C3D10060 (I simply took them out from different amp project). They reach ~40 C @ 200mV bias after hours of playback. I measure ~22.2V on caps output with 0,22R 12W for voltage dropping.
C3D10060 are quite strong according to datasheet (especially that there a four of them per one rail per one channel, 16 in total, four bridges), but let me know if I done anything stupid here ... 🙂
Actually I do not want to drop the idea of SMPS. It seems for me that base control was better with them. But I might be biased ... It needs audition, measurements and ABX testing. Waiting for 2x500W SPMS units ...
C3D10060 are quite strong according to datasheet (especially that there a four of them per one rail per one channel, 16 in total, four bridges), but let me know if I done anything stupid here ... 🙂
Actually I do not want to drop the idea of SMPS. It seems for me that base control was better with them. But I might be biased ... It needs audition, measurements and ABX testing. Waiting for 2x500W SPMS units ...
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Great build Tio!
Really too bad about the SMPS. I hope the new ones work well since they do look
very interesting.
Really too bad about the SMPS. I hope the new ones work well since they do look
very interesting.
Looks amazing Yoshida. And I love that case, just beautiful.
Can you provide a source for your transformer?
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And as I said last time I checked the thread after a long layoff, so great to see more people really loving this amp. Mine won out over Coincident Frankenstein 300b monoblocks, Atma-Sphere M60 monoblocks, a Lyngdorf tdai 3400, and a Nelson's own xa-25. I recommend it all the time over on audiogon, but of course there's little interest because it's not a sexy new amp. Thanks again everyone for helping me build it.
Could this be a Takachi HY? ( http://www.takachi-enclosure.com/data/c16/HYR_02.pdf ) I was very tempted to get one of these, but they didn‘t tell me the thermal qualities, and I wasn‘t confident enough to just try it.
say what's line stage you're using with F4, then we have full info
XA25 is by itself damn good amp, but obviously too low in THD amount for your liking
rest of them I can't comment (in general - liking idea of any decent made toob amp, but being absolutely indifferent to any digital drek around) .......
For the chassis? You don‘t want to know [emoji84]
( HY1773333SS KuhlkorperAluminiumgehause 330x330x177mm Aluminium Silber IP40 Takachi — there‘s a German site selling them for a bit less, or contact Takachi...)
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Re. Your 2nd question: no it will not affect the class-a envelope of the amp: while each half of balanced monoblock will see 2 ohm load, it will also need to swing half of the voltage (as balanced mono brings 6db voltage gain).
And this corresponds to same current need
Re. Your 1st question: there are many highly regarded amplifiers with high output impedance: e.g. first watt sit’s, dartzeel’s, dan dagostinos come to mind (see stereophile reviews), so not necessarily a bad thing: ideally you try for yourself.
One thing is for sure: balanced monoblock enables substantial 2nd harmonic cancellation which also helps for lower intermodulation distortion.
And if you are digital only, you might even be ok with a dac with volume control that can swing 6vrms from balanced output (which corresponds to ~10w power per channel to 4 ohms), and ditch the preamp, just saying..
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The case is takachi's HY177-33-33SS.
This heatsink is a bit smaller for F4 so I reduced the bias a bit.
The R-core transformer was custom made by Phoenix Corporation. They are popular for DIYer in Japan because they accept custom orders for amateurs.
However, they do not seem to accept small lot orders from overseas.
It would be nice if the Store handles it.
Great info. Many thanks. I actually have a DAC with volume control and 6v at XLR. How did you know 🙂
If 6 vrms is not enough what XLR vrms is needed for max output for bridged balanced F4?
You can use the classical formula
Power = VxV / R
To calculate voltage swing need
Say you need 50 watts, for 4 ohm load, applying the above formula ->
V = sqrt (50 x 4) which makes roughly 14 V rms.
That being said, I suggest you first test the loudness level with 6 Vrms output then look for any higher gain options.
I looked at this post.
Is it correct that I would only get 18w in Class-A 4 ohm bridged bit up to 50w Class-A parallel?
https://www.diyaudio.com/forums/pas...s-4ohm-load-balanced-input-2.html#post4198300
It's around that range, assuming you are using the standard ~1.3A bias and ~ +/-24V
rails.
For bridged, the bias current is the limiting factor, while for parallel, the limit is the
rail voltage.
rails.
For bridged, the bias current is the limiting factor, while for parallel, the limit is the
rail voltage.
Perhaps that you may find 18W sufficient. Of course, that depends heavily
on your speakers and listening space and personal preference.
on your speakers and listening space and personal preference.
Yes sure.
But which version would you chose? I am ok with 50w max power.
Use bridged and get 18w Class-A and max power 200w and damping factor 20
OR
Use parallel and get 50w Class-A and max power 50w and damping factor 80.
I tried to say ([emoji51]) that only 18w out of a f4 could be very very good. Sorry on my side (my Englisch is sometimes weird)