Hello!
I've just built an integrated amplifier using this kit:
http://www.autocostruire.com/catalog/product_info.php?cPath=42&products_id=258
When finished I also built a pair of high effeciency fullrange speakers (Audio Nirvana). But when connected the amp (not the source, a Rega Planet 2000) - or I believe it's the amp - generates a very loud hiss. I've tried changing amps (Onix and Naim) and while they also generate some hiss it's not as loud as the t-amp.
I don't know much about these things but I really want to find a solution.
Any advise and help is appreciated !
/Mirland
I've just built an integrated amplifier using this kit:
http://www.autocostruire.com/catalog/product_info.php?cPath=42&products_id=258
When finished I also built a pair of high effeciency fullrange speakers (Audio Nirvana). But when connected the amp (not the source, a Rega Planet 2000) - or I believe it's the amp - generates a very loud hiss. I've tried changing amps (Onix and Naim) and while they also generate some hiss it's not as loud as the t-amp.
I don't know much about these things but I really want to find a solution.
Any advise and help is appreciated !
/Mirland
OK, if it's the 2020-m amp that you have built, it does have quite a high gain. This would be consistent with it producing more hiss than the other amps and that may indicate that the hiss is eminating from somewhere before the power amp stage.
Can you tell us exactly what you have in the 'chain' form source to speakers?
Can you tell us exactly what you have in the 'chain' form source to speakers?
Sorry for the late answer. Had to catch some sleep 🙂
My chain is:
Target stand -> Rega Planet 2000 -> Rega Couple interconnect -> t-amp w. external regulated 13.5W/5A psu -> Supra speaker cables -> Audio Nirvana 8" / 8ohm / 96db / 18L fullrange bassreflex internal wiring Supra Ply 3.6 speakers on Audiomagic stands.
/Mirland
My chain is:
Target stand -> Rega Planet 2000 -> Rega Couple interconnect -> t-amp w. external regulated 13.5W/5A psu -> Supra speaker cables -> Audio Nirvana 8" / 8ohm / 96db / 18L fullrange bassreflex internal wiring Supra Ply 3.6 speakers on Audiomagic stands.
/Mirland
OK, you tried different amps but the hiss was still there so do you have another source that you connect in place of the Rega Planet?
I've tried disconnecting the Planet with no difference... I know the preamp-part often is a bit noisy in the upper areas but this is too much. Last night I connected my Royd Saphires instead of the fullrange speakers. There is still a hiss but much much less audible. Is it possible that the high effeciency is revealing too much ?
I haven't tried using a SMPS yet as I still need a cabinet for it. Might that make a difference ?
/Mirland
I haven't tried using a SMPS yet as I still need a cabinet for it. Might that make a difference ?
/Mirland
OK. Well as you state, having more efficient speakers is more likely to expose hiss or hum but the point is there shouldn't be any there to expose in the first place.
I would still like to know if the hiss is there with a different source, not just with the Planet disconnected. If it is not the source, then you have to start looking at your interconnects!
I would still like to know if the hiss is there with a different source, not just with the Planet disconnected. If it is not the source, then you have to start looking at your interconnects!
OK ! I will connect my mp3 player tomorrow (I won't be home until late tonight) and see if it acts differently. But what you're saying is that there should be NO hiss whatsoever ?
I must say the only time I haven't had hiss was when I used an Acurus DIA-100 amplifier - and that one has no preamp stage but only a very effecient poweramp. Unfortunately I haven't got the Acurus anymore. But I have always had hiss when using either Onix or Naim no matter which speakers I used.
I find it rather hard to believe the source or the interconnect should be the problem ? How could they ?
Am I the only one with this problem ? Or am I too touchy ?
/Mirland
I must say the only time I haven't had hiss was when I used an Acurus DIA-100 amplifier - and that one has no preamp stage but only a very effecient poweramp. Unfortunately I haven't got the Acurus anymore. But I have always had hiss when using either Onix or Naim no matter which speakers I used.
I find it rather hard to believe the source or the interconnect should be the problem ? How could they ?
Am I the only one with this problem ? Or am I too touchy ?
/Mirland
Without hearing the level of hiss, I can't comment but I think that I would be like you, ie any hiss/hum is too much and we should take steps to get rid of it. So no, you ar enot being too fussy!
I had a (very) loud hum coming from an amp the other day. It was nothing more than a bad connection in one of the interconnects!
I had a (very) loud hum coming from an amp the other day. It was nothing more than a bad connection in one of the interconnects!
I forgot to explain that I have no dedicated earth/ground in the mains connection. Could that be the cause ?
/Mirland
/Mirland
Check bypass caps
I seem to remember reading in this forum, that the Tripath-chips will generate strong hiss when the supply bypassing is faulty. It's specifically the small (100nF?) capacitors close to the chip.
So Mirland, check your solder work on these.
Regards, Niels
I seem to remember reading in this forum, that the Tripath-chips will generate strong hiss when the supply bypassing is faulty. It's specifically the small (100nF?) capacitors close to the chip.
So Mirland, check your solder work on these.
Regards, Niels
Nuuk said:
Well, my house is partly grounded, and I have checked the background noise level with grounded and ungrounded plugs. Using the grounded plugs the amp is considerably quieter.
However, this concerns noise levels only audible when your ear is very
close to the speaker. A loud hiss, audible from a normal listening distance surely has another reason.
Mick
Re: Check bypass caps
I will check this today. I have been in contact with Daniele Zingoni of Audio Digit. He writes that it might be the high effeciency speakers revealing a background noise more than others. He then suggests that I either:
1. "use the output caps for the 8 ohm setting. This will probably attenuate the peak in the frequency response"
2. If possible bypass the inputs and the speaker outputs
Either way I have to modify the amplifier it seems. Which in some way I find a bit annoying since I thought it would be "perfect" as is.
I am thinking about buying a Sonic Impact just for testing. But today I will try to switch sources though something tells me it won't change a thing.
But it still annoys me that I have tried 3 sets of speakers with 3 very different amps with and without a source and they all generate a hiss in the treble. Argh...
/Mirland
nilaus said:
I will check this today. I have been in contact with Daniele Zingoni of Audio Digit. He writes that it might be the high effeciency speakers revealing a background noise more than others. He then suggests that I either:
1. "use the output caps for the 8 ohm setting. This will probably attenuate the peak in the frequency response"
2. If possible bypass the inputs and the speaker outputs
Either way I have to modify the amplifier it seems. Which in some way I find a bit annoying since I thought it would be "perfect" as is.
I am thinking about buying a Sonic Impact just for testing. But today I will try to switch sources though something tells me it won't change a thing.
But it still annoys me that I have tried 3 sets of speakers with 3 very different amps with and without a source and they all generate a hiss in the treble. Argh...
/Mirland
Mirland,
You haven't quantified the volume of the hiss very clearly. Also you say you have efficient speakers, but exactly how efficient are they, for example do you have a figure for sensitivity (dB/W @ 1 metre)?
I recently listened to a Sonic Impact T-amp and was surprised by the amount of hiss audible from the speakers, I don't recall hearing this much hiss from any another amplifier. The speakers used at the time were of average efficiency, probably less than 90dB/W, and no hiss was audible at the listening position. The situation with high efficiency speakers may well have been rather different. In the absents of firm figures for efficiency etc, my own guess is that your speakers' high efficiency, possibly their character too (full-range drive units often sound relatively 'forward' to me, exagerating such problems) may not be ideal for this amplifier....assuming it is similar to the T-amp in this respect, also assuming that your source is 'quiet'.
Tim.
You haven't quantified the volume of the hiss very clearly. Also you say you have efficient speakers, but exactly how efficient are they, for example do you have a figure for sensitivity (dB/W @ 1 metre)?
I recently listened to a Sonic Impact T-amp and was surprised by the amount of hiss audible from the speakers, I don't recall hearing this much hiss from any another amplifier. The speakers used at the time were of average efficiency, probably less than 90dB/W, and no hiss was audible at the listening position. The situation with high efficiency speakers may well have been rather different. In the absents of firm figures for efficiency etc, my own guess is that your speakers' high efficiency, possibly their character too (full-range drive units often sound relatively 'forward' to me, exagerating such problems) may not be ideal for this amplifier....assuming it is similar to the T-amp in this respect, also assuming that your source is 'quiet'.
Tim.
TimA said:
Sorry ! I have snipped the following from the Audio Nirvana speakers website:
"The Audio Nirvana '8' has a frequency response from 40 hz to 20,000 hz. You can expect at least 98 db efficiency in any of our cabinets. It handles 30 watts continuous RMS (normal listening level will be about 1/10 watt). Impedance is 8 ohms. Voicecoil is 1.4 inches (35.5mm). Magnet weight is 3 lbs. Total weight is 7.8 lbs. The cone is made of paper. The surround is accordian style and made of treated cloth."
So I guess they're pretty effecient !
/Mirland
I think 98dB efficiency may well have caused problems with audible hiss from the T-amp that I tried as the hiss would have sounded around twice as loud as it did with my speakers and probably would have been audible across the room. My own experience is that the sonic characteristics of full-range paper cones makes matters subjectively worse in this respect.
Tim.
Tim.
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