F5 Listening Impressions & Discussion

[jamj]

Your uncle could be right. Has to do with speakers in use
as well as the listening room. One could widen the soundstage
by reducing the value of the feedback resisitor value. That is
if theres a feedback circuit.

[bear]

Probably means nothing... amps sound different, that's all.

The question is, which one is "right"?

Hard to know.

Besides, if the only issue is "sound stage" width, then there's no reason to build an F5, if the sound stage width is ok already. Imo, what the F5 does (depending on your implementation) goes beyond that into "fidelity" and "timbre"...

_-_-

[galop]

I sold him onkyo system few years ago,but i dont remember what was sound,but i dont think that onkyo sound is better than F5.

[vdi_nenna]

Hi Everyone,

Yesterday a few of us compared my 1st F5 to a second F5 build.

1st one was a 2 transformer (Antek an-4218)mono down to the power cord. Vishay/Dale resistors, V/D power resistors and 4 standard bridge rectifers. DH labs silver on copper wire and Connex silver on copper wire. The Mosfets were IRFP9140s and IRFP140s. The amp included the thermal compensation and protection circuit.

The 2nd was built on a single transformer (Antek an-4218) feeding 4 diode bridges using Hexfreds that were filtered by independent CRC power supplies.
All wiring was Connex silver on copper, except Kimber Kable 19ga copper for inputs. All resistors were Caddock MK 132 and Mills on the power supply. This version had the thermistor and protection circuit removed. The Mosfets were IRFP9140s and IRFP140s.

The second amp was only alive for a day and a half, but there was a noticable difference in attack and decay- it was faster. The instruments were more etched in the space between the speakers. I thought at first that the "etched' sound might be due to harsh highs and lack of break-in time, but it was not annoying. I found no loss of power in the low end because of using one transformer. The bass definition was still there.
There was a bit more realism in everything it did.

The second F5 did not kill the first version. Was it worth upgrading parts, yes it was. Am I going to toss out or sell off my first version? No way!
They will make a killer bi-amp setup.

Any questions, feel free to email me.

Associated Equipement

Vinyl front end (direct drive) can't remember the brand. Clear acrylic table with beautiful wood base. Clear acrylic table has lead shot inside.
I know, I just described a hundred turn tables.
Sony DVD, modified tube output
I/O phone stage
VTL tube preamp
Gallo Nucleus Reference
Nutty expensive cabling, not crazy expensive, but just enough to make you ask, "How much again?"

Vince

[a.wayne]

Great report Vince .! ......................

What would you account to for the difference , No limiters, by having thermistor and protection circuit removed?

[vdi_nenna]

I think a smoother power supply can give a circuit a sense of greater ease. The new Hexfred diodes helped IMO. The new F5 doesn't seem to run out of gas or compress as much as the first version. This might be due to the diodes and lack of extra circuitry. I think the Caddock still need to break-in, as do so many other parts, and even the wiring. But, out the gate the new version just rocked!
I'm not imagining it. We A/B'ed a few tunes. All three of us heard it. Only things that chaned in the system were the source equipment and amps.

[Tea-Bag]

Vince, have you considered trying some Toshiba outputs on this rig?
I did that with my minimalist F5 and liked it.
I think the Toshiba's may smooth things a bit.
I dont think Caddocks are forgiving resistors.

[vdi_nenna]

Tea-bag

When you say, "I dont think Caddocks are forgiving resistors." What do you mean exactly?
I interpret this as they may be clinical or critical of the sound. Like not soft or warm?
I want critical.

Yes, I have thought about the Toshibas. I held some in my hands yesterday. Not mine though.

Why not? Gone this far, right?

I have even thought about the "naked" Vishay resistors.

Lord forgive me. For I know not what I do. Well...maybe I do!

[Peter Daniel]

Nude Vishays are only $2 more per pc. comparing to Caddocks and MK132s tend to sound a bit edgy indeed, that's why I don't use them too much, mostly as input shunt and feedback position, everywhere else I would choose Vishays.

I also didn't find much difference switching from a single supply to dual mono.

[vdi_nenna]

Peter, do you think the "naked" Vishays are closer to wire with resistance with no added color or warmth?

I also didn't find much difference switching from a single supply to dual mono.

Yes! Exactly! Make me think I should re-work the 1st version to 1 transfo build and build a third one with......No. I better just stop here.