Not to mention that it seems like a lot of master tapes have noticeably deteriorated since the last time they were transferred. So, for instance, a vintage recording transferred to CD in 1990, now being remastered in high-res, may in fact sound worse than it did 35 years ago.
That's an idea of the late and great Michael Gerzon. I don't know if it was just a nice idea or if it is actually used.
I was hoping that Roon or Jplay Windows players, https://www.sonicstudio.com/amarra/ or https://audirvana.com/ would have developed software-based fixes for this and for the other damage I've discussed. But nothing from them so far.
Maybe https://theresanaiforthat.com/s/audio+restoration/ ?
Note here in the earlier Rev E. where John speaks of the electrolytic free power supply. thttps://tubecad.com/2018/03/blog0415.htm
Which power supply https://glass-ware.stores.turbify.net/hiposu.html for the updated Rev F http://glass-ware.store.turbify.net/ainost.html which relies least on (large value) electrolytic cap circuitry?
In my scratch build I use a 6X5 rectifier, a 20uF film cap, then a Neurochrome Maida regulator followed by 10uF film cap. That's it. The Neurochrome board is pricey but you can easily adjust the voltage for different configurations and it sounds lovely. The filaments are provided with 6 volt in > 6 volt out board made by diyaudio member v4lvelover.
Others may have already suggested what I'd recommend, but here it is already.
Somebody might pay serious money for what seems to be originals. Sell these & buy retakes.
If you keep them, the proper sound system would be something from the era they where marketed in.
Think hi powered V8 pony cars, fierce competition at the stop lights & the local midnite drags.
Diamond Cut has their comprehensive package of tools ("DCART11") on sale for $39 - including many filters - an expander - emulation of valves - adding distortion - even - odd - both
https://www.diamondcut.com/st3/2017/06/19/dcart10-details/
https://www.diamondcut.com/st3/2017/06/19/dcart10-details/
You already acknowledged in post #13 that we are possibly glimpsing a new era where AI bends the rules that we have accepted for so long. I do anticipate a time when someone can simply install some software and run their old, DR-compressed (or badly mastered) material through it and end up with something much, much better.
I've recently installed and tested an application named Upscayl, which is a free and open source software that uses AI to upscale photo/picture resolution. The results are nothing short of incredible. It can take a low resolution JPEG that is completely inadequate for printing and upscale it to a gorgeous, printable photo. I do believe it is only a matter of time before we have software for music that is this impressive.
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About your SP14 preamp which you described here https://www.diyaudio.com/community/...arm-tube-preamp-to-pair-with-pass-amp.384364/ Would you say that this preamp sounds warmer-but still just as clean (BUT not bright), and with accurate 3D lifelike mids, airy, tinkling highs but no bloopy bass-like your Aikido preamp?
If yes, did you not have to raise the bias on the 6SN7 tubes at all for any degree of satisfying warmth (however much you may like that sound)?
But if you tend to use one preamp more than the other why might this be so?
And can both preamps deliver at least 7 volts?
Honestly, I'm not interested in "warmth." The SP14 version of the Aikido, with the operating points that Roy settled on when he designed the board, simply sound natural, like voices and instruments in a live setting. There is no "brightness" or etching or anything like that. The music sounds like it ought to sound--involving, engaging, realistic. It doesn't make noise, it conveys the performers. And yes, the 6SN7 Aikido can deliver well over 7 volts output.
Yes an Akdio is an excellent preamp.
My Noval EL34 driver version with 12AT7 input and 12AU7 output tubes produced the results shown on this thread.
https://www.diyaudio.com/community/threads/akido-preamp-query.408669/#post-7589471
2H distortion drops as the input level is reduced. Eg at 30mv in, it''s 0 .034%.
For low level signals, a 12AX7 input tube doubles the gain to 24x.
My Noval EL34 driver version with 12AT7 input and 12AU7 output tubes produced the results shown on this thread.
https://www.diyaudio.com/community/threads/akido-preamp-query.408669/#post-7589471
2H distortion drops as the input level is reduced. Eg at 30mv in, it''s 0 .034%.
For low level signals, a 12AX7 input tube doubles the gain to 24x.
Thanks for this-only problem I'm not sure if this will how make it harder to choose between your preamp and Grovegardner's SP14 for driving the F4.
I didn’t know who Roy was until I searched- and wow! http://www.tubes4hifi.com/SP14.htmBut you called your preamp “the SP12 version of the Aikido”. I thought they were different preamps entirely, since they were designed by different people.
In any case, you’ve clearly described several of the reasons why you love the sound of the SP12. But how then would you compare it with how the Aikido would present those same recordings?
There is always a dilemma when more than one option is available and only by listening to them can you tell.
With tube gear in particular, there are so many variables that you can entertain yourself for many many hours or go mad trying them. E.g HT voltage, AC or DC heater supply, tube type etc.
I must have mis-typed. The only Aikido preamp circuit I have used is the SP14. Initially I modified one for a friend. I liked it so much I bought my own board and assembled one in a not very nice case. I have since rebuilt that using p-to-p wiring, a Neurochrome Maida board for the high-voltage supply and a 6 volt regulator board for the filaments. That is what I used now, with the same operating points as the SP14. Possibly the SP14 operating points contribute to the very nice sound. I have not experimented with changing them.
I should also clarify that when I talk about the "naturalness" of my Aikido preamp, I'm referring specifically to the 6SN7 Aikido. A friend of mine built an Aikido preamp with high-transconductance 9-pin tubes (I forget which, possibly Russian ones) and it's also very transparent but with a more analytical sound. It's my experience that the Aikido circuit will reflect very clearly the sonic character of the tubes you use in it. I prefer the 6SN7 for it's ease and naturalness of sound. This is true for my classic Williamson amplifiers as well, and also contributes to the very pleasing signature of several of the Eico amplifiers that use the 6SN7 for a driver.
Two of those you cite are examples of cathode heater circuits? If yes, I'm trying to remember from my tech school day the plusses and minuses of AC (indirect) and DC heater (direct). I think the direct heating circuit is supposed to yield the best sound, though it involves more circuitry, yes?
Direct and indirectly heated (cathodes) are separate from an AC or DC heater supply.
With directly heated tubes, the filament is also the cathode so can't be AC for lowest distortion.
For indirectly heated cathodes, the filament can be AC or DC powered.
One could assume that DC will produce less mains hum and noise...
With directly heated tubes, the filament is also the cathode so can't be AC for lowest distortion.
For indirectly heated cathodes, the filament can be AC or DC powered.
One could assume that DC will produce less mains hum and noise...
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