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In Reply to: Now, a killer 45 push/pull amp done right . . . posted by Poindexter on January 21, 2007 at 17:45:37:
Are you volunteering, Poinz? Coz if you are, come to Cyprus with the machine and sign me up for a review. The only production 45 push/pull I've managed to identify is the DIY HiFi Supply one - and Brian's put me on the books for a review unit when one becomes available before it sells to a paying customer. It seems he's selling them fine so it may be a while. But that's cool, I'm not in a rush. I'm just curious about the inherent promise now that the Canary 300B SE vs. p/p comparo pointed to the very real possibility that a 45 push/pull (I'm a 45 man, not a 300B dude) might just take the cake and go for a loooong walk -:)
Follow Ups:
I have a variation of the Machine circuit that I was planning on using for 2A3s, it's certainly directly applicable to 45s, but there are some little snags. The 45 has twice the plate resistance and half the transconductance of the 2A3; it's a bit of an excercise to get decent power out of it, PP or SE. It seems everybody is loading the thing to death, which I hate; but maybe it works with this device.Also, we have a common associate, your neighbor, who considers the 45 the Device at the Top, and he has experimented exhaustively. He also showed me his stash of NOS 45s, which would put most tube junkies into cardiac arrest. This is definitely a Situation.
Stay tuned, my man.
Aloha,
A Situation. I luv it. Keep talking dirty, Poinz!
Srajan, I would be curious of your view of 845's compared to others. I like them myself but sometimes wonder (like Thorstens description of them as bleached sounding).
Well, I've heard some but I don't consider myself an expert.It seems that the kind of transformers necessary for the very high voltages 845s operate on have their own signature. Of course as a listener, you can't distinguish - you just hear the amp/speaker combo. Unless you build yourself, there's no way to point the finger at the tube or transformer or any other part in the amp.
For my ears, 845s always sounded a bit fuzzy and fluffy and loose, especially compared to 45s which to me sound crystalline, fast and accurate and do energy. You might say that the 845s sound far push-pullier even in a single-ended circuit than 45s - again, to my ears. And I seem to be an SET man in general though I'm always open to be proven wrong in my preferences. Hence my curiosity over a superior 45 push/pull.
Of course 45s don't drive anything except for a few 100dB+ speakers (roughly) whereas 845s open the doors to a wider speaker audience. Given that you can now enjoy single-ended tube sound, there's much to be said for 845s. But in my universe, you get yourself speakers that are copasetic with micro-power SETs first, then explore the 300B, 2A3, 45, 50 and other exotic flavors that are available in that field to find out what you like. That, to me, lands you in the heartland of what that whole thing is about. Going to 845s and 211s and GM70s and 833s is a different game - high-power SETs. Mind you, I didn't say worse or better, just different. For the time being, I'm still in exploratory mode on the low-power thing - for my personal bias. When it comes to reviews, I do anything and everything I can accommodate and have suitable gear for. When it comes to what I'm personally most curious about, it's the low-power hi-eff meeting and how to maximize its magic while minimizing its liabilities. Hence Zu, WLM, Ocellia, HornShoppe and other assignments I'm planning on this year on the speaker front... if I'm "promoting" low-power SETs thru my writing and personal enthusiasm, I better also introduce speakers that work with them or I do a disservice to my readers.
It's all a give and take and making your compromises work for you. That's, in the end, what it comes down to. There'll never be the point where you couldn't visit a buddy and hear his system do something yours can't do as well - or merely differently -:)
Intersting thoughts on the 845 sounding push pull like. Could be the same thing others are hearing when they ssay it sounds more mechanical.
I think this actually adds to it for me. While not having the most creekiest, make your hair stand on end violin sound, it adds from push pulls dynamic capabilities. So it gives up something but gains elsewhere.
Now if I went from my 100db speakers to a 116db Klipsch maybe I would think otherwise.
there is just something about the tone of a 45 that's just right for acoustic instruments. Anyway, if you take one of Lynn Olson's designs and drop in a 45 you should have something close to magical.
...if his Mono 10 (PP 2A3) can be modded to take 45s. Probably it would just involve a change of cathode resistors. Those amps show up used from time to time, if cost is an issue.
If you're a fan of the 2A3, give a listen to his AU-15. George brought by a pair for us to hear in our home, and three months later, we just couldn't get them off our mind. We now have a pair on order, as does a friend. The AU-15 were the first push-pull to really hit me in the gut.
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