JRDG Company Special – Model 2

1994-1999

Retail price in 1998 in the Netherlands 7.940 euro

The model 2 (the black one on top) is a more modern design than the model 1. Inside it is highly sophisticated and well-worth using a transparent cover! Fully balanced, efficiently biased highly but not too high using bipolar transistors and with several adjustments possible on the rear this is a very flexible amp. Both technically and audibly it is like a stereo version of the model sixes.

In my opinion one of the best stereo poweramps around. It doesn’t have it’s predecessor’s thickness/warmth but it threads a fine balance between resolution, pace, openness, air, transient speed and attack on the one hand and fluidity, warmth and sheer musicality on the other. This amp is incredibly fast and well-controlled and you might even find it slightly lean in balance, but is it ever so musical! It has the most airy and fluid/continuous treble that I have ever heard. It surpasses even all the tube amps that I heard in my setup so far in this respect while maintaining speed and control and that’s saying something. I compared it directly to the model 6 monos on both B&W Nautilus 804’s and Martin Logan SL3’s and they are sonically very close. You really have to know your system well to be able to tell the differences. The sixes do have some more bass and a wider soundstage. But that’s about it. Sure the sixes also have more power reserve but you don’t notice this unless you start abusing the volume control, or have more demanding speakers.

Above: Model 2 + BPS2

Above: Model 2 + BPS2 rearside (no DC cable connected, and amp socket shorted with cap). Notice the two switches on the rear, near the right hand speaker binding posts? They are for gain and impedance. With these switches you can influence the sound quite a bit. Low impedance makes for less attack and perceived dynamics but is a lot smoother and more fluid in the highs while high gain has again more attack but is also more dry and low gain is more relaxed. These switches are both on the model 2 and model 6 as well as on a lot of other Rowland amps.

Model 2 flightcase

Inside Pics

The model 2 is very closely related to the model 6. While the latter are mono blocks in which each side handles one phase of the signal to combine into one balanced mono signal per amplifier, the model 2 divides the available 16 transistors over two channels while retaining the balanced topology.

Above: Model 2 top side inside

Above: Model 6 mono block top side inside

Above: Model 2 underside inside

Above: Model 6 monoblock underside inside (front-rear reversed)

Troubleshooting

Model 2 Fuse blown

I’ve had an instance where the fuses in my Model 2 were blown and apparently this has happened to others. The fuses are located in the sidepanel heatsinks, two on the left and two on the right. Just in case that a previous owner has installed different fuses here’s what is supposed to be in there: Fast Blow 5 to 7 amp.

(Optional) BPS unit DC Cable Compatibility

Model 2 Features

XLR Balanced Input jacks for balanced (Differential Mode™) system configurations

XLR to RCA Input adapters included þUser-selectable overall gain of 26 or 32 dB

User-selectable input impedance of 36kΩ(HI) or 600Ω(LO)

All internal signal circuitry is totally isolated from chassis and system ground potentials to eliminate noisy ground loops and to provide extreme immunity from RF interference

Optional remote (wired or wireless power ON/OFF switching)

Automatic temperature stabilizing circuitry maintains constant operating temperature

Standby power condition reduces warm-up time

Fail-safe operation provided by user-resetable AC circuit breaker located on rear panel

Quiet, transient-free operation during power and function mode switching

Automatic input muting under anomalous input or output operating conditions

Balanced Differential Mode™ circuit topology implemented from input to output

Plug-in modules, containing critical electronic circuitry, enhance thermal stability, mechanical integrity and serviceability

Low-resonance, structurally integrated chassis of precision machined aluminum alloy components.

Model 2 Technical Specifications

Output Power Continuous RMS watts
@ 8 ohms 75 watts
@ 4 ohms 150 watts

Power Bandwidth
0.1 Hz to 160 kHz, -3 dB

Slew Rate
80 volts per microsecond

THD and Noise
Less than 0.05% at rated power

Damping Factor
Greater than 100, 20 Hz to 20 kHz, 8 ohms

Output Current
20 amps continuous
35 amps peak

Overall Gain & Sensitivity
User selectable on rear panel (1 watt, 8 ohms)
26 dB or 32 dB; 141 mV or 71 mV

Input Impedance
User selectable on rear panel
Unbalanced 36k or 600 ohms
Balanced 36k or 600 ohms

Common Mode Rejection Ratio
Greater than 60 dB, 20 Hz to 20 kHz

Power Consumption
25 watts standby
175 watts operating, idle;
400 watts maximum

Inputs
User selectable on rear panel
Unbalanced With supplied XLR/RCA adapter
Balanced 2 XLR connectors

Outputs
1 pair binding posts per channel

Dimensions
17.5 in. W x 14.25 in. D x 5.25 in. H 44.5 cm W x 36.2 cm D x 13.3 cm H

Shipping Dimensions
24 in. W x 20 in. D x 12 in. H 61 cm W x 50.8 cm D x 30.5 cm H

Weight
47 lbs. (21.5 kg)

Shipping Weight
75 lbs. (34.0 kg)

BPS (Battery Power Supplies)

BPS-2
BPS Main Page

More Jeff Rowland

Jeff Rowland Company Special Main Page
Jeff Rowland Company Special Power Amplifiers