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Get thee an elna silmic....

C

ced

Guest
into your preamp feedback loop IMMEDIATELY.
Ok, been doing the preamp capacitor tryout over the last few weeks. The outstanding winner so far is replacing the red roederstein 47uf cap in the feedback loop on the main gain boards (of my 32.5 but would bet this is a winner on any naim preamp) with a 47uf 35V elna silmic from audiocominternational.com. Price is a couple of quid each + £2.90 delivery, delivery within 2 days so service seems good. We are only 2 hours into burn in and already hairs are standing up on the back of my neck etc etc etc. This may be premature but to sum it up in a word, exquisite. This is a seriously good mod, which builds excellently on all naim attributes and adds more. More detail but without brightness, greatly widened and deepened soundstage (that wall of sound just gets bigger) while increasing the ease in following instrumental lines and seriously increased involvement.
To put this into context 56uf, 25V oscon sps (from farnell) on the power rails are also unreservedly excellent and increase the prt and 'groove' or 'boogie' factor but don't open out or make the music more accessible. The silmics really draw you in. So far am not a fan of black gate Ns. Been playing with these for a while replacing the 10uf coupling tants in various combinations and while I understand their seduction; they have a very beguiling 'sound' and sophisication to them, I find them uninvolving musically. Instumental strands get mushed together so it becomes difficult to follow the music and everything gets squashed between the speakers. I also have doubts about their bass & dynamics nevermind the minimum of 2-2.5 weeks burn in time. Saying that they might work well as a feedback cap but I suspect from trying a couple of elna 10ufs for coupling that elnas will give you 80% of the black gates sophistication but 300% more musicality (and they're cheaper). As further context so far, BC128s and SMRs have also been tried for coupling caps. Both are extremely musical and involving though find the BC128s are just too bright and a bit of a turn off ultimately IMO. Will shortly give the SMRs a proper try vs elna silmics as coupling caps and post a more informed review. So far oscons and silmics are unreserved winners for the 47uf power rail and feedback caps though. Thanks to Andy Weekes and Les W for posting the leads to these components as ever.
cheers
Ced
 
Hi Ced,
I've been reading the Neil mcbride preamp tweaking pages Link and on the "Miscellaneous mods" section, paragraph 4 he recommends bypassing the caps with a polypropylene cap. Have you tried this?

Also do you know what "value?" volume pot i should use in my Naim 62? 10k or 20k?
 
:)

Silmic's are great being just about the best electrolytic cap around (in terms of linearity and sound) nice that you can get them through Audiocom now.

BTW, they're an interesting insight into the economics of part supply to DIY'ers - the Silmics are really cheap to buy, even large, high voltage values are only pennies each, but you have to buy a 1000 or so minimum.

That's an awful lot of stock messing up your cashflow, hence the prices charged once handling and overheads are factored in.

That 47u is a real pain, any electrolytic here is a huge compromise in terms of linearity.

Fortunately the ones in my preamp are free samples, but I've seriously considered buying a batch of them!

SMR's (if you're talking PPS caps) are excellent, and will p**s over any electrolytic, of any type, on any day, almost anywhere.

They will reveal a lot more though and may show up problems elsewhere, but persevere with those problems and you will be rewarded ;)

You should be able to use 3.3u's everywhere in the signal path except before the volume pot, the impedance is too low here and you will get unnaceptable LF rolloff.

Also good and sensibly priced are the Vishay MKT1826 (IIRC) polyester caps.

The SMR are better, but the MKT's are a 5mm lead spacing and will drop in.

Andy.
 
Fat Mat - re volume pot - I think 47K log. Did you see LesW's recommendation of the cheapo pot (<£2) from CPC recently? I have a spare if you're interested - not tried it in my 32.5 yet, but am hoping to do so this weekend.

R
 
the Silmics are really cheap to buy, even large, high voltage values are only pennies each, but you have to buy a 1000 or so minimum
Click to expand...
OK, I'll bite. So the 47uF is probably the most ubiquitous of the values for us Naim tweakers, and anyone with a Naim pre is likely to have at least 10 of the 47uF caps in their amp, are we in a group buy situation here? How many pennies are we talking here Andy? If something like this sounds vaguely feasible, I'll volunteer to organise it.

EDIT

Just found a supplier of Silmics who is a little cheaper than Audiocom. 47uf 50V Silmics, 1.50 Euro (£1.04 or so). From Audiokit in Italy - you'll have to navigate the frameset to find them, but they're there.

Looks like shipping will be under £3.00, but if a few of you chaps want some, I'll order a load in and distribute from here.
 
Richard,

I did see Les's recommendation of the cheapo pot, I was trying to find it on CPC's site last night but got sidetracked and gave up in the end. Thank you very much for the offer that's very kind of you but i want to fit a stepped attenuator if it's possible/ would sound better.

I would be interested in the group buy!
Do you think the 50v silmics would sound ok compared to the 35v ones?
I read somewhere that increasing the values can slow down the sound! or is that just the (uf) rating?

I'm not sure how many i would need for my 62 because i hav'nt received it yet (still in the post), first thing will be to strip the phono boards

I was also going to order some transistors (BC550's) and some BC solid aluminium caps (10uf,25v) from Farnell + some (2sb737) transistors from the Signal transfer company.

Does this sound like a good plan? and what about these (SMR PPS caps) that Andrew just mentioned, where can you buy these from?
 
I just received the 62. The Alps volume pot says 20kx2, Does this mean i would need a 40k pot?

There are only two of the red plastic-canned roderstein 47uf's in the pre amp but there are five 47/40v big gold one's in it, should these be replaced? if so with what?
 
The pot is 20k,the X2 bit is because it dual gang for stereo.I have some new Sfernice P11 cermet pot's 22K Log which would sound loads better than the stock Pot.PM me if interested.

Paul.
 
Thank's for the offer Paul. I have a spare 10k panasonic pot that i can swap for the 20k DACT in my Onix, i will fit the DACT in my 62. :)
 
Didn't realise you still had the DACT pot.This would be better than the Sfernice,as it won't wear like these pots do,and should offer a slight performance gain;)

Paul.
 
Originally posted by RichardH
OK, I'll bite. So the 47uF is probably the most ubiquitous of the values for us Naim tweakers, and anyone with a Naim pre is likely to have at least 10 of the 47uF caps in their amp, are we in a group buy situation here? How many pennies are we talking here Andy? If something like this sounds vaguely feasible, I'll volunteer to organise it.

EDIT

Just found a supplier of Silmics who is a little cheaper than Audiocom. 47uf 50V Silmics, 1.50 Euro (£1.04 or so). From Audiokit in Italy - you'll have to navigate the frameset to find them, but they're there.

Looks like shipping will be under £3.00, but if a few of you chaps want some, I'll order a load in and distribute from here.
Click to expand...



Hi Richard,

Count me in if you need to make up the numbers - Ill take 15.

Cheers
Mike
;)
 
Originally posted by RichardH
OK, I'll bite. So the 47uF is probably the most ubiquitous of the values for us Naim tweakers, and anyone with a Naim pre is likely to have at least 10 of the 47uF caps in their amp, are we in a group buy situation here? How many pennies are we talking here Andy? If something like this sounds vaguely feasible, I'll volunteer to organise it.

EDIT

Just found a supplier of Silmics who is a little cheaper than Audiocom. 47uf 50V Silmics, 1.50 Euro (£1.04 or so). From Audiokit in Italy - you'll have to navigate the frameset to find them, but they're there.

Looks like shipping will be under £3.00, but if a few of you chaps want some, I'll order a load in and distribute from here.
Click to expand...

Richard,

If the offer it still open you can count me in for 20 please.

Thank you very much.
 
Richard,

Those prices are pretty good for a re-seller, are they Silmic, or Silmic II - the latter is a newer, even better version (it's what I use).

For prices, I've dug out one of the quotes I had, for three Elna Audio grade caps, all 47u, 50V: -

ROS-50V470M (Elna Silmic) 0.1975 ea., MOQ 1000 making them a gnats over 23 pence ea. with VAT

ROA-50V470M (Elna Cerafine) 0.2339 ea, MOQ 1000 making them just over 27p ea. with VAT

RFS-50V470MH4 (Elna Silmic II) 0.3429 ea., MOQ 1000 making them just over 40p ea. with VAT

The 50V parts have an advantage in terms of loss / leakage, but it's not critical.

Starts to add up when you look at the total spend between Slimic I and II, almost another £200.

So how many can we sell - maybe we could filter off the ones we want and Tony L can re-sell them to make some money for his PFM fund.

It's easy to see how a range of values starts to hit the cashflow, and since the best place for these caps is probably the gain stage rolloff (I've not tried them on the PSU rails) there may not be so much demand. May be worth comparing them to my normal preference for the SP series Oscon's here?

i'd also be very interested in a signal path check too, I doubt though that even Silmics would come close to Films.

Andy.
 
Just checking my records I have an even cheaper quote for the Silmic II's, from another dsitributor, at 27p ea. + VAT (£317.25 / 1000).

If enough people were genuinely interested a group buy would be a viable option.

For example, just 10 people could get 100 caps for just over £30 + any overhead (carriage etc.).

Delivery for these is 10-14 weeks, based on the quotes, which are 5 months old.

From Audiocom you'd only get 10 for the same money!

Andy.
 
Pondering the above a little further, the 47u is only that value because of the impedances within the gain stage.

I wonder if a more elegant approach could be to raise the impedances around here (which means re-designing this circuit element which may even call for different semiconductors) to eliminate the necessity for such a large electrolytic.

It's a big change though, the largest, sensibly sized film I can get is 4.7u, with a personal preference for the 3.3u films - this means raising Z by 47 / 3.3 = 14 time approx.

That's worthy of some thought, I reckon, but would take some work and listening to accomplish.

Andy.
 
BTW, when you try the SMR caps, try them at the inputs of each stage first - the ones at the output run into lower impedance inputs (vol pot or power amp) and will roll-off bass a little.

Andy.
 
since the best place for these caps is probably the gain stage rolloff
Click to expand...
Presumeably they would work equally well in this position in the phono stage then?

You're right re the economics of holding a range of cap values.

Well, maybe we ought to kick this around a bit longer to see if these caps are worth having, and where in the circuit. Then I'll post a thread will a poll to see how many poeple are interested. I have a web page set up already for this sort of group buy (I did a cable group buy a while ago), so I'd be happy to manage it.

Andy - those Italian supplied caps were Simic 1 I think - no mention of the II, so they must be.

Mat - re higher voltage caps - I have read somewhere that higher voltage caps of the same uF value can sound better. No presonal experience, though.
 
I agree, worth collecting some more listening results first. I'm really interested in trying 10u's for the output cap of each stage (films are best for the i/p).

I've a pair of phono boards to mod here, I was also going to try the 47u there too, it should work well.

Andy.
 
Fat mat - SMR PPS caps - are available from Farnell - the 3.3uF Andy mentioned is 389-1082 - nearly £3 each though, and might be a bit of a beast to fit into the board...

Andy - 10u caps for the output stage - you mean to replace the present tant 10uF caps that sit in the signal path? I'm using 10uF Oscon SP on both in and out at the moment on the phono boards.
 
Interesting stuff, Richard.

I never liked the SG series Oscons in the signal path, but haven't tried the SP's because of that.

A film cap will almost definitely be better at the input though.

Andy.
 
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