Hi
It has been quiet in this thread for a long time now.
Any updates on the listening test? Compared to AN? Tried other op-amps?
Do the IRFPs on AN run at approximately the same temperature?
To me, it seems that the temperature is very high considering your cooling system.
RGDS
As far temperature goes:
70 degrees C, measured at the back of TO-264 transistor is consistent with my measurements on original AN,
with similar cooling. With fans off, this temperature goes up immediately, so it seems like they do their job OK.
70 degrees is a compromise between 'loud' and 'less loud' fans. They are supposedly 'quiet' Noctuas,
but since I'm usually sitting 2 meters from the amp, I still hear them, and I don't like it.
70 degrees is also consistent will all other temperature measurements I recall for AN thread.
Not talking about temp of the heatsink.
I was following AN thread carefully, and all people who actually measured temperature
AT THE TRANSISTOR, reported 70 or more degrees.
Haven't seen any reliable measurements below 70.
Yes, it's hot. Can be cooler, at the cost of fan noise.
Music tests:
Here I'm little bit in awkward position.
To me all GOOD amps sound the same. See this post for details.
See this post for a parody of so called audiophile's music tests, that I think are totally useless.
I'm one of these people who do not hear any difference between different input capacitors, different op-amps,
and metal-film vs. carbon resistors, I think this is all BS.
I know these resistors may measure differently, but I fail to hear this difference, and I don't believe anyone else can.
You want to hear about 'depth of music stage' or 'mobility of trebles' you need to ask someone else 🙂
"It remains an intriguing question: why do sound amplifiers different, even when their
specifications are similar?"
That's not my experience. To me all good amps of similar class (that I built) , all sound the same.
Now what is the definition of "the same"??
Here is my experience: If I switch from amp A to amp B, it doesn't sound the same.
I feel differences. Then I switch to amp C. Also feel differences. Then switch to A again - feel difference.
I can't tell which sound is ''better' or 'worse'. Just different.
Sometimes I can tell which one I like better. The problem is that one day I like amp A better, the other day amp B.
All in all, if I repeat these tests many times in different order, different amps, blind or not,
there is clearly NO PATTERN of which amp I prefer.
Conclusion: in 'short term' testing amps of similar class sound different.
For a long run, they all sound the same.
I think this is caused not by amps, but rather by human's hearing system being not perfect,
and craving for a change.
Summary:
I guess that's not what people around here want to hear, but here it is....
Beta Nirvana is a good amp, that I can't distinguish from any of my other 16 amps I consider 'good'.
Especially given it's simplicity. But then there is heat....
The same applies to original AN.
70 degrees C, measured at the back of TO-264 transistor is consistent with my measurements on original AN,
with similar cooling. With fans off, this temperature goes up immediately, so it seems like they do their job OK.
70 degrees is a compromise between 'loud' and 'less loud' fans. They are supposedly 'quiet' Noctuas,
but since I'm usually sitting 2 meters from the amp, I still hear them, and I don't like it.
70 degrees is also consistent will all other temperature measurements I recall for AN thread.
Not talking about temp of the heatsink.
I was following AN thread carefully, and all people who actually measured temperature
AT THE TRANSISTOR, reported 70 or more degrees.
Haven't seen any reliable measurements below 70.
Yes, it's hot. Can be cooler, at the cost of fan noise.
Music tests:
Here I'm little bit in awkward position.
To me all GOOD amps sound the same. See this post for details.
See this post for a parody of so called audiophile's music tests, that I think are totally useless.
I'm one of these people who do not hear any difference between different input capacitors, different op-amps,
and metal-film vs. carbon resistors, I think this is all BS.
I know these resistors may measure differently, but I fail to hear this difference, and I don't believe anyone else can.
You want to hear about 'depth of music stage' or 'mobility of trebles' you need to ask someone else 🙂
"It remains an intriguing question: why do sound amplifiers different, even when their
specifications are similar?"
That's not my experience. To me all good amps of similar class (that I built) , all sound the same.
Now what is the definition of "the same"??
Here is my experience: If I switch from amp A to amp B, it doesn't sound the same.
I feel differences. Then I switch to amp C. Also feel differences. Then switch to A again - feel difference.
I can't tell which sound is ''better' or 'worse'. Just different.
Sometimes I can tell which one I like better. The problem is that one day I like amp A better, the other day amp B.
All in all, if I repeat these tests many times in different order, different amps, blind or not,
there is clearly NO PATTERN of which amp I prefer.
Conclusion: in 'short term' testing amps of similar class sound different.
For a long run, they all sound the same.
I think this is caused not by amps, but rather by human's hearing system being not perfect,
and craving for a change.
Summary:
I guess that's not what people around here want to hear, but here it is....
Beta Nirvana is a good amp, that I can't distinguish from any of my other 16 amps I consider 'good'.
Especially given it's simplicity. But then there is heat....
The same applies to original AN.
Try using the speed reducer cable that comes with the Noctua. It will reduce air flow and transistors will be hotter but they can take 90C just fine. It will be pretty silent with the reducer. I think my actives are typically 85C with fans at lowest speeds.
Hi. At +/-20v its safe to use ne5534. Im betting that getting rid of d1 and d2 might be worth whatever the trade off there is downgrading from lt1056. There is also opa551 thats jfet and works up to 35v differential.
Also ill be building mine as a line stage/headphone amp, with to220 mosfets. Is there anyway i could keep it temperature stable on small to220 heatsinks? Perhaps mount the vbe bjt on one of the heatsinks?
Also ill be building mine as a line stage/headphone amp, with to220 mosfets. Is there anyway i could keep it temperature stable on small to220 heatsinks? Perhaps mount the vbe bjt on one of the heatsinks?
Thanks for your great work. i would like to "play" with it using my sprint layout 6.0. thanks again.
Pls PM me. The system doesn't allow me to start private conversation with you. Or email me at minek at yahoo.com.
Minek,
Watching carefully that wonderful pcb carefully, I have noticed a track from Sgnl ground to the direction of (Above) R1 with a dead end(nor a spare part connected or any other pad) What is its purpose? Thanks
It's a 'screen' - ground track separating input circuitry from the nearby power supply tracks.
Not sure if it really gonna be effective, or really needed..
Not sure if it really gonna be effective, or really needed..
