Difficulty levels for amp building

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2 picoDumbs

2 picoDumbs

Member
Joined 2013
Very true.
ACA and Aleph J (or other Aleph circuit) almost guarantee a successful clone of the original.

The other's will still be very good but there is no guarantee of getting a clone of the original without the ability to measure distortion harmonics or years of experience knowing how to achieve such things, simulation usually gets you close but only if your models match your actual parts.
 
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2 picoDumbs

2 picoDumbs

Member
Joined 2013
6L6 said:
You could just omit the thermistors, as the circuit works just fine without them, merely the warm up becomes slower and less stable. (I don't actually suggest this, however)
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I've never used thermistors in any of my F5 circuits.
I recently realised I have an obsession with parts minimization.
Haha

My latest version is all Toshiba parts biased at 2A.
Even less parts than F7.
Hahaha
 
6L6

6L6

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Joined 2010
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With reasonable matched parts (input Jfet) the best sounding position (in my opinion) of the THD pot is right in the middle.

If matched Jfets are bought from the store, you are guaranteed a nice tight match, as I have matched them all. :D

I think the AJ is probably the best 'big' firstwatt for beginners as it's quite easy to set all the parameters with just a DMM or two. The AJ also sounds glorious.

The most common issue people have when building an AJ is a bad solder joint somewhere, and 90% of the time re-flowing the joint solves the problem for good.

2 picoDumbs said:
My latest version is all Toshiba parts biased at 2A.
Click to expand...

Lucky!!!! I have yet to source a set of the output Mosfets.
 
A

Alistair72

Member
Joined 2007
I’m a little worried pico has been looking through my window...

But the ACA first approach gives you something to listen to whilst you look at (my case) your F6 boards and wonder if they will ever get built.

I’m hoping (if I get the replacement FETS in time) I’ll have the F6 running for Xmas - it’s been 2 years coming. But the answers to all the issues can be found on the forum so get an ACA kit and press on 🙃

2 picoDumbs said:
They are all easy circuits.
It's the small details that people often get stuck on. Ground loops, bad connections, poor solder joints, correctly wiring up things, drilling and tapping holes, time wasted on forgetting to order parts, what fasteners do I need, where do I get that from, what thermal pads should I use, what transformer should I use, what capacitors should I use, what IEC socket should I use, what fuses should I use, what gauge hook up wire should I use, copper, tin plated, or silver plated, how do wire all this up without killing myself ir destroying the amp, how tight is 1.1 Nm of torque, aah crap this is costing more than I thought, and taking much longer than I thought.
Hahaha
A year goes by and the project is still unfinished.

ACA less things to think about. Finished in a weekend.
Click to expand...
 
S

Sprags

Member
Joined 2013
So...I reexamined the build guide for the BA-3 Complimentary amp and I also checked out the bill of material and started putting together a cart at Mouser. And I soon had questions about things that I found to be things I did not understand. So I went through the build guide for the F4 and the Aleph J and I also out together carts for those. I think the Aleph J seemed fairly easy for me to grasp and the build guide seemed to be straight forward for the most part.

However since you said a new kit for ACA may be available shortly perhaps I should hold off and see what that entails. My thought from looking over the current ACA is that if there is a way to put both channels in one chassis and be able to incorporate a power supply that can hand both channels as well that that would a nice alternative.
 
6L6

6L6

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Joined 2010
Paid Member
The new ACA will be single chassis and PSU. It's a nice amp, the PCB has been laid out to fit the new chassis and incorporate on the board an additional resistor that was added to the circuit, but aside that, there's no difference from the old.
 
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