Saturday, August 2, 2008

Likely World Quietest Vendetta Research Pre-Pre amplifier SCP1 Hand Made by John Curl



















This may be the Quietest Pre-preamplifer in the World!
Look at the deisgn in details:
  • An indenpendent power supply
  • There is no power switch
  • There is a Trim pot whereby we can adjust the input capacitance to match with the output impedance of the Cartridge!
  • Gold plated PCB which is still Bling bling shinning after so many years.
  • Consideration of RF interference and to keep hi frequency response by trimming some of the resistance.
  • The Expensive dual coupled FET pair X4 on the main board, that component was selling at about USD$20,00 a piece in 1983!
The power supply has a soldered cable of approx. 6 feet in length connecting to the amplifier.
There is no Power indicator nor even an LED pilot lamp, that is why John believes all these are not necessary as they may introduce noises!
I have changed the yellow REL-CAP x4 into Jensen Silver foil and silver leaded capaicitor 0.1 MFD600V. I spent HKD$5,700.00.
I found that the treble is more transparent and the bass is  tighter as comparing with the original Rel-cap. Picture shown here is the original designed Circuit board hand made by John Curl.
HK Snob

13 comments:

YCLee said...

I own a set of the SCP-1 pre-preamp too. It is just damn quiet. And I like it to match with tube phonos. I possibly will change the rectifiers to some soft recovery ones later. The change of the older caps to Panasonic Gold have bring the aged performance back to its top level.

YCLee said...

By the way, I also own a SCP2A too. Just excellent!

fever said...

Hi YC Lee,
Well, I am glad that you have this piece of GEM, and more...SCP2A!!
Are you from HK or Singapore?
How come you can find my stuff in my blog? from Google search?

I am jealous that you have SCP2A, as I am looking for SCP2 for years and months!

Well, I know John Curl, and He taught me on how to modify the Board. as a Summary:
1. Change biggest Power supply Smoothing cap. to 10,000 MFD or more.
2. Change to fast recovery rectifiers at the power supply.

3. He reminded me not to touch the 0.1 MFD400 Cap X4 as is is the magic.

4. He advised to use newer Op amp of finest grade.

I did changed the 0.1 MFD with Jansen Silver Cap, damn expensive HKD1,380 a pieces after I got the advised from him. Of course, I keep those four Rel Cap.

I used good smoothing cap added two more in parallel with the original, due to space concern, I can not use a real big cap in it.

I added an UEC adaptor and added a better power cable.

Other caps such as the decoupling cap. show be used bigger to 470 MFD. but I did not change it as it is a big operation to the board and I do not want to do too much on it.

Now My SCP1 sounds perfect... not just quiet, all the low is there, and treber is having the kind of timbre of real music. Overall is musical, only the one who has one can tell how good it can be.

John is building Blow Torch with similar circuitry but I wonder he should not able to get commercially the bi-FET transistor anymore, So he might have to use epoxy to bond two identical FETs together as a substitute.
That is a tedious works!!

Can you tell me where did you get the SCP1 and SCP2A?

What kind of euqipment you are using? and You are Vinyl fan?
Wish you all the best!

Fever

Y.C. said...

It's almost a year before I get back to my comment!
I got my SCP2A and SCP1 from Audiogon, after years of waiting. I have compared SCP2A to numerous current design, and it still beats them all.
For SCP2A, I am going to build a different power supply for it. I will still keep it as dual mono. Two ILP toroidal transformer will be used. Then 20000uf of caps per side and Hexfred diodes. discrete FET based regulator (Erno Borbely design) will be used for +/-29V. For the main unit, I will not touch it except the electrolytic caps should be aged and will be changed to newer ones (Matsushita gold). I have also get a copper chassis that I will put the SCP2A boards to it, with telfon board underneath. I will try to change the hook-up wires from the original Mogami to some silver ones.
My other gears are Cello Suite preamp + Jeff Rowland model-7 power amps and Tannoy Kingdom12 speakers. CD combo is Mark Levinson ML31.5+30.6. Turntable is Platine Verdier with FR64S tonearm and Phasetech P1 for the time being.

YCLee

Anonymous said...

YC Lee, Are you station in HK?

Well, your equipment is one of the top line of all the classes. Glad to know as I can see that not so many lucky people had a chance to own SCP1 and SCP2 at same time...

At least not so many HK people had a chance. You have got so much knowledge to modify and tune up the Audio gear to a higher level of excellence in transforming the LP into live music in your living room!

Enjoy Audition!

feverip

Y.C. said...

Yes, I station in Hong Kong for the time being.
Didn't do much work on hifi lately but just sit down and enjoy the music for the little time left everyday...

Y.C. said...

By the way, I also own a TCP-1, which is an electronic crossover designed by John Curl in his days of Vendetta Research...:-)

Anonymous said...

YC, Well that is the ultimate goal of music lovers, I know friends of mine speding money, time and energy moving in and moving out the Hi Fi equipment at the Shops, leaving no time to listen to music, and soem one who has HKD2,000,000.00 valued equipment but 10,000.00 disks... His time on music audtion is limited. only the Hi Fi Audio test disk!
What a pity!

I do not know about TCp-1 must be anotehr piece of GEM from John Curl!
feverip

Y.C. said...

I am quite contented with my setup right now. Surely it can be better but it is to a level that I am more focused on the music now. And I keep myself as a hifi electronics hobbyist too...:-)

Anonymous said...

Hi YC,

Hope that Audio and Music can repair my lonely heart some how days of a relax after a dog's work.
It is not easy to get a balance of pursuing a Hi Fi that is 100% matching or exceed your expectation. and Music that is of your type and favourite. I think I have to stop upgrade my system as I have been searching for 30 years, It never come to an end!

Why not Just sit down with some tolerance on the less tight bass, not too transparent treble, and some pops sound from the wrecked LPs, I had a 10 hours music audition last Saturday, that was quite rare as my daughter went to meet her friend so that I can concentrate on my music.

Hi YC, You must have a good collection of LP I beleive!

Hope that there is a chance, I want to se the John Curl Materpiece! and listent ot you top gear!

by the way I ahve another two blogs, I welcome you to come and look at them:

http://led-fever.blogspot.com/

and

http://youonlyliveonce-fever.blogspot.com/


have a nice day!

Feverip
Travelling in Penang!

Anonymous said...

Hi YC,

Hope that Audio and Music can repair my lonely heart some how days of a relax after a dog's work.
It is not easy to get a balance of pursuing a Hi Fi that is 100% matching or exceed your expectation. and Music that is of your type and favourite. I think I have to stop upgrade my system as I have been searching for 30 years, It never come to an end!

Why not Just sit down with some tolerance on the less tight bass, not too transparent treble, and some pops sound from the wrecked LPs, I had a 10 hours music audition last Saturday, that was quite rare as my daughter went to meet her friend so that I can concentrate on my music.

Hi YC, You must have a good collection of LP I beleive!

Hope that there is a chance, I want to se the John Curl Materpiece! and listent ot you top gear!

by the way I ahve another two blogs, I welcome you to come and look at them:

http://led-fever.blogspot.com/

and

http://youonlyliveonce-fever.blogspot.com/


have a nice day!

Feverip
Travelling in Penang!

fever Ip said...

Hi YC,

Hope that Audio and Music can repair my lonely heart some how days of a relax after a dog's work.
It is not easy to get a balance of pursuing a Hi Fi that is 100% matching or exceed your expectation. and Music that is of your type and favourite. I think I have to stop upgrade my system as I have been searching for 30 years, It never come to an end!

Why not Just sit down with some tolerance on the less tight bass, not too transparent treble, and some pops sound from the wrecked LPs, I had a 10 hours music audition last Saturday, that was quite rare as my daughter went to meet her friend so that I can concentrate on my music.

Hi YC, You must have a good collection of LP I beleive!

Hope that there is a chance, I want to se the John Curl Materpiece! and listent ot you top gear!

by the way I ahve another two blogs, I welcome you to come and look at them:

http://led-fever.blogspot.com/

and

http://youonlyliveonce-fever.blogspot.com/


have a nice day!

Feverip
Travelling in Penang!

Y.C. said...

My LP collection is just so so. Stopped for quite a few years when I first moved back from Australia to Hong Kong, before I picked up the hobby again.
Surely we should arrange a time to see the John Curl masterpieces.
Email me at yukclee@hotmail.com