SET Asylum: REVIEW: Antique Sound Laboratory Limited Explorer DT Amplifier (Tube) by cjfrbw

Model:	Explorer DT
Category:	Amplifier (Tube)
Suggested Retail Price:	$2500
Description:	50 watt SET
Manufacturer URL:	Antique Sound Laboratory Limited
Manufacturer URL:	Antique Sound Laboratory Limited

Review by cjfrbw ( A ) on April 26, 2005 at 15:00:22
IP Address: 68.164.94.225

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for the Explorer DT

I felt a little bad about talking earlier about one of these blowing up. I managed to fix it myself with a new KT 66 tube and a new fuse and a power supply capacitor ordered from Michael Percy. Anyway, I am using it in an unorthodox manner with a low efficiency ribbon (Apogee Stage) with an active tubed crossover to the high frequency ribbon. I will quote my impressions posted on the Apogee board. The 805 Explorer functions extremely well as a mid/high ribbon amplifier through an active crossover. I can say I have never heard anything quite like it with my Apogees and the impressions are favorable. The SET sound comes through, and it is spacious, detailed with great timbre and texture to the sound. It also manages to be as relaxed and laid back as anything I have heard with these speakers. Apogees are seldom mentioned in the same breath with SET, but this seems to work quite well with an active crossover covering the 300hz to 20,000 hz range. There is no complex impedance, just a flat 4 ohm from the ribbon, and the lower frequencies are filtered by the active crossover. I can't detect any meaningful power limitation when used this way, althogh volume matching through the active crossover is necessary. I quote my impressions posted on the Apogee speaker board. The model I have is the older anode capped model with four transformers. I guess this was the first "DT" version.
"I am so glad I tried these SET amp. I fixed the broken ASL 805 Explerer mono block myself, courtesy of a new power capacitor a la Michael Percy, and a new fuse and a new KT 66 tube.
Anyway, operating the MRT ribbons of the Stage through the active crossover (Luxman Viintge 2001@12db per octave @ 500 crossover point, bass panel rolled off below 90 Hz at 12db/octave) with the 805 SET monoblocks in stereo sounds wonderful. The SET does everything push pull and triode tubes do but better. Great space, detail, separation of instruments and voices but also timbre rendition and recognition of different instruments. It sounds seductive without being sweet, maybe just a tinge warm without blurring anything. This is with stock tubes and no tweaking. It is definitely the best sound I have ever heard from my Stages. You can hear a lot of strange, tiny details as well. Jim Morrison on some cuts of the album "Strange Days" keeps hitting the mike or the mike boom with his mouth and hands and/or stamping his feet, and in some instances, you can hear the hum in the recording instruments and/or electronic instruments. The Stages keep up with the improvement without breaking a sweat. I left the tonearm suspended above the turntable and switched over to the passive crossover and the extremely competent high current solid state amps in the Yamaha RX Z9 full range. This is one of the best solid state amps I have ever heard with the Stages run full range through the passive crossover. However, after the SET/ Bel Canto combo through the Manley Steelhead/ active tube crossover, it sounded slightly like a tin megaphone and although it was the same music, it didn't even sound like the same music signal, the collapse of space and texture was so dramatic.
The 805 SET soundly beats the VTL 450 Sig monoblocks when used on the MRT with active crossover. On a scale of 1 to 10 (without implying that 10 is the best, only for comparison purposes) the 805 SET on the MRT of the Stage would be a 10, and the VTL in triode mode would be a 7. The VTL is powerful, spacious, and great sounding, but it doesn't produce the detail, space and the utter smoothness of the SET. Using the Bel Canto 200.2 on the MRT/active crossover sounds pretty crummy by comparison, I would call that a 2 or 3 on a scale of 10 by comparison, it just does not carry the detail or the depth of either the VTL or the SET.
In contrast to its wretched performance on the high frequency ribbon, however, the Bel Canto does extremely well with bass ribbon crossed over at 500 Hz above and 90Hz below. It sounds agile, detailed and very disciplined in this range. Oddly, it outperforms the VTL(In triode and tetrode mode) on the bass panel. The VTL has some audible bloom and overhang in this range. With the extreme power of the VTL amp, this punches through fairly aggressively. On a scale of 1 to 10, again only for comparison, the Bel Canto on the bass panel only would be a 10 and the VTL an 8. The Bel Canto is a seamless match on the bass panels with the SET on the MRT high frequency ribbon,better even than the VTL in triode mode, quite a shock an surprise to me, given the power and finesse of the VTL mono blocks.
This experiment seems to be leaving the VTL an orphan. I believe that the VTL is one of the best amps in existence for 3 ohm and above apogees full range through passive crossovers. However, with an active tubed crossover, the SET is better on top with the MRT and the Bel Canto is better on the bass panel.
I guess the first watt philosophy of the SET crowd is important for the Apogee Stage MRT at least. I will be using an SET for the MRT with active crossover from now on.
System: SME 10 turntable, SME 10 arm, Benz MC-3 rebuilt cartridge, Manley Steelhead preamp, Yamaha RX Z9 for digital sources through Steelhead as line stage, CEC Transport with Meridian 518 digital processing preamp. Amplifiers: Yamaha RX Z9, Bel Canto 200.2, Antique Sound Labs Explorer 805 mono blocks, VTL 450 Sig mono blocks. Crossover: Luxman 2001 tubed crossover MRT crossed over @ 500 Hz, Bass Panel crossed over @ 500Hz and 90Hz at 12db/octave, Velodyne and Klipsch subwoofers below 90 Hz."

Product Weakness: lowish power
Product Strengths: Great smooth detailed sound quality, unlike any other type of push pull tube or transistor amp

Associated Equipment for this Review:
Amplifier:	see system cjfrbw
Preamplifier (or None if Integrated):	see system cjfrbw
Sources (CDP/Turntable):	see system cjfrbw
Speakers:	see system cjfrbw
Cables/Interconnects:	see system cjfrbw
Music Used (Genre/Selections):	jazz, fusion 70'rock etc
Room Size (LxWxH):	19 x 13 x 10-16
Room Comments/Treatments:	see system cjfrbw
Time Period/Length of Audition:	Weeks
Other (Power Conditioner etc.):	see system cjfrbw
Type of Audition/Review:	Product Owner
Your System (if other than home audition):	see system cjfrbw

Product Weakness:	lowish power
Product Strengths:	Great smooth detailed sound quality, unlike any other type of push pull tube or transistor amp