Just throw a Speltz Zero autoformer in front of each Scintilla and use any old 4ohm capable amp.
https://www.zeroimpedance.com/story.html
https://www.zeroimpedance.com/story.html
Raising the impedance of any speaker by up to four times - Interesting concept
(apart from finding a Speltz Zero or making one) if the below were true, there’s gotta be a big catch or two. Otherwise they’d be owned by thousands of audiophiles
Have you heard any of these? Especially on a Scintilla or similar “nightmare” for an amplifier
Speltz states
“Typical reported improvements from people who used the ZEROs to increase their speaker's impedance are:
(apart from finding a Speltz Zero or making one) if the below were true, there’s gotta be a big catch or two. Otherwise they’d be owned by thousands of audiophiles
Have you heard any of these? Especially on a Scintilla or similar “nightmare” for an amplifier
Speltz states
“Typical reported improvements from people who used the ZEROs to increase their speaker's impedance are:
Oh and BTW: The entirety of the sound improved with the Zeros in place - Lows, Mids and Highs.
I bought the naked autoformers at the link below and put them in custom black anodized Landfall chassis boxes to match my amps.
https://zeroimpedance.com/
I bought the naked autoformers at the link below and put them in custom black anodized Landfall chassis boxes to match my amps.
https://zeroimpedance.com/
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Use a Sunfire 300-2 amp and change out the air coils on the amp cards only, not the TDC!
Use 11 gauge on a 1” former 31” long magnet wire along with changing R49, R50 to 1.8k 1 watt for both amp cards (4 PCs.)
Relaxes the protection limit
Runs cool as a cucumber and sounds like an ultra smooth high powered tube amp
Use 11 gauge on a 1” former 31” long magnet wire along with changing R49, R50 to 1.8k 1 watt for both amp cards (4 PCs.)
Relaxes the protection limit
Runs cool as a cucumber and sounds like an ultra smooth high powered tube amp
Unless you have a strong urge to stability test ClassD amps, this is not a great match.
There is a good reason for the power drop, and not doubling, into low and very low impedances.
Pay attention to the typical statement for low impedance loads - where the ClassD module manufacturers typical list the lowest impedance into which these are stable. That is 2-2.7ohms at best. Below you are at the edge of protection cut-out (or burn-out).
I have some custom ClassD amp modules adjusted for 1 ohm stability. I wanted to use these for magnetostatics in an active system. (3-400W on 1.3KVA & 0.3F PSU)
This brought another aspect to the table that I had missed - the residual switching frequency is typically filtered - some more than others. Into normal dome tweeters which are electrodynamic drivers with a coil the inductance means the impedance at the switching frequency is high - and thus the power consumption and dissipation in the unit negligible.
For a ribbon speaker - the inductance is very low in comparison and it will load the amp hard at the switching frequency.
In my case that made the ClassD's run really hot and eventually the rc filter also had a melt down...
Stability and robustness will surely vary across the different design out there - but be careful.
Anyway, it is not thousands of watts = high voltage svings that is needed for Scintillas and the like, it is current in raw and consistent supply, a proper arc welder 😎 (sorry for stating the obvious).
This all reminds me that I have a set of 1KVA toroids that have a usable ratio for autoformer use - I am just yet to verify the frequency and impedance linearity.
The Speltz design started life like that - but they have several changes compared to a typical power transformer.
There is a good reason for the power drop, and not doubling, into low and very low impedances.
Pay attention to the typical statement for low impedance loads - where the ClassD module manufacturers typical list the lowest impedance into which these are stable. That is 2-2.7ohms at best. Below you are at the edge of protection cut-out (or burn-out).
I have some custom ClassD amp modules adjusted for 1 ohm stability. I wanted to use these for magnetostatics in an active system. (3-400W on 1.3KVA & 0.3F PSU)
This brought another aspect to the table that I had missed - the residual switching frequency is typically filtered - some more than others. Into normal dome tweeters which are electrodynamic drivers with a coil the inductance means the impedance at the switching frequency is high - and thus the power consumption and dissipation in the unit negligible.
For a ribbon speaker - the inductance is very low in comparison and it will load the amp hard at the switching frequency.
In my case that made the ClassD's run really hot and eventually the rc filter also had a melt down...
Stability and robustness will surely vary across the different design out there - but be careful.
Anyway, it is not thousands of watts = high voltage svings that is needed for Scintillas and the like, it is current in raw and consistent supply, a proper arc welder 😎 (sorry for stating the obvious).
This all reminds me that I have a set of 1KVA toroids that have a usable ratio for autoformer use - I am just yet to verify the frequency and impedance linearity.
The Speltz design started life like that - but they have several changes compared to a typical power transformer.
This thread is entirely above my head, but perhaps an enormous F4 scaled up for the task and a minisplit somewhere nearby to deal with the heat could work?
🙃
🙃
Xa252, BBA3 6 deep monoblocks, F5TV3 monoblocks.
But perhaps just wait for MZM’s last iteration of the XA252.
Perhaps the easiest way would be to use the mains inlet
But perhaps just wait for MZM’s last iteration of the XA252.
Perhaps the easiest way would be to use the mains inlet
Thanks for the suggestion, no, I don’t know how to calculate the desired dB based on the few criteria. I live in an apartment with fairly decent insulation. I like my music to be loud enough without being a nuisance to my neighbours in the adjacent apartments.
By 100W it is at 8 Ohm, and it will be 800W at 1 Ohm, with 2500VA transformer per channel I think it should have no problem supplying the current demand.
I am actually thinking of keeping VCC at +-34V, keeping the 64 output MOSFET amp to 60-75W@8 Ohm ==> 480-600W@1 Ohm, but still keeping the 2500VA, to increase the safety factor.
🤣I happened to have a few vintage arc welders, that was actually what prompted me to this current round of audio DIYing after my absence of 30+ years, trying to see what I could do with them.
They hum, but not quite in unison🤣 perhaps you know a way to stop them humming?
Attachments
I am trying to scale up my Aleph 5 clone to have 64 output MOSFETS, question now is what is the optimum VCC if I use a 2500VA transformer per channel.
Any stable amp delivering 60 A for longer time with low distorsions can drive the SC 1Ohm proper to the limits.
Not so much voltage swing needed.😊
Not so much voltage swing needed.😊
Well, if you are trying to keep it Pass and want to go off of the designs from this forum, I would try the BBA3 with as high of rails as the JFETs can tolerate. Maybe even cascode them to achieve a higher bias. The F5 in a balanced configuration should work as well. Same thing, as high of voltage rails as the JFETs can tolerate. That way you can use the class B envelope. If you look at Mr Pass's first suggestion (X600) it is a AB amp. And then a big transformer to deal with the low impedance...
You could do the same thing with a F4 if you have a nice preamp to drive it all.
You could do the same thing with a F4 if you have a nice preamp to drive it all.