Request : DIY PASS LAB Power Amp GroupBuy

[SaurabhK]

Just Curious.. How can you buy a DIY ??? then it wouldnt be "DIY"

 

[jls001]

Just Curious.. How can you buy a DIY ??? then it wouldnt be "DIY"

Group Buy of the parts. DIY aspect starts after all the parts arrive.

 

[cmsajith]

Check out magma's new cabzilla for the F5 Turbo monoblocks. Can we not use a more domesticated version of this design for the F5 Turbo? I am just thinking aloud. I didn't even ask if magma will have the time and inclination to make something similar for us.

http://www.hifivision.com/diy/12016-amp-enclosures-chasis-cabinets-30.html

Somehow I am not able to digest the design, a tower design would be much better.

 

[Audiodoc]

I second cmsajith. The design is asymmetrical and humongous for a pass 5. Some good ones were posted by omishra. These look decent too.

Project | Homebuilt Hi-Fi - A user submitted image showcase of high quality home built hi-fi components.

http://www.soundscapehifi.com/images/first-watt-f5-100719-2_LRG.jpg

Pass Labs X350.5 solid-state stereo power amplifier Review - Equipment Reviews - Dagogo

DIY Pass F5 amp

 

[captrajesh]

But guys, tell me what is happening with the build? Any updates?

 

[omishra]

But guys, tell me what is happening with the build? Any updates?

I have ordered parts from element 14 and PCB available with jims_audio. Now reading at least 25 pages everyday. R&d in stability and studying all aspects. I hope all parts will be in hand by month end.

After completin of GR research Speaker box completion I will start with F5 turbo build.

 

[jls001]

I second cmsajith. The design is asymmetrical and humongous for a pass 5. Some good ones were posted by omishra. These look decent too.

My suggestion was that magma might be able to build the cab + heatsink for us. I am not saying we should go with that particular design.

In any case omishra is already working on a prototype so I guess we should await the outcome of his project before looking at other options.

 

[Hiten]

Somehow I am not able to digest the design,

If Cranky is doing it I would never doubt his design. Same for magma's workmanship and finish.
By the way it is for F5 Turbo Monoblocks.
Regards

 

[omishra]

As per Nelson Pass, whatever I am reading the DIY audio threads, larger the heatsink, it is the best. But you need only getting the thermal equilibrium near to ambiance to get stability of bias current wrt temperature change of output devices.
Also I have seen, for F5 (60W dissipation /ch) people using half of the heatsink which I already shown here. For F5 turbo (100W dissipation /ch) I suggested that mass of metal with 12mm thick and plain surface base. Here I am curious to know how mounting of 8 output devices will be done while placing them equally distributed over heatsink area. May be planned PCB layout may allow that, for me , per channel its 12" strip holding 8 devices (4 MOSFETs and 4 dual diodes) in single line, powered by own capacitor bank and own toroid. I need to start new thread for my build and will do that shortly after finish of GR Research LS project or right now as a slow moving project.

This is another design we may look for.

 

[quad]

Om, not sure if I understood correctly what you are asking.
Anyway, here are a few mounting ideas - essentially mount outputs to
an L shaped aluminium angle, and connect the angle to a heatsink.

http://robotx.sourceforge.net/bridge/img_0171_sml.jpeg
http://www.a-and-t-labs.com/K6_Sw_Amp/Supplyboard.jpg
http://www.abload.de/img/to-3_symasym_birger97v1.jpg
http://www.hardwareanalysis.com/images/articles/large/11985.jpg

 

[omishra]

Om, not sure if I understood correctly what you are asking.
Anyway, here are a few mounting ideas - essentially mount outputs to
an L shaped aluminium angle, and connect the angle to a heatsink.

http://robotx.sourceforge.net/bridge/img_0171_sml.jpeg
http://www.a-and-t-labs.com/K6_Sw_Amp/Supplyboard.jpg
http://www.abload.de/img/to-3_symasym_birger97v1.jpg
http://www.hardwareanalysis.com/images/articles/large/11985.jpg

I was mentioning 3 points, regarding magma's cabinet -

one piece heat sink for 1 amp module
When we joint two metal parts, it does create thermal resistance. So I am not getting to use of 2 pieces of heatsink for 1 channel module. The devices on loosely (thermally) coupled heatsink will have different temperature if there is some tolerance if bias current. This can result into asymmetric output.

thickness of base

High mass (weight) = higher specific heat, means more heat required to rise and more time required for fall of temperature.

When heat producing part is mounted to heavy metal it will take large time to get away from stable temperature at any point. Near the attached part it will have less temperature rise due to high specific heat (due to high mass) of heatsink . Parts attached to lighter/thinner part heatsink will get hot quickly. So near the attached part temperature rise will be more.

flat surface
As PCBs edges are straight, you need single flat surfaced heatsink inline to PCB layout. As PCBs edges are straight, little hump in heatsink will need some milling etc.

So I will prefer that as last option from the links which you provided in above post, though heatsink will be n times bigger.
http://www.hardwareanalysis.com/images/articles/large/11985.jpg
This link shows direct attached components in same heatsink piece with best possible thickness. That's what I am thinking of about mounting amp PCB on heatsink.

BTW, please forgive and correct me if I am wrong. I am interested in the use case of Magma's cab and not criticizing his creations. I know he his nice and wonderful gentleman.

 

[Hiten]

When we joint two metal parts, it does create thermal resistance. So I am not getting to use of 2 pieces of heatsink for 1 channel module. The devices on loosely (thermally) coupled heatsink will have different temperature if there is some tolerance if bias current. This can result into asymmetric output.

For F5 turbo (100W dissipation /ch) I suggested that mass of metal with 12mm thick and plain surface base. Here I am curious to know how mounting of 8 output devices will be done while placing them equally distributed over heatsink area.

You are more experienced and absolutely right Omi. What i was guessing is sometimes necessity forms the design. So from Magma's pic I think heatsink are vertical for heat dissipation and will be hidden from front view and each large heat sink for 2 devices so no need to of joining two heatsink for one channel. Only guessing though.
Regards