @xiaozi0624
On page 112 I drew a layout and schematic for an M2 with line-out, which might help. But you can also take a line out just from the attenuator output, either with a pot to control it, or directly provided you set the attenuation level to a suitable level for your DAW. Ive done...
That's right. At the time of the JCM 800's there wasnt anything as effective as an IR to get you a good DI sound, and raw would sound bad. Hence many might note it as unusable. But worth trying now with new IR tech!