AKSA 55 driving to full volume?

Brownee · « **on:** 20 Aug 2004, 04:21 am »

Hi all

I have just finished my first AKSA 55. It is the first amp I have ever built and all has gone well.

(will post some pictures soon) Like every other post I have read I have found Hugh to be exceptional. In the couple of conversations I have had with him it is evident that not only is the technical support excellent but he takes interest in the person. It almost feels like you are talking to a long lost friend. Congratulations Hugh, you certainly will be doing more business with me.

Enough of the accolades. Is there any way I can test to see if the amp is being driven to full volume? It sounds great but I find that I have to turn the source up over 75% to get to reasonable levels. There doesn’t seem too be much headroom.

Thanks
Lyndon

mb · « **Reply #1 on:** 20 Aug 2004, 07:30 am »

Congratulations!

Are you using a passive volume control? If that's the case, then with a standard cd player as source with the usual 2-2.4Vpp max signal, turning the volume to 2 or 3 o'clock is fairly normal with medium sensitivity speakers. I believe at this level you are still a good way off maxing out the AKSA 55 on loud passages.

If you're using a preamp, then what you describe sounds like the senstivity is lower than normal.

AKSA · « **Reply #2 on:** 20 Aug 2004, 08:14 am »

Hi Brownee,

Thank you for your accolades. Toss them my way any time......

It sounds to me as though there could be something wrong. The AKSA has a gain of 38.3, or 31.6dB, and this means that 1Vpp input - almost any CD player can do this without raising a sweat - will give you 38.3Vpp output into 8R, which corresonds to 23W, which would be quite loud, even on an 84dB/watt/metre speaker.

Do you have a variable output on your CD player, or fixed output? If you are using an internal volume control, there is a chance it is not correctly wired. Right side to ground, wiper to amp, left side to source.

Hope this is helpful,

Cheers,

Hugh

Brownee · « **Reply #3 on:** 20 Aug 2004, 08:34 am »

Thanks for the reply

I am using my computer to run the AKSA in at the moment. It is a reasonable sound card (Audigy ZS) and I am using one of the speaker outs which should be line level ??? The volume is reasonable but I just thought it should have been a bit louder. As I said, I have to ride the volume sliders quite high to get adequate volume. I thought there might be a way I could check?

Lyndon

AKSA · « **Reply #4 on:** 20 Aug 2004, 12:25 pm »

Ah, Lyndon,

'line' level is something of a variable feast.

Most CD players will generate more than 1Vrms, which is 2.83Vpp. I do not know the Audigy soundcard, but my understanding is that the standards here play to a different tune, and may be a little lower.

Have you a CD/DVD player? If so, this is the way to verify volume is adequate.

Cheers,

Hugh

Carlman · « **Reply #5 on:** 20 Aug 2004, 01:27 pm »

I would suggest trying a headphone to RCA adaptor from the headphone output as a test. That way you have a volume control you know. I tested my AKSA with a Panasonic portable cd player and it was surprisingly good.

-C

PSP · « **Reply #6 on:** 21 Aug 2004, 05:35 pm »

In my main system, using a TLP-N preamp, AKSA 55N, and 90.5db efficent speakers (GR-Research Pardox 3 floorstanders) "comfortable" listening is between 8-9:30 o'clock on the TLP attenuator. "Loud" is at noon, and once in a while I listen at 1:00, but that is really, REALLY loud (100db, at least).

In my bedroom system, with a Foreplay preamp, AKSA 55N, and 87db Paradox 1 monitors, nice listening is always below 9:00 o'clock (but this is in a much smaller room vs. my main system).

I agree that you should borrow a CDP (or tuner, tape, etc) with a more standard output to check out your new AKSA to be sure that all is well.

Good luck,
Peter

Brownee · « **Reply #7 on:** 21 Aug 2004, 11:11 pm »

Hi again, thanks for the replies.

I hooked up my daughters cd walkman and got similar levels to the computer. I also AB tested against my Onkyo HT amp. The difference was not huge but the Onkyo was defiantly louder (but also distorted). It is rated at 60 watts I think. I am still not sure if all is well. Does anyone have a 55 in the Newcastle area I could compare to?

One thing I did notice. I left the amp playing for an hour or so while I was doing other things. When I came back it seemed louder. I could be imagining things, but is this possible? Does run in effect volume?

Thanks
Lyndon

AKSA · « **Reply #8 on:** 22 Aug 2004, 02:23 am »

Lyndon,

Can you colour photograph the AKSA, top and bottom, and send to me? I will have a gander and see if perhaps there is a problem.

What are the offset and bias figures?

Cheers,

Hugh

Brownee · « **Reply #9 on:** 26 Aug 2004, 08:52 am »

Just A word to let you know how I got on.

It appears that it is the disk that I was using to test that is the problem. I have been using a music DVD (Eagles- hell freezes over) to test. But for some reason it is not putting out the level that a normal audio cd does. I put in “Dire Striates – sultans of swing” cd and was turning down the volume rater than turning it up. The amp is certainly capable of some loud volumes. It also appears that some cd's are mastered much louder than others.

Thanks for the help.

PSP · « **Reply #10 on:** 26 Aug 2004, 05:11 pm »

I see the same thing for some movies... for a music CD, really loud = 1:00 o'clock on the attenuator, for some movies, "loud enough" = 4:00 o'clock....