F5 Listening Impressions & Discussion

[ichiban]

Originally Posted by bear

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).

I will revisit the F5 vs DC100 (2sk176/2sj56 3 pair/ch) 3again before it's conversion to use the F5 driver. I have done a test using the B60's 2sk135/2sj50(one pair/ch) outputs with the F5 driver and found the Hitachi's a little more detailed/resolving. By darker I refer to the space in which the performance was recorded. With the F5 the hall/wall reflections are revealed and the spaces between performers, like the stage lighting was turned up to illuminate more? The detail was also greater with the F5. The DC100 does have a WIMA 3u3F cap at its input, I've been wondering if it might be responsible for the darker sound. The DC100 driver is built with the Old Colony Boards/Kits from 1987. I have found that when I have it running dual mono it has greater detail/resolution as does increasing capacitance. Also inserting a 2m2H coil between the first and second caps results in better resolution. Currently setup with a single tranny.
No surprises there. So, yes running the DC100 as dual mono with a macho cap bank would increase resolution.

[bear]

Darker is usually used to refer to less bright sounding...

I'm wondering what you heard WRT sibilance between the two amps?
And ar eyou putting the choke in the ground lead between the cap sections?

You can remove the 3.3ufd input cap (bypass) IF you have no DC of any significance going to the input, since the amp will amplify DC. It will sound more better.

Or you can put a "botique" cap like a film/oil in and see if that does anything...

I think I'd just get some more mosfets before stripping out the DC100, unless maybe it is sitting on a plywood board or something akin to that.

_-_-

[bear]

So no one else has any listening impressions about any of the F5 variations??

Good or not good, have no fear...

Please don't feel that it isn't reasonable to not like this amp more than some other amp...

Going back to what I said at the top, the local experience so far is that the power supply implementation appears to have a significant influence on the perceived character of the amp.

I am quite curious to know what others have experienced thus far.

_-_-bear



PS. also going back to the top, the lack of capacitors in the signal path is an attractive feature to me, and might make it possible (given the simplicity) to identify the "source" of certain sonic "factors".

[fishski13]

Originally Posted by bear

So no one else has any listening impressions about any of the F5 variations??

Good or not good, have no fear...

Please don't feel that it isn't reasonable to not like this amp more than some other amp...

Going back to what I said at the top, the local experience so far is that the power supply implementation appears to have a significant influence on the perceived character of the amp.

I am quite curious to know what others have experienced thus far.

_-_-bear



PS. also going back to the top, the lack of capacitors in the signal path is an attractive feature to me, and might make it possible (given the simplicity) to identify the "source" of certain sonic "factors".

x2.

[mthoi]

I have a Quad 606/Quad 34/Harbeth SHL5 and a diy F5/B1/Harbeth3ES. I have made some upgrades to the Quad 34 using Burson op-amps and Mundof ZN/Blackgate NX caps. Quad was recognised for its clarity and uncoloured sound in the 1980s.

The F5/B1 was a diy-project 3 months ago when my friend highlighted this project. The F5/B1 was a real surprise - its effortless presentation, spot-on soundstaging and clarity with a hint of warmth. I spend more time listening to the F5 now.

The man is a GENIUS! Thank you Mr Pass.

[EUVL]

Someone has written a long description recently at the F5 thread about the balanced versions. Maybe you should take a look there.

F5 power amplifier

There were others, including one from me very very early on (must be more than a year) in the same thread.

Patrick

[bear]

Patrick,

Thanks I have been reading the F5 thread, but that thread is mostly about the contruction and circuit design. I thought it would be useful to separate out the subjective result from that part. Also the few subjective reactions that are there have been spread sparsely throughout a very very long thread, hard to pick them out in a hurry.

So, it is not early on, what is your impression at this point? And, have you experimented with A) different brand outputs B) power supply variations C) resistor variations??

_-_-bear

[EUVL]

I have not been listening for over a year, so my impressions have not changed.

I have built 4 F5-balanced in total, 2x with Fairchild and 2x with Toshiba MOSFETs. And I do like Toshiba more. But everyone here knows that and I am thus not entirely neutral. Toshibas just sound smoother to me, especially at the HF end. They have the magics of the laterals at HF and yet still have the control of the IRFs at LF. This summer I sold the 2 Fairchild boards, fully tested.

I did not play with power supplies, just CRCRC as I had lying around. Also resistors were as they were shown in the photos -- PRP 0.5Ws / 1Ws in parallel (up to 4x), and MPC74s for source degeneration. I don't think you have much more to gain by changing to Caddocks, etc. But Peter Daniels must be the expert on these.




Patrick

[alazira]

Originally Posted by bear

Patrick,

Thanks I have been reading the F5 thread, but that thread is mostly about the contruction and circuit design. I thought it would be useful to separate out the subjective result from that part. Also the few subjective reactions that are there have been spread sparsely throughout a very very long thread, hard to pick them out in a hurry.

So, it is not early on, what is your impression at this point? And, have you experimented with A) different brand outputs B) power supply variations C) resistor variations??

_-_-bear

Hi bear,

I've built 2 F5's.

F5 1.0 - full circuit on CViller's PCB, tech-diy kit parts, Fairchild mosfets.
(CRC) 300VA antec, panasonic power caps, home depot copper wire, 4.7uF sonicap bypass, custom bridge rectifier w/ 10R-0.1uF snubbers.

F5 2.0's - Fairchild mosfets. Monoblocks with 300VA antec, mundorf HC caps, 16g silver wire, custom bridge no snubbers(yet), no bypass caps (yet). Point to point with similar grade parts as the tech-diy kit. Deleted thermal compensation and protection circuit portions. Also left out R9 and soldered the jFets directly to the female RCA, although do this with caution as leaving out R9 may cause oscillations depending on your source.

Impression:
2.0 has a substantial (as in no way its a placebo effect) improvement in detail and smoothness. Much better separation of instruments. Ambient detail also had a richer quality. I could practically hear the dust coming off the floor with the foot stomping on "Grandmother Song" by Vienna Teng.
Obviously too many changes to determine the value of each.

[TerribleT]

[QUOTE=alazira;1994833]Hi bear,


F5 2.0's - Fairchild mosfets. Monoblocks with 300VA antec, mundorf HC caps, 16g silver wire, custom bridge no snubbers(yet), no bypass caps (yet). Point to point with similar grade parts as the tech-diy kit. Deleted thermal compensation and protection circuit portions. Also left out R9 and soldered the jFets directly to the female RCA, although do this with caution as leaving out R9 may cause oscillations depending on your source.

Alazira,
Thanks for sharing your F5 impressions. If it is not too much bother, could you post some pictures of your build? I'd be interested in your PCB and PS component layout.
Thanks,
David