JJ 828 Push Pull Thrill Ride
By David Bardes 2002 All Rights
Maybe you're like me. I take great pride in my single ended rig. My friends are always amazed and delighted when I play it for them. Small Jazz ensembles and female voices are recreated with a realism beyond anything they have imagined. But secretly I sometimes wish for a sound that my single ended rig can't produce. Sometimes I crave the power and grip that only big amps can provide. Power to make orchestras in cavernous venues sound as large as life. Power to make rock and electronic music really, really rock. The power to play music way too loud!
Brawn and Beauty.
If it is this kind of power you seek, look to the JJ 828! From the makers of those Slovak tubes, JJ Electronic, comes an integrated stereo amp with all the power you desire. Sporting a total of eight KT88's, this stereo amp is conservatively rated at 70 watts per channel.
But brawn is not the only feature of this amp. It is an attractive and full-featured integrated amp. The front face has a beautifully sculpted wood finish, and the remote control is similarly finished. This amp was easy to use, with all the controls intuitively placed. Five inputs are provided and can be selected on the front of the amp or from the remote control. The motorized volume pot and power switch are also on the front, but may also be operated from the remote control. While there is no phono stage, or a tape monitor loop, Tape out jacks are provided in the back. Bias is set by matching LED's set next to the tubes and does not require opening up the case and using a meter.
In Da House!
The JJ 828 was designed by JJ Electronic engineers and is manufactured in the house. Some of the caps and all of the transformers are designed and manufactured by JJ Electronic specifically for this amp. Separate transformers are used for each channel. The C core output transformers utilize special air gap techniques to keep the signal linear at all power levels and they also have special secondary windings used in the amp's two feedback loops. Total feedback is a modest 11db.
In addition the amp uses the ECC99, a special JJ driver tube designed to drive KT88 and 300B tubes. The ECC99 most closely resembles a 12BH7 on the tube tester, but provides more gain, greater linearity, and requires less bias. 12AU7's power the Concertina phase inverter and the preamp section of the amp. (Tech Editor note: The ECC99 is available for anyone to use, and is a very linear 7119-like tube with a 12AU7 pinout.)
Unlike monster solid state amps, the JJ 828 has a firm composure to it without any hint of grit, glare or zing. But it shares the unmistakable deep well of reserve power that makes big amps so exciting to listen to. Plus, this amp sounds much bigger than the 70 watt spec, implies.
The JJ 828 is unflappable. Cranking up the volume knob will distress your ears and may distress your speaker cones, but the signal from the amp remains the same, with no increase in harshness or audible distortion, and no hint of compression. This amp has the power to fill large rooms or drive diminutive monitor type speakers with the damping and control they need to sound their best. It would have been fun to hook this amp up to some planar speakers, I'm sure they would have handled these greedy these speakers with easy.
Familiar recordings sounded quite different played through the JJ amp when compared to my single ended amp. While the JJ amp doesn't have quite the detail or musical depth of a single ended amp, other aspects of the music come to the fore. For example, the JJ amp had more control and clarity in the mid-bass and bass which gave the music a firmer foundation and enhanced the musical tempo in Diana Krall's Besame mucho (The Look of Love - Verve Records). Reverb was clean and well defined if not as deep and liquid when played through my single ended amp.
large complex music such as Beethoven's Fifth (Leonard Bernstein and the New York Philharmonic Sony Classical) revealed the amps dynamic character, clean definition of instruments and the all important "big" factor. I was truly convinced I was listening to 70 plus musicians playing their hearts out! parallel push-pull pentode amps have a reputation for sounding veiled and smeary. I am happy to report that the JJ 828 does not suffer from this malady. (Tech Editor Note: The high-current capability of the ECC99 probably helps drive the multiple KT88 grids better than most.)
taking off the kid gloves, I played some of the music from Thomas Newman's American Beauty film score (American Beauty - Dreamworks Records). The score is a torture test for many sound systems with lots of complex percussion and synthetic deep bass. At reasonable levels the floor shook and a smile brook out on my face. At loud volume levels the windows rattled. Beyond loud, the 12 inch woofers of the JBL S312 loudspeakers couldn't handle the extreme excursions necessary to produce the deep loud bass, but the amp still had plenty of gain and headroom. The JJ 828 gave electronic music such as Crystal Method's Vapor Trail (Vegas - Outpost Records) drive and intensity that I have not heard from any other tube amp in my living room. It rocked!
JJ Electronic has produced a wonderful amp to showcase their vacuum tubes. it is good looking, powerful, and has a big, clean sound. Designing the amp and many of it's components in house, JJ Electronic has been able to leverage efforts into s superior product. Rock on!
The scale is 1 to 5 with a score of 5 being the very best.
Overall Rating: 4.5
Dynamic Range: 5
Frequency Extension: 4
Pace and Rhythm: 4.5
Musical Involvement: 4.5
MSRP: $4000.00 with remote
Output Power: 70 watts per channel
Tube compliment: Eight - KT88's, Four - 12AU7's, and Two ECC99's
Frequency Response: 20 Hz - 22kHZ +/- 1db
Noise & Hum: 88db below full output
Input Sensitivity: 5 volts RMS
Dimensions in Inches: 18.9" W x 13.8 D x 7 H
Weight: 75 lbs.
Power Requirements: 115/230 V - 50/60 Hz
JJ Electronic CADCA, Slovak Republic www.jj-electronic.sk
US Distributor: Eurotubes, Milwaukie OR 503-659-7401 www.eurotubes.com
Test System Components: Jolida JD 603 CD player with Mullard CV4004 tubes in the analog output section. JBL S38 and S312 loudspeakers. Homebrew fine wire speaker cables using three strands of 30 awg silver-coated copper wire in a kynar jacket. TEK LINE PC2 Signature power cords for both the amp and CD player, and VSE Super Clear Interconnects.