ARC pre amp-modded with Kimber caps-anybody used these caps before? - Page 4 - diyAudio
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Old 27th October 2002, 09:37 PM   #31
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Location: Belgium
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Hi there,

Quote:
Cheers frank for the imfo,i will deffinately keep the player out of the phono.I usualyy use the tape inputs for cd,hope this is ok?
Must be ok and the CF will nicely isolate the tuner,tape,cd from the ouside world and it can swing 120V PP in case you worry about that.
In laymans terms,it can drive even the most unreal stuff.





Quote:
The caps look like there from RS components,the volume pots are big and clumsy and i was told that they were from a quad pre-amp
On mine the caps were Roedestein MKP1841,most resistors were Roederstein Resistas and the volumepot was from ALPS.

I wouldn't touch the PSU,it's pretty much beefed up as is.
About 100 x that of any other preamp you can find:regulated (valves) B+ for every single tube,left and right channel separately,
500mF storage perchannel and so on,four dedicated transformers,dual moni to extreme....
Why would anyone change that?

Quote:
Would love to know what Glen thinks of the other manufacturers products(arc,mark levinson,counterpoint).
Don't tempt the man.

Cheers,
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Old 27th October 2002, 09:51 PM   #32
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Default Hi Frank,caps away

Thanks frank,Will deffinately start with the caps,sounds like your unit was modded before?Mine looks like its still in its original state the sound is very remarkable but having heard more expensive caps i think that the rs ones are letting it down I tried jeff waynes "the war of the worlds soundtrack"on remasterd sony cd and this was so incredibble i had to go in the garden and get some fresh air,when the alien lid fell off on the common i "felt"instead of "heard"the weight of the metal being moved.Sometimes i wonder if this is possibly one of the best pre-amps ever built.In todays money it must cost a fortune to construct

An unknown legend
Thanks for the imfo on the psu,like you say Frank everything is pretty well taken care of,good point
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Old 27th October 2002, 10:14 PM   #33
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Hi,

Maybe mine is not his run off the mill stuff but I got it directly from Glenn so no previous modding there.

Back in the early nineties I changed the coupling caps for MIT polysterene and foil,the pots for selfmade 1M rotaries,cathode resistors for Holco (I regretted that) and all series resistors with Vishay S102 bulk foils(at 20 UKL a pop),I used leadfree silver solder and replaced all wiring with silver wire.
I perfected the RIAA correction to get 0.08 dB tolerance,upped the cathode decoupling caps (WIMA polyester standard) with some extra MKPs to gve me 10Hz extra bandwith in the bass (you need a well isolated TT for that) and that is about it.

In all honnesty it was about a 10% improvement,just to give you some idea about how good it was standard.

We have a thread on volumecontrols:

Ladder attenuator: Where to solder resistors

The addictive part about this design is IMO dynamics,awesome!
CDs sound compressed in comparison.

Regards,
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Old 27th October 2002, 10:39 PM   #34
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Default Many Thanks Frank

Brilliant imfo Frank,100%usefull.Not to many have shed me any light on this pre-amp since i owned it 5 years ago.

Have printed off all of the mods that you mentioned and was thinking of taking the unit to croft who are now based in IRONBRIDGE.All of the main caps in the output look cheap and nasty so i think any upgrade should take it a step closer to its full potentiol

Was thinking of making the cable lenghts shorter within the top box and less bunched up and taking out the tape facility.
Have you any idea what the valve comliment is on this pre Frank,reason being the valves in my unit do not have very readible text on them and i am curios to which valves to order

The volume control sounds fassinating,will deffinately give this some reading,
I have just took some pics of the pre and will try and scan them inn
Many Thanks,
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Old 27th October 2002, 11:13 PM   #35
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Hi,

Quote:
All of the main caps in the output look cheap and nasty so i think any upgrade should
Maybe I was lucky with the Roederstein caps which I still regard as a fine coupling cap.




Quote:
Have you any idea what the valve comliment is on this pre Frank,reason being the valves in my unit do not have very readible text on them and i am curios to which valves to order
I do,in the regulator you will find per stage a EL86,85A2 and ECC807(the ECC807 is a typical Brimar valve,dual triode with no equivalents,if you can find any and want to spend the money buy them although they should not need replacement.Glenn claims they would last a lifetime,I concur.)
Phonostage 1 x ECC83 per channel (Telefunken's are his favourites,same goes for me,another make that sounds fine is the E83CC from TESLA)
Finally the 12BH7A,I don't think you will hear much difference there,it's a CF)

Hope this helps,
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