Current feedback headphone amp

At the moment I really like current feedback amps. I have designed three of them now and my latest which left my computer recently is waiting to be built.

The amp consists of a discrete built current feedback with peformance close to this , two separate power supplies, one for each channel and those PS' have super regulators with "snubberisation". I have added a resistor in series with the 100 nF decoupling cap. Check the schematic and you'll see what I mean.

The design of the amp itself is an improved version of the QRV-06 . I have added input bias current network and an optional DC servo.

http://sjostromaudio.com/pages/hifi-projects/36-hifi-projects/94-qrv08-headphone-amp

I expect I'll order prototype pcb's in a couple of months. I'll guess nobody will scream for this design but if so, I'll maybe order sooner.

 

The design looks nice enough Peranders but a lot of people run scared at the site of smd
Personally I have no problem with smd but it seems a lot people find it fiddly

 

I have got the pcb's now. Can't wait to get the soldering iron heated up.

 

Sorry can't cope with SMD even with glasses.......Which is a shame,as I was thinking of building a headphone amp.

 

That's life, sorry. Shaky hands aren't so good... It's a very good idea not to exhaust your muscles just before you are going to solder. Once I had braked pretty hard with my bicycle and afterwards I was so shaky it was ridiculous. Guess what happens if you tremble 1-2 mm when your are going to solder something with 1.28 or 0.63 mm pitch.

 

Hi,

I have allways liked them. BUT, why ON EARTH a headphone amp?

Anyone wanting to listen to current recordings needs a headphone Amp like a fish needs a Harley.

How about making the next one a battery powerable (+/-12V), bridged poweramp good enough to get near "rail to rail" performance and ability to drive 2 Ohm, still using discrete CFB?

L8er T

 

For me at least half the pleasure is to design, the journey is the goal, so why not. What type of topology do you prefer?

 

Hi,

Headphone Amp's I prefer to ignore, together with headphones.

Otherwise, if using feedback solid state circuit anywhere classic CFB (diamond transistor) circuitry is hard to beat, j-fet inputs are nice in that, adding a lot of cascoding can be great too.

So, how about a BYOB SMD CFB Poweramp, with only output transistors as leaded components?

Ciao T

 

I'll guess you haven't seen this:
CFB, SMT, 4-layer pcb etc.

http://mirand.dk

 

Jeez, hundreds of transistors - and it still needs a trimpot

 

Is this a comment without any technical insight or do you think many transistors automaticly give you a fixed bias? Power amps normally have adjustable bias.

 

Care to expand on that? Not sure if that's a criticism of modern recordings or of headphone listening in general? Many people (myself included) are pretty much forced into at least some headphone listening due to neighbours and poor soundproofing.

 

Hi,

Virtually all stereo recordings ever made only work if played via speakers. If playd via headphones the whole thing is FUBAR. The notes are still there, but the music & experience is absent, which is fine for casual background listening, but then a "high quality" headphone amplifier makes no sense.

Ciao T

 

I would beg to differ

 

Probably a discussion for another thread, so I'll just say that I stongly disagree with that.

 

Hi,

You can beg all you like.

EVEN with extensive analogue acoustic modelling (crossfeed, re-equalisation etc.) done really well it is at best a major turnoff.

The only way to sort out that mess is to replay the recording in a "normal" listening room and to re-record it binaural OR to simulate the process in software sufficiently closely, which is looking like itmay be available some time soon, but is not there yet.

Ciao T

 

.... mm, I also prefer loudspeakers but this thread was about my headphone amp and not about headphones are better than speakers. Anyone who has a comment about the amp, technically or otherwise?

 

More tosh!

There are situations where people may need headphones, for what ever reason.

Why not persue a quality amp design. Just because you dont like them is no reason to be so offensive to the OP.

 

Thorsen, I will thanks in a non arrogant indo European way

 

Hi,

London transport comes to mind.

My point is that headphones take you so far from anything resembeling a coherent, at least semi-realistic experience that there is little point persuing quality.

I can tolerate Koss or Stax ESL Headphones (too heavy though) with free-field EQ and crossfeed applied, but if I'm sitting down to listen with this kind of setu I rapidly find better stuff to do.

Ciao T