The Wire - Low Power Ultra High Perfromance (LPUHP) 16W Power Amplifier

[regal]

Originally Posted by hochopeper

regal, I think because there will be a bunch of people driving them from a DAC I/V output with digital volume control rather than an active pre-amp with gain.

If I understand these buffers correctly they need to be in a fb loop with the input or gain opamp (like the buff634's) for dc coupled output.


I was listening to my TOL Asus soundcard analog out into the O2 to get a taste of S-D (Ak4396's), I could literally hear the jitter shifting like sand between the channels, exactly like the famous 2+nS jitter sound sample have, quite dissapointing.

So I guess I should build this software controlled wolfson kit first then, hopefully the wm8805 will help matters or I'll I will find a good hirez asynch usb.


Am I the only one building this for headphone only duty (probably 1 or 2 buffers per channel.) It seems it should offer exceptional ss performance for headphones. But I may splurge for the full buffer set to see how it does with my fostex 127E's, the designers description that it reminded him of an SET amp without the drawbacks cought my attention.

[bcg27]

There is a decent chance I will be using them with headphones. My speakers are not very efficient, 87 dB, so I don't know how loud they will get. My space is quite limited as well so I won't be buying/building a new pair of speakers soon. I don't listen very loud and the room isn't huge, so the 16 watts may still be sufficient in which case I will use the amp with the speakers. Otherwise they will be powering headphones until my speaker situation changes.

[qusp]

Originally Posted by regal

If I understand these buffers correctly they need to be in a fb loop with the input or gain opamp (like the buff634's) for dc coupled output.

nope, like i said in my reply to your post, they can be used open loop, in fact opc tried it both ways in the original BAL-SE wire headamp and found not a lot of difference in performance. the offset issues with the buffer are down to bad layout/implimentation, not the chip. in fact the reference design had issues with offset in the buffer due to the servo, not the buffer, but the buffer had a bad name for offset because of it for a while.

but and this is a big but, this was just open loop from the input VAS to the buffers, not at the end of a long cable and a couple of connectors. it might be nothing to worry about, but it would certainly be something i checked for oscillation

Am I the only one building this for headphone only duty (probably 1 or 2 buffers per channel.) It seems it should offer exceptional ss performance for headphones. But I may splurge for the full buffer set to see how it does with my fostex 127E's, the designers description that it reminded him of an SET amp without the drawbacks cought my attention.

maybe, wolfsin has that in mind too I think, i'll be playing with it like that for ***** and giggles, but its aimed squarely at my tweeters. using it with only 1 or possibly 2 buffers you have basically just build the bal-se headamp, so there wouldnt be many no, perhaps a couple who missed the headamp GB

[Wolfsin]

Originally Posted by qusp

wolfsin has that in mind too I think

wolfsin izIn HogHeaven: too many toyz He has a wonderful pair of heatsinks that would call for mounting the pcbs vertically so is considering a range of alternatives. Being able to mount varying buffer counts is very attractive for driving headphones even 'hungrier' than Senns.

[Ed LaFontaine]

I think the first (after test) drivers I will hook this up to will be B&C DE250's

[hochopeper]

Mine will drive the HF input of these

[qusp]

do you listen to modelled music too? =D

[hochopeper]

What is this reality you speak of?

[AAK]

Hi All

Just curious has anybody other than Owen finished one of these? I've designed my own 4 layer PCB with 20 devices with all kinds of options but I'd like to know how it sounds before having the boards manufactured.

Thanks!

Al

[qusp]

there might be a couple, we are still waiting on custom trannies, heatsinks etc and about to put the passives GB through this weekend. i've worked out shipping etc wanted to confirm with DK i was all covered for duty etc and just when i thought i had a lul, anyway the passives will be here before trannies and sinks are ready so no delay. keen to get going, not sure how much additional benefit you'll get with 20 buffers though TBH, will post/PM/email later this afternoon.