The Burning Amp Festival- an Audio Happening

[AR2]

Originally posted by gl
Hi Vladimir,

Thank you for posting more information about your amps. Having seen them and heard them in person I have to say that I have never come across a finer DIY project! I really think that they deserve their own thread over in the PL forum. I fear that all this wonderful info will get buried here and be forgotten.

I have one question for you.

I count 10 output transistors on the one main heatsink you show out on the bench. That means that your amp has 20 output transistors total. But the X600 manual on the Passlabs site states that that amp has 48 output transistors. Can you help me understand the difference?

Cheers,
Graeme

Regarding the output transistors,

You are correct, but essentially this is an AB class amp. With that in mind MOSFETs are not cooking like in the class A amp. The design for X600 and X1000 is the same, with only difference in the power supply voltage and amount of output transistors. X350 is almost the same. As we know in regards to the Mosfet capacitance it is always better to have less MOSFETs in the output. Since I have plenty of heatsinks that gave me a luxury to bump up the current through the smaller amount of MOSFETs. Even with that my sinks are handling cooling really well. My power rails are just a few Volts less than what is in original, so that helps as well. The boards that I use are meant for X600/X1000. This amp is a real monster, and it has endless power. I am using them for my base speakers in three way active system and the bass is - you remember it I hope from BAF2007.

Regarding the thread on this I didn't start it with the reason. Nelson never intended to have this as DIY amps. I happened to stumble upon offering from our reputable member who was selling a few boards here in the market place. He made just a few for his own pleasure and wanted to recover the cost of making them for himself.

I was lucky, but did not want to talk about the circuitry in respect toward the Nelson. That is why I never started the thread. What we are talking here is more about the machining and that is OK. Graeme, thank you very much for the compliments. Coming from you they have the special meaning for me.

Now note to readers:
I will use this chance to answer any possible inquiries sent to my email: No schematic is available from me until and if Nelson makes it public. Please, please, please do not write to me with questions like that - nothing will change my mind. Sorry.

[FastEddy]

" ... Since I have plenty of heatsinks that gave me a luxury to bump up the current through the smaller amount of MOSFETs. Even with that my sinks are handling cooling really well. ..."

I believe that you may find that, unless you really pump up the volume (MOSFETs generally are power passers, rather than just current or voltage gas passers), ... and will run quite within thermal specs at lower listening levels and still provide the headroom you expect. ...

[wrenchone]

AR2 - Thanks for the heads up on DIY powder coating. I may try getting a rig, as spray can wrinkle coating is a bit hit or miss - mostly miss. The powder coat finish is probably more durable in the long run as well.

[FastEddy]

" .... The powder coat finish is probably more durable in the long run as well. ..."

And it is more environmentally correct (cough, cough) ... and harder to scratch ... and easier to clean up after spray on ... and less flammable and better temperature resistant (to ~ 350 F.) ... and IMOP better looking than a spray can paint job.

[tommak]

Originally posted by hayenc


The emails I sent to the site for heatsink quotes get returned as undeliverable. Has anyone else had any success?

I cut and pasted the email address and got a response the next day ( see below ).

The cheaper one is 5.25" long, while the $42 one is 11.75".

Regards,

Tom

1-19-09

Good afternoon

For your request on the following……

6 pcs G12264

Your cost $ 23.50 each.

We have 34 pcs in our stock, subject to any prior sales

6 pcs G12265, Rev D

Your cost $ 42.00 each

We have 121 pcs in our stock, subject to any prior sales.

When and if order is placed, we will then quote shipping cost.

If you should need anything further, please let me know.

Thank you



Joann List

Customer Service

Darrah Electric Company

5914 Merrill Avenue

Cleveland, Ohio 44102-5699

216.631.9944 Direct Line

216.631.0440 Fax

www.darrahelectric.com



Your Source For: Aavid, ABB, Crydom, Dynex, Enerpro, Iconopower, IXYS, LEM, Powerex, R-Theta Thermal Solutions, and Power Assemblies

[AR2]

Just came back from Willie Nelson concert at Filmore. Had a good time. I would call it more celebration than concert. The last day! Happy tomorrow morning!

[AR2]

Originally posted by tommak

I cut and pasted the email address and got a response the next day ( see below ).

The cheaper one is 5.25" long, while the $42 one is 11.75".

I hope you agree with me. These prices are steal! Also I remember now, these prices are the same I paid two years ago. You know that they will cut on a appropriate size for you?

[ashok]

With all the doom and gloom around us , the next BAF should be a bright spot and hopefully more people will have time to drop by.

Maybe 2 days next time ? Hopefully more people will bring in their DIY equipment for demo.

Should make up a demo CD list so that people can get familiar with the music that will be used for demos. Hearing a familiar recording helps to form one's opinion of the demo equipment.

[AR2]

Originally posted by wrenchone
AR2 - Thanks for the heads up on DIY powder coating. I may try getting a rig, as spray can wrinkle coating is a bit hit or miss - mostly miss. The powder coat finish is probably more durable in the long run as well.

Originally posted by FastEddy
" .... The powder coat finish is probably more durable in the long run as well. ..."

And it is more environmentally correct (cough, cough) ... and harder to scratch ... and easier to clean up after spray on ... and less flammable and better temperature resistant (to ~ 350 F.) ... and IMOP better looking than a spray can paint job.

It is all true. I find it even much easier to apply than any regular paint. Keep this in mind as well: If you screw up anything before you start baking you could always just blow powder off and start from scratch. What do you think how I know that?

The hardest part is putting the part to the oven while is hanging from the baking rack without touching anything or falling from the hanging hooks. Keep your owen close to where you are spraying. I sifter powder coat any time I fill the bottle. Buy enough powder because it goes fast.

[wrenchone]

There are some fascinating and lurid possibilities for powder coat colors, especially if you check out the folks who cater to the custom automotive crowd. There are also several rigs available on E-pay for under $100, including some blower types and some needing a small boost of compressed air.