I'm cheating sometimes
using sandwich of big M4 washer, regular M3, spring M3
that when I'm lazy to drill coins
which I am, lately
using sandwich of big M4 washer, regular M3, spring M3
that when I'm lazy to drill coins
which I am, lately
operator error is a given in my case...
it's showing about 35 watts each channel with THD of about 0.1% which seemed good to me.
Don't understand the comment about keeping things at -10dBfs.
I used the standard 4U-400mm deep. Drilled & tapped the heatsinks myself because I'm cheap (and it's easy).
Washers are installed and it's playing nicely. Now, back to trying to make my DAC project work.
ZM quote:
"I can guess that Pa once was bored and bought mini torque thingie to use for exact purpose, just to give it as gift to someone, after day or two
and that must be decades ago, hard to imagine anything at PL being over engineered (neither product nor production procedure step)"
Maybe Nelson or Wayne might fill us in if they read this - most interested.
"I can guess that Pa once was bored and bought mini torque thingie to use for exact purpose, just to give it as gift to someone, after day or two
and that must be decades ago, hard to imagine anything at PL being over engineered (neither product nor production procedure step)"
Maybe Nelson or Wayne might fill us in if they read this - most interested.
5th December 2002, 09:13 PM #6
Nelson Pass
The one and only
Join Date: Mar 2001
Proper mounting of TO-247 Devices
I recommend a nice wide washer on top.
The TO247 case has good support at the hole, and you
just want to avoid cranking down too hard. We use
torque wrenches set at 8 inch-pounds.
Nelson Pass
The one and only
Join Date: Mar 2001
Proper mounting of TO-247 Devices
I recommend a nice wide washer on top.
The TO247 case has good support at the hole, and you
just want to avoid cranking down too hard. We use
torque wrenches set at 8 inch-pounds.
well, for 35W that maybe is good ....... need to look at graph more and think more
what I was saying about -10dbfs is - always keep level of signal going to analyzer at that value, with external attenuator
it is, at least, what I was taught and what I read, when those PC thingies are in case .......... everything above that and you're too close to clipping
however , I believe there is clipping LED at QA401, and if it didn't lit, you're good
I have QA400, still didn't resolve to use it, entire software package lacking in usability comparing to ARTA, which I'm using with my EMU1212
OK, THD Spectra measurements are sorta straightworward ( even if ARTA's screen capture routine is way better) but Freq. linearity measurement is something which is wrong (huge and pretty linear drop at higher freq.) shown in pure loop mode ( just analyzer)
or I "just" still didn't figured out some important setting
can you show us measurement for 1W@8R?
and please, just one channel shown 🙂
that's the Power of Proper (search) Tool Usage
I'm still Master of All Wrong Guesses
according to my method, that would be 0.903879Nm
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What determines the power output of the amp? Could I get 100-150w of power output using the parts hirscwi used aside from a different transformer(s) for higher output?
6 deep OS
Sanken SA1386 and SC3519 outputs
25v-300va transformers-about 50wpc
6 deep OS
Sanken SA1386 and SC3519 outputs
25v-300va transformers-about 50wpc
150W
P=Urms^2/Rload
so Urms=34V64rms
x2 x 1.41 = 97V97pp
so, that means you need 100Vpp across 8R
which calls for at least 56V rails (sum being 112Vdc,, there is your envelope for Vpp)
then go back and find what Pa said about FE transistors and rails voltage
for 150W, I would go with 8deep
P=Urms^2/Rload
so Urms=34V64rms
x2 x 1.41 = 97V97pp
so, that means you need 100Vpp across 8R
which calls for at least 56V rails (sum being 112Vdc,, there is your envelope for Vpp)
then go back and find what Pa said about FE transistors and rails voltage
for 150W, I would go with 8deep
I believe 2+6 (8deep) would cope with measly 150W of output power
though, there is still need to determine how much of that you want in A Class, so that would determine dissipation (both sum and per device) and applicability - one case for stereo, or monoblocks
see, who sez that finalizing construction of (good) amplifier is complicated task?
there is myriad of lousy ones on market
(just to remind of possible OS arrangement per channel,staying in cases of normal height :
-SE :
6deep, 8deep, 6deep + 6deep, 6deep + 8deep, 8deep + 8deep
-Bridged:
6deep b. to 6deep, 8deep b. to 8deep)
though, there is still need to determine how much of that you want in A Class, so that would determine dissipation (both sum and per device) and applicability - one case for stereo, or monoblocks
see, who sez that finalizing construction of (good) amplifier is complicated task?
there is myriad of lousy ones on market
(just to remind of possible OS arrangement per channel,staying in cases of normal height :
-SE :
6deep, 8deep, 6deep + 6deep, 6deep + 8deep, 8deep + 8deep
-Bridged:
6deep b. to 6deep, 8deep b. to 8deep)
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I finally got back to looking on the qa401. Here are results for left and right at 1 watt into 8 ohm. Very low THD - good I suppose? No real signs of any low harmonics.
Thought I had Gen 2 turned off... guess not.
so it looks as expected? It sure sounds nice on even small Polk speakers. Going into good system with Tekton speakers today or tomorrow. I need more heat in my house.
so it looks as expected? It sure sounds nice on even small Polk speakers. Going into good system with Tekton speakers today or tomorrow. I need more heat in my house.