Yes, 1k is perfectly good for R1270 and you have a zero adjustment Class A amp! This amp works so brilliantly and after firing up two sets now - I can say it’s not a white knuckle experiment anymore (can’t be said of some other amps - especially ones that have 4 pots all interdependent and affect offset AND bias, uggh ... to think we used to deal with that - and then the DC offset drifts from startup to warm, and changes depending on if amp lid is on or off!
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Not able to read polish but Stereophile review says INT-60 at $9k and 55kg is an awesome amp. Class AB though. Again, the dominant 3rd order and presence of 5th & 7th harmonics makes for a different sound than the Alpha I’m sure.
Pass Laboratories INT-60 integrated amplifier Specifications | Stereophile.com
Here is Stereophile measurement for 20w into 8ohms:
Pretty clean actually for that level of power.
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Thanks X,
I will try to get those updates done today, listening to this ALPHA20 has become addictive
....Also, I have an amplifier just like you’re talking about and can’t figure out why the cover changes the bias? It’s not related to heat because it happens immediately once the cover is on.
No maintenance ALPHA20 sweet!!
I will try to get those updates done today, listening to this ALPHA20 has become addictive
....Also, I have an amplifier just like you’re talking about and can’t figure out why the cover changes the bias? It’s not related to heat because it happens immediately once the cover is on.
No maintenance ALPHA20 sweet!!
Thanks X,
I will try to get those updates done today, listening to this ALPHA20 has become addictive
....Also, I have an amplifier just like you’re talking about and can’t figure out why the cover changes the bias? It’s not related to heat because it happens immediately once the cover is on.
No maintenance ALPHA20 sweet!!
The lid changes bias or DC offset? If it changes offset immediately there may be a change in the ground to 0v impedance when kid screws are in. Maybe it connects front to rear panels electrically?
The Alpha appears to have a self correcting auto DC tracking functionality built into the topology (like an opamp servo) even though there are only 6 transistors total. Because that’s the only way you can get 0mV DC offset from cold to hot without a pot.
For feedback resistors it seems high quality (Vishay Dale or Yageo) metal thin film and carbon film are about the same. But increased 3rd order for thick film metal oxide.
For power source resistors on Aleph CCS and Aleph current sense resistors it would appear high quality metal oxide (Light blue Panasonic ERX) are same as Aliexpress 3W 1% metal thin film (bright blue ones), are good equally. However, Vishay Dale wirewound:
ALSR03R3300JE12 are not suitable. Neither are Vishay Sfrenice wirewound RWM0410R150JR15E1 and I assume these are all inductive.
The white cement filled non inductive prismatic box style KOA Speer use a single U shaped metal filament like a fuse so should be good. I have not tried those but expect they should be decent.
For power source resistors on Aleph CCS and Aleph current sense resistors it would appear high quality metal oxide (Light blue Panasonic ERX) are same as Aliexpress 3W 1% metal thin film (bright blue ones), are good equally. However, Vishay Dale wirewound:
ALSR03R3300JE12 are not suitable. Neither are Vishay Sfrenice wirewound RWM0410R150JR15E1 and I assume these are all inductive.
The white cement filled non inductive prismatic box style KOA Speer use a single U shaped metal filament like a fuse so should be good. I have not tried those but expect they should be decent.
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Mine are always done using a heatsinked metal body 8ohms 25w resistor. I do measurements circa 2.8vrms or 1watt. Actual voltage level always stated in graph title.
EXPOSURE XM7+2xXM9
Wzmacniacze stereo - testy
Wzmacniacze stereo - testy
By the way, I can view a polystyrene cap (aka styroflex) like I have in my cheap tweaked KEF Q100 coaxial speakers.
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A head-up for those using processor cooler and planning the final set-up: some modern Mini- or Cube PC cases can be misused as eye-catching minimalistic amp enclosures, see brands like Jonsbo, Lian Li or Fractal Design. They are mostly well designed for good inner accessibility and airflow, some with really silent 120mm or even 140mm fans. Some as Kolink Satellite+ on UK Amazon go for under GBP35 and are real bang for the buck, some as Streacom DB4 are even for 300 bucks terrific aesthetics, if you go for such kind of things...;-)
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How many commercial amps do you know with H2 predominance?
Class AB H2 predominance?
You know, I like very much the sound of your F5 Juma's. But I need power with my 86dB (2.83V/1m) -4.7 Ohms minimum- speakers.
I would like an ALPHA class AB amp with same harmonic profile.