Gainclone with pseudo-balanced input?

Mad_K

Member
2002-09-12 11:14 am
Norway
-Wouldn't this balance the impedances, so that I can use my BZLS to drive a gainclone?
 

Attachments

  • bal_gainklone.jpg
    bal_gainklone.jpg
    20.9 KB · Views: 3,736

Mad_K

Member
2002-09-12 11:14 am
Norway
After having fiddled a little with these bits, I have decided upon a design for my own gainclone. If everything works out (ie the rest of the parts arrive) it'll be finished next week. BTW -I have finally got myself a job as an EE (I finished school 2 years ago!!!;)
 

Attachments

  • opa549balip.jpg
    opa549balip.jpg
    92.7 KB · Views: 3,499

Mad_K

Member
2002-09-12 11:14 am
Norway
Nobody interested? Or is this old news?

-I was just going to say that I have buildt the circuit, and I can only say that it works beyond my wildest expectations:bigeyes:
All that, and it is only buildt as a proof of concept-rig with less than optimal components, layout etc. Next week I'll have my finished version up and running, with much better components, wiring, connectors, dual-mono etc. Sad to say really, but it demolishes my aleph30 clone..

BTW, my reason for having balanced input is that I already have a Pass BZLS, that I'm very fond of and I think it's simply MAGIC (-everything it connects to turns to "Aural Gold") . Much better sounding than standard gainclone methinks, but that depends on individual systems i suppose..

This version has lower gain; 20dB (versus 27dB for the original), and a little higher input impedance 22Kohm per phase (or 44Kohm balanced) to make it a better match with my pre. Oh, I forgot to mention -the use of a smd resistor for the feedback is highly recommended. It fits really nice on the opa549:)

I'll report back with some pictures and listening impression after the final version is done.

BR,
 

Mad_K

Member
2002-09-12 11:14 am
Norway
pinkmouse said:
Looks good mate, does it sound as good as the original?

I have yet to try SMD resistors, mainly 'cos I know nothing about them. What brand did you use, and how easy was it to solder?

Congrats on the job:drink:


-In my system it sounds way better than both std. app. note circ, std GC, IGC, minimized GC and every other config I tried. The SMD I used is a std metal film unit made by KOA in 1206 size (3mm) -Real easy to solder; just tin the legs of the OP, put the SMD in place -hold in in place, and touch the leg/resistor for a second and VOILA!

It fits real nice between the pins on the opa549 http://focus.ti.com/docs/prod/productfolder.jhtml?genericPartNumber=OPA549
You could even use one size smaller resistor I think (2mm)..
 
Hi Mad_K

When you say it sounds way better than IGC you compare the sound of balanced versus non-balanced operation and a whole lot of additional factors like preamp/cabling would affect the way it sounds. It would seem difficult to distinguish whether the chip amp prefers both inputs being driven or whether your external setup sounds better this way.
 

Mad_K

Member
2002-09-12 11:14 am
Norway
analog_sa said:
Hi Mad_K

When you say it sounds way better than IGC you compare the sound of balanced versus non-balanced operation and a whole lot of additional factors like preamp/cabling would affect the way it sounds. It would seem difficult to distinguish whether the chip amp prefers both inputs being driven or whether your external setup sounds better this way.

You're completely right ofcourse. I don't believe the chip to be sounding any better from being driven balanced, rather it's the sum of the circuit, preamp, cables, speakers, TT, CDP, phonopre etc etc. that makes it sound much better to my ears, in my setup. Mainly, I think it's because of the BZLS -I just love it. I imagine it sounds a little like having a tube buffer infont of it. Softens it up a little, makes it sound more liquid (the 22K to gnd on inv. inp. also does this). I can see why P.Daniel likes the minimized version better; it becomes more upfront, a little clearer, with a very pronounced midrange. In this balaced setup with BZLS it becomes a little darker, smoother and the bottom end is a little more pronounced, while the treble eases down a bite.. More neutral to mee. Don't get me wrong, -it's still very agile! I believe everyone will have to tune their own GC to their own system to make it optimal to their taste/system/preferences/music etc.

The circuit above is merely my own version of what Thorsten explained in the "not just another GC..." -thread, post 372 and 375. He actually doesn't think this would be optimal, but wants us to use a transformer instead (like S.E.'s circuit above). Maybe I'll try it someday, but for now, this one does it for me.:nod:
 

moe29

Member
2002-12-11 10:27 pm
Florida
Hey Mads!

Congrats on the new job! always nice to get paid $$!

"Sad to say really, but it demolishes my aleph30 clone..."

i don't know why, but i was sad to see you say that! At least you
still think the BZLS sounds good. I guess when i finally finish my
other projects i'll have to give a gain clone a try. Probably your
balanced one, since i have the BZLS too.

Now for the pictures!

take it easy


moe29
 
Mad_K said:


You're completely right ofcourse. I don't believe the chip to be sounding any better from being driven balanced, rather it's the sum of the circuit, preamp, cables, speakers, TT, CDP, phonopre etc etc. that makes it sound much better to my ears, in my setup.

Well yes and no.You can easily try the bzls in single ended mode with xlr adaptors to a/b se vs balanced.
I agree that with balanced drive the gc sounds a clear level better than se.But of course so does the Aleph.Some might say that the bzls is not optimal in single ended output and that's why it sounds better balanced.Even though my speakers are very easy to drive I find that passive vol control gc is lacking in dynamics and some separation, active pre is better but with active balanced pre - u de maaan!
 
Mads
You shoud try to X your BZLS (BOSOZ), it´s simple to do, just a couble of ressitors, and I think your balanced GC might benefit from it.
I am interested in your pseudobalanced GC, an have just read the posts from Torsten that you pointed out. Thanks. I have the parts to build it, but it might take some time for me to make it, I am not a full time DIY´er and I also have other audio projects.

Protos
I agree that BZLS in unbalancd output mode in general doesn´t sound as good as in balanced.
But don´t you think, that the balanced topology itself explain this?