Audio Asylum - Inmate Systems

Bold Eagle's JBL L-110/Onkyo/Rotel System
IP Address: 174.130.120.241	Last Update: December 30, 2010 at 18:08:06
Amplifier:	I'm currently using an Onkyo Integra A-8190 integrated amp, vintage 1989. Rated at 100 W/ch into 8 ohms, and with Dynamic Power ratings of 150/240/303 W/ch into 8/4/2 ohm loads. Damping Factor is measured at >50. The amp has been somewhat modified by the addition of gold plated five way binding posts, and the addition of a pair of 6800 uF Elna Cerafine caps to the power supply, along with film bypass caps. The "Real Phase" transformer that Onkyo touts was removed (it follows the main power transformer)to tighten up the bass and reduce power supply impedance. The preamp section has a 100% passive line stage with tone controls. There is a tone defeat switch which bypasses all the tone and controls; and a CD Direct input which bypasses everything except the volume control. The amp easily handles the moderate impedance of the JBL's, although it is rated to 2 ohms and is comfortable with Double Advents. The amp has an unusual ease, clarity, and transparency. The speaker output jacks are gold plated dual 5-way binding posts on 3/4 inch centers to allow use of dual banana plugs on the speaker cables. Through the CD input with tone controls centered, frequency response is +/- 0.1 dB from below 20 Hz to over 20 kHz. All internal connections are soldered, and a ferrite filter was added to the line cord internally. I do find the highs much smoother and more natural with the addition of the bypass caps. The highs have a Non-Bright property in which they seem lacking at first, but you then realize they are there, just very smooth and with no edge or grain at all. Like live music, in fact. This Non-Bright effect is particularly noticeable on high strings and soprano vocals where the usual edge is gone and a very natural sound is heard. At least part of this must be due to the passive line stage.
Preamplifier (or None if Integrated):	part of the integrated amp.
Speakers:	A pair of JBL L-110's with a few modifications. The speakers have really solid cabinets with an 1" front panel and 7/8" sides and back. The cabinets are not mirror imaged pairs; but the drivers are in a vertical line which gives very good imaging. The crossover is primarily first order except for the midrange high pass filter which is second order. All three drivers are fitted with Zoebel networks, so the impedance is virtually flat from about 80 Hz to 20 kHz; making the speaker a very easy load to drive. The speakers are a ported three way with a 1" semi-soft dome, a 5" paper cone midrange, and a 10" woofer. The mid and tweeter are original; but the woofer was replaced with a SEAS 25F-EW which is the replacement driver for the Dynaco A-25 and has a much nicer midrange than the original. The woofer inductor was the only change needed to adapt the woofer electrically. The port was extended with a plastic sleeve to tune the speakers to 26 Hz, which is the woofer's free air resonance, and the enclosure is about 60% filled with Acousta-Stuf to get the bass Q set to about 0.8 and to prevent standing waves and internal reflections. There are L-pads on the midrange and tweeter. Measured frequency response is +/- 2 dB from 80 Hz to 18 kHz in-room at my listening position. There is a bass rise from 80 Hz down to 25 Hz due to room gain, and useful bass response to below 25 Hz. The highs roll off gradually above 15 kHz but extend to 20 kHz. All internal connections are soldered and the original twist terminals for wire connection changed to dual, gold-plated, 5-way binding posts on 3/4 inch centers. Sensitivity is 89 dB/Watt and power handling is a conservative 150 Watts per channel on music, well matched to the Onkyo amp. The speakers are on 4" risers with a 6 degree tilt back which puts the listener on the tweeter axis. The sound is amazingly clear, clean, transparent, and open; with very smooth highs. Bass is deep, solid, powerful and very tight and articulate. The bass extends to 25 Hz with authority. The sound is completely detached from the speakers and exists totally in the virtual image. The speakers do not seem to be the source of the sound. Instruments have accurate timbre, and voices sound uncannily live. High strings have the right timbre and sound very natural and never bright or edgy. There is a profound sense of ambience and depth. The soundstage is wide and deep and has a good sense of height.
Sources:
CD Player/DAC:	The CD player is a Rotel RCD-971 from 2001. This is an excellent and very well built player, fully up to the amp and speakers. It does better than most CD players in retrieving depth and hall ambience clues. I auditioned 7-8 CD players, some much more expensive, before selecting this one. Extra low output impedance makes it insensitive to the interconnects used or to the preamp it's connected to. There are five seaparate power supplies for different sections, and there is an elaborate filter on the line cord.
Turntable/Phono Stage:	none
Other Source(s):	Onkyo Integra T-4087 tuner. This tuner is from 1988-89 and has a five gang equivalent front end. Excellent sensitivity and selectivity and a wonderfull sound. Excellent rejection of multi-path distortion and other spurious responses. Very low noise. This was near Onkyo's top of the line model in a much overlooked series. It works very well and I place the reception about on a par with my Sony ST-J75 and fully equal in sound quality. Imaging is particularly nice. The T-4087 has an output level control so I can match the level to the CD player. Sony CDR-W1 CD recorder. Tied into the preamp to be able to record from the system. This is a dual tray CD recorder with 4x speed. Gives very good results. Copies are used in our cars. It also is a very good player, and the two trays sound identical to each other and very nearly as good as the Rotel.
Other Accessories/Room/Misc.:
Speaker Cables/Interconnects:	The speaker cables are 12 gauge fine strand cable, precisely equal in length. The end connections are giant gold spade lugs crimped and soldered to the cable, and then very tightly clamped to the gold plated dual banana plugs on both ends. Interconnects are custom made to minimum length to minimize capacitance. RCA plugs on both ends are heavy and gold plated. The short interconnects also make a much neater backside without hanging loops of cable.
Other (Power Conditioner, Racks etc.):	Everything is plugged into a power strip/surge protector which in-turn is plugged into a second surge protector.
Tweaks:	Lots in power amp and the speakers, few elsewhere, see the amp and speaker sections for details. Probably the biggest tweak was matching the components into a synergistic system, and placement and room treatments; which together are far more important than the components individually.
Room Size (LxWxH):	18 x 12 x 8
Room Comments/Treatments:	The room is fairly dead with wall to wall carpeting and a fair amount of furniture. Speaker placement is critical, and a location was found that gives the same sound from left and right speakers from my listening chair for best imaging. So I have acoustical symmetry. Toe in and center distance between speakers was adjusted to give the best sound and image. There are enough bookshelves on the walls to act as excellent diffusers of the reflected sound.
Music Preferences and Comments:
Music Used (Genre/Selections):	Rather broad tastes. Classical including symphonic, chamber music, and solos from most periods. I'm particularly fond of Vivaldi, Beethoven and Mozart. Popular, folk, and especially jazz. I love Brubeck, Ramsey Lewis, and Oscar Peterson. Over 400 CD's in all.
System Goals/Comments:	The system is about as good as the smallish room will allow. I believe in keeping it fairly simple and working on the matchups of the pieces rather than throwing money at it. Finding the synergy between the pieces is much more important than the cost. I have about $1400 invested in this system and only the CD player was bought new.
System Strengths:	Remarkable transparency and naturalness. You feel like you are hearing back through the recording chain to the original performance. The system does extremely well in reproducing the acoustic of the original performace to the extent you feel you are there. It completely overcomes the acoustic of my listening room. Put on a well recorded CD, close your eyes, and the room falls away and you-are-there. Much nicer perspective than the in-your-face, they-are-here we so often see. My best system to date in this room, and one of my best ever.
System Weaknesses:	None really, I live in a condo and have to keep the levels down most of the time. I'd like to be able to crank it up more often.
Video/HT System: Separate
TV/Projector:	32 inch RCA console with space in the bottom for components. (Got to replace this)
Processor/Receiver/Amplifiers:	Onkyo Integra TX-870 receiver. A big brute from 1989-90. I have two and the second one is in the living room system.
Speakers (Center, Surrounds, Sub):	Speakers are stereo only. Bose AM-5 series II. Very difficult to set up properly; but once that's accomplished, they sound quite good. Their best point is the high WAF. The little satellites are white and virtually invisible against the off white walls in our living room, and the woofer module hides behind the TV which sits across the corner. I was surprised how good they sound when well set up. But given the difficulty, I'd guess very few are properly set up.
Sources (DVD/VCR):	LG DVD player/recorder/VCR combo.
Other HT Gear:	none
Comments on HT System:	When watching movies on the TV, the set's speakers are left on to provide a nice center fill and a three channel effect.
Other Interests/Hobbies/Occupation:	Retired Engineer, professional background in vibration and acoustics for 12 years of my career, car and racing fan, golf club builder/player, computers, serious photography (now digital), and I have a nice electronics bench for hobby projects and audio.