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85.19.92.6
Hi, i have an old Electrocompaniet 4.5 preamp
I do not know its actual age ... maybe 15 years ?
A friend of mine insists that a recapping with good parts would be extremely beneficial.
Then he also suggest replacing PS diodes with better parts (i.e. Schottky types)
I am thinking about it.
What is your advice ? which parts you would address ?
It is a line only preamp.
Thanks a lot.P.S. the picture is not mine ... but very similar of course.
Kind regards,
bg
Edits: 07/15/14Follow Ups:
Great pic!
keep us posted on this project. The Electrocompaniet gear is onmy short-list to demo.
Hi and i am sorry and surely i can do better
Better picture at the end of the work
But this is going to take some time
I have decided to wait a new desoldering pump i have ordered
I want to do an as clean as possible work
Unfortunately no schematics available
I see one little cap missing also
I will report with the new caps in place
Only i do not understand why there is a different lay-out for the two channels, small differences but still i wonder why
too trivial maybe.
Thanks again.
Kind regards,
bg
Edits: 07/19/14 07/19/14 07/19/14
I definitely would do the electrolytics. Consider same value Mundorf filter caps or Nichicon gold.
Hi and thanks for the helpful advice
About the "Nichicon gold" do you have direct experience or articles ?
I like them very much ... at least visually.
Are they better than Panasonic FC, the other candidates ?
This weekend i will order ... i have just to measure sizes because space is unbelievably tight.
the more i look to the internals the more i see a Silas' attitude
With all this space available ... why parts must be placed so close ???
Anyway ... thanks a lot indeed
Kind regards,
bg
I have used the golds in a number of power supply applications. I recently re-capped a amp with the Mundorf filter caps and they are a nice step up. Like you pointed out, space is the biggest obstacle. Most of the boutique caps are bigger. I suspect you will note a good improvement by just replacing them with any decent cap.
Hello and thank you very much indeed again for the valuable reply
I am attaching a bad photo of the unit
A better one will follow
But ... i am experiencing big problems in the desoldering
I am disappointed with the desolderind device i bought on ebay
The traces are very very thin and delicate on the pcb as they are the terminals on the pcb .. the risk of damaging them is high.
I would not start another complain versus audiophile equipment.
But working on them i get the feeling that they are designed and built more to please the eye
The pro equipment can sustain abuse .. and i think almost always they can be more or less easily repaired ... like a normal car.
Instead the build quality of most of audiophile units is flimsy
To end the ramblings, what do you use for desoldering ?
I think that this action is even more delicate than the actual soldering
I will then desolder all caps, measure them and buy new caps compatible for size
Thanks a lot again
Kind regards,
bg
I know what you mean. It seems to me the machine assembled boards have a higher heat type solder? I have ruined my share of traces. I use a variable temperature Iron. I have several different width tips. I use both solder wick and a solder sucker. The bigger components can be moved back and forth while heating the solder. That helps break them loose after removing most of the surface solder. All I can say is good luck.
" I know what you mean. It seems to me the machine assembled boards have a higher heat type solder? I have ruined my share of traces.
I use a variable temperature Iron. I have several different width tips. I use both solder wick and a solder sucker. The bigger components can be moved back and forth while heating the solder. That helps break them loose after removing most of the surface solder. All I can say is good luck."Hi and thanks a lot again for the kind advice
Sorry if i am petulant but my life has changed ( ehm ... ) really after discovering the eutectic alloy with 2%Ag (i think it is called like this)
This is an extremely easy to solder alloy, even if a little expensive
In comparison the common 60/40 is already a pain at least for meI do not know which kind of alloy they have used for this preamp but i am afraid you are right
For sure it is not flowing like my first choice alloy.
You can solder and desolder it many times and it is always a joy.
I have even the feeling that just add a little of that on old joints can improve them ... it is like a "panacea"
The quality of joints i think it is also important for sound.But this time i am really serious about desoldering
And i also will try braid with a powerful iron
I am very intrigued by restoring old units
I have no enough skills to start from scratch but i have a friend who usually finds in 2nd hand markets old quality pieces, with a really great potential
There are some units from the late '70s (i.e. around 35 years old) of which the service manual is available and that i am sure after a revamping can sound fine.I have mixed feeling with this Electro here
I very much like better simpler circuits ... and this is not simple at all there are dozens of transistors
Let's say that is a try
Maybe new caps can lower the noise and impedance in power supply lines
I have also bought 100 UF5408 fast diodes
There are 12 1N4007 that can be replaced
I am curious and more than everything it will be an experience
I am also thinking to bypass completely the balance
I hate any form of tone/balance control
I am sure they introduce distortion and lower channels separation (the balance at least)I am attaching a very interesting page i found on Cardas solder, from what i understand a really good one
Thanks a lot again.
Kind regards,
bg
Edits: 07/20/14
EC was an excellent active pre, and it sounds great even for today's standard. It has a silky velvet sound and I enjoy mine a lot. For sure it does not belongs to minimalist design. If anybody wants its schematic I can provide it but only beginning August when back from trips. It's a musical pre like fews, IMHO.
Beppe,
please whrite a few words after changing the couppling caps.
Peter
Hi and thanks for the question
Let's say that i am extremely gullible from what i read
But some words make me sense like:
1) cilindrical caps are better than squared ones (like the original for instance)
2) brands that are able to make very top quality parts have the know how that they tend to apply also on entry level parts (they have a reputation to defend)
So in the end i decided to go with entry level MKP from MundorfThe sound ... nice i think. There is detail ... not particular distortion ... voices are nice.
But i am expecting much bigger improvements from the work on power supply.
I am sure that the quality of the power supply can make a bigger difference
I am a little stuck now because the soldering pump i bought it is not for me ... i do not like they way it works
I have ordered another one ... electrical
The diodes leads are very tiny ... and are a lot
I would have bought nice big diodes ... of the Schottky kind
But diodes are spaced so close that i do not really understand how they design the lay out
Sometime i am mesmerized by the quality of some pcbs for DIY projects compared to also not cheap audiophile units
This is for me a joke ... it should never happened
But i understand that many Companies are ruled by the marketing demons !
The products must please the eyes most than every other thing.To end the rambling the complete work will take me a while
I need to receive first the new desoldering tool and a better grade of solder (i love the alloy 2% Ag - 62% Sn - 36%Pb that i have ordered as well)
Then any decent soldering tool will be fine. This alloy is fantastic.
I have a very very heavy hand .., and still the joints are very good indeed. And i believe that the quality of joints can also influenced the result.I will report again at the end of the work.
Thanks a lot indeed for your kind advice ... and question.
I am a little excited. No one has ever asked my opinion.
Well ... my former boss did.
He used to give me his reports to read and then to ask if i understood them, saying that if i were able to understand them every body else would have also understood them.
Kind regards,
bg
Edits: 07/19/14 07/19/14 07/19/14
The owner of Sonic Craft likely knows about the "best" diodes. Tweaker
Hi and thanks for the suggestion.
Speaking of preamps i have some ideasFor instance i think that if i have to build a preamp i would take out the mains transformer from the preamp chassis.
I would leave inside only the diodes bridges and i would use a huge amount of capacitance after the diodes.
Like the preamp can go on singing for a minute or so after disconnecting it from the mains.
Then i do not like very much toroidal ... i prefer EI transformers even if the circuit is not digital but analog.
But without a clear schematic is difficult.The current diodes i understand are of the lowest grade
Almost anything would be better.And those cheap caps ... so close one to another ...
I would have double the uF immediately but there is no space
What a pity.
More uFs improve everything ... they decrease noise and impedance and creates a bigger energy reservoir.
I would have put them closer to the amp circuit ... like i have seen in some amps to reduce the distance between the caps and the active devicesI still think that batteries is the way to go anyway for a PS for preamp.
And the all circuit looks to me a little complex for just a line preamp.
I have had a line preamp with just one mosfet ...
So maybe something in between would be the optimum ?Thanks again.
Kind regards,
bg
Edits: 07/16/14
The guys from Romania or Bulgaria ship to Norway ...
For the Kemet there is a supplier in Sveden.
Below is a link to a guy who did some experimenting with electrolytic caps in the power supply. I don't take it as the ultimate truth, but at least it gives you an idea of what each cap might sound like. He seems to really like the Elna Silmic caps, and so does Nelson Pass.
As for the diodes, Schottkys can make a nice improvement. If you can't locate a schematic, see if you can get the number on the diodes which are already in there. Their PIV voltage and current rating can then be used to choose the Schottky equivalents.
I agree with fmak that you should start with the electrolytics. Not necessarily because they'll give you the most improvement, but simply because of their age. But I do agree that the power supply is almost always the place to start for a quiet circuit. Speaking of which...
Another thing to consider is the voltage regulator(s) in the power supply. If it's built using generic regulators, consider changing them to something better. I have had great luck with the Belleson SuperPower regulator. It made a significant improvement [link to my Vinyl Asylum post] to my Graham Slee phono stage, and I was running that off batteries!
Then there's the Wima caps. Those could be changed out, but personally I happen to like the sound of the Wimas, especially when bypassed with a polystyrene cap.
It's difficult to tell from the picture, but it looks like there may be two op-amps behind the two Wima caps toward the center, close to the input / output jacks. Little eight legged spiders. If so, get the number off those and search the Asylum (and elsewhere) for upgrades. Just be aware that your power supply has to be able to supply the new op-amps with the voltage, current and noise free DC they may require.
Are these upgrades worthwhile? I've never heard an Electrocompaniet 4.5, so I'd say that's for you to decide.
Good luck with it.
Hi and thanks a lot for the kind and valuable reply.
I will try to reply between the lines ..." Below is a link to a guy who did some experimenting with electrolytic caps in the power supply. I don't take it as the ultimate truth, but at least it gives you an idea of what each cap might sound like.
He seems to really like the Elna Silmic caps, and so does Nelson Pass. "Thanks a lot for the very interesting link. Silmic seem really a notch above the others.
I see them on ebay. First thing i will list values and sizes of the ones to be replaced.
I guess Silmic could be a little bigger. Also Panasonic FC series seems a good 2nd choice." As for the diodes, Schottkys can make a nice improvement. If you can't locate a schematic, see if you can get the number on the diodes which are already in there. Their PIV voltage and current rating can then be used to choose the Schottky equivalents. "
The diodes seem all IN4007. Is there a Schottky equivalents ? or a better part in general ?
Unfortunately no schematic available.
I think that Electrocompaniet are quite secret on their units.
I must list every parts not to make orrendous mistake during the replacement." I agree with fmak that you should start with the electrolytics. Not necessarily because they'll give you the most improvement, but simply because of their age. But I do agree that the power supply is almost always the place to start for a quiet circuit. "
Unfortunately i cannot place precisely in time this unit ... maybe in the late 90s ?
So i think the caps have about 15 years.
Good new caps should lower maybe the noise a little more ?
" Speaking of which... Another thing to consider is the voltage regulator(s) in the power supply.
If it's built using generic regulators, consider changing them to something better.
I have had great luck with the Belleson SuperPower regulator. It made a significant improvement [link to my Vinyl Asylum post] to my Graham Slee phono stage, and I was running that off batteries! "I am sure that the PS quality is decisive. I do not see LM317 or similar.
Without schema i think i have no hope to understand the various parts function.
I will stick with caps i think." Then there's the Wima caps. Those could be changed out, but personally I happen to like the sound of the Wimas, especially when bypassed with a polystyrene cap. "
I have already bought some Mundorf Mcap ... they should be better.
I read an article against squared caps ... cylindrical are recommended. I do not know if this is true or what.
Mundorf is a good brand i think. Mine are the entry level PP.
" It's difficult to tell from the picture, but it looks like there may be two op-amps behind the two Wima caps toward the center, close to the input / output jacks. Little eight legged spiders. If so, get the number off those and search the Asylum (and elsewhere) for upgrades. Just be aware that your power supply has to be able to supply the new op-amps with the voltage, current and noise free DC they may require "I think this is more tricky. I think that at least for now i will stick with caps.
I have to practice also with the tools. If the outcome will be decent i could try other mods." Are these upgrades worthwhile? I've never heard an Electrocompaniet 4.5, so I'd say that's for you to decide.
Good luck with it. "I listend to it and the sound was nice but not completely clean and a little soft in the bass.
I do not think it will change a lot with the new caps.
Unfortunately without a schematic the risk to damage the unit is high, especially for me.
Anyway i will let you know about the outcome.
It will take me some weeks because i have ordered solder wire and i still have to order caps
But i will do it for sure ... i am curiousThanks a lot again
Kind regards,
bg
Edits: 07/15/14 07/15/14
I would be very surprised if the power supply wasn't regulated. Even without a schematic, a circuit can often be sorted out by following the traces on the circuit board. Quite often they're laid out like this:Power transformer> diodes to rectify AC to DC> capacitors (usually banks of eletrolytics) to smooth DC > regulator(s) to control voltage etc. . Follow the traces after the 1N4007s and caps and I'd bet you find one or two regulators.
The 1N4007 (1000v PIV @ 1A) are pretty bad. "Bat Guano", Eli Duttman calls them. At the very least, replace them with UF4007. Even better would be the Cree 1200 PIV @ 2A. Link below.
As for the caps, I've had good luck with Panasonic FC, and the even lower ESR FM. I also like the Nichicon KW electrolytics.
Good luck.
Edits: 07/15/14
Hi and thanks a lot again !
i will do both caps and diodes especially now that you confirm me that is a valuable mod.
as the original 1N4007 are very close one to the other and the distance between the holes in the pcb is very small i think i will buy the uf4007.
Unfortunately also the caps are very closed placed ... i would have doubled the capacity ... that is never enough in my experience.
Next time i will look inside before buying something
I so much prefer less components and better spaced
Why they must put all things so close one to the other i really do not understand
Thanks a lot again
Kind regards,
bg
I'd recap the electrolytics first. Get low esr ones.
Hi and thanks a lot for the kind and valuable reply.
Do you have any specific suggestion of brand/series ?
I read that many brands in ebay are low quality
So i was looking at Rubycon, Panasonic or Nippon Chemicon, 105C series
But i do not know the specific best series ...
Then i see a lot of diodes and read that the Schottky type are better
So i was thinking also to replace diodes.
Unfortunately i could not get the service manual
I have already some red Mundorf to place at the output
Honestly i liked it better closed than open
I am a believer of minimalism ... when i saw these endless rows of transistors i almost fainted.
Why in the world so many transistors are needed to give a very little voltage gain and some buffering effect to an already high level signal ?
But i like it because it is balanced and remote controlled.
Thanks again.
Kind regards,
bg
Edits: 07/15/14
There are no Wimas.
The 4 Coupling-Caps are ERO MKC and there is no need for a change.
Peter
Hi and thanks
To be precise in my unit they have been already replaced with some black Audyn Cap i think MKP, really too big.
I have instead bought four of these in the picture that i intend to use
They are the Mundorf entry level.
Problem is that both Audyn and Mundorf are much larger than the original
Do you mean that the ERO MKC are perfectly ok ?
I could try to find some like the originalBut the really sad thing is that PS caps are closely mounted (why they do this with all the space available is a mystery to me).
I would have double their uF very happily.
And i am sure that this could be beneficial, maybe even more than signal coupling caps replacement.
More energy available, lower impedance, less noise, higher quality caps ... every parameter would be better.
I should find a way to do this, maybe leaving some length in the terminals
Kind regards,
bg
Edits: 07/16/14
"Do you mean that the ERO MKC are perfectly ok ?"
In my opinion they are neutral and I prefer them to MKP which often 'sound' like plastic.
If you want them a little warmer, shunt little Styroflex Caps like 1nF.
For me, the entry level Mundorf MKP is no good cap.
Peter
" In my opinion they are neutral "
Hi Peter and thanks again
Now that you mention them i have seen them also in a bryston preamp
The original ones are lost unfortunately
But looking on ebay i see squared and cilindrical ones
Are equally ok ?" and I prefer them to MKP which often 'sound' like plastic.
If you want them a little warmer, shunt little Styroflex Caps like 1nF.
For me, the entry level Mundorf MKP is no good cap.
Peter "arrgh ... i was sure of the selection ... even if they are entry level
I will take out the present ones and measure the distance between the pins
on the pcb
Are also the cilindrical ok ?
Thanks a lot.
Kind regards,
bg
Edits: 07/16/14
The axial/cylindrical ones are ok.
You could also try Kemet (Rifa/Evox) SMR or Siemens MKL, my prefered caps in low voltage applications. Look @ ebay (.de)
Peter
Hi and thanks again
I will go hunting for them. They are less common i see
I have found one vendor but i have to check if he ships to Norway where i am
Thanks a lot again.
Kind regards,
bg
The Bulgarian or Romania guys will ship to Norway.
For Kemet there is a supplier in Sveden.
Hi and thanks again.
I will try them. Siemens caps are quite famous.
I remember the mythical Sikorels ... now Epcos i think.
Kind regards,
bg
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