Cubie2

[Samuel Jayaraj]

http://www.diyaudio.com/forums/pass-labs/244106-lsk-pre-baf-2013-a-12.html#post3710957

Can anyone comment on the sound of the above linked amp, compared to Cubie2? Thanks.

 

[Samuel Jayaraj]

Any views on my query above? Thanks.

 

[juma]

Obviously, nobody else built both. The amp you linked needs polishing anyway - I've built it just out of curiosity, as a quick prototype/proof of concept. Serious build would call for more than a few changes and I don't have enough free time for all the promising projects...

 

[mikvous]

I've built both. Cubie 2 (without feedback) is a match better amp.

 

[gaborbela]

I've built both. Cubie 2 (without feedback) is a match better amp.

Hi
Based on the circuit on the first page the Cubie2 has some feedback (Am I wrong about that)
Can you tell us how you built without feedback, did you made some other tweet or the amplifier stable without feedback just leave out the feedback resistor.
Thank you

 

[mikvous]

See first post last sentence by Juma

 

[gaborbela]

OK thank you. I will read it carefully again.
Greetings

 

[Samuel Jayaraj]

Obviously, nobody else built both. The amp you linked needs polishing anyway - I've built it just out of curiosity, as a quick prototype/proof of concept. Serious build would call for more than a few changes and I don't have enough free time for all the promising projects...

Juma, I'd like to think you are joking. I have built the amp I linked but not the Cubie series. I only needed to separate supply for the Front End. It is a phenomenal amp. Juma, thanks for your great work. If I can just give some pointers for improvements, I can experiment.

 

[juma]

Thank you Samuel,
please let us not contribute to already high confusion level of the forum
This is the thread about Cubie 2 and if you want to discuss the amp you linked, please open a separate thread about it.

 

[marsupialx]

Irritating. Just finished my F4 with a SET Flea Powered Tube front end. Cubie 2 is better. My run at the absolute sound is thwarted by Cubie 2. Damn you, juma.
At least I own Cubie 2. Nobody is going to run off home with it. It is s-o-o-o-o right. Everything else is slightly compromised. Thanks, juma!!!!!

 

[Cambe]

 

[juma]

No marsu, that can't be true!
It doesn't have sub-ppm THD and uses that terrible feedback; no holy iron inside nor thermionic and extinct parts - you must be wrong !

 

[marsupialx]

Lateral Mosfets and Jfets are close enough to extinct parts for me! Easier to get tubes! It's uncanny how good it is. Freaking awesome. I'm going to use the laterals and jfets out of Cubie to make another two channels of Cubie 2. I'll have a four channel Cubie 2, just right for bi-amping. I don't know what I'll do with my F5 and new F4. Not really powerful enough for subwoofer use, tho' I'll give it a shot. People should build themselves a Cubie 2. It's it. (Probably not for metal, unless you have horns.)

 

[juma]

... (Probably not for metal, unless you have horns.)

Like this ?

 

[bluevas]

I can not find IRFP044 for Cubie2 PSU, are there any substitute for IRFP044?

Thank you Juma.

 

[juma]

Any high power, high gm HEXFET will do.

 

[bluevas]

Can IRFP240 do the job for this?

 

[marsupialx]

Like this ?

No, these. Get rid of that stuff in between, and put in a Cubie 2, or a dozen.

 

[juma]

Can IRFP240 do the job for this?

Sure

 

[marsupialx]

Ok, wild speculation time. I'm not an EE, and have no test gear other than a multimeter. Cubie 2 started what I assume is oscillation. Sort of a trill or "flutter" distortion. Could be thermally related. Stock "Pass" FW power supply. Circuit has cap at input and (100?) pF cap. Any stupid human tricks I might try to get my favorite amp back? I'd love to hook it up to an oscope and look at it intelligently and knowingly, but alas, that is not an option. Thanks!!!