F5 Listening Impressions & Discussion

[Nelson Pass]

Well, I didn't buy a bunch just to admire them on the shelf,
but there is only so much time in the day.

[EUVL]

It's all a matter of priority.
Or are you subconsciously worried that they would turn your extensive stock of IRF devices into junk overnight ?

Just pulling your leg ..........


Patrick

[bear]

Not sure about the Tosh's but the Hitachi N & P ch are not exact matches when you look at the complement's curves(!). So, to some extent the feetback is going to be responsible for "correcting" the curves in practice...

I've listened to slow, fastish and Mhz bandwidth amps and I can not draw any correlation to listening fatigue or pleasure on that basis alone. Others may have had different experiences.

So, wondering if the Tosh's are better compliments or??

_-_-bear

[Nelson Pass]

Originally Posted by bear

I've listened to slow, fastish and Mhz bandwidth amps and I can not draw any correlation to listening fatigue or pleasure on that basis alone.

Me either. I have good and bad examples of both, so I
don't find myself worrying about it very much.

[EUVL]

> So, wondering if the Tosh's are better compliments or??

I have already published curves of the TOS MOSFETs at the F5 thread ages ago. They are perfect. The JFETs are not, so you need to fiddle a bit to get open loop gain to match by mismatching degen resistors, etc..

(The grey coloured crosses belongs to the 2SK1530, the red line 2SJ201. If I use red & blue lines, you cannot tell them apart.)


Patrick

[h_a]

You just need to play 10kHz sine wave, triangular wave and square wave, and hear the differences. Then you know why you want 300kHz+ power amps.

Well, this is to be expected if you feed high bandwidth signals into an amp. I could as simply say, try a 100kHz square wave on a 300kHz+ power amp and you will need a MHz-amp for your pleasure.

In music, frequency content above 1 kHz goes down at 6dB per octave, so at least technically no need for such radio receivers.

Your mileage may vary though.

Have fun, Hannes

PS: the 10kHz sine wave should be ok on any amp with a frequency response of above 10kHz.

[bear]

The technical relationships regarding bandwidth and N & Pch curves are of course interesting. But what I am interested in is more what the listening experience becomes when a comparison is made between them/it!

Obviously something needs to be said to provide context to those comments since a "dark" sounding amp connected to a "bright" speaker will "sound better" than a truly "neutral" amp connected to the same speaker, etc... But I am still interested in hearing what others have heard from this F5 amplifier.

One of the interesting aspects is that since there are so few parts involved one might expect that it could be possible to correlate some sort of actual empirical measurement back to the resulting sound - whereas with a complex "modern" amplifier design the number of variables is extremely high.

So for now I am curious if others (especially those with other high performance amps and supporting gear) are hearing the same thing or something different than i do here.

_-_-

PS. An interesting note which speaks to the subjectivity and sensitivity of all of this stuff to the specific and particular system & implementation is that in the main F5 thread a poster said that his implementation of Borbely's DC100 amplifier was "darker" than his F5. My own experience with the DC100 is the opposite, the F5 seemed to have less sibilance than the DC100 - which BTW is a rather nice , clean, and somewhat warmish sounding design (properly implemented).

[fishski13]

it's the hook-up wire . seriously, i hope to have a functional F5 planked out on plywood within the next week to compare with my Krell.

[bear]

Originally Posted by fishski13

it's the hook-up wire . seriously, i hope to have a functional F5 planked out on plywood within the next week to compare with my Krell.

You'll sell the Krell. If you do the implementation well.

(not so simple)

But there is a huge diff in the power available so that may prove to be a real issue for you.

But maybe ur joking about the Krell?

And, yes the wire made a difference - he started out with some rather thin stuff for things that carry some current...

_-_-bear

[fishski13]

i'm using Peter Daniel's boards with Toshiba JFETs and IRF MOSFETs. i have a 500 VA SumR TX with standard recovery rectifier bridges - i'll have plenty of room to try some boutique diodes down the road. my PS will have 132,00uF of caps - i'm building it P2P with turrets and G-10 fiberglass. the PS will be in a "proper" chassis with 2 towers of heatsinks mounted on top, housing/sandwiching the amp PCBs. Cardas wire, jacks, and binding posts. i've spent nearly a month just drawing and planning the chassis and layout.

the Krell is an integrated KAV-400xi 200W/8ohms, driving a piggish load ATC SCM12 83-85dB. my room is only 10x13'. i'm not sure that the F5 will be up to the task, but after living with a friend's uFonkens with Fostex FF85K for a week, i don't care if the ATCs go. i have an extra set set of drivers and CNCed BB for a pair of uFonkens to build for myself with intent on pairing them with a small sub. these little suckers are sublime, especially in my small room.

Originally Posted by bear

You'll sell the Krell. If you do the implementation well.

(not so simple)

But there is a huge diff in the power available so that may prove to be a real issue for you.

But maybe ur joking about the Krell?

And, yes the wire made a difference - he started out with some rather thin stuff for things that carry some current...

_-_-bear