Aleph J illustrated build guide

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#9,061
Deactivate the normal commands and put in the new commands in the circle.
Show the output signal and the residual signal in one window. You must magnify the residual in the window with the signals.
 

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#9,062
Thank you, learned something again.
Am I correct in assuming that:
When f1 is a frequency and T1= 360°means a period of a sine H1 as fundamental,
And H2 is its second harmonics
Then H2 phase is from -90° to +90° or from 0° to 180° always related to H1

I know that:
• Negative phase H2 in REW is shown as 90°
• With this LTspice tool and DIANA as you showed it

But how does it correlate with values 'Phase' and 'Normalized phase' for H2 from Error_log in LTspice?
 
#9,065
Here's another H2 phase dialysis with residual decoder.
Pic is magnified part from my sim with residual decoder and FFT. H1 is fundamental - green, H2 is 2nd harmonics - blue.
Residual decoder: fi(H2) = fi(H1) - 108°
LTspice Error log: fi(H2) = fi(H1) - 147°
There is some discrepancy between the LTspice error log and the residual decoder, but the trend is OK.
 

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#9,066
Hi all-

Soon after soldering the R5 resistors to the amp boards, in my case a pair of 1/4 watt RN60Ds as specified by BOM Rev. D, I noticed the other resistor specified for that position is a 1/2 watt Vishay. I’ve seen a couple of posts reporting that more than 250mW was seen there. I’m wondering if anyone else has found themself in this situation and felt compelled to desolder and replace that resistor with the higher rated one. I’d just like to hear from the forum in general what the consensus is and what is recommended to do here, before I execute a tricky desoldering operation I’d really rather avoid.
 
#9,075
Perhaps others will chime in, but I personally wouldn't worry about using the KOA-Speer.

I thought Mouser still has some of the Panasonic resistors available. Perhaps not anymore. 🙁

Anyway, if you can order from other sources, the Panasonics are still available (at least for now) should you wish to persue them.
For example they can be found at Digikey and Newark (and probably other retailers):

https://www.digikey.ca/en/products/detail/panasonic-electronic-components/ERX-3SJR47/36497
https://canada.newark.com/panasonic/erx-3sjr47/resistor-0-47ohm-3w-5-axial/dp/52W8322?ost=erx-3sjr47
 
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#9,078
Oh, one question. If R6 and R30 are jumpered, and in the LTP bias position is a 2K pot, where to measure to ensure the pot is set to 1K (as I forgot setting this in the procedure)? What should be the voltage at the top (emitter ) of Q2 or below R8 with respect to ground?
Thanks!
 
#9,079
Zen Mod said:
put 1KHz sine, 1W at output, through dummy load (8R)

measure voltage AC across source resistor in lower rail, write down
measure voltage across AC resistor in upper rail, write down

inform here

goal is to find what Aleph CCS AC gain you have actually

meaning - when said is approx 50%, that means that upper half of amp OS ( exactly Aleph CCS) is having same voltage/current contribution as lower part of amp, practically amp acting as regular PP amp

if said gain is lesser than 50%, amp is leaning more to pure SE mode of operation, thus being more dependable of load value and behavior

now, having 604, efficient as bigbadaboom, you can try trick with load shunt - if you put 10-20W 16R resistor in parallel to spk, silly amp should think that 8R speaker is connected

some power to speaks, some heat to resistors, but who cares, with their efficiency
Click to expand...

R16 and R17 (upper half) = 34mV
R18 and R19 (lower half) = 56mV
 
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