• Disclaimer: This Vendor's Forum is a paid-for commercial area. Unlike the rest of diyAudio, the Vendor has complete control of what may or may not be posted in this forum. If you wish to discuss technical matters outside the bounds of what is permitted by the Vendor, please use the non-commercial areas of diyAudio to do so.

Increasing the bias current on my NAKSA80s & Sorayas ... seems to be a good thing!!

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Sorry, I have no idea, maty (but I don't think bias changes power output - this depends only on the +/- DC rails).

Make the change (to 60mV bias) and see how it sounds! :)

Andy

Higher bias: class AB amps work like class A few watts more, if I am not wrong. In my AV -> only more bass and cleanner sound. And more heat but until reasonable, even in the Mediterranean summer.

You are right, I should have asked better: how much the NAKSA 80 works as class A and how much with the new bias?
 
Last edited:
Maty,

I have not experimented with the NAKSA, or the new SAKSA, under heavy bias. I have tried it at 150mA, and aside from producing quite a bit of heat, it does sound richer and more scale.

When you do this you increase the range of both outputs on. At 150mA quiescent, I make this range 6Vpp on LTSpice, which corresponds to 36/64=547mW, not a lot of power in Class A, but probably worthwhile for very quiet listening. Certainly the transitions are very smooth and well controlled.

Hugh
 
Just looked at this thread again as I just had the lids off my Soraya's to replace a fuse (it was only 3amp, must of run out of 7.5amp ones the last time I changed it), anyway, decided to check the bias which I originally set at 65mv, both channels were at 60mv, just wondering again what I should try as the heatsinks never even get warmish running Vaf I93's at high levels
 
Just looked at this thread again as I just had the lids off my Soraya's to replace a fuse (it was only 3amp, must of run out of 7.5amp ones the last time I changed it), anyway, decided to check the bias which I originally set at 65mv, both channels were at 60mv, just wondering again what I should try as the heatsinks never even get warmish running Vaf I93's at high levels

Just checked - I use 7a fuses on my Soraya monoblocs. :)

Yes, as you increase bias current - the heatsinks get warmer.

But if yours "never even get warmish " ... I would thoroughly suggest increasing the bias reading to 120mV.

Andy
 
Thanks for the advice Andy and Hugh, I will head to the Aztronics to get new fuses, so does the increase in bias also increase current through the fuses?

I was also using some Holton based monos for bass, but I decided to tidy up my system and reduced wiring/clutter and have happily settled on the Aksas for full duties, I am tempted to maybe update the Holtons, they both have 400VA 45v toroids(which I would like to recycle), Hugh what would you suggest I purchase Aksa based these days that would suite?
 
Hi Dennis,

I just put in a lovely post and the system swallowed it, drat..........
That voltage will give you around 200W from 65V rails. My only offering for that is the Maya, made for it, and five generations on from the original AKSA and better of everything; resolution, musicality, depth of image, natural presentation, silence, etc.
A pair of warrantied 2 year modules of the Maya would cost $2600 plus GST, but I doubt you'd ever need any more amps in your life after that!! In a proper enclose and fully plug 'n play, the cost is $5600, much more expensive, but I would assume you have a nice enclosure you are quids ahead...... expensive, but the best.

Ciao,

Hugh
 
Hi Dennis,

I just put in a lovely post and the system swallowed it, drat..........

Aah - so that doesn't just happen to me! :)

Hi Dennis,

That voltage will give you around 200W from 65V rails. My only offering for that is the Maya, made for it,

Are these monobloc modules, Hugh? (So each needs its own traffo ... as Dennis has 2 traffos.)

Andy
 
Absolutely, Dennis. Normally I use good quality 300VA, and never had any complaints! 400VA would give you more capacity with 4R loads.......

I think you have bipolar outputs, Dennis, and they need only about 60mA quiescent, and more is very little difference in sound. This is not true of mosfet outputs, however.

Cheers,

Hugh
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.