ninanina Posted April 23, 2013 Share Posted April 23, 2013 This is probably a million dollar question but: I am trying to choose between a 845, 2A3 or 300b based amp to drive my Heresy's I have only heard a 300b amp and that was pretty sweet (not connected to Heresy's at the the time though), I've not yet heard a 845 or a 2A3 based amplifier Any help greatly recieved Bev Quote Link to comment Share on other sites More sharing options...
Daddy Dee Posted April 23, 2013 Share Posted April 23, 2013 845 is probably too low power to work well with Heresy. i've done some listening with Heresy and 2A3 and thought the sound was good as long not alot of loud listening is needed. Heresy not being as efficient as the large Heritage speakers, it's not a sure thing for a satisfactory option. conventional wisdom would probably recommend 300B over 2A3 and 845, though some would still think this was under powered. i'm a fan of the sound of SET and Klipsch Heritage, though. think it would work ok for me. 300B would likely be my pick for driving Heresy given the options. of course, any way you have of auditioning the amps before committing is a plus. Quote Link to comment Share on other sites More sharing options...
mike stehr Posted April 23, 2013 Share Posted April 23, 2013 http://tdsl.duncanamps.com/show.php?des=845 Quote Link to comment Share on other sites More sharing options...
Marvel Posted April 23, 2013 Share Posted April 23, 2013 Dee, I think you are confusing the 845 with a 45. The 845 can rather easily do 25 watts, if not higher. The 45, on the other hand is only about 1.5 watts. Bruce Quote Link to comment Share on other sites More sharing options...
tube fanatic Posted April 23, 2013 Share Posted April 23, 2013 It is wonderful to encounter so much interest in tube amps on the forum lately! As DD said above, auditioning an amp in your own system is the only way to make a judgment about what will be most satisfactory. I presume you are looking to purchase a commercial amp as opposed to building your own (is anyone even making an amp using the 845? That tube requires very high voltage, current, and drive- not something to tackle without lots of experience!) But, if you are planning to build your own, there are much less costly ways to get sufficient power than using a 2A3 or 300B. Maynard Quote Link to comment Share on other sites More sharing options...
Guest David H Posted April 23, 2013 Share Posted April 23, 2013 Of the 3 listed, I would vote for the 300B, however there are a lot of amps nicely suited for use with Heresy's I see a lot of suggestions going around to try different amplifiers, and although I think this is a great idea, I find there are less and less shops willing to loan amps for testing, and if they are willing, you a probably paying a premium for it. Dave Quote Link to comment Share on other sites More sharing options...
Marvel Posted April 23, 2013 Share Posted April 23, 2013 I don't even want to know the price... http://www.usatubeaudio.com/naf-845-se-special.php Made Bruce Quote Link to comment Share on other sites More sharing options...
Daddy Dee Posted April 23, 2013 Share Posted April 23, 2013 Bruce. you are right. i had the amps confused. 845 at 25wpc or so would be killer! Quote Link to comment Share on other sites More sharing options...
tube fanatic Posted April 24, 2013 Share Posted April 24, 2013 I don't even want to know the price... http://www.usatubeaudio.com/naf-845-se-special.php Made Bruce Thanks for posting that Bruce! It was costly indeed: http://www.audioasylumtrader.com/ca/listing/Integrated-Amplifier-Tube/New-Audio-Frontiers/845-SE/Special-Edition/77354 The designer of that monster is even more insane than I am!!! Maynard Quote Link to comment Share on other sites More sharing options...
ZAKO Posted April 24, 2013 Share Posted April 24, 2013 There are MEDS. for that.. Quote Link to comment Share on other sites More sharing options...
moray james Posted April 24, 2013 Share Posted April 24, 2013 some quality audio tubes are EL34, 6V6 in an octal (6AQ5 in a mini rugidized, better), 6BQ5 and a 6BM8 which is to the Japanese what the 300B is here. I would not discount the 2A3 with serious supplies can easily power a Heresy in single ended mode. I would highly recommend that you stay away from the big gun tubes mentioned as they require supply voltages which are lethal. If you do not have much experience attempting to build an amp with supply voltages this high is not a good idea. I would suggest that you do some listening to get some sense of flavor. Remember that the supply is every bit as important as the tube. Best regards Moray James. Quote Link to comment Share on other sites More sharing options...
tube fanatic Posted April 24, 2013 Share Posted April 24, 2013 some quality audio tubes are EL34, 6V6 in an octal (6AQ5 in a mini rugidized, better), 6BQ5 and a 6BM8 which is to the Japanese what the 300B is here. I would not discount the 2A3 with serious supplies can easily power a Heresy in single ended mode. I would highly recommend that you stay away from the big gun tubes mentioned as they require supply voltages which are lethal. If you do not have much experience attempting to build an amp with supply voltages this high is not a good idea. I would suggest that you do some listening to get some sense of flavor. Remember that the supply is every bit as important as the tube. Best regards Moray James. Some excellent tubes cited by Moray and there are many more. But, even the voltages used by those tubes can be lethal, so don't be lulled into a false sense of security by a 250 volt/40 or 50 milliamp supply for example. Quote Link to comment Share on other sites More sharing options...
moray james Posted April 24, 2013 Share Posted April 24, 2013 Good point made by tube fanatic but voltages over 1000 volts and your margin of error is very small so only for those who are well experienced on the bench. You can buy one though. Best regards Moray James. Quote Link to comment Share on other sites More sharing options...
oldtimer Posted April 24, 2013 Share Posted April 24, 2013 Heard enough yet Bev? Stick to SS or you will end up looking like thebes. Quote Link to comment Share on other sites More sharing options...
Dr Morbius Posted April 24, 2013 Share Posted April 24, 2013 Wow, $14,000 for an 845 integrated amp. I believe I'll stick with my H.H. Scott 299C amp for $670, and that includes a going over by Craig at NOS Valves. Couldn't be happier!!! Quote Link to comment Share on other sites More sharing options...
tube fanatic Posted April 25, 2013 Share Posted April 25, 2013 Heard enough yet Bev? Stick to SS or you will end up looking like thebes. Are you implying that Marty isn't handsome????????????? Quote Link to comment Share on other sites More sharing options...
JBryan Posted April 26, 2013 Share Posted April 26, 2013 Being a long time SET enthusiast, I'd never steer anyone away from the experience but I've gotten a lot of pleasure listening to EL-84 SE amps through smaller-sized efficient speaks, including Heresy's and single driver designs. At 10-12 w/ch, the EL84 SE amps (I've had 2) convey much of the detail and 'air' of triode amps but also offer a bit more control and power to the woofers. The EL-84 tube seems to have a very nice balance that works particularly well in these applications. Of the 3 amps mentioned, the 2A3 would be my choice although it may come across a little bright on the Heresy's and you'd be limited to sub-90dB levels in an average room before compression and distortion would become noticeable. The 300b is a good match if you prefer a thicker, more syrupy presentation compared to the 2A3 and an 845 amp would be an outstanding choice but I've had 2 and listened to several others and have yet to come across one that didn't have a slight hiss or hum in the background - regardless of price. The quietest ones cost $10K+ but still weren't as quiet as 2A3 and 45 amps I've heard that cost 10x less. Of course, it's all about synergy and half the battle is to match gear that doesn't create or enhance noise. Quote Link to comment Share on other sites More sharing options...
mike stehr Posted April 26, 2013 Share Posted April 26, 2013 Being a long time SET enthusiast, I'd never steer anyone away from the experience but I've gotten a lot of pleasure listening to EL-84 SE amps through smaller-sized efficient speaks, including Heresy's and single driver designs. At 10-12 w/ch, the EL84 SE amps (I've had 2) convey much of the detail and 'air' of triode amps but also offer a bit more control and power to the woofers. The EL-84 tube seems to have a very nice balance that works particularly well in these applications. Are you sure the two SE EL-84 amplifiers you had were 10-12 watts per channel? With my adventures of single-ended EL-84/6BQ5 amplifiers/amplifier circuits, I'm more used to 4-4.5 watts per channel. (or less) The SE 6BQ5 amplifier circuit I always enjoyed is the RH84. I did up a breadboard circuit of RH84, using big ol' James 20 watt universal OPTs with the 5K primary taps. I used metal polypropelenes for each cathode of EL-84, which I think is better than a electrolytic soundwise, provided you have the room. The circuit called for 10uF for de-coupling/filtering for 12AT7...I used a 100uF value. Things sounded best to my ears with the tube power supply set at 275-280 vdc...any more and things sounded a bit stressed. Wonderful sound on my Cornwalls, a bit better than my Maggotbox SEP 6BQ5 amp, which sounds rather nice as well. I dunno what commercial offerings are in the way of single-ended 6BQ5/EL-84 amplifiers, but one can build one for peanuts and be rather close to the sound of a DHT triode SE amplifier. This is a ongoing project...RH84, using some pulled German OPTs or some such. Not on par with the James OPTs, but fairly close. Quote Link to comment Share on other sites More sharing options...
tube fanatic Posted April 26, 2013 Share Posted April 26, 2013 Of the 3 amps mentioned, the 2A3 would be my choice although it may come across a little bright on the Heresy's and you'd be limited to sub-90dB levels in an average room before compression and distortion would become noticeable. The 300b is a good match if you prefer a thicker, more syrupy presentation compared to the 2A3 and an 845 amp would be an outstanding choice but I've had 2 and listened to several others and have yet to come across one that didn't have a slight hiss or hum in the background - regardless of price. The quietest ones cost $10K+ but still weren't as quiet as 2A3 and 45 amps I've heard that cost 10x less. Of course, it's all about synergy and half the battle is to match gear that doesn't create or enhance noise. As I've mentioned in previous threads, it's impossible to compare the sound of various output tubes unless identical output transformers and voltage amp tubes (if suitable), at the very least, are used. An amp which is bright sounding may be made more smooth by juggling operating parameters which change the distortion characteristics, or by using a little negative feedback where appropriate (yes, even in some SETs, a little fb can't hurt.) There is simply no way to generalize about this. Synergy is absolutely critical if buying commercial equipment, as stated. An advantage of having a custom amp designed and built is that the designer can start at the speakers/room and work backwards to achieve exactly the kind of sound desired. Hiss is often related to a voltage amp stage which has too much gain (common with super efficient Heritage Series speakers.) That's easily dealt with in a custom amp, but not with most commercial equipment. Out of curiosity, are you still with this thread Bev? Hopefully you haven't been chased away by all of us crazy audiophiles! And, if you are sufficiently skilled to go the DIY route, the rewards will be amazing and well worth the effort. Regards-- Maynard Quote Link to comment Share on other sites More sharing options...
Marvel Posted April 26, 2013 Share Posted April 26, 2013 Maynard, I'm going to send a pm to ask some questions about a Hammond 3 channel amp out of a PR20 tone cabinet... Bruce Quote Link to comment Share on other sites More sharing options...
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