Passion to mod Aleph-5

[tomchaoda]

Not that my Aleph-5 isn't good, but rather this is my passion to make is better if I could! In this, I learn a lot and enjoy my learning all the way....

My passions:

1. My Aleph-5, after about an hour, settles its DC offset at 56mv and 48mv. I saw some DIY has rather good at 10mv. What's the trick (parts? circuit mod?) to make it that good?

2. Is there a way to increase the bass to Aleph-5 (and the Aleph-2 I am about to make)?

Again, many thanks to all who replies!

Thomas

[Nelson Pass]

1 You can adjust the value of the 392 ohm resistor that comes
off the Drain of Q1.

2 Actually, the 5 tends to have a little more apparent bass
because of a little less bias and a little more current source
gain in ratio to the other models. If you up the bias and lower
the current source gain a bit, it starts to lean out, more like
an Aleph 2, which I happen to prefer.

In any case, playing with these two parameters will give you
a slightly different bass characteristic, and I would encourage
you to try it out.

[tomchaoda]

Nelson:

Thanks for your reply. I definitely will give it a try!

Thomas

[tomchaoda]

In testing and monitoring my newly made Aleph-5, all 3 sets of my IRFP240's bias voltage are in the range of 0.5V. However, one set is one at 0.6V and the other two is at 0.5V. Should I worry about this or not? (these MOSFET are matched to 0.01v and on the last set, they have the exact number) or should I change it?

Thanks,

Thomas

[dantwomey]

You might find the following thread an interesting read.

Top ten ways to a better Aleph?

Regards,
Dan

[tomchaoda]

Yes, I did follow this thread and add a Wima 1uf MKP cap to the Z5 and the treble did sounds better.

What I am not sure is in one of my output board, I have this bias:

1st mosfet: 0.6 v
2nd mosfet: 0.5 v
3rd mosfet: 0.5 v

All other 3 output boards are in the range of +/- 0.5 v. In your opinion, should I change the first mosfet, or I should be fine?

Thomas

[GRollins]

Did you match the output MOSFETs?

Grey

[tomchaoda]

Did you match the output MOSFETs?

Grey:

Yes, I did matched down to 0.01v (match time about 10 to 20 min for each mosfet). That's why I am wondering why is the difference and should I care about it? or change it?

All other 3 sets are fine!

Thomas