Tubes Asylum: REVIEW: Raleigh Audio PP line stage Preamplifier (Tube) by Bas Horneman

Model:	PP line stage
Category:	Preamplifier (Tube)
Suggested Retail Price:	$599
Description:	Transformer coupled Push Pull
Manufacturer URL:	Raleigh Audio
Model Picture:	View

Review by Bas Horneman ( A ) on September 22, 2003 at 04:14:23
IP Address: 212.123.206.71

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for the PP line stage

Manual, board quality and feedback.
The manual is very good..providing step by step instructions...however it has been improved in the meantime. Since there were one or two things that I thought could be better, and since I am/was a beta-tester my remarks have been incorporated in the manual. To me it was not a 100% clear which way the transformers should be mounted. So I had soldered them in the wrong way. This brings me to the de-solder part of my story.
I had to de-solder the transformers...requiring repeated heating and using a de solder vacuum pump.
I must have heated each individual transformer connection more than 50 times. After this operation the tracks on the PCB where still pristine and none of the internal connections in the transformer failed! Excellent PCB and transformers in other words.
Help during building was excellent. Either via the K&K forum at AA or via e-mail from Dave Davenport or Kevin Carter.
I really thought the transistor sockets for the CCS were a stroke of genius. Even though none of my CCS's have failed, by now de-soldering is something I despise...it is a comforting thought that the CCS's may simply be pulled out and re-inserted. I suspect the sonic penalty is negligible.
I also like the ferrite "chokes" in the heater supply of the tubes, with a little cap across them. The heater filaments are DC and current regulated by LM317's that come with and are part of the kit.
Switches, connectors and potentiometers have to be provided by yourself. I used Alps "blue velvet" pots at $10 a piece, simply because they were affordable and available. Connectors used were good quality teflon isolated gold plated RCA's. Output connector was provided by a good quality DIN type. (I believe however that a complete kit will be made available in the future, even with a remote control option!)
Development.
During the evaluation phase, Dave kept tuning/improving improve the Kit. One of the things that came to light was that the 100R gate stopper
was replaced with a 2,4k resistor. Dave sent me these for free. Which I find "over and above" what a manufacturer ought to do. Thanks once again Dave.
The kit sounded virtually as good with the 100R resistor. Bass seemed to improve slightly as did subtle details with the new resistor value.

Parts.
The parts quality is great. Kimber caps, Kiwame, Mills and Caddock resistors ..not that boutique types are important to me, as the sound quality is all that counts. Furthermore these parts where
not chosen because of their boutique quality, but because Dave found them to sound best in their respective positions. It is somehow comforting that these parts are generally just well made. Quality however is also in the eye of the beholder.

PSU.
One of the big discoveries I made is that the CCS's used are not a brick wall filter (Which I thought they practically were), and that the PSU is still a vital part of the pre-amp. In that sense I would
say that none of the Kits will sound the same, unless they use the Raleigh Audio / K&K audio psu. I heard a very different amp when my VR tubes did not fire up one day. Message is, I guess...to build the best PSU possible or get the RA / K&K audio psu which I suppose sound good. (Trusting Dave and Kevin's judgement;-)

Listening.
I've listened to this pre amp with the following.
A Sony CD-player using a Sony Minidisc MJE 520 as DAC, power amp a SE 6c41c based amp, and mission 761i speakers. My room
is fairly large for European standards. Not ideal sources and speakers to judge the pre amp with, however I took the pre amp to a fellow Dutch diy'ers. The one with SE 300b and Single Driver speaker, the other with OTL tube amp and QUAD esl63.
First a general observation about the sound. My system is quieter now, I suppose because of the complete absence of ground loops (Because of the transformers)
The amp has input transformers that do the phase splitting and parafeed output transformers ...thus providing complete galvanic isolation between
the source and power amp. The tranformers also form a "natural" way of filtering out a lot of ultra-high frequency rubbish (gratis ;-).
Secondly I love listening to my system more than ever and find the music very natural sounding. I find myself listing to the music instead of analysing what my system sounds like, it was sometimes sickening the way I tried to listen to the highs or lows or whatever. Now I find myself listening just to the music. It is so utterly natural and has none of the ever so slight hardness (I know harshness is usually used but that does not describe it well enough) that previous cap-coupled designs using the same tube (6N1P) had.
So is there nothing wrong with this kit?
Yup, this kit is all I wanted from it and more. To my system it has been a "force multiplier" making it sound much more refined. I feel it has enabled me to hear just how good my homebrew SET amp is. It extracts everything from my sources, and it makes my speakers sound surprisingly like musical instruments.
Only when comparing it outside my own system, I would have to say that the vertical soundstage is comparatively flatter than for instance one DHT SET transformer I have listened to. Somehow the horizontal sounstage is just as wide though as the DHT SET preamp I heard..so no remarks about the horizontal soundstage.
I have read though that this is common of PP amps, and that SE wins out in this regard. Horses for courses. So it comes down to voicing again...and believe you me this pre amp has given my soundsystem a beautiful voice. (The very comparison that lead to this paragraph was however not very fair. As I have improved the PSU a lot after that listening session, and it was listened to straight after plugging it in without a warming up period. (The other amp had been switched on hours earlier))
Summary
Would I buy this kit if I knew what I know now? Yes. Because apart from what it has done for listening to music, it has shown me a different
way forward and that way is transformer phase splitting and PP. I will still build SE amps...for sure, but now I have a lot of faith in transformer coupled designs. One of my best investments ever.
Evaluation period.
Been listening virtually everyday for the past 6 months. (Transformers need at least 2-3 months running in before they provide their midas touch. IMO)
Music
Jazz, Classical, Pop, Rock, World music
I would like to make a page with other photo's of this PP line stage kit. So if you have built one, please send me an email via AA so I can post your version. TIA.
PS...I think this line stage should get a name as well!
This kit is by Raleigh Audio and distributed by K&K Audio.

Product Weakness: Vertical soundstage?
Product Strengths: Musicality, Organic, Finesse and very quiet.

Associated Equipment for this Review:
Amplifier:	DIY SINGLE ENDED 6C41C
Preamplifier (or None if Integrated):	This one
Sources (CDP/Turntable):	Sony
Speakers:	Mission 761i
Cables/Interconnects:	Monster Cable
Music Used (Genre/Selections):	Jazz, classical, pop, rock and so called world music...
Time Period/Length of Audition:	6 months
Type of Audition/Review:	Product Owner

Product Weakness:	Vertical soundstage?
Product Strengths:	Musicality, Organic, Finesse and very quiet.