Fjd Posted October 16, 2015 Share Posted October 16, 2015 I've got another post on this; however, since I don't have this one in the Talkin' Tubes forum, many years ago there was an unusual class of tubes designed for the sweep circuits in tube-type TV sets that have substantially large reserve current capability; hence the name “sweep tubes” was coined. While sweep tubes are no longer made and some versions are getting much harder to find, there are examples that are still quite common. The sweep tubes can put out huge power levels and still have substantial reserve capability. Pete Millett’s Engineer’s amplifier [also known as a “Distortion-cancelling Push-Pull" (“DCPP”) amp], uses these unusual sweep tubes. If following Pete Millett's actual design, the DCPP amplifier is actually a 2-stage push-pull pentode design with the output stage biased so it will remain in Class A1 operations until somewhere over 10 watts where it then enters Class AB1. The input/driver stage uses a pair of 6CB6 pentodes in a differential amp configuration using a silicon CCS in the tail. In Pete's design, the output stage uses 12-pin compactron TV sweep tubes, such as the 6JN6 (no plate caps required) or 6JM6/6GV5 (plate caps are required), which have a 17.5 watt plate dissipation. Here is a link to Pete Millett's page where more information on the DCPP amp can be found. http://www.pmillett.com/dcpp.htm Several years ago when Pete Millett started to sell PCBs with his DCPP circuit, George of DIY Audio Tubelab fame, decided to test the upper limits for power in relation to these sweep tubes. George used a power supply that would generate 650 volts at 1.7 amps and plugged in his samples of sweep tubes. The amplifier generated 250 WPC in this configuration with a 2,500 ohm load. Not satisfied, he decided to wire both channels in parallel through a common OPT set for 1,250 ohms and lo and behold; this combination generated 504 watts at 5% distortion and 525 watts at clipping. I bought a PCB but had not done much in the way of putting together my parts list when I found a completed version of the DCPP amplifier come up for sale for slightly less than the parts would have cost me from my preliminary estimates. Here is my Pete Millet DCPP amplifier. My DCPP amp uses the 6JN6 sweep tubes for output and is nowhere near George’s 504 WPC. My amplifier does the 20 WPC that Pete originally designed it for; and at that output, the sweep tubes will probably last a few life-times at that abuse-rate. . 3 Quote Link to comment Share on other sites More sharing options...
Wolfbane Posted October 17, 2015 Share Posted October 17, 2015 1 Quote Link to comment Share on other sites More sharing options...
Tarheel Posted October 18, 2015 Share Posted October 18, 2015 Yamamoto A-08? Quote Link to comment Share on other sites More sharing options...
xxJPMxx Posted October 18, 2015 Share Posted October 18, 2015 (edited) I need to dust lol Edited October 18, 2015 by xxJPMxx 1 Quote Link to comment Share on other sites More sharing options...
Wolfbane Posted October 18, 2015 Share Posted October 18, 2015 Yamamoto A-08? Yes it been happily hooked up to my Belles for the last 700 hours (over 18 months or so). Quote Link to comment Share on other sites More sharing options...
Wolfbane Posted October 18, 2015 Share Posted October 18, 2015 I'm also running the Opera 211/222 and Droplet 5.0 CDP combination in alteration with the Yamamoto Amp. Power tubes are circa 1927 RCA VT4-B's in the Monoblocks and Russian 6H30P-DR Super Tubes in the CDP. Quote Link to comment Share on other sites More sharing options...
Wolfbane Posted October 18, 2015 Share Posted October 18, 2015 My Leben CS300XS. NOS Mullard EL-84 tubes and NOS GE 5751 tubes. Puts out around 15 WPC. Name sounds German but this amp is actually made in Japan. The combination of the gold and silver face with ash reminds me of the Fisher and HH Scott amps and receivers of the early 1960's. Quote Link to comment Share on other sites More sharing options...
Wolfbane Posted October 18, 2015 Share Posted October 18, 2015 A couple of my tube testers. Upper tester is an RCA WT-100A and should have come with a mule from the factory to move it around. The portable tester is a Tripplett 3444. It is a accurate tester which quickly allows you to test a variety of different tubes. The RCA is great for serially testing and matching large numbers of the same tube accurately and quickly. 1 Quote Link to comment Share on other sites More sharing options...
mike stehr Posted October 18, 2015 Share Posted October 18, 2015 Nice gear....especially the Leben. Quote Link to comment Share on other sites More sharing options...
xxJPMxx Posted October 18, 2015 Share Posted October 18, 2015 I love clean tube testers! I gots to get some pics of my Hickok 539b up, it's in really nice condition. Quote Link to comment Share on other sites More sharing options...
Wolfbane Posted October 18, 2015 Share Posted October 18, 2015 Nice gear....especially the Leben. Thanks. The Leben is the best sounding EL-84/7189 tube amp of a number I've owned over the years. The best sounding amp (when matched) with my Klipsch Belle's is the Yamamoto. Quote Link to comment Share on other sites More sharing options...
Fjd Posted October 18, 2015 Share Posted October 18, 2015 (edited) Yamamoto A-08? Yes it been happily hooked up to my Belles for the last 700 hours (over 18 months or so). Do you actually have the Yamamoto A-08S or the Yamamoto A-08, since it appears you have not uploaded actual pictures of your own Yamamoto amp since the amp in the picture is an A-08S? The photos you linked to from the jacmusic and 6moons sites are actually of the Yamamoto A-08S, not the A-08. Please note that there are differences between the two models such as the A-08S added the meter, switched to DC-coupled and switched from the 5U4G rectifier to the 80. Edited October 18, 2015 by Fjd Quote Link to comment Share on other sites More sharing options...
Wolfbane Posted October 18, 2015 Share Posted October 18, 2015 SNIP: Do you actually have the Yamamoto A-08S or the Yamamoto A-08, since it appears you have not uploaded actual pictures of your own Yamamoto amp since the amp in the picture is an A-08S? It is indeed the later A-08S which uses the both the EML Solid Plate 45's and the EML Limited Edition Globe 45's and the EML 80 Rectifier tube shown above. The Globe 45's have been discontinued by EML (they were too fragile to ship safely, even in the giant padded box EML shipped them in). In any case, the Solid Plates version tubes actually sound better than the Globes in my Yamamoto Amp. Quote Link to comment Share on other sites More sharing options...
Fjd Posted October 18, 2015 Share Posted October 18, 2015 (edited) SNIP: Do you actually have the Yamamoto A-08S or the Yamamoto A-08, since it appears you have not uploaded actual pictures of your own Yamamoto amp since the amp in the picture is an A-08S? It is indeed the later A-08S which uses the both the EML Solid Plate 45's and the EML Limited Edition Globe 45's and the EML 80 Rectifier tube shown above. The Globe 45's have been discontinued by EML (they were too fragile to ship safely, even in the giant padded box EML shipped them in). In any case, the Solid Plates version tubes actually sound better than the Globes in my Yamamoto Amp. Cool! I have the EML mesh plate 45 and the EML Globe 45 (rather than risk shipping I picked up in person at tubesusa in NY when I worked on a job close to that area); however, I have not heard the EML solid plate 45. I have not done any comparisons between mesh and globe since I run them in different amps. Here is a picture of my mesh plates in my Electra-Fidelity silver 45 amp, but I can only find pictures of the underside of my Yamamoto A-08S and can't seem to find my pictures of the top side of the amp with the globes. Here are a couple of pictures of the underside of my Yamamoto A-08S amplifier that was a kit build. I've wanted to rewire it, but the guy I bought it from did not have the instructions or schematic and voltages and I have not been able to track any of this down. I suppose at some point I will take voltage measurements and just try to draw it out then rewire. . Edited October 18, 2015 by Fjd 1 Quote Link to comment Share on other sites More sharing options...
Fjd Posted October 18, 2015 Share Posted October 18, 2015 (edited) Here is a nice bi-amp set up for my Jubilees with the Wright Sound Mono 10 push pull amplifiers with 2A3 tubes (more info on prior page) on the bass bins and the Wright Sound Mono 3.5 DHT SET amplifiers also with 2A3 tubes on the K-402. . Edited October 18, 2015 by Fjd 1 Quote Link to comment Share on other sites More sharing options...
tube fanatic Posted October 18, 2015 Share Posted October 18, 2015 Gorgeous pics of all of those amps!!! If I weren't so cheap I'd try to come up with similar cabinetry! Leben is still my favorite modern amp company, not only in terms of their appearance, but also because of their under chassis construction. The folks building them are obviously artists who really care about the quality of their work. Maynard Quote Link to comment Share on other sites More sharing options...
mike stehr Posted October 18, 2015 Share Posted October 18, 2015 The Leben CS300XS is one tube amplifier that I desire to have, and would buy it if I could afford it. For now, the lowly ol' Scott LK48B will get me by... Here are a couple of pictures of the underside of my Yamamoto A-08S amplifier that was a kit build. I've wanted to rewire it, but the guy I bought it from did not have the instructions or schematic and voltages and I have not been able to track any of this down. I suppose at some point I will take voltage measurements and just try to draw it out then rewire. They look to be nice quality parts. The layout and wiring could be a bit tighter, but doesn't appear to too bad. It shouldn't be difficult to follow the circuit and draw up a schematic without measuring any voltage...of course, indication of voltage is a nice option with a schematic. Quote Link to comment Share on other sites More sharing options...
whatever55 Posted October 18, 2015 Share Posted October 18, 2015 Does anyone here have any OTL amps ? Quote Link to comment Share on other sites More sharing options...
Wolfbane Posted October 18, 2015 Share Posted October 18, 2015 I love clean tube testers! I gots to get some pics of my Hickok 539b up, it's in really nice condition. Lol! The pictures above I 'borrowed the link(s)' from the internet. Mine are pretty clean but not clearly visible or packed away. I also don't need some Klipsch Wit here accusing me of selling him something. I'm a good buyer, but bad seller. Quote Link to comment Share on other sites More sharing options...
Wolfbane Posted October 18, 2015 Share Posted October 18, 2015 Here is a nice bi-amp set up for my Jubilees with the Wright Sound Mono 10 push pull amplifiers with 2A3 tubes (more info on prior page) on the bass bins and the Wright Sound Mono 3.5 DHT SET amplifiers also with 2A3 tubes on the K-402. . Very nice!! Are these from the 'Wright' amp builder who lived in Washington State before passing away 5 or so years ago? Quote Link to comment Share on other sites More sharing options...
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