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Best Tube Amp Today? Cost maybe an object


fierce_freak
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Which should I build?  

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  1. 1. Which should I build?

    • TubeLabSE 45
    • Aikido
    • Over-the-top Morgan Jones or Waarde
    • Raven/Karna/L'espressivo (differential)
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The output is taken from the plate. Thing is the 6C33 has a pretty low plate resistance, I think it was somewhere around 90-100 ohms so with a bit of negative feedback around the tube the output impedance can be dropped to a reasonably low level. I remember KG posting the numbers somewhere but I can't find them at the moment.

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The output is taken from the plate. Thing is the 6C33 has a pretty low plate resistance, I think it was somewhere around 90-100 ohms so with a bit of negative feedback around the tube the output impedance can be dropped to a reasonably low level. I remember KG posting the numbers somewhere but I can't find them at the moment.

You got it - output from the plate. And since the 6c33c has a pretty low plate resistance as is (craig has it at 90 ohms), just a bit of negative feedback and he drops it to 12 ohms output.

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(before Jon L jumps in to slap me, this is old photo, I have an upgraded XLR to speaker wire adaptor)

almarro5.jpg

Heck, you get a beating anyway! :stick:

For giving up on 'stats and selling off your Stax SRD7 MkII so quickly :o

Oh, well, maybe later.. once HE Audio cleans up their game.

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best i've heard so far (dynamic) is the tube rectified SDS-XLR. Then the ZD, HD2. I'm not much of a fan of the Maestro/B52/rudi/or WA5, but that's just my opinion. in theory, i'd pick a custom amp like the noise duality or Xana.

that being said, K1000 amps are a totally different ball game

The best I've heard so far is the SDS-XLR (w/ 6BL7gta output tubes), stock SDS-XLR, SDS (w/ high voltage), Supra (w/ high voltage), stock SDS, Zana Deux, stock Supra, and Woo Audio 5. IMO, the Zana Deux and stock Supra is pretty much equal....both are a good bit better than the Woo Audio 5.

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Thanks guys. It seems like an over the top morgan jones, an over the top waarde, or an over the top aikido will be what I'll do (though I'm still eyeing the TubeLabSE). It seems if such great results can come from something similar to a morgan jones (much sds love everywhere) that what looks like a better topology to my n00b eyes (balanced aikido i linked to earlier) could perhaps be even better...though, of course, there could be some distortion or other negative characteristic (from a perfectionist point of view) that makes the sds more pleasing to the ear. That, or just the overbuilt nature of it.

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Try this one. I'm using this for my RS-1 right now and I'm quite happy with it. Instead of the 1+1:1+1 phase-split transformer that's on the schematic, I'm using an old UTC 1+1:1.5+1.5 that's wired up in reverse so that it's a step-down instead of a step-up. Depending on how neat your wiring layout is you might also have to adjust the value of the 4pF grid neutralization caps, which should be >400V silver micas. 4pF is a fairly safe value to avoid oscillations while speeding up the amp a bit. The cap between the centre-tap betwen the output transformer and the cathodes which I forgot to label can be anywhere from about 20-50uF, use a motor run cap that can handle 330V or more. I've wired the Lundahl as a 11k to 8R output. All caps in the PSU are 330V motor run caps, not to be confused with motor start caps. Motor run caps are the big oil impregnated poly film caps, like the ones found in n_maher's Menace amp.

76_amp.jpg

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I might start with a L'espressivo to break myself into ptp wiring first, especially since it's relatively cheap if I screw something up (I've been emailing dsavitsk about this off and on for 6 mo. now).

After that, I think I'll gun for an OTL design as that's what interests me most (though I'm now looking more seriously at the Karna without the third stage using 6w6's). Is it more common for OTL amps to use negative feedback? SP specs less than 20ohm z-out, so those must have negative feedback.

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I might start with a L'espressivo to break myself into ptp wiring first, especially since it's relatively cheap if I screw something up (I've been emailing dsavitsk about this off and on for 6 mo. now).

After that, I think I'll gun for an OTL design as that's what interests me most (though I'm now looking more seriously at the Karna without the third stage using 6w6's). Is it more common for OTL amps to use negative feedback? SP specs less than 20ohm z-out, so those must have negative feedback.

If you want some Hammond 119DA's let me know.

R

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I might start with a L'espressivo to break myself into ptp wiring first, especially since it's relatively cheap if I screw something up (I've been emailing dsavitsk about this off and on for 6 mo. now).

You know, I was afraid of PTP wiring for the longest time but the more that I thought about it I figured it was pretty much the same approach that I take when laying out a project in a chassis. In the end it wasn't really all that big of a deal and I actually enjoyed the experience a great deal.
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OK, then I also recommend the SDS or Dragon (never owned it, seen it, touched it, caressed it, licked it)

I must say that I am very happy with the Dragon. The amount of tubes and adapters that I've tried with it really changes the sound in regards to detail and sound stage. I definitely have fun tube rolling to get different sounds that I enjoy with my different set of cans. :dance:

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best i've heard so far (dynamic) is the tube rectified SDS-XLR. Then the ZD, HD2. I'm not much of a fan of the Maestro/B52/rudi/or WA5, but that's just my opinion. in theory, i'd pick a custom amp like the noise duality or Xana.

that being said, K1000 amps are a totally different ball game

Intelligent choice! O0 Don't forget it is tube regulated also. :police: In fact, I am currently jamming some Albert King on SACD from the EMM Labs to the SDS-XLR with Sylvania Bad Boys for in and 6BL7GTs for out. Oh, and the cans are my balanced Equinox PS-1s that I have been running in for days. Loving every second. :prettyprincess:

I am hoping that The Maher Menacing Millett and the TTVJ Millett give the SDS-XLR a run for the money. More thoughts to follow next week from SoFla.

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I might start with a L'espressivo to break myself into ptp wiring first, especially since it's relatively cheap if I screw something up (I've been emailing dsavitsk about this off and on for 6 mo. now).

Just don't build it with the 6C45P or 5842 on your first go, those tubes are damn twitchy and require a really good clean layout or else they oscillate at some absurd MHz range frequency. Personal experience, I learned that the hard way. You might get lucky, but the odds are against you.

(though I'm now looking more seriously at the Karna without the third stage using 6w6's).

I'm looking at that one too, problem is I can't source the transformers at a price I'm willing to pay. With good transformers you're looking at something like $500-1000 for transformers alone, the parts cost gets out of hand real fast.

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Thanks again for all the suggestions guys. Anyone know what tubes were used in the Blackie Pagano Duality? From the top it looks like a pretty simple and standard topology, but who knows without looking under the hood. I would consider an HD650-specific amp.

aerius, the more I look at your schematic the more I like it. I've never seen grid-neutralization caps before, but the idea seems solid. I'm sure it smokes the lower end SP's...have you had the chance to compare it to some higher-level stuff?

Lastly, can anyone put into words the general difference between transformer coupled and OTL sound? I've read that transformer is more "musical" and OTL is more "accurate." Does that sound...accurate?

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Lastly, can anyone put into words the general difference between transformer coupled and OTL sound? I've read that transformer is more "musical" and OTL is more "accurate." Does that sound...accurate?

I hate to use that description but honestly that is the best that I can put into words. If I were to attempt to be more specific, the transformer amps appear just a tad slower. image outlines are more blurry, images appear to sort of bleed into each other more. OTL is more precise, focused, faster, pinpoint. I am not the expert but I would suppose a cap in the signal path offers a bit more linearity than a transformer. I am making transformer amps sound bad but with really good iron you would never fault the sound unless you compared directly to a top notch OTL that had kickass output caps. If you were to compare apples to apples, a PERFECT kickass transformer no distortion no ringing whatsoever with the best cap, I believe the transformer will sound better because it will offer better drive, lower output impedance, better damping factor, with less loading of the tube. I am not sure if the perfect transformer exists though and if it did man I would imagine it would cost at least 4 figures. You can find great caps for specific topologies for significantly less. I think the best way to compare transformer to OTL is to find designs from the same manufacturer as it will provide a common base to make references from. For example when I compared the moth s2a3 with electraprint trannies to the Zana Deux. I will say that when I compared the OTL HD300 to tranny coupled HD25 I found the HD25 to be way more linear and neutral, with much better soundstage and overall drive than the HD300, but I attribute that more to the HD300 being a more simple raw design and the hd25 using some tricks up its sleeve to get that killer sound at that pricepoint.

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aerius, the more I look at your schematic the more I like it. I've never seen grid-neutralization caps before, but the idea seems solid. I'm sure it smokes the lower end SP's...have you had the chance to compare it to some higher-level stuff?

Grid neutralization works, but it can have issues. Sometimes it can cause instability, sometimes it can cause ringing on transients, and some say it just sounds funny. I've generally had good results with neutralization and have been using it in all my P-P amps.

Lastly, can anyone put into words the general difference between transformer coupled and OTL sound? I've read that transformer is more "musical" and OTL is more "accurate." Does that sound...accurate?

Personally I find transformer coupled amps to be more musical AND accurate, mind you I haven't heard a Zana Deux or any of the other high-end high current output OTL's whereas I've sampled some stupidly good transformer output amps. I like transformers since it gives me more tubes to choose from when building an amp, if you want high current low output Z from an OTL you pretty much have to use a 6AS7, 6C33, or other such large output tubes, while with transformers I can use 6BL7's, 7044's, and even 6SN7's if I wanted to.

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Personally I find transformer coupled amps to be more musical AND accurate, mind you I haven't heard a Zana Deux or any of the other high-end high current output OTL's whereas I've sampled some stupidly good transformer output amps. I like transformers since it gives me more tubes to choose from when building an amp, if you want high current low output Z from an OTL you pretty much have to use a 6AS7, 6C33, or other such large output tubes, while with transformers I can use 6BL7's, 7044's, and even 6SN7's if I wanted to.

I can see where your coming from with that. Take an awesome transformer and couple it to a very linear and transparent tube like a 45 and your pretty much there to riding the line right between great musicality and very linear, accurate, detailed, focused sound.

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Thanks for the replies, guys. I'm still a bit mixed up on which direction I'm going to pursue when I start this project, but that's to be expected ;) I've been reading a lot of stuff about the Darling (1626 output tube) and think it would probably make a really nice headphone amp (possibly great if built correctly), but I'll wait to see what Earl thinks of his when he finally receives it (then breadboard a couple different layouts like SE or DRD). I've done a lot more looking into the TubeLabSE (with 45's if I can find a decent pair) and think it could be the base of a great tube headphone amp, also. I could try to do a knock-off of Blackie's Duality (anybody know what tubes he used?), or I could go for an over the top WCF. Lastly, I could do the first two stages of the Karna, but I'm somewhat afraid that it could be a bit above my ability.

So, choices are Darling, TubeLabSE, something with WCF follower output, Karna, or knock-off of Blackie's Duality (if anyone has any info) or maybe something along the lines of the new Millett amp (again with the DHT's). What do you guys think?

Lastly, anyone have any opinions on James transformers? From everything I've read they look pretty nice, especially for the price, and I've read that the guys behind Tango run it. Other than that I guess it's Lundahls or Electra-Prints?

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