So I was poking around on Spencer's site (FETaudio) a while back and saw that he had a few Toshiba 2SK1530/2SJ201 parts available. I was intrigued and bought two N/P pairs for an F5. I finished the build a few days ago (stock build with boards from the store) and swapped them into my one, trusty chassis.
DANG, this thing sounds fantastic!
Twiddling around with P3 is a delight with this amp and– just as reports suggest – makes it one versatile machine.
All of that preamble to ask: has anyone out there built and measured this configuration yet? I've seen other Toshiba parts have been used, but haven't found many reports with these parts. I don't own a scope and haven't been able to look much beyond THD. I'm specifically curious if anyone has made any other component edits based on using the Toshiba parts. Also wondering how much of my delight is due to the Toshiba parts, vs the F5 topology. Maybe one day I'll throw the IRFP standards in to see how the 'standard' F5 compares. Either way, I can't recommend this F5/Toshiba combo enough
DANG, this thing sounds fantastic!
Twiddling around with P3 is a delight with this amp and– just as reports suggest – makes it one versatile machine.
All of that preamble to ask: has anyone out there built and measured this configuration yet? I've seen other Toshiba parts have been used, but haven't found many reports with these parts. I don't own a scope and haven't been able to look much beyond THD. I'm specifically curious if anyone has made any other component edits based on using the Toshiba parts. Also wondering how much of my delight is due to the Toshiba parts, vs the F5 topology. Maybe one day I'll throw the IRFP standards in to see how the 'standard' F5 compares. Either way, I can't recommend this F5/Toshiba combo enough
Toshiba's output FETs are worth every cent, even at current prices.
https://www.diyaudio.com/forums/pass-labs/183362-f5x-euvl-approach-16.html#post3208260
Patrick
https://www.diyaudio.com/forums/pass-labs/183362-f5x-euvl-approach-16.html#post3208260
Patrick
I also have 4 matched pairs of these (from the same source). I never bothered to substitute them into my F5 (did not fit the pcb). I think on fetaudio he commented long ago that he could not hear the difference.
as for using 2SK1530/2SJ201s: a few years back Nelson commented in a thread that he still might slap together a circuit aimed at using these but it did not happen (those darn Vfets and their lasting magic spell).
The one graph I found interesting in fetaudio F5 (turbo) assembly instructions was on floating input being preferred over chassis grounding (if I understood it right).
as for using 2SK1530/2SJ201s: a few years back Nelson commented in a thread that he still might slap together a circuit aimed at using these but it did not happen (those darn Vfets and their lasting magic spell
).The one graph I found interesting in fetaudio F5 (turbo) assembly instructions was on floating input being preferred over chassis grounding (if I understood it right).
Attachments
> Nelson commented in a thread that he still might slap together a circuit aimed at using these
F5X -- the EUVL Approach
"Even Nelson likes how the Toshiba's sound."
http://www.firstwatt.com/pdf/art_f5_turbo.pdf
Sony VFET Amplifier Part 2
Patrick
F5X -- the EUVL Approach
"Even Nelson likes how the Toshiba's sound."
http://www.firstwatt.com/pdf/art_f5_turbo.pdf
Sony VFET Amplifier Part 2
Patrick
I read in M2 thread that they have beter sonic results than IRFP's but require to change some component values.
You remember Nelson hints for the output pair matching….?
if not look here
Official M2 schematic - Page 6 - diyAudio
Because I was a bit irritated he was so friendly to give me an "extended version"…… THX Nelson!
"The numbers are get have about 1 volt more Vgs (about 5V) for P channel FQA12P20
vs about 4V for FQA19n20c at 1 amp (cold). That is why you see the trim pot on the
top side for the DC offset.
"The transconductance of the N type is a little higher, but in practice I see a consistent
3rd harmonic character, so it’s not much higher.
There are better parts out there, although my favorites would be the Toshiba 2SK1530
and 2SJ201. If you look them up you will see why, but they are discontinued."
hope sharing Nelsons words is no sacrilege in this case…..
If you do not have unlimited ammunition, you save the most potent ones for the biggest battle.
Patrick
Agreed. I considered a few different options, but the F5 seemed like it could give the best bang for the buck with these parts.
The Toshiba's are the correct choice for the F5.
IMHO a bit of a waste for the M2.
I would try the FQAs there first.
We have very good results with the FQA9P25.
UDNeSS, or You don't need Semisouth's
Patrick
IMHO a bit of a waste for the M2.
I would try the FQAs there first.
We have very good results with the FQA9P25.
UDNeSS, or You don't need Semisouth's
Patrick
Wow, Cody! I saw something "strange" in your signature yesterday...
Tell us MORE about the mod: operating points, adaptations, etc.
