Head-Fi.org › Forums › Misc.-Category Forums › DIY (Do-It-Yourself) Discussions › A simple BUF634 headphone amp design
New Posts  All Forums:Forum Nav:

A simple BUF634 headphone amp design

post #1 of 9
Thread Starter 

Hello. I just finished the design for a very simple but high quality headphone amp. It's built around the BUF634 IC buffer. All the info, schematics, gerber files etc. are available for download at my site:

 

http://mdiyab.blogspot.com/2012/07/buf634-headphone-amplifier-driver-pcb.html#.UBACVaOQ5IE

 

Any comments are welcome biggrin.gif

 

Regards, Venci.

post #2 of 9

The design looks pretty much right out of the Data Sheets.

 

BUF634 with OPA132...probably sound kinda bland.

BUF634 in DIP...limited output power.

 

Layout looks ok even if a bit bigger than it needs to be.

No heat sinks for the regulators? There should be room

planned for even if you don't use them.

 

Instead of DIP8 for BUF634, use TO-263.

Or better yet use LME49600.

 

Edit: R6/R11 are an order of magnitude too low.

        Should be more like 200K for a 20k pot...


Edited by Avro_Arrow - 7/25/12 at 12:49pm
post #3 of 9
Thread Starter 

Hi,

there are a lot of commercial designs that use the "pretty much right out of the Data Sheet" and sell for a lot of money.

 

Actually the BUF634 is in SOIC package here and the DIP is for the front end op-amp. It's power rating is more than adequate for this application. Consider a load of 32 ohms and voltage swing across that load of about 2v p-p (0.7Vrms). Larger voltage swing is high unlikely(for people who want to keep their hearing). This would result in about 32mA peak current or 64mA p-p. A simple soic ic is more than capable of providing this current and the device will be well within its safe operating conditions.

 

 

BUF634 and LME49600 are esentialy the same (except for the packages).

 

Regards, Venci.

post #4 of 9

 How difficult is it, or even worth the trouble to add an active ground channel?

post #5 of 9
Thread Starter 

Hi,

I don't quite understand the question confused.gif

 

Regards, Venci.

post #6 of 9
Quote:
Originally Posted by vixr View Post

 How difficult is it, or even worth the trouble to add an active ground channel?

 



not worth it IMO, a real split supply (preferably regulated) is lower impedance despite the marketing claims. plus 3 channel is more expensive and higher noise. its this low current 'virtual ground channel' format that he who shall not be named thoroughly debunked as well


Edited by qusp - 7/26/12 at 1:00am
post #7 of 9

I'm not seeing how an article based on data that can only be repeated when the ground channel op-amp in that amp is damaged debunked anything.... Especially after he noted the amplifier had usually high current draw.    

post #8 of 9

his is just one point of reference, i'm not one of his groupies … far from it, but i'm sorry there is no way that it can be anything but higher impedance and higher noise than an actual ground reference. its simply not possible to add parts in series with ground without adding to the impedance and it will always be limited in current performance by the current limit of the parts used. working with a fairly limited power source already it just seems like a bad idea to me.

 

now with AC power you can raise this current limit, but you also at that point have a pretty easy way of using a proper ground. for me and IMO a well realized layout with a straight forward bipolar supply is always a better idea. with battery power, just add another battery for split supply and a charge management system with the budget and space for the 3rd channel.

 

dont mistake me for him, I think he handled the whole thing badly and i'm not convinced the borg is all good, but there is truth to many of the issues raised


Edited by qusp - 7/26/12 at 7:24am
post #9 of 9

Why would anyone even consider using a virtual ground in a desktop amp when you can use a real ground??

If you're making a portable requiring smallest size possible I could understand.... I guess the Obj2 is a good example of a (trans)portable that uses real ground, and well I just wouldn't call that a "Portable" amp. Certainly not something I'd use On-the-Go.

New Posts  All Forums:Forum Nav:
  Return Home
Head-Fi.org › Forums › Misc.-Category Forums › DIY (Do-It-Yourself) Discussions › A simple BUF634 headphone amp design