Aleph J illustrated build guide

Hi

I am building Aleph J. And i am kinda new to this. So i have a question. when i measure over the pot on r27 my multimeter counts for a long time. it always settles on 68k but i take approx one minute. the same happends on r7 but never on any other resistors. The same happends on both boards. And with both multimeters i have.
 
Want you are seeing is the multimeter charging a capacitor in the circuit. Once the cap is fully charged you get the steady resistance reading. That is typical behaviour for pretty much all multimeters.

Thank you for reply. So then it is nothing to worry about. I am very glad to hear that. Just waiting for silikon pads to insulate my transistors. and i can try this great amp :)
 
So I may have had a “aha” moment but just looking for verification. Been studying up on different circuit designs and came back to this one. Since the front end is balanced from the ltp, if one had the time could you modify the output and bridge them? Also could you even go to the great lengths and make a push pull? I guess you would have to move the feedback loop to the tail and maybe ground one gate and do a lot more modifications? Just curious, though I may be way off
 

6L6

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Like this...?

alephx.gif
 
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Aleph J Bias and Adjustment

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The important thing is to look at the general shape (well behaved, no hiccups, or strange bumps, looks mostly like a sinewave) and size of the distortion residual. (Bottom trace)


And here is the measurement. The meter is set to the 0.3 scale, look at the arc below the mirror and read 0.21%

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I've been reading on connecting an amp to a scope for measurement of various things and understand you will want a voltage divider to keep from blowing things in the scope. I've read various numbers like 10:1, 50:1 and 100:1, etc and understand they are referring to the resistor value ratios but what values should be used in general for a FirstWatt type amp (50W and below for example) and is there a guideline on how low is too low and how high is too high (current limiting)?

I see people building boxes between their sound cards and amp, is it just a selective resistor divider or selector switch for resistor values in the case of preamp measurements?

Sorry if this is not directly related to the Aleph-J but if I can get this understood I will definitely be putting my AJ on the scope :D
 
You probably need to have a look at member Eric's site in his signature. Lots of AlephX info!

I'm in the process of rebuilding much of my online materials. After 20 years, my employer decided to kill off faculty web pages, so I'm rebuilding this as a Google Site which has turned into a tedious and time-consuming task because I can't just drop my HTML code there...

The Aleph-X stuff is there, just working on updating the images.
 
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Joined 2003
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I'm in the process of rebuilding much of my online materials. After 20 years, my employer decided to kill off faculty web pages, so I'm rebuilding this as a Google Site which has turned into a tedious and time-consuming task because I can't just drop my HTML code there...

The Aleph-X stuff is there, just working on updating the images.

Great to hear. Lots of good info there!

Russellc