{"id":9087,"date":"2016-11-25T11:10:57","date_gmt":"2016-11-25T09:10:57","guid":{"rendered":"http:\/\/www.hifi-advice.com\/blog\/?page_id=9087"},"modified":"2022-12-12T14:20:05","modified_gmt":"2022-12-12T12:20:05","slug":"jrdg-company-special-model-5","status":"publish","type":"page","link":"https:\/\/www.hifi-advice.com\/blog\/jeff-rowland-power-amplifiers\/jrdg-company-special-model-5\/","title":{"rendered":"JRDG Company Special – Model 5"},"content":{"rendered":"

1986-1991<\/b><\/p>\n

Retail Price unknown<\/p>\n

\"jeff-rowland-model-5-0251813922_g_550pix\"<\/p>\n

The model 5 can be seen as a more affordable but still hugely powerful stereo version of the model 7. You can tell model 7 and model 5 apart by looking at the handles’ shape: the model 7<\/a> (not pictured) has square parts while the model 5 has rounded parts.<\/p>\n

\"rowland-model-5-front_400pix\"<\/p>\n

The model 5 was available in gold, black, and silver<\/p>\n

\"rowland-model-5front-silver_550pix\"<\/p>\n

And there was also an option for rackmount holes as can be seen below<\/p>\n

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\"rowland-model-5-in-black-2955388299_g_550pix\"<\/p>\n

Like its bigger brother the model 7, the model 5 was available in a few versions that are functionally different. From the information that I found there are at least 3 versions with respect to back panel functionality. The below two pics for example have double speaker connector strips.<\/p>\n

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\"model-5-0b_550pix\"<\/p>\n

The two pics below show a version that has both metal strips and knobs for speaker connection.<\/p>\n

\"model-5-0c_550pix\"<\/p>\n

\"jeff-rowland-model-5-rear-0251813922_2_g_550pix\"<\/p>\n

The picture above shows a version that only has cinch inputs, no XLR.<\/p>\n

Originally Jeff Rowland amps such as the model 1, model 3, and model 7 used strips with screws for connecting loudspeaker cables. This worked fine for bare wire and spades but would not play ball with bananas. Also, the screws were prone to damage after being tightened and loosened multiple times and would eventually wear out either on the head (making the screwdriver lose grip) or even in the thread. The thing is that the screw sizes used are US standard and these are not easily available in Europe.<\/p>\n

More information about JRDG speaker binding posts<\/a><\/p>\n

On the inside, too, there are distinctions pointing to several different versions having been available.<\/p>\n

\"rowland-model-5-inside-2955388299_2_g_450pix\"<\/p>\n

\"rowland-model-5-dsc_0005_550pix\"<\/p>\n

\"rowland-model-5-dsc_0011_550pix\"<\/p>\n

\"rowland-model-5-dsc_0009_550pix\"<\/p>\n

The above pics show a model 5 with 4 extra bypass capacitors on top of the big main caps but the picture below shows a model without them.<\/p>\n

\"rowland-model-5-internals_400pix\"<\/p>\n

Below is a picture showing a third version with not only the 4 bypass capacitors but also some extra electronics near the (knob) speaker terminals.<\/p>\n

\"model-5-1d_550pix\"<\/p>\n

Below is a model 5 with its side panels opened as would be needed for repairs. Although Rowland amps in general rarely need service, it’s admirable how user-friendly this amp is put together.<\/p>\n

\"model-5-2_550pix\"<\/p>\n

Model 5 Features<\/h2>\n

Lack of overall or nested negative feedback eliminates time-domain distortion.<\/p>\n

Proprietary distortion canceling techniques minimize amplitude-related distortions.<\/p>\n

Each transistor individually tested and matched for optimum operating characteristics.<\/p>\n

Constant output impedance is maintained over the entire audio range, allowing for universal compatibility with associated equipment.<\/p>\n

The large number of high-speed bipolar output transistors provides uncompromising reliability and eliminates the need for electronic protection circuitry.<\/p>\n

A single voltage amplification stage utilizes field effect transistors (operating in transconductance mode), which increases low-level signal recognition.<\/p>\n

The absence of capacitors, inductors, fuses and protection circuitry throughout the signal path eliminates the adverse effects of these devices.<\/p>\n

A specially designed toroidal power transformer is supported by the substantial output stage capability.<\/p>\n

All critical circuitry is encapsulated in a thermally-conductive epoxy to ensure excellent thermal stability, mechanical integrity and to facilitate ease of service.<\/p>\n

Model 5 Technical Specifications<\/h2>\n

Output power<\/strong>
\n150 watts RMS continuous, 8 ohms
\n300 watts RMS continuous, 4 ohms
\n475 watts RMS continuous, 2 ohms
\nPower Bandwidth<\/strong>
\n0.15 Hz to 250 kHz, -3 dB
\nSlew Rate<\/strong>
\n75 volts per microsecond
\nTHD and Noise<\/strong>
\nLess than .03%, 1 kHz, 8 ohms, 20 watts
\nLess than .075%, 1 kHz, 8 ohms, 60 watts
\nDamping Factor<\/strong>
\nGreater than 175, 20 Hz to 20 kHz, 8 ohms
\nGreater than 60, 100 kHz, 8 ohms
\nOutput Current<\/strong>
\n40 amps peak, continuous
\n90 amps peak, 0.1 ohm, 20 msec, 1 kHz
\nOverall Gain<\/strong>
\nSelectable: 20, 26, 29.5, 32 dB
\nSensitivity<\/strong>
\n36 mV, 1 watt, 8 ohms
\nInput Impedance<\/strong>
\nSelectable: 100k, 20k, 600 ohms
\nCommon Mode Rejection<\/strong>
\nRatio Greater than 90 dB
\nBridged Mono Output<\/strong>\u00a0Power
\n550 watts RMS continuous, 8 ohms
\n800 watts RMS continuous, 4 ohms
\n1000 watts RMS continuous, 2 ohms
\nPower Requirements<\/strong>
\n100V-240V<\/p>\n

More Jeff Rowland<\/h2>\n

Jeff Rowland Company Special Main Page
\n<\/a>Jeff Rowland Company Special Power Amplifiers<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

1986-1991 Retail Price unknown The model 5 can be seen as a more affordable but still hugely powerful stereo version of the model 7. You can tell model 7 and model 5 apart by looking at the handles’ shape: the model 7 (not pictured) has square parts while the model 5 has rounded parts. The […]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":8319,"menu_order":0,"comment_status":"open","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-9087","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.hifi-advice.com\/blog\/wp-json\/wp\/v2\/pages\/9087","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.hifi-advice.com\/blog\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www.hifi-advice.com\/blog\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/www.hifi-advice.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.hifi-advice.com\/blog\/wp-json\/wp\/v2\/comments?post=9087"}],"version-history":[{"count":7,"href":"https:\/\/www.hifi-advice.com\/blog\/wp-json\/wp\/v2\/pages\/9087\/revisions"}],"predecessor-version":[{"id":33662,"href":"https:\/\/www.hifi-advice.com\/blog\/wp-json\/wp\/v2\/pages\/9087\/revisions\/33662"}],"up":[{"embeddable":true,"href":"https:\/\/www.hifi-advice.com\/blog\/wp-json\/wp\/v2\/pages\/8319"}],"wp:attachment":[{"href":"https:\/\/www.hifi-advice.com\/blog\/wp-json\/wp\/v2\/media?parent=9087"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}