HiFi News review of Jadis Defy DA-30

The reason for describing my system is that it may give you an idea of my sonic philosophy and maybe provide some useful hints.

CD Player:
Pioneer PDS-901 with Trichord Clock 3 modification and improved voltage regulation
 
D/A Converter:
Audio Note DAC Kit 1.1 with some tweaks described on the 'Tweaks' page
 
Record Player:
Unamco T-1 with Formula 4 tonearm and Luxman 115-C moving coil cartridge
 
RIAA Amplifier:
Elektro Akustik RIAA-3000 tube amplifier with Audio Technica AT-630 MC transformer
 
Main Amplifier:
Jadis DA-30 De Luxe with triode coupled EI KT90
 
Subwoofer Amplifier:
Rotel RB-980BX
 
Loudspeakers:
Quad ESL-63 slightly tweaked
 
Subwoofers:
Gradient SW-63 with my own (MT Audio Design XO-2001) crossover
 
Tuner:
Luxman T-33
 
Headphones:
Stax Lambda Pro Signature
 
Interconnects:
Supra DAC
 
Lodspeaker Cables:
Supra PLY 2.5 for the QUAD's and Monster Cable for the Gradient's
 
Power line filters:
I use filters for the CD, DAC, RIAA, Quad ESL-63 but not for the amplifiers as I think it reduces the dynamics too much.
 
My opinion on the parts in my system
 
CD + DAC:
The Pioneer PDS-901 has benefited enormously from the installation of the Trichord Clock3 and quite a bit from the improved voltage regulation (extra electrolytic capacitors in parallel with polypropylene capacitors installed on all voltages). It sounds good with its own DAC but the Audio Note DAC Kit 1.1 improves the performance in the most amazing way. This DAC is the best I have heard regardless of price (I have not heard all). It replaced my Meridian 606, a very good DAC indeed but it is several years old and a lot has happened since it was released. Still, it can stand off most competitors in the sub $1000 range. I have tweaked this DAC a bit and a new section on the 'Tweaks' page will cover my improvements (some already done). As interconnect between the CD and DAC I use a triaxial 75 ohm cable with the outer shield connected only in the source end (CD). I am very happy with this combination and even if I hope that the new digital format will be here soon the performance level is high enough for me to enjoy the CD collection without feeling that there is a severe limitation because of the 44 kHz sampling frequency. I think it will take some time for DVD audio to reach this level at a reasonable price, the SACD format looks more promising and I hope this is going to win the battle.
 
Record Player:
The Unamco T-1 is a Swedish belt-drive design with floating suspension, 24-pole syncrone motor and originally fitted with a 12 inch tonearm.  The record player is heavily improved, with the sub chassis damped with clay, the suspension is oil-damped (see tweaks), and the tonearm is changed into a Formula 4 unipivot oil-damped arm. I run the record player on 115 VAC instead of 230 VAC to bring the motor vibration down. The fitted cartridge is a Luxman 115-C (moving coil), a little out of date perhaps but still sounding good. When I bought it several years back I compared it with Ortofon MC-30 and I preferred the Luxman because of it's more alive and musical sound. The record player is standing on sorbothane feet and of course I use a clamping device when playing records. Getting rid of acoustical feedback in record players is essential. The used MC-transformer is a quite cheap Audio Technica AT-630 which performs surprisingly well, but if I would make any improvements on the record player the MC-transformer would be the first choice.

RIAA amplifier:
When I bought my Jadis amp I was left with no RIAA amplifier, so I looked around for such and impressed as I was of the tubes the choice was simple, it had to be tubes. Elektro Akustik sells some interesting and not too expensive kits, one of  them the Elektro Akustik RIAA-3000 which I bought. It is an SRPP construction with passive filtering, using 7025 in the amplification stages and ECC82 in the output buffer stage. It is amazing what the old LP format can do when no semiconductors are involved, the sound is marvelous. Initially I had some problems with hum (my fault) which was solved by moving the power transformer and rectification to it's own box and changing the heater feedings into DC.

Main Amplifier:
Let's not fuzz around, I love it, the Jadis DA-30 De Luxe is great! Specified at only 30W class A, but still powerful with great dynamics and detail. The Jadis replaced my previous Accuphase E-305 amp, a very good amplifier of it's kind. I do not wish to ridicule Accuphase as I think they make some of the finest semiconductor amplifiers there are, but the Jadis outperformed it in every way. The most surprising was that the bass was so much better, more weight and certainly more tuneful (I think almost all semiconductor amps have trouble playing bass tunes, although they are mostly better at bass transients). I have changed the cathode bias of the output tubes into separate cathode load, for some reason Jadis used a common cathode load which decreases the life span of the tubes if they are not perfectly matched. I have also changed the connection of the output tubes into triode connection which improved the sound a bit, but not as much as I have heard with other amplifiers, it seems as if Jadis has found a good tapping point for ultra-linear connection. Triode connection means even less power but as I do not use the amplifier as fullrange anymore because of the Gradients it is enough for me (about 100dB output with no loss of dynamics). The output tubes currently in use are Yugoslavian EI KT-90. The KT-90s replaced my JJ (Tesla) KT-88, and the JJ tubes are overall the best I have tried. The KT90 has a wonderful sweet midrange, a nice smooth and extended treble but the bass is not to my liking. Many think the KT-90 bass is superb but in my system it adds its own bass, the distortion is much higher than with the JJ KT-88 and this is easily heard with the 100Hz sinus tone I use for SW level adjustment. With the KT-90s in place the bass drums have almost no skin sound and the bass is a bit on the boomy side. The KT-90 may well be the best tube of its kind in an amplifier with more feedback, it seems to need more feedback than the Jadis DA-30 delivers when triode connected. The small signal tubes are from JJ electronics (2xECC83, 3xECC82) and these are very good. Lastly, a little tweak, I use the tape output as input for the DAC with the selector set for an open input. By doing this the signal does not have to pass through the selector, try it (it does not work on all amplifiers).
 
Bass Amplifier:
The Rotel RB-980BX performs alright, when the Gradient bass units are driven in parallel (4 Ohm), in the serial (16 Ohm) connection it does not. Maybe it's the very high impedance in the region 20-50 Hz that is the trouble. The specification says 120W at 8 Ohm, if you calculate a little this means a voltage swing of 44 Volts and a power output at 60 Ohm (peak at 20 Hz with 16 Ohm connection) of around 32W! Probably this is part of the reason why tube amplifiers tend to sound more powerful than semiconductor ones at the same specified power, tube amplifiers are not as limited when it comes to voltage swing and should certainly cope better with loudspeakers bass resonances in the region where power really matters.

Loudspeakers and Subwoofers:
As Gradient so eloquently put it "the Quad ESL-63 is one of the finest speakers in the world and combined with Gradient SW-63 it is probably the best". I have had the Quad's for well over ten years and they never disappoint me. Previously I used them with an Audio Pro B2-50 subwoofer (Swedish classic) but when it broke down I bought the Gradient's and they certainly blend better with the Quad's, especially when the crossover is my own MT Audio Design XO-2001, giving a bass quality I think is unsurpassed. It takes some time getting used to the bass though as the room resonances are not as apparent and the extra sound boxes make also helps giving a little more fat bass. When you first listen to the dipole bass it seems a bit thin, but when you get used to it, there is no going back. The bass certainly is present but in a much more sublime way. More about the tweaks, connection and use of this splendid speaker combination is found in the 'Quad ESL' and 'MT Audio Kits' sections.
 
Tuner:
I bought my Luxman T-33 over 20 years ago second hand, it is still going strong and I am still satisfied with it's performance. Not bad for an entry level tuner of that age! In my wardrobe I have an even older (slightly) Luxman SQ-507X amplifier which is an old love-affair of mine, this I intend to refurbish when I get the time.
 
Headphones:
You probably know that the Stax Lambda Pro Signature is one of the finest headphones there are, and I am very satisfied with them. Actually these are my sonic reference apart from a little sharpness in the treble. The Quad ESL-63's improvements have actually resulted in less coloration from the speakers than from the Stax headphones! The headphones remains good references though.
 
Interconnects:
I do not intend to spend too much money on cables as some do. Therefore I use the Swedish no-nonsense Supra DAC, a low capacitance cable with very good transparency and detail. It costs about 6-7 $ per meter and I use WBT-type RCA connectors with the screen connected only in the source end (lower impedance in the source end means better grounding).
 
Loudspeaker Cables:
As speaker cables for the Quad's I use the Swedish no-nonsense Supra PLY 2.5, a low inductance cable costing about 7$ per meter. The Quad's does not seem to be too sensitive to cables, probably because they have no filters to interact with this source impedance. The Gradient's are connected with a slightly larger Monster Cable.
 
Conclusion:
I am very happy with the way my system sounds, as a matter of fact I have never heard anything better (of course I am biased, after all this system is set up entirely to my preferences of sound). The stars of my system are the tweaked Quad/Gradient combination closely followed by the Jadis amplifier and the CD/DAC combination. Apart from the parts involved I think it is important to have a philosophy of sound and stick to it, in order to make the system work as an organic whole. I do not believe in the forward and backward type of matching that is quite common (meaning that you mix for instance a laid back amplifier with forward sounding loudspeakers), I think the only way to reach magic is to use equipment with equal sound character (within reason of course). The set-up is also VERY important and that may be the reason to why the very expensive gears showed for the public never sounds as good as a properly set up system at home. I have spent many ours changing speaker position (the most important factor) and testing all sorts of tweaks. That pays off in the end.

 

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