[Deuterium]

I have been reading a number of threads recently that has impacted my thoughts on adding a headphone amp to my primary rig. Right now, I am using the Lavry has my headphone amp, but I bought this piece with the intention of adding a headphone amp at a later time. I had been considering a Raptor or an MPX3, but a recent SinglePower thread on this forum and the balanced headphone amp/dyanamic cans thread on the headphone forum, have piqued my interest in considering a balanced rig (the Lavry has a balanced output). I am looking for a US made balanced tube headphone amp for less than $2,000, but haven't found any. I would appreciate any suggestions you might have. Thanks.

 

[tkam]

Give Mikhail a call I think you can get a balanced singlepower amp for under $2k.

 

[Meyvn]

you could try gerG's method and use two single-ended amps.

 

[Deuterium]

Thanks for your comments.

Meyvn,

Can you point me to a thread where there is a discussion about using two single ended amps configured for this purpose. Thanks.

 

[jpelg]

Quote:

Originally Posted by Deuterium Can you point me to a thread where there is a discussion about using two single ended amps configured for this purpose. Thanks.

Left source channel to amp1, right source channel to amp2, balanced headphone cable left channel plugged into amp1, balanced headphone cable right channel plugged into amp2. Other amp channels unused.

 

[Riboge]

I have been trying to figure this out for myself not being especially informed about the technicalities. As far as I can understand a separate amp for each channel does NOT by itself make it a truely balanced arrangement. To have balanced output an amp must oppose the signal to the inverted signal for each channel thus doubling the 'information' amplitude from the ground to peak of single ended to a peak to trough level with balanced and tending to diminish noise. If I don't have this right, I wish someone more knowledgeable would offer a more correct explanation.

 

[tom hankins]

I would think Mikhail could build a nice PPX3 or even an MPX3 balanced amp for under your $2K limit. www.singlepoweraudio.com Good luck!

 

[philodox]

I am getting a balanced amp built by Peter McAlister. Still waiting on the final specs, but I wouldn't imagine it is going to be $2k... most likely a fair bit less.

It is loosly based on his PL12 [the PL10 is on his website], but uses 12SN7 and 6H30 tubes. Tube based regulation as well, though not rectification as he prefers solid state there. Mine is being built without volume control as well which should cut down on the cost significantly [using my Lavry Black DA10 for volume] I spoke with him on the phone for a few hours and came away very impressed with his knowledge. He uses a tube based ccs that apparently provides "infinite plate resistance", which is desirable in a tube circuit as it cuts down on the impact of various tubes. ie. It will still sound great even if you don't take out a second mortgage on exotic NOS tubes.

His amps are starting to look a lot nicer aesthetically than the pics on his website as well. There is a recent McAlister audio thread on here that shows of the new look a bit.

 

[Uncle Erik]

Riboge- I think you're referring to using two stereo amps in a bridged configuration instead of two mono amps. There's a nice Wiki entry on that here:

http://en.wikipedia.org/wiki/Bridged_amplifier

Also to go "fully" balanced, you need a balanced source, too. There are a few DACs and CD players that offer this.

To address the main topic here, the cheapest way to get a balanced tube amp is to build two and bridge them in a balanced configuration. There are some inexpensive plans out there (~$200 per amp) and you'd save a few bucks by only using one case. I daresay you could pull one off for $500 or less if you did it yourself.

If you're not the DIY type, take a look at some of the builders here. You'll have to pay for labor, but you ought to be able to find someone to build *exactly* what you want at a price under your budget. And if you don't know what kind of topology, etc. you want, talk to a builder anyway. They should be able to offer you a lot of information.

 

[Doug411]

I'm also thinking about experimenting balanced configuration myself, and if you have a little bit of experience with DIY electronics, it's not very hard.

Let me explain.

Different from single ended signal path, balanced signal has hot and cold (in-phase and out-of-phase, respectively) and ground. This ground acts as a reference bias for both hot and cold signal, thus the balanced has a merit of eliminating unwanted in-line noise. But driving headphones in balanced configuration does not use ground, it just needs hot and cold.

Step 1. Buy or build two identical amplifiers. I would think about building S.E.X. myself, but there are bunch of options for single ended output headphone tube amplifers you can buy.
Thus we have two amplifers, 1 & 2, which have 2 outputs (left and right) each. And each output has hot and ground. So let's label
1RH - 1RG, 1LH - 1LG
2RH - 2RG, 2LH - 2LG

Step 2. Get a truly balanced source, I mean signal with hot, cold, ground.

Step 3. Make a balanced - two channel converting interconnect and headphone cord.

The overall connection should be like this.

The critical factor here is the two amps. They should be identical, or closely identical at least.

Doug

 

[InSides]

Quote:

Originally Posted by Doug411 The overall connection should be like this.

Done here, ad least by two people.

#1. [gerG] - procedure described here and followed up here.

#2. [myself

] - procedure described here.

Volume control issues resolved by means of stepped attenuators in gerG's case, and a single remote for both amps in my case.

 

[Doug411]

Hey
I knew somebody already has done it!

How do you like it? I wonder if two $500 amp operated in balanced mode sound better than one $1000 amp operated in single ended mode. Ah yeah, if I find a particular amp of my taste, I can improve even more to go for twin balanced configuration. But...

Doug