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Any thoughts or advice on the following will be appreciated.I have a good LP front end with m/c into a Sonic Frontiers phono stage -
early non Signature version. Amp is Assemblage L-1 / ST-40 pre-power,
speakers are decent small transmission lines.The sound is very good, and LP is significantly better than CD.
However, I have two small concerns:
. female vocals seem to lack a bit of body and have a slight edge
. piano can sound a touch jangly, almost a slight clatter to the sound.The problems are slight but I'd like to fix them - esp if I get an overall
upgrade at the same time.
I don't have the problems via CD, and didn't have them with the old Naim
amps, so I think it's in the phono stage.I've changed tubes to Mullards and Tungsram which helped.
I propose to upgrade the capacitors. I hope to get most of the benefits
of the 'signature' upgrade by this - very little else gets changed
fundamentally by the signature upgrade.The caps in question are :
2 of 2uF
4 of .22uF
2 of .1 uF
all Multicap PPMFX metalised polypropylene.My quandary is whether to go for:
. Multicap PPFX polypropylene and alum. foil, as used in the
SFP-1 'Signature'
. the nominally better Multicap PPFX-S or RTX (polystyrene) ones;
but if they are better, why don't SF use them in the Signature?
. VTV Silver foil PIO ... which I've seen highly recommended, but
have to regard it as an expensive risk!If the VTV's are likely to give me what I really want, the money's not
a problem; but I'm reluctant to risk it on a wild goose chase if I can
get great results without risk with say the PPFX-S.I stress that I don't want a massive change to the sound - it's superb
for all types of music, and even the problematic things are very good
really!Any thoughts are welcomed.
The greatest upgrade you can make is to change the cheap diodes to hexfreds in the power supply. I have the SFP-1sig and am using Telefunken 12AT7's and SIEMEN's 6922 LN for phono. The Tungsram are no comparison. Too tizzy.No magic in the midrange. The diodes are IN5404 and are rated 400v/3amp. There are 4. They can be upgraded to IXYZ DSE1806-ND from Digikey or the IR version. I also believe ther are 4 others that are IN4006 or IN4007. They can be replaced also.The difference you will hear is a blacker background, more accurate and open highs , and the soundstage and depth will totally open up.The bass is better also.These changes are easy to do, just respect the polarity of the diodes. The silver band is the cathode side and will correspond to the left leg of the hexfred.Changing the caps may not work if there is not enough room. The better MIT 's are larger but if you change them, do the 2mF first. Be careful with soldering because the traces burn up easily.Also mass load the enclosure for isolation.Big difference .Let me know how it goes.I don't know what wiring is in yours but change it to silver solid core .I'm experimenting with 22 ga,26ga, and 32ga.Mike
Thanks Mike for so much great info.
I've decided to keep the SFP-1 and upgrade it - I like it, and at the
weekend it was really sounding good with little sign of the (minor)
problems.I think I'll do the following things:
(a) Power Supply
HEXFREDs
75uF Solen for B+ (as Signature model)
(b) Multicaps
Upgrade 2uF, .22uF and .1uF caps (in signal path I guess)
to PPFX-S polypropylene/tin
(c) Tubes
Siemens 6922's (but keep the Mullard CV4024/ECC81 for 12AT7)
(d) Resistors
See if I can identify those in the RIAA eq stage and replace
them with Caddocks.
(e) Damping
I'll use some special feet, damping panels, and mass loadingRationale:
(a) as an (almost ex!) Naim owner, I know the value of the PSU;
thanks Mike for the details of hexfreds
(b) I don't think I want a massive culture change so I guess I'll stay
with the same 'family' that SF use, rather than the VTV's.
But I think I'll go for PPFX-S as apparently a shade better than
the PPFX used in the Signature
(c) I'll end up rolling a few I think anyway ... I don't mind having
some spare sets of decent workable tubes as backup
(d) I don't expect resistors to make mauch difference; OTOH, the difference
I expect is the right kind of difference so it's worth a few dollars.
(e) Special feet and chassis damping are used in 'upgrade' versions of
Assemblage products and 'Signature' SF products.
So I've pretty much decided what to do ... thanks Mike.BTW, feel free to pull the above plan to pieces - I'd rather know now
than later if I've got it wrong.
I'm feeling pretty confident about it all though.I'll have a go and report back in due course.
Regards
Mike
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