And some think the A75 has too many output devices!!! Nothing like all those devices for control.
BDP
Hi
In post 59 Nelson Pass stated;
5) Sound. An XA30.5 with fewer devices sounds thinner and
has less control than the larger XA amplifiers. Since we want a
"family similarity" sonically, we use more devices than absolutely
necessary
I have experienced this in power amps particularly with mosfet output stages but less so with bipolar putput stages. I have assumed it was due to the limited ability of one transistor to deliver the current needed for transients - but I am guessing. I would like to know why the improvement occurs if someone could explain.
Don
In post 59 Nelson Pass stated;
5) Sound. An XA30.5 with fewer devices sounds thinner and
has less control than the larger XA amplifiers. Since we want a
"family similarity" sonically, we use more devices than absolutely
necessary
I have experienced this in power amps particularly with mosfet output stages but less so with bipolar putput stages. I have assumed it was due to the limited ability of one transistor to deliver the current needed for transients - but I am guessing. I would like to know why the improvement occurs if someone could explain.
Don
Nelson Pass said:
Mr. Pass,
The XA30.5's high current capability is amazing. Does it still have the aleph current source? If yes could you explain how the modified current source delivers the high current? In the owner's manual you mentioned that the X.5 and XA.5 have similar circuits with different bias, does it mean that the X.5 series also have the aleph current source?
CT,
You are reading the wrong thread. This has already been explored (and answered) in The Aleph-X thread (see the more recent postings).
Ian.
You are reading the wrong thread. This has already been explored (and answered) in The Aleph-X thread (see the more recent postings).
Ian.
AMV8 said:
Who knows? I do know that it is possible to overdo it, and the
sound gets very not-thin.
😎
Importance of temperature?
With bias also comes a higher temperature.
Are the heatsinks dimensioned just from reliability point of view?
Or is there an optimal temperature region in the transistors for best sonic performance?
If the answer already exists in another thread please give me a hint 😉
With bias also comes a higher temperature.
Are the heatsinks dimensioned just from reliability point of view?
Or is there an optimal temperature region in the transistors for best sonic performance?
If the answer already exists in another thread please give me a hint 😉
I don't see an optimal temperature as such. I tend to design
around standardized heat sinks, and the result is a trade-off
between power and bias, as the heat sinks usually are the
limiting factor. I inevitably seem to end up at about 55 deg C on
the heat sink.
😎
around standardized heat sinks, and the result is a trade-off
between power and bias, as the heat sinks usually are the
limiting factor. I inevitably seem to end up at about 55 deg C on
the heat sink.
😎
Hi there!
Referring to Post #1:
I`ve made an A30 building report on my (commercial) web site with just these relations a while ago.
http://www.audioprojekte.de/html/diy2_en.html
Combined with a lot of measuring work on the input/power devices i have reached a very low distortion figure.
Amps are sounding extremely good!
Ralf
Referring to Post #1:
I`ve made an A30 building report on my (commercial) web site with just these relations a while ago.
http://www.audioprojekte.de/html/diy2_en.html
Combined with a lot of measuring work on the input/power devices i have reached a very low distortion figure.
Amps are sounding extremely good!
Ralf
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