Hi Fellow hi fi tweakers.I recently bouht an audio research sp9 pre amp from a second hand magazine.The has had all of the caps replaced with kimber cappacitors and i am not shir if this is an upgrade or a down grade.the sound of the unit is very good but my freind who also owned an sp9 said that the original majick was missing.Anybody ever used kimber caps before,should i get the pre re modded,was thinking of some better rel multicaps etc than the ones that arc originally used.any advice would be very usefull and save me from thinking that i just bought a pig in a poke of a pre amp.
Many Thanks,Ian.
Many Thanks,Ian.Kimber caps
I have used the Kimber and they were quite good. I might put some money in other areas instead of replacing very good caps with expensive different caps. Resoldering the solder joints with 4% siver solder, cleaning the jacks, and resistor and diode updates wound be a be good starting point. Your friends magic statement is suspect as hundreds of variables are involved and deciding the cap change is the whole story is pretty silly. New electrolytics are a good idea if the preamp has a few years on it.
Any SP-9 schematics out there?
I have used the Kimber and they were quite good. I might put some money in other areas instead of replacing very good caps with expensive different caps. Resoldering the solder joints with 4% siver solder, cleaning the jacks, and resistor and diode updates wound be a be good starting point. Your friends magic statement is suspect as hundreds of variables are involved and deciding the cap change is the whole story is pretty silly. New electrolytics are a good idea if the preamp has a few years on it.
Any SP-9 schematics out there?
Resoldering all joints
That's a though one. I like the Allpha metals 4% silver lead free but differences are subtle depending on many factors like surface prep, soldering iron size, ect. There is also more to the solder joint than silver content. I often pretin larger parts with 2% silver with lead and tin solder. The lead really help wetting on older parts with oxidation. In the case of pre soldered joints a would use a solder sucker and retouch the joints with 4% silver lead free solder. With virgin joints I might pretin with 2% silver with lead and follow with the 4% lead free silver solder. Quality of the flux is also very important as well suface prep and technique. This is a learned art and I will not get authoritive on it. Practice, experiment, listen, and learn by doing on this one I am afraid. Lead free solder require higher temperature and is not practical on many things like speaker wire and RCA jacks for any but the well equiped and experienced And I often end useing two irons in these cases. Temp controlled irons and different tip sizes are a must for many soldering jobs with silver solder. I also use a solder pot on occasion. not ihave raised 10 questions for eveyone that I answered......
Fred
That's a though one. I like the Allpha metals 4% silver lead free but differences are subtle depending on many factors like surface prep, soldering iron size, ect. There is also more to the solder joint than silver content. I often pretin larger parts with 2% silver with lead and tin solder. The lead really help wetting on older parts with oxidation. In the case of pre soldered joints a would use a solder sucker and retouch the joints with 4% silver lead free solder. With virgin joints I might pretin with 2% silver with lead and follow with the 4% lead free silver solder. Quality of the flux is also very important as well suface prep and technique. This is a learned art and I will not get authoritive on it. Practice, experiment, listen, and learn by doing on this one I am afraid. Lead free solder require higher temperature and is not practical on many things like speaker wire and RCA jacks for any but the well equiped and experienced And I often end useing two irons in these cases. Temp controlled irons and different tip sizes are a must for many soldering jobs with silver solder. I also use a solder pot on occasion. not ihave raised 10 questions for eveyone that I answered......
Fred
SOLDERING
And that's how it is expected to be.
Soldering is an art all of its own.
People can give tips but eventually it's a thing requiring lots of practice.
Knowing your iron helps too.
Also I always spunge away any residual rosin.
To me the nicest job I have seen was on an AITOS OTL amp by mr
Cabell.
Wrirewrapping + soldering you could hardly detect by the naked eye!
A masterpiece.
He uses leadfree high sliver content solder too,so you must be doing something right Fred.
Regards,
P.S.Lovely lady you have.
And that's how it is expected to be.
Soldering is an art all of its own.
People can give tips but eventually it's a thing requiring lots of practice.
Knowing your iron helps too.
Also I always spunge away any residual rosin.
To me the nicest job I have seen was on an AITOS OTL amp by mr
Cabell.
Wrirewrapping + soldering you could hardly detect by the naked eye!
A masterpiece.
He uses leadfree high sliver content solder too,so you must be doing something right Fred.
Regards,
P.S.Lovely lady you have.
great advice fred,thankyou.
Thankyou for the brilliant advice Fred,very usefull.I will deffinately look at changing the components you mentioned.
Am looking at trying to mod the amp as best as possible seeing that it has already been hacked at.Was thinking of taking out the balance,selector,switches as i hardly ever use them and have read many articles on the advantage of this.Cool imfo regarding the soldering tip,thanks to other people with there questions aswell,glad that there are experinced audiophiles out there who reall know there subject.
Many Thanks,
Ian
Thankyou for the brilliant advice Fred,very usefull.I will deffinately look at changing the components you mentioned.
Am looking at trying to mod the amp as best as possible seeing that it has already been hacked at.Was thinking of taking out the balance,selector,switches as i hardly ever use them and have read many articles on the advantage of this.Cool imfo regarding the soldering tip,thanks to other people with there questions aswell,glad that there are experinced audiophiles out there who reall know there subject.
Many Thanks,
Ian
Fred Dieckmann
I had a blind faith in the expensive different film caps because I was led by
kind of ill info. But, no more.
As regards the soldering, the pretinning of the leads is a good value I have
to employ. O… I use the 4% silver and 96% tin solder. Do not ask me why.
I do not like to blame myself again. By the way, for tin soldering, I use about
350 degC of iron tip temp. In this case, I always wonder how long I could keep
the hot tip on the leads of transistors without giving the transistors damage.
Could you suggest any idea?
JH
I had a blind faith in the expensive different film caps because I was led by
kind of ill info. But, no more.
As regards the soldering, the pretinning of the leads is a good value I have
to employ. O… I use the 4% silver and 96% tin solder. Do not ask me why.
I do not like to blame myself again. By the way, for tin soldering, I use about
350 degC of iron tip temp. In this case, I always wonder how long I could keep
the hot tip on the leads of transistors without giving the transistors damage.
Could you suggest any idea?
JH
Hi Frank
In certain area, the expensive nice film caps might
be necessary.
I use large size of electrolytic caps for power supply,
with the nice bypass film caps and without. I do not
hear any considerable difference in the sound.
I use large enough sizes of input and output electrolytic
coupling caps for my amplifiers, with the nice bypass
film caps and without. I do not sense any considerable
difference in the sound.
For my speakers (and my old tube pre amp), I tried both
expensive and cheap caps, but I could not distinguish
which one is considerably better.
Probably, I am too generous with the sound to make
the honest difference.
My point is whether the result/investment has any value
or not. I am not saying all nice caps are unconditionally
12S34H56I78T90S.
JH
In certain area, the expensive nice film caps might
be necessary.
I use large size of electrolytic caps for power supply,
with the nice bypass film caps and without. I do not
hear any considerable difference in the sound.
I use large enough sizes of input and output electrolytic
coupling caps for my amplifiers, with the nice bypass
film caps and without. I do not sense any considerable
difference in the sound.
For my speakers (and my old tube pre amp), I tried both
expensive and cheap caps, but I could not distinguish
which one is considerably better.
Probably, I am too generous with the sound to make
the honest difference.
My point is whether the result/investment has any value
or not. I am not saying all nice caps are unconditionally
12S34H56I78T90S.
JH
SP9
Hi,
Can't say I'm really familiar with this particular model so I must generalize:
The balance should be easy: just connect input and output together at the pots with a jumperwire and you're done.
But carefully read what I mentioned previously.
Controls?
What are these for?
Input selectors would hardly change the sound if you left them in,so I'ld leave these as is.
Rgds,
Hi,
Can't say I'm really familiar with this particular model so I must generalize:
The balance should be easy: just connect input and output together at the pots with a jumperwire and you're done.
But carefully read what I mentioned previously.
Controls?
What are these for?
Input selectors would hardly change the sound if you left them in,so I'ld leave these as is.
Rgds,
Thanks frank(brilliant)+++++++
Hi Frank,
Thanks for the imformation.
The arc pre amps have some pots that are hardly ever used like balance pot and reverse,mono,left,right,option on the other pot.
I never use them and would be great to get them out the way of the signal,like my other croft valve pre amps from--www.eminent audio
The hack sounds like its not to much work,have you ever done this before on a pre?
Cheers,
Ian.
Hi Frank,
Thanks for the imformation.
The arc pre amps have some pots that are hardly ever used like balance pot and reverse,mono,left,right,option on the other pot.
I never use them and would be great to get them out the way of the signal,like my other croft valve pre amps from--www.eminent audio
The hack sounds like its not to much work,have you ever done this before on a pre?
Cheers,
Ian.
SP9
Croft,
Sure done it before.
Trace the wires from these controls back to the PCB.Unsolder them,get them out of harm's way and you're done.
Ah,ah!
Kinda suspected this when I first saw your acronym.
I used to import Glenn's stuff into the Benelux.
Great sound!
Still use a MegaMicro preamp (naming wasn't his forte,esthetics either) and a pair of 120W OTL monoblocks.
I'll never sell any of this.
Ever met Glenn?Amar Bismar?
Cheers,
Croft,
Sure done it before.
Trace the wires from these controls back to the PCB.Unsolder them,get them out of harm's way and you're done.
Ah,ah!
Kinda suspected this when I first saw your acronym.
I used to import Glenn's stuff into the Benelux.
Great sound!
Still use a MegaMicro preamp (naming wasn't his forte,esthetics either) and a pair of 120W OTL monoblocks.
I'll never sell any of this.
Ever met Glenn?Amar Bismar?
Cheers,
crofts united
Wow,Coincidence frank,i also have the mega micro mate.Is this one "killer pre amp or what"i paid £175 for it from a hi fi shop backroom,it was just lying around doing nout,god favoured me that day.
had some magneplanner speakers and run them through some croft modified leek 20,s(monoblocked).Combo was the closest to reality that i ever got.
Now have decca kelly ribbon horns+decca 12"midd bass(ebay).
Never met amar or croft but know plenty of hi-fi storys,i only live miles from them,amazing.
Am considering having the mega upgraded from rs caps etc,
Would be unstoppable i think.Freind just bought arc sp 10---no competition against megas marvelous midband
superb-------
Wow,Coincidence frank,i also have the mega micro mate.Is this one "killer pre amp or what"i paid £175 for it from a hi fi shop backroom,it was just lying around doing nout,god favoured me that day.
had some magneplanner speakers and run them through some croft modified leek 20,s(monoblocked).Combo was the closest to reality that i ever got.
Now have decca kelly ribbon horns+decca 12"midd bass(ebay).
Never met amar or croft but know plenty of hi-fi storys,i only live miles from them,amazing.
Am considering having the mega upgraded from rs caps etc,
Would be unstoppable i think.Freind just bought arc sp 10---no competition against megas marvelous midband
superb-------
killer croft
Hi Frank,
Freind has a one of a kind croft power amp that glen built for him,it is huge.Some storys from the good old days include;
One day a guy bought one of glens amps back to him for upgrade,this was flung into a bin over the otherside of the room and glen said that his desighns did not need any alteration??
At the hi-fi show in 1980? everybody was busy trying to sell there products,glen had enough of this a took the badge of he was supposed to wear,then had a strole as a punter as he felt more relaxed from the "commercialism"of hi-fi.
Glen once built a pre with so many valves that when it was used in a basement it took the whole mains supply out in the house,after repair one guy(listner)told me it was as iff the band where playing under the houde,even when the musicians knelt down to the audience on the live recording you could tell in the sound.
So underated its amazing,£275 for a valve pre----people must be blind
????????
Hi Frank,
Freind has a one of a kind croft power amp that glen built for him,it is huge.Some storys from the good old days include;
One day a guy bought one of glens amps back to him for upgrade,this was flung into a bin over the otherside of the room and glen said that his desighns did not need any alteration??
At the hi-fi show in 1980? everybody was busy trying to sell there products,glen had enough of this a took the badge of he was supposed to wear,then had a strole as a punter as he felt more relaxed from the "commercialism"of hi-fi.
Glen once built a pre with so many valves that when it was used in a basement it took the whole mains supply out in the house,after repair one guy(listner)told me it was as iff the band where playing under the houde,even when the musicians knelt down to the audience on the live recording you could tell in the sound.
So underated its amazing,£275 for a valve pre----people must be blind
????????
WOW INDEED
Hi once again,
If your Mega Micro has a separate (two box affair) PSU and is just a phono stage with 1 ECC83 and 12BH7A per channel we got the same thing.
Every stage had a dedicated valve regulated HT supply.
175 UK pounds you say??
Phew,I think they were sold for at least 10 x that!
If Glenn's still at the same addres you should find him in Erdington.
It's been years.
I also am good friends with Tom Fletcher from Nothingham Analogue.
I can give you countless tips on that,indeed.
You can always e-mail me in private if you whis to do so.
Cheers,
Hi once again,
If your Mega Micro has a separate (two box affair) PSU and is just a phono stage with 1 ECC83 and 12BH7A per channel we got the same thing.
Every stage had a dedicated valve regulated HT supply.
175 UK pounds you say??
Phew,I think they were sold for at least 10 x that!
If Glenn's still at the same addres you should find him in Erdington.
It's been years.
I also am good friends with Tom Fletcher from Nothingham Analogue.
I can give you countless tips on that,indeed.
You can always e-mail me in private if you whis to do so.
Cheers,
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