Hi,
I think now the dust must have settle a bit. Is there a prefered list of parts and schematic to build using the group buy PCB?
Regards,
Chris
I think now the dust must have settle a bit. Is there a prefered list of parts and schematic to build using the group buy PCB?
Regards,
Chris
chris ma said:
Check post #305 of the following thread http://www.diyaudio.com/forums/showthread.php?s=&postid=176060#post176060
If you need electrolytics, send me an e-mail 😉
anyone have a part number for the 0.22 ohm 3 watt resistors?
The Blue Panasonics form Digikey only go down to 0.47 ohm.
Was just wondering what was being used.
The Blue Panasonics form Digikey only go down to 0.47 ohm.
Was just wondering what was being used.
Parallel two .47 Panasonics or spring for Caddocks. I think I remember seeing some folks going for Mills. See what Michael Percy has on hand these days. The Resistor Police will only arrest you if you use some kind of non-audiophile grade sandbox ceramic 5W.
On the other hand, the Resistor Police don't seem to care what goes into commercial amps, so use whatever you like. It's not like Nelson is going to come break your door down and shake a finger in your face, scolding you. Neither will I.
Grey
On the other hand, the Resistor Police don't seem to care what goes into commercial amps, so use whatever you like. It's not like Nelson is going to come break your door down and shake a finger in your face, scolding you. Neither will I.
Grey
There was Mills resistor group buy. You can order them from percyaudio.com, or use Panasonics in parallel
thanks guys
for some reason i like the idea of all the resistors being the same,
so i guess i'll use Panasonics in parallel... then again, the 1/4 watt
resistors are Dales, so that shoots the sameness all to hell! 🙂
...but the ZEN amp is like that and it sounds just fine.
(would the resistor police knock on your door, or use the doorbell? 😕
for some reason i like the idea of all the resistors being the same,
so i guess i'll use Panasonics in parallel... then again, the 1/4 watt
resistors are Dales, so that shoots the sameness all to hell! 🙂
...but the ZEN amp is like that and it sounds just fine.
(would the resistor police knock on your door, or use the doorbell? 😕
The Resistor Police use a battering ram.
Note that Dale has higher power resistors. Or at least I think I remember seeing some in the Mouser catalog.
Grey
Note that Dale has higher power resistors. Or at least I think I remember seeing some in the Mouser catalog.
Grey
Moe,
you can alway parallel a few Dales😀 The power rating for 1A bias per Fet and 0,47 ohm resistors is only 0,47 Watt. So if you use 4 x 2 ohm Dales as source resistors you can keep your amp free of any different Brands🙂
william
and for 0,22R it´s only 0,22 watt so 4 x 1 Ohm is overrated 4 times!
you can alway parallel a few Dales😀 The power rating for 1A bias per Fet and 0,47 ohm resistors is only 0,47 Watt. So if you use 4 x 2 ohm Dales as source resistors you can keep your amp free of any different Brands🙂
william
and for 0,22R it´s only 0,22 watt so 4 x 1 Ohm is overrated 4 times!
after of hours of reading the threads I was inspired to start building a pair of ams for my tweeters.
I ordered a few boards already and I can´t wait to see how this turns out.
I ordered a few boards already and I can´t wait to see how this turns out.
Hi all
I'm planning to rebuild my xsoz monoblocks into aleph-x. Each block have a 500VA/15V trannie. A CLC filter wich give something like 20V with no load, and 17,85V under the load of xsoz. Is it possible to use the same power supply, just to throw in some more caps? How much capacitance do i need?
If you take a look on this spread sheet you can see what I want. My speakers have a nice and flat impedance curve around 5,5 Ohms. This setup will give me 103W into 5,5 Ohms. A huge difference to my 7W I have for the moment.
How do I calculate the actual voltage at the fets?
What is the the AC current gain? And how will it affect the sound if I choose 66%?
Is irfp044 still the best choice?
cheers,
vit
I'm planning to rebuild my xsoz monoblocks into aleph-x. Each block have a 500VA/15V trannie. A CLC filter wich give something like 20V with no load, and 17,85V under the load of xsoz. Is it possible to use the same power supply, just to throw in some more caps? How much capacitance do i need?
If you take a look on this spread sheet you can see what I want. My speakers have a nice and flat impedance curve around 5,5 Ohms. This setup will give me 103W into 5,5 Ohms. A huge difference to my 7W I have for the moment.
How do I calculate the actual voltage at the fets?
What is the the AC current gain? And how will it affect the sound if I choose 66%?
Is irfp044 still the best choice?
cheers,
vit
Cant compress the spread sheet to zip. Only have drop stuff.
I'll post it ths way instead:
voltage 20
bias 4
ac current gain 66%
number of fets 8
Peak current 5,882352941
power 8 Ohms 81
power 4 Ohms 69,20415225
power 2 Ohms 34,60207612
Dissipation 160
Dissipation per fet 20,00
I'll post it ths way instead:
voltage 20
bias 4
ac current gain 66%
number of fets 8
Peak current 5,882352941
power 8 Ohms 81
power 4 Ohms 69,20415225
power 2 Ohms 34,60207612
Dissipation 160
Dissipation per fet 20,00
vit said:
You can use the same power supply maby add some extra capicity. I use a 300VA/15V trannie and get with 4.5 A bias circa 17V rails. I don't know the difference in sound with 50 or 66 AC current gain.
Vit,
the power supply and transformer look ok. Your calculations also.
AC-current gain at 66% in my case gave a punchier bass and certainly has some influence on the treble although I can´t comment on this cause my amp (Aleph5, NO X)was clipping (or near to it) at 50% ACCG cause of my speakers 2.3 Ohms impedance at higher frequencies.
Theoretically if you go over 50% the current source will shut of at some point wich means it´s not really class A anymore and this certainly has some influence on the sound.
As long as this isn´t the case (low power) the current changes through the lower fet (connected to the negative supply) will be smaller for a given power wich could have a positive influence......
Since it it quite easy to set the ACCG with a pot or two resistors and some dip-switches you could just try and listen.
william
the power supply and transformer look ok. Your calculations also.
AC-current gain at 66% in my case gave a punchier bass and certainly has some influence on the treble although I can´t comment on this cause my amp (Aleph5, NO X)was clipping (or near to it) at 50% ACCG cause of my speakers 2.3 Ohms impedance at higher frequencies.
Theoretically if you go over 50% the current source will shut of at some point wich means it´s not really class A anymore and this certainly has some influence on the sound.
As long as this isn´t the case (low power) the current changes through the lower fet (connected to the negative supply) will be smaller for a given power wich could have a positive influence......
Since it it quite easy to set the ACCG with a pot or two resistors and some dip-switches you could just try and listen.
william
It's certainly true that a higher current gain will give punchier
bass (and higher damping, and lower distortion).
Actually, it's not the case that higher gain figures will necessarily
cause AB type operation. It all depends on the bias current.
It is also true that I have observed punchier sounding bass
in output stages which are current starved for bias, and it
is likely that the harmonics generated, while pleasing, are
false.
bass (and higher damping, and lower distortion).
Actually, it's not the case that higher gain figures will necessarily
cause AB type operation. It all depends on the bias current.
It is also true that I have observed punchier sounding bass
in output stages which are current starved for bias, and it
is likely that the harmonics generated, while pleasing, are
false.
sound
Which sounds better an Aleph @25 volts 1.5 amp bias or @18 volts 2 amp bias? Both into the same load.
Which sounds better an Aleph @25 volts 1.5 amp bias or @18 volts 2 amp bias? Both into the same load.
Re: sound
30V 3 amp bias 😉
More voltage more bias more sound more heat
MikeW said:Which sounds better an Aleph @25 volts 1.5 amp bias or @18 volts 2 amp bias? Both into the same load.
30V 3 amp bias 😉
More voltage more bias more sound more heat
Speaker impedance / power efficiency
I know that power efficiency is low for Class A amplifiers and hardly an issue for Class A fanatics but still...... 😉
What are the effecs of a higher versus a lower speaker impedance on efficiency (and audio quality?) for an AlephX?
Say that I would have the choice to wire two 8 Ohm drivers in series for 16 Ohm's or to wire them in paralel for 4 Ohm's, what would be better or isn't there any diiference?
There is an obvious difference in the current needed to reach a certain power level (I^2.R) and probably you could lower the bias current, but you will probably need a higher supply voltage to avoid clipping.
Are there any reliable formula's around the forum (with all due respect to the makers, no spreadcheats please!
) that explain the situation for an AlephX?
I know that power efficiency is low for Class A amplifiers and hardly an issue for Class A fanatics but still...... 😉
What are the effecs of a higher versus a lower speaker impedance on efficiency (and audio quality?) for an AlephX?
Say that I would have the choice to wire two 8 Ohm drivers in series for 16 Ohm's or to wire them in paralel for 4 Ohm's, what would be better or isn't there any diiference?
There is an obvious difference in the current needed to reach a certain power level (I^2.R) and probably you could lower the bias current, but you will probably need a higher supply voltage to avoid clipping.
Are there any reliable formula's around the forum (with all due respect to the makers, no spreadcheats please!
) that explain the situation for an AlephX?