Is the Jade really a balanced Amp?
Nov 24, 2009 at 1:15 AM Thread Starter Post #1 of 55
moodyrn

moodyrn

Headphoneus Supremus
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I'm looking to get a balanced(tube) amp for my Christmas present, but I don't have four figures to drop on most of the balanced tube amps out there. As far as I know, the cheapest fully balanced tube amp is the little dot mkVII. I think I might be able to afford this, but I will really stretch my budget. I read impressions of using the Jade as a balance amp. I would like to know is this really a balanced amp. If so, then how. From everything I've read, a balanced amp is basically two amps in one case(which is why they are so expensive). If this is a balanced amp it would be an unbelievable value for a balanced tube amp for under 400. I've also considered purchasing a second ming da to use in a balanced configuration. This would also be much less than purchasing a fully balanced tube amp, but I would prefer to just get a fully balanced amp.
 
Nov 24, 2009 at 1:58 AM Post #2 of 55
by MKVII I'm guessing you meant MKVI+. The MKVII is a solid state balanced amp.

I have the MKVI and love it. Tons of power to control the drivers very nicely. A nice bonus to buying this amp is if you decide to try the AKG K1000, you simply flip a switch and you are good to go, it is powerful enough to play them.

If you decide to go with the MKVI+ make sure (if you are buying used) to get the MKVI+ with the + not the MKVI like I have as the + has an unbalanced (single ended) 1/4 jack for more flexibility. The MKVI originally didn't include this and I'm seriously considering selling mine and ordering the updated version, even though I'd lose quite a bit.
 
Nov 24, 2009 at 2:11 AM Post #3 of 55
Quote:

Originally Posted by moodyrn /img/forum/go_quote.gif
I read impressions of using the Jade as a balance amp. I would like to know is this really a balanced amp.


Not that I can see.

Perhaps you're confusing the "dual outputs" (meaning it just has two headphone jacks) with "balanced"?

Quote:

If so, then how.


You'd have to either add some output transformers, or buy two of them and bridge each one.

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From everything I've read, a balanced amp is basically two amps in one case(which is why they are so expensive).


Only in the somewhat backwater world of headphones. The rest of the audio world (including the also somewhat backwater car audio) calls these "bridged" amplifiers.

se
 
Nov 24, 2009 at 7:15 AM Post #5 of 55
To be balanced or not .. that is the question!

In a nutshell, the main advantage for a balanced rig for headphones is that you drive the +ve and -ve signal in/out of the headphone driver (on a SE rig, you just send the signal out and drop it to ground, the ground being shared by both channels). This is what the Jade does, it has two avaiable outputs, one +ve and 1 -ve, and with the balanced cable they make, you can connect to both to drive your cans in balanced mode.
 
Nov 24, 2009 at 7:30 AM Post #6 of 55
Quote:

Originally Posted by BigTony /img/forum/go_quote.gif
To be balanced or not .. that is the question!

In a nutshell, the main advantage for a balanced rig for headphones is that you drive the +ve and -ve signal in/out of the headphone driver (on a SE rig, you just send the signal out and drop it to ground, the ground being shared by both channels). This is what the Jade does, it has two avaiable outputs, one +ve and 1 -ve, and with the balanced cable they make, you can connect to both to drive your cans in balanced mode.


Could you explain just how they manage to pull off that trick?

Unless I'm looking at the wrong amp, the Jade uses one 12AX7 and one 6AS7. These are dual triode tubes. Which means that the Jade has just two single ended channels in it.

How do you manage to get a +ve and -ve for two channels using just two single ended channels?

Or are you referring to using two bridged Jade amps instead of one?

se
 
Nov 24, 2009 at 8:42 AM Post #7 of 55
Quote:

Originally Posted by Koyaan I. Sqatsi /img/forum/go_quote.gif
Or are you referring to using two bridged Jade amps instead of one?


I believe he is, however is a Jade amp bridged? Wouldn't what he's talking about be 'bridging' 2 single ended amps in a similar fashion as most of these commercial (and diy) 'balanced' amps (although in separate enclosures)?

I also assume you are correct as I've seen it countless times, yet the 'balanced' terminology appears to be here to stay. We have HeadRoom to thank not only for dual 3pin XLR, but also "balanced", instead of "bridged". I suppose I can start changing my own terminology, perhaps we can turn over the wave... eventually.
 
Nov 24, 2009 at 10:00 AM Post #8 of 55
Jade topology is never use in output stage before but it available in tube world for a long time - P/K splitter. 6AS7 is output tube but also a phase splitter. When output at plate has local negative feedback in cathode. When working in cathode output has negative feedback at plate. It also can get both output same time. Yes ! Jade is balance output headphone amp but not balance input. Jade also can use as real pre-amp if you replace 6AS7 with 6SN7. It no need any modification. It become a Pre-amp with balance output.
 
Nov 24, 2009 at 4:33 PM Post #9 of 55
Quote:

Originally Posted by Maxvla /img/forum/go_quote.gif
I believe he is, however is a Jade amp bridged? Wouldn't what he's talking about be 'bridging' 2 single ended amps in a similar fashion as most of these commercial (and diy) 'balanced' amps (although in separate enclosures)?


If that's what he was referring to, then yes, that would be "bridged."

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I also assume you are correct as I've seen it countless times, yet the 'balanced' terminology appears to be here to stay.


Sadly, that may well be the case.

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We have HeadRoom to thank not only for dual 3pin XLR, but also "balanced", instead of "bridged".


True. Though I had something other than "thanks" in mind.
atsmile.gif


Quote:

I suppose I can start changing my own terminology, perhaps we can turn over the wave... eventually.


Perhaps. Or we could have some fun and start calling all amplifiers "balanced." I mean, the output swings both positive and negative. Let's call that "balanced."
atsmile.gif


se
 
Nov 24, 2009 at 4:40 PM Post #10 of 55
SE mode - Signal from amp + output & return by common ground but Jade Signal from amp + to Headphone return to negative output but not ground. Sure it can call balance output but not balance input.
 
Nov 24, 2009 at 5:01 PM Post #11 of 55
Quote:

Originally Posted by Hz_joe /img/forum/go_quote.gif
Jade topology is never use in output stage before but it available in tube world for a long time - P/K splitter. 6AS7 is output tube but also a phase splitter. When output at plate has local negative feedback in cathode. When working in cathode output has negative feedback at plate. It also can get both output same time. Yes ! Jade is balance output headphone amp but not balance input. Jade also can use as real pre-amp if you replace 6AS7 with 6SN7. It no need any modification. It become a Pre-amp with balance output.


I considered the possibility of the output tube being configured as a phase splitter, but I don't consider that to be a "balanced" output. "Balance" refers to a balance of impedances, which is required in order to achieve good common-mode rejection. This is the whole purpose of balanced interfaces.

However the output impedances from the cathode and the plate are dramatically different and would only serve to severely degrade CMR.

While phase splitters are fine for creating symmetrical signals for driving a push-pull output stage, they're not something you want directly driving the output.

To call the Jade a "balanced" amplifier is yet a further perversion of the term "balanced."

The Jade's output (assuming you're correct that it's configured as a phase splitter) is neither bridged nor balanced, and would not provide any of the benefits of either.

se
 
Nov 24, 2009 at 6:02 PM Post #12 of 55
Quote:

Originally Posted by Koyaan I. Sqatsi /img/forum/go_quote.gif
I considered the possibility of the output tube being configured as a phase splitter, but I don't consider that to be a "balanced" output. "Balance" refers to a balance of impedances, which is required in order to achieve good common-mode rejection. This is the whole purpose of balanced interfaces.


I think you are fighting a losing battle! You are right of course, but the term "balanced" can mean just about anything now and has little to do with balanced impedances, differential amplifier stages and CMR. If it has at least a pair of 3 pin XLR jacks, then it is balanced. At least, that seems to be the logic on this forum!
wink.gif
 
Nov 24, 2009 at 6:32 PM Post #13 of 55
Quote:

Originally Posted by Parafeed /img/forum/go_quote.gif
I think you are fighting a losing battle!


You may very well be right.

But hey, if I buy a lottery ticket, while my odds of winning may be millions to one, they're infinity to one if I don't buy one.
atsmile.gif


Quote:

You are right of course, but the term "balanced" can mean just about anything now and has little to do with balanced impedances, differential amplifier stages and CMR. If it has at least a pair of 3 pin XLR jacks, then it is balanced. At least, that seems to be the logic on this forum!
wink.gif


No comment.
atsmile.gif


se
 
Nov 24, 2009 at 6:46 PM Post #14 of 55
This is why I asked the question if the Jade was really a balanced amp, and if so how. I wasn't confused about anything. I pretty much know what balanced is, but after reading impressions of people using the Jade in a balanced configuration, I wondered how could it actually be balanced. So I pretty much needed some convincing, but now I see my initial thoughts were correct.
 
Nov 24, 2009 at 9:43 PM Post #15 of 55
Quote:

Originally Posted by Koyaan I. Sqatsi /img/forum/go_quote.gif

No comment.
atsmile.gif


se


should have put up your signature :lol:
 
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