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Good Tube Amp for Denon D2000/D5000? - Page 4

post #46 of 93
Thanks, the Cyber 20 looks interesting.
post #47 of 93

I'd Agree...

Quote:
Originally Posted by Cool_Torpedo View Post
... Knowing a bit the D5000 I'd recommend better a good SS than a tubes one, but by no means I'm suggesting SS is "the way to go", just that you're more likely to find a good match and not falling short of power with "decent" SS than with "decent" tube amps...
At this point in my experience with the D5000s... I'd agree. They sound great with the Graham Slee Solo.

Though... they could sound better... if I ever get the bass to sound as fast, clean, clear and tight as my other phones. To me it makes little difference how low it goes (and it does)... if... its not as fast and tight, as even the HD580/600s.
post #48 of 93
Quote:
Originally Posted by Cool_Torpedo View Post
That I have used none. My opinions about SET amps are based on my experience with them feeding loudspeakers.

Most of the claimed SET HP amps are actually OTL designs (like the Earmax, MicroZotl, etc), and again for my experience using OTL with speakers, they're not quite the same thing, though they have an edge over conventional OT push-pull amps. I'm not sure if the Antique Sound Labs OTL mkIII in its high impedance output gets rid of the OTL circuit and uses an output transformer preserving the SET topology.
Other likely SET HP amp would be the Cary Audio 300SEI, it's a SET integrated with a HP output which should preserve the SET topology, but I'm not sure about it, maybe other members are more familiar with it.
The only SET HP amp I'm completely sure is SET and uses output transformers is the Opera Audio Consonance Cyber20. It's very likely there are more chinese made headamps using similar approach.

If any serious tube amp maker released a HP SET amp I'd be willing to try it. Being a SET for its own sake is warranty of nothing, but if it delivered that special and unique texture of SET speaker amps, it'd be very worth investigating.
Were you aware of more pure SET, not OTL, headphone amps, please share with me.

Rgrds
First, OTL is a cap coupling method of the tube to the load vs transformer coupling the tube to the load. This really has no relevance to SET. SET can use either coupling method. All of MY best sounding headphone amps are both OTL and SET.

I also think you are comparing apples and oranges here. A headphone amp requirements are much different than a speaker amps requirements. A headphone amp doesnt have to deal with the low ~ 4 ohm impedences of speakers. Moreover, a headphone amp does not have to produce multiple watts of output to drive headphones, while integrated/power amps do to drive speakers.

Most of your popular headphones like Grados start @ 32 ohms and spec out @ 100-200 maximum input. Consequently, you have many headphones that dont need tube amps with transformer coupling to have adequate current delivery. You can do SET / OTL for the maximum in tranparency and accuracy.

The higher impedence headphones like the 300 ohm Senns actually thrive on the high voltage/ low current nature of OTL's. But, with headphones needing only miliwatts it is quite easy to make an OTL/ SET tube amp that has plently of power to drive any impedence headphone .... the Singlepower Extreme being one such example @ > 1.5 watts

I have three SET transformer coupled headamps and seven SET/ OTL headamps, plus one push pull / transformer coupled integrated amp. Two of these transformer coupled SET's cheat and use a triode strapped EL84 pentode in the output stage. One transformer coupled SET (Space Tech Lab) uses the same 6AS7G triode output tubes and 6SN7 triode input/ gain tubes as the OTL/ SET Singlepower Extreme which gives you the most relevant headamp comparison between the two types.

In short, the Extreme has better dynamics, more clarity, a richer tonality that still seems very neutral, and finally, a much more expansive soundstage. In this case the transformer seems to be chocking off some of the sound quality. Interestingly as well, the Space tech does not drive low impedence headphones without hum. The transformer tap seems optimized for high impedences. I sometimes like the lazier, less resolving sound of the Space Tech when I want to relax. But, if I want the music to invigorate, involve and excite me it is OTL everytime.

Being able to remove the output transformer is going to give you an output signal that much more closely matches the input signal. Even really expensive output transformers still impact the signal to some extent. I like the SET / transformer coupled sound, but with headphones, atleast in my experience, give me a single ended OTL for the most "real sounding" presentation.

So, in summary, my point is what is relevant with amping speakers is not necessarily relevant with amping headphones.

Pics for the interested ....

Extreme SET/ OTL headamp and Sound Quest SQ-84 PP triode (6V6 triode strapped) transformer coupled 10 watt inegrated speaker and headphone amp.



Space Tech Lab 6AS7G SET headamp with NOS output transformers/ 6080 triode output tubes .... and a heavily modded Doge 6210 SET (cheats with triode strapped EL84's) / transformer coupled headamp.



Another shot of the Space Tech Lab fitted with 6AS7G output tubes and tube socket adapters allowing me to use 6CG7 input/ gain tubes.

post #49 of 93
Quote:
Originally Posted by Cool_Torpedo View Post
If any serious tube amp maker released a HP SET amp I'd be willing to try it. Being a SET for its own sake is warranty of nothing, but if it delivered that special and unique texture of SET speaker amps, it'd be very worth investigating.
Were you aware of more pure SET, not OTL, headphone amps, please share with me.
taking the very narrow definition that the signal is not handled by more than one active device at any stage of the amp here is a PARTIAL list.
carey 300sei is SE input to output, but transformer coupled.
bottlehead sex but parafeed transformer
the mapletree audio design (MAD) headphone amps are single ended, but also with parafeed transformer output.
woo5 (transformer)
woo 1 (otl, cathode follower)
there is another Transformer coupled woo amp that is SE.
singlepower extreme is SE end to end (otl cathode follower).
zana-deux is single ended & otl, but uses a decent bit of GLOBAL feedback. while not specified by the quoted bit, or in specfic violation of what makes an amp "SET", its worth note with the trends of single ended design...

by the absolutely purest definitions of the word, the earmax and most of the singlepower amps are not single ended because multiple devices handle the signal in the output stage. their topology requires full class-a opperation or they will clip hard. i do disagree with whether that is really a problem, but i think that is a mater of how loud we listen. i would listen to one and see if it can meet his sound requirements with dynamic music. a meet is actually a BETTER place for this as you (at least i find myself doing it) listen louder than at home.

the berning zotl amps mostly run PP although he covers single ended opperation in his patents. they have the advantage of NO caps in the signal path but at the expense of extreme complexity and an RF switching power supply.
post #50 of 93
There are several ways to design the output of a SET amp. OTL can be handled by a coupling capacitor or using more tubes to lower the high source impedance of the output tube. Since speakers have much lower impedances than cans, the coupling cap solution is never used -AFAIK- on speaker amps and they use several chained tubes to get a low output impedance, matching the speakers one.

It's all a matter of personal preference. My impression, based on my own experience and which of course is biased and not necessarily matching any of yours, is that a properly made output trannie can be as transparent to sound as no trannie, but regarding caps... well, you can use V-Caps TFTF, the most transparent ones I know of (my tube amp uses them), but still have their own sound signature and are very expensive.

That's why in my post I said "when a serious manufacturer..." My hope is that someone doing a SET amp for cans using really good trannies, can get the same type of balanced, pure and properly textured sound of SETs as I know them used with speakers. Of course speakers that can be used with 9-15 wpc, otherwise it's a moronity to be speaking of SET amps with them.

As I said, OTL SETs have an edge over push-pull designs, but they're "not yet there" IMHO. They do nothing substantially better than a properly made SS amp, and have power delivery limitations, due to the fact of needing a coupling cap or auxiliar circuit to match output tube's impedance to can's impedance. This makes them to be only at their maximum power output in a very narrow impedance range. Provided we have cans with impedances ranging from 16 to 600 ohms... not a big deal as I see it. But if you get the properly matched output amp for a pair of specific cans, and you use a very fine cap... well, never tried it, but it could be a good compromise.

Rgrds
post #51 of 93
Thread Starter 
*sigh* Some of these look really great, but they are sadly all too expensive. The Darkvoice 337 has 2W of output (that's pretty rare from what I've personally seen, most are 1W max). I'd love to get it, but yikes, way out of my price range. I'd like to stay at about $300 or less, but my absolute max is $400. I wish there were more options out there for low impedance 'phones.. *sigh*

My ideal amp would be very high current, if not a tube amp then the ability to roll single-channel opamps (AD843 and OPA627/OPA637!), and (please, no one hit me for saying this!) a bass boost option.
post #52 of 93

Hmmnn...

Hmmnn...

... this is all... "very i-n-t-e-r-r-e-s-t-i-n-g..." (he says with a yawn).

If you all really dig "this stuff" - my advice is...

... the next time you're in the men's room standing at the urinal... just look over the partition at the guy standing next to you... and snicker... and say "what can you do with that little guy."

It works every time... "kinda like bein' the last dog to 'visit' the fire hydrant."

Or... in other words... a "fire hydrant hydrating contest."

Loads a fun!
post #53 of 93
Quote:
Originally Posted by Cool_Torpedo View Post
There are several ways to design the output of a SET amp. OTL can be handled by a coupling capacitor or using more tubes to lower the high source impedance of the output tube. Since speakers have much lower impedances than cans, the coupling cap solution is never used -AFAIK- on speaker amps and they use several chained tubes to get a low output impedance, matching the speakers one.
i think that is slightly misworded. perhaps far misworded.

MOST otl amps have a coupling cap. for that matter though, most transformer coupled amps have a cap in the signal path too.

once you have settled on a topo for an OTL amp, there are few ways to decrease the output impedance. different tubes will effect the output impedance if they can be used (6080VS 6528 as an example or 6sn7/6sl7/6bl7/6bx7 for that matter) but generally OTL guys stick with one type of tube, and the only way to decrease output impedance is by PARALLELING several of them.

Quote:
It's all a matter of personal preference. My impression, based on my own experience and which of course is biased and not necessarily matching any of yours, is that a properly made output trannie can be as transparent to sound as no trannie, but regarding caps... well, you can use V-Caps TFTF, the most transparent ones I know of (my tube amp uses them), but still have their own sound signature and are very expensive.
this gets into a REALLY big debate.

the big problems show up when you start to factor in current through transformers and buying bandwidth. really good flat transformers are really expensive. although caps are not perfect, when you start to look at very good iron, caps dont look so bad.

Quote:
That's why in my post I said "when a serious manufacturer..." My hope is that someone doing a SET amp for cans using really good trannies, can get the same type of balanced, pure and properly textured sound of SETs as I know them used with speakers. Of course speakers that can be used with 9-15 wpc, otherwise it's a moronity to be speaking of SET amps with them.
reading that i would REALLLY advise listening to a few good OTL headphone amps.

Quote:
As I said, OTL SETs have an edge over push-pull designs, but they're "not yet there" IMHO.
i dunno.

the OTL SET amps rely on either HUGE tubes paralleled in a cathode follower or a HUGE tube driving the load off of the plate with gobs of feedback to get output impedance down. feedback is old news. everyone knows the arguments against it. the arguments against the BIG tube designs stem from the dificulty that good gain tubes have driving them directly. so you do the right thing, and you add a driver stage. so now, what a SEPP amp does with 2 stages (in and out) you are doing with 3.... cool! thats one more, it must be better!

the SEPP amps use generally smaller tubes BECAUSE they are easier for the input stage to drive.

Quote:
They do nothing substantially better than a properly made SS amp, and have power delivery limitations, due to the fact of needing a coupling cap or auxiliar circuit to match output tube's impedance to can's impedance.
distortion spectra are still there. thats a little better
a coupling cap has no effect on the output impedance of the amp once you get out of the low bass regions. most headphones give better bass with a slightly higher output impedance anyways, so this is a REAL non-issue.

as a third point, and the best place to put it, you dont NEED an output cap for an OTL amp, nor do you NEED the circuitry as used in teh berning amps. you can apply a DC servo to a tube output stage and get the output to zero. i would look up the bamaslamma. it is something of a complex project, but not much worse than the DC coupled electrostatic amps that are all the norm.
Quote:
This makes them to be only at their maximum power output in a very narrow impedance range.
the failings of SS amps to deliver power into high impedance loads are as well known as OTL tubes into low loads. i suppose this thread is about the D2000/d5000, but other headphones were mentioned with fairly high impedances.

as far as adequate power delivery is concerned, i maintain that this is most likely a non-issue.
post #54 of 93
Great post mate, I mostly agree with all your statements.
I don't like very much the idea of having several paralleled tubes to lower impedance. They affect sound and it's a nightmare finding the right ones, and once you do after spending a lot of dough, then you need a replacement hehehehe.
You stated the main issue here regarding the D5000. Most tube amps aren't happy driving low impedances and the Denons are in the low side of things, not being very sensitive. Bad combination.

Maybe you're right and I need to listen to a really good OTL-SET amp for headphones, but I'd only do if:
- The number of tubes to tweak and fine-tune is sensible, not more than three.
- It can handle decently low impedance-low sensivity cans like the Denons or K701.
- Its sound is really neutral. No boomy or utra lean bass, no highs roll-off, no thumpy midbass, not edulcorated midrange... I don't want the amp to colour the sound, I want it to have great voltage swing and to provide the clean, natural and "make-up" free sound that good SET amps can deliver.

I'd say that I'd skip chinese amps, or too edulcorated or too unrefined. Any suggestions?

Rgrds
post #55 of 93
Quote:
Originally Posted by Cool_Torpedo View Post
Maybe you're right and I need to listen to a really good OTL-SET amp for headphones, but I'd only do if:
- The number of tubes to tweak and fine-tune is sensible, not more than three.
- It can handle decently low impedance-low sensivity cans like the Denons or K701.
- Its sound is really neutral. No boomy or utra lean bass, no highs roll-off, no thumpy midbass, not edulcorated midrange... I don't want the amp to colour the sound, I want it to have great voltage swing and to provide the clean, natural and "make-up" free sound that good SET amps can deliver.

I'd say that I'd skip chinese amps, or too edulcorated or too unrefined. Any suggestions?

Rgrds
i will freely admit to being biased towards the singlepower amps, i have never heard one i did not like the "sound and tonality" of. the extreme is more powerfull than the MPX3 although the MPX3 will probably work out very well. both use 3 tubes.

some of the Chinese amps can do well if you are willing to mod them. from what i have read, the darkvoice amps do very very nicely with a couple mods, and quite well out of the box.

i would definitely try go to a meet. the last few European meets make me wish i had the money to fly over for the weekend everything looks nicer than the local NYC meets.
post #56 of 93
Quote:
Originally Posted by nikongod View Post
i will freely admit to being biased towards the singlepower amps, i have never heard one i did not like the "sound and tonality" of. the extreme is more powerfull than the MPX3 although the MPX3 will probably work out very well. both use 3 tubes.

some of the Chinese amps can do well if you are willing to mod them. from what i have read, the darkvoice amps do very very nicely with a couple mods, and quite well out of the box.

i would definitely try go to a meet. the last few European meets make me wish i had the money to fly over for the weekend everything looks nicer than the local NYC meets.
Thanks! I might have the chance to listen to a MPX3 since a spanish mate, but about 500 miles away from my town, owns one. We could possibly join at some future meeting.
Regarding the Darkvoice... I distrust products that need tweaking and modding to sound right. Moreover experience tought me that what some modders like as an improvement, is just something changing certain aspects of performance, that most of the times, for my own taste and priorities, isn't really an improvement in my right direction.

I love tube amps, I own several for speakers, and have tried dozens -tube preamps too-, but I'm very peculiar, I dislike what most people take for "tube sound" and I'm using tubes for certain very specific features that SS amps hardly match.
If the Singlepower amps provide those features without sounding "tubey" I might like them. In any case they should be terrific performers to make me happier than the RPX-100, this little beast is amazing. I've been living with it for almost two months and I still have to find a pair of cans it can't drive, or a sonic signature I can attribute to his own. Probably when I find it, which I guess is just a matter of time, it will be the time to try something else.

Rgrds
post #57 of 93
If the Darkvoice is out of your league consider the Cayin (Spark) HA-1A. It works beautifully with the D5K, especially with Mullard tubes.
post #58 of 93
thanks for the infos
post #59 of 93
Maybe this is the wrong crowd to be making this comment to, but I see several recommendations for amps in this thread that cost $1,000+.

Perhaps I have an unusual view of things, but I don't see the point of spending more on your amp than you do on your headphones. My (limited) experience has been that speakers/headphones are by far the greatest factor in a system's overall sound, so instead of picking up a $1,000 amp for $500 headphones, I'd be much more likely to buy a cheaper amp and upgrade the headphones (although I suppose asking what would be an upgrade from the D5000s is a valid question).
post #60 of 93
You'd be surprised how far certain <$1K (in some cases, even <$500) headphones can scale. Putting multi-thousand source components or amps behind them will open them up like a parting of the heavens!
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