Bonzo Posted January 30, 2015 Share Posted January 30, 2015 (edited) I have a beautiful pair of Single Ended Tube, Class A, mono block amplifiers for sale. These were expertly built by a tech. in Northern California. I can provide more information to interested members via PM or e-mail. Quite simply, these are stunning! Best amplifiers I have ever had and I have had a boat load. Unfortunately, in the interest of marital harmony, I am going to sell them. The 813 power tubes were originally designed for AM transmitters and can take up to 3K volts on the plate. These amps are set at 750 VDC so they aren't even breaking a sweat. Here is a summary of the build provided by the tech: "The amps use custom Edcor power transformer feeding a pair of Svetlana 6D22S damper diodes.I have found them to be excellent, especially for higher voltages. This feeds a CLCLC type supply, 3 uF stacked solen film caps to a NOS Stancor 300 mA, 8 Henry choke, 3 stacked Nichicon electrolytics chosen for low ESR. 3X450 for a total of about 125 uF, then to a 3H Hammond choke, then 40 uF Solen film caps. I have a separate power supply for the front end. It is a Glassware PS1 with choke load set to 300 VDC. This feeds the front end section which is a Glassware Aikido featuring the 6SL7 into the 6SN7 driving the 813. The 813 is currently ran in Ultralinear mode to the Hammond 1628 SE transformer. I am using Rod Coleman regulators on the 813 filaments to ensure quiet operation. The 813 uses NOS EF Johnson socket and plate cap. NOS Superior Electric Binding Posts were used. The bias adjustable via a 10 turn pot on top,reading the milliamps of plate current directly on the meter allowing one to vary the operating point and sound quality. The amp is built in a modular fashion making upgrades very easy. I also designed the amp to be scaleable in terms of power output. Currently the plate voltage is set at about 750 VDC but by changing the value of the first cap can be upped to easily over 1 KV which will increase the power output to maybe 60W. Right now I see 40 clean watts which is plenty for me. The base is Honduran Mahogany and the plate is 1/8 inch Brass that I had polished and clear coated at a place in Sacramento to protect the finish. The clear coat is so thin as to be undetectable. Tube compliment is NOS RCA throughout. The amp presents a very easy to drive load (100 K) compatible with most pre-amps. Rich and punchy is the best way to describe the sound of these.They respond well to tube rolling on with the 6SL7 especially. If you like vocals they deliver in spades with headroom to spare do to the 40 watts available." They are mirror imaged save for the driver tubes due to the configuration of the boards. I will include spare driver tubes and damper diodes. I will be happy to answer any questions to the best of my ability. I can also provide additional pictures to interested members. I prefer local pick-up in Redding, California where they can be demonstrated. I am willing to travel a reasonable distance for the right deal. Shipping is possible but, naturally, will be very expensive. They are about 60lbs each unpacked. I would get the help of a local packing company that I have had great success with in the past. My asking price is $2000.00 US OBO. I do have a Paypal account and would prefer to at least split the fees. Postal Money Order or cash would be preferred. Thanks! Edited February 4, 2015 by Bonzo 1 Quote Link to comment Share on other sites More sharing options...
OO1 Posted January 30, 2015 Share Posted January 30, 2015 very nice set - sure must sound great Quote Link to comment Share on other sites More sharing options...
Bonzo Posted January 30, 2015 Author Share Posted January 30, 2015 Thanks, they do sound great and I will miss them! Quote Link to comment Share on other sites More sharing options...
toolz Posted January 30, 2015 Share Posted January 30, 2015 Sweet, GLWYS. Quote Link to comment Share on other sites More sharing options...
alexg5775 Posted January 30, 2015 Share Posted January 30, 2015 Very nice Quote Link to comment Share on other sites More sharing options...
SonicSeeker Posted January 30, 2015 Share Posted January 30, 2015 Those are very nice GLWS Quote Link to comment Share on other sites More sharing options...
Daddy Dee Posted January 30, 2015 Share Posted January 30, 2015 really, really nice. good looking, too. GLWS Quote Link to comment Share on other sites More sharing options...
Bonzo Posted January 31, 2015 Author Share Posted January 31, 2015 Thanks guys, I have a potential deal in the works. Quote Link to comment Share on other sites More sharing options...
Bonzo Posted February 4, 2015 Author Share Posted February 4, 2015 These beauties are sadly SOLD. Quote Link to comment Share on other sites More sharing options...
Kasanay Posted April 20, 2016 Share Posted April 20, 2016 Bonzo, I know these were sole over a year ago but I was wondering if you happened to have a schematic of the amp & power supply? I have been gathering info to build an 813 amp. Thanks, Quote Link to comment Share on other sites More sharing options...
Bonzo Posted April 20, 2016 Author Share Posted April 20, 2016 (edited) Hello, Sorry, I don't have information on them any longer. Edited April 20, 2016 by Bonzo Quote Link to comment Share on other sites More sharing options...
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