My Raleigh audio PP line stage kit page

a Kit?
This will be my first ever audio kit. Why a kit if you generally do DIY? I have become more and more convinced that KITS are eventually
the same price if not CHEAPER than scratch diy build (apart from people that have a whole shack full of parts lying about.)
Add up all the shipping and handling, fuel prices driving down to your favourite HAM fest or store, and don't forget: time is money
a Kit is (usually) all thought out, with sometimes literally hundreds and hundreds of hours spent listening (by more than one person, and in several different
systems and rooms.
Now I hear you saying...getting an amp to sound "right" is where the fun is at.
True, except that I have a family as well. Maybe when I am 65 I will have enough time on my hands, but not now.
The final trigger was that K&K audio (The distributor of the kit) and Raleigh audio where looking for beta testers, that would build the kit and
provide feedback on building and listening to the kit. So there was a discount to be had. :-). After all the hard work building my first amp and
fooling around (in vain) trying to build a proper cd tube output stage. I wanted to spoil myself.

Choices, choices
The reason that led up to actually buying THIS kit is was Lynn Olson's "Raven". Lynn originally built the Raven with Magnequest Choke loads, Sowter transformers
and variants of the 5687. That caught my attention.
However around that same time Dave Davenport of Raleigh Audio was designing a line stage that used Lundahl, and CCS's.
Without knowing Dave, I sense that he is more of a practical man than Lynn... Lynn is more of a concepts man, he admits to this on his website
(I am not a tweaker by instinct or inclination), Dave seems more like a DIY man
getting down and dirty with his designs, tweaking, listening and actually trying out... this resistor or that cap.
The fact that Lynn Olson's current iterations of his Raven look very much like Dave's is a validation of the direction Dave Davenport
has taken with his line stage.

(Update 16-06-2004) I don't mean to say Lynn does not listen to designs. 
For instance : Lynn has currently (see update date) taken the parafeed cap out of his Raven.
Since he found the cap to have too large an influence on the sonic signature of the amp.



PSU
The kit may be bought with or without psu kit. If you choose to not get the PSU KIT... You obviously have to build that yourself.
That is just what I am planning to do. This is what it should look like. Voltage might be too low for the VR tubes..



The OD3 is actually a G180/2M or CV395 a beautiful loctal tube I got from Fatbottle. Fatbottle also sells teflon loctal sockets!
This fellow is another good guy in the tube world.
Dhaen got me some EY81's and topcaps, returning a favour I did for him.
These 2 Brit Brats ;-) have been very helpful as well when it comes to answering the many stupid questions I have!




K&K Audio and RaleighAudio

Unlike the tubestore link on the my webpage I don't get a dime for referring people to Raleigh audio or the distributor K&K Audio.
In other words I have no affiliation financial or otherwise with K&K or Raleigh Audio other than that I purchased this kit from them.


Building the kit
So far so good. Actually it is a breeze, except for the fact that I did not READ the manual PROPERLY. At time of writing it is 16th of May 2003.
And the kit itself is finished. Reckon if you do it right straight away... around 3 hours.







Building the rest
Chassis is made of wood. Mainly because I have tools for wood and not for metal. Plus it is cheap and easy.

Design considerations/points of note.

1.) Low rectifier switching noise. (Damper diodes, quasi choke input)
2.) Voltage and current regulation for the filaments of 6N1P (Schottkey diodes).
3.) Electrostatic shield in the toroïdal HT transformer (The screen reduces the capacitive coupling by more than 40 dB).
4.) Mu-metal (magnetic shielding) shield around the toroïdal HT transformer (+/- 30dB of hum rejection)
5.) EMI/RFI shield (3M copper tape) around the PSU choke (60dB to 80dB attenuation (30 MHz to 1 GHz)).
6.) Solid core internal wiring. (Teflon coated CAT5).
7.) Shunt regulated HT supply with VR regulation tubes and CCS (DN2540) in the PSU.
8.) Single point star earthing.
9.) Input mains power line noise filter.
10.) Wooden chassis. Thus no induced magnetic fields/eddy currents from onboard transformers.
11.) No Electrolytic caps (Tried it first, thinking the shunt regulated psu would mask their sound. However the
when the PSU was not ready yet. (Waiting for VR tubes) I decided to plug in Polyprop instead of the 2 * 100uF lytics
Unbelievable change. Suffice it to say never will any lytics in my psu again.

Downside of the wooden chassis.
More susceptible from outside RFI/EMI.

Here is the Raleigh Audio design



Listening impressions
Don't know where to start. Maybe by stating my conclusions first. This is the last preamplifier I will ever ever build! It is that good.
As some of you might know I have crappy Mission 760i speakers (Well I like them but they sound a bit ragged when pushed hard)

Poweramp is my "Frontrow". This setup craps all over the Cronzilla amps setup
I heard at the Doelen Hifi Show in Rotterdam...In fact I don't recall anything beating my setup. ;-)
Don't know how it is possible because previously my sources were plugged in straight into my poweramps, but it simply does not compare
to this preamp. Thanks Dave Davenport of Raleigh Audio and Kevin Carter of K&K audio for a splendid amp. In my case the preamp to end all preamps.


The Mains Filter



A picture of the linestage...finished...well almost....notice the untreated feet!..a little C37 and it will really sing!

 In use

A picture of the linestage bottom oooohh...naaasty


RaleighAudio

K&K Audio

Nutshell High Fidelity