DIY: Pass F5 turbo v2 initiated

[anilva]

Finished up populating the PCBs. I must say the PCB layout by Om is first class and very thoughtful, with speaker and ground options given at multiple places to give flexibility of right and left mounting of PCBs.

I had collected in the last few months some of the best components for my v3 build and I must say, I abandoned those components in favour of components received as a part of the kit. The quality of the components is super and no shortcuts have been taken.

My only observation is that the PCB style is little different, as there are no large component pads on the solder side, but very small PTH holes. It requires quite of bit of soldering skill and practice to solder them properly. Bigger component pads afford relaxed skill levels on soldering.

Some PCB pins are sent as a part of the kit. Are they meant for the PS PCB? These pins do not fit the amp PCB in any of the holes. Sachu or Om can throw some light.

Another observation, we could have provided a LED on each PCB to indicate PCB 'ON' status. We can then extend the leads to the front panel to use them as amp indicator lights like original PASS design.

Cheers.

 

[kroyin]

I intend to incorporate
10x KSD9700 75? Thermostat Temperature Switch | eBay
As per

http://www.lifelongenjoyments.net/audio/images/aleph2_pswire.jpg

To break the circuit when the heatsink temps reach ~75C

 

[omishra]

Finished up populating the PCBs. I must say the PCB layout by Om is first class and very thoughtful, with speaker and ground options given at multiple places to give flexibility of right and left mounting of PCBs.

I had collected in the last few months some of the best components for my v3 build and I must say, I abandoned those components in favour of components received as a part of the kit. The quality of the components is super and no shortcuts have been taken.

Thanks Anil, I thought of thermal dissipation and making final box flat instead of cube, same like you and pandu has made. I am too following the same approach but tower model.
We were looking for parts many days (almost 4 weeks) on different builds and vendors who can deliver us in India. That took a while but will benefit us. Sachin used to do lot of online research and given me wide selection list to choose from.

My only observation is that the PCB style is little different, as there are no large component pads on the solder side, but very small PTH holes. It requires quite of bit of soldering skill and practice to solder them properly. Bigger component pads afford relaxed skill levels on soldering.
.

Only problem I had - part manufacturers pin and lead dimensions are used and thermal isolation kept on. This we got as per manufactueres library. Which made pads of required minimum and fine thermal cutoff near solder pad and PCB copper. For next time any other PCB I will modify component library to create custom components and then lay on PCB.

Some PCB pins are sent as a part of the kit. Are they meant for the PS PCB? These pins do not fit the amp PCB in any of the holes. Sachu or Om can throw some light.

There are 20 spade type 6.3mm wide tabs and 60 pcb pins. Spade type tabs are for pass amp and gound isolator diode bridges. You need to do little filing before pushing into PCB. Small 1.2mm diameter PCB pins are for PS filter and rectifier boards where you are expected to terminate wires. Same wires for transformer with provided small clips and snapped over pair of PCB pins on those boards.
Wire terminals are provided with proper sleeves and 2 sizes - 6.3mm and 4.8mm. Smaller are for wires ending on PS boards and bigger are for wires ending on Amp boards and ground isolaters.

Another observation, we could have provided a LED on each PCB to indicate PCB 'ON' status. We can then extend the leads to the front panel to use them as amp indicator lights like original PASS design.[/QUOTE
Yes, I agree this is missed. But we can make it from ps lines.
But people say ignoring it gives you peace of mind, as if you are not burning to much

 

[captrajesh]

I intend to incorporate
10x KSD9700 75? Thermostat Temperature Switch | eBay

IIRC, thermal protection is already incorporated in the design. Is this in addition to the stock protection? In any case, the ones linked are being sold in a lot of 10. If I made a mistake in understanding and thermal protection is not available in the current design, I'd like to team up with you for the number required to make a stereo amp which I assume is 4 Nos.

 

[omishra]

I intend to incorporate
10x KSD9700 75? Thermostat Temperature Switch | eBay
As per

http://www.lifelongenjoyments.net/audio/images/aleph2_pswire.jpg

To break the circuit when the heatsink temps reach ~75C

This is the image from the post.

I felt it will bounce back one temperature declined below 75. I am using this board which will need hard power reset after thermal cutoff. No affiliation with seller.

Class A Power Delay Soft Start Temperature Protection Board 110V 220V | eBay

IIRC, thermal protection is already incorporated in the design. Is this in addition to the stock protection? In any case, the ones linked are being sold in a lot of 10. If I made a mistake in understanding and thermal protection is not available in the current design, I'd like to team up with you for the number required to make a stereo amp which I assume is 4 Nos.

Captain we have incorporated thermal drift by means of NTC on board Amp PCB. Softstart is meant with another set of NTC. These are precautions and corrections only.
Also the suggested solutions by me as well as kroyin are debatable as after reaching 75 on heatsink mains fuse was rendered useless. What is left to save in amp?

 

[anilva]

Word of caution to all the F5T builders. When connecting the power supplies to amp boards, make sure you are connecting both + and - rails appropriately and do not disconnect one rail for any reason such a measurement etc. The amp output will swing to the other side and in the process damage the mosfets and the speakers.

 

[omishra]

Word of caution to all the F5T builders. When connecting the power supplies to amp boards, make sure you are connecting both + and - rails appropriately and do not disconnect one rail for any reason such a measurement etc. The amp output will swing to the other side and in the process damage the mosfets and the speakers.

Why not to add all these to one document which will ensure topics - before starting build, how to build, before power on and after power on. We can skip soldering lessons and individual part soldering. Please pm me your thoughts. I will compile and put into one document for all builders.

I have already got,few inputs from George and other guys, courtesy Sachin.

 

[pdhanwada]

This is the image from the post.

I felt it will bounce back one temperature declined below 75. I am using this board which will need hard power reset after thermal cutoff. No affiliation with seller.

Class A Power Delay Soft Start Temperature Protection Board 110V 220V | eBay

Description

KSD9700 Series Thermostat ( Auto Reset ).
Action temperature : 75+-5 degrees Celsius, Reset temperature : 55+-10 degrees Celsius.
Action Type: N.C. Type ( Normally Close, Connected )

This thermostat switches when the temperature is @75 and switches back on at around 55-60 centigrade. 15 degree difference is good enough for us to act on.

The advantage I see is just one component.

Thanks

 

[vktarun]

Some pictures of my F5T v2 chassis which came back from anodizing and powder coating. The chassis and the heatsink costed me around 14000/-. The build is turning out to be not a small investment...

Each side has two heatsinks with fins aligned vertically and both of them are thermally coupled by a nickel plated copper flat to ensure thermal balance between both the heatsink elements.

Cheers.

Hi,

Its looks build like a tank!
Thanks for sharing, Please let us know the dimention & weight .

Regards,

Vipin

 

[kroyin]

I for all practical purposes am not bothered about amp blowing ..small parts that can be sourced & replaced .... am I bothered about what happens to my speakers after the amp blows, so rather than looking at soft start I should be looking at spk protection.
But its just me (not ordering spk protection) what's life without a little risk

 

[captrajesh]

we have incorporated thermal drift by means of NTC on board Amp PCB. Softstart is meant with another set of NTC.

Mishraji sorry for the noob questions. What is the full form of 'NTC' I'm guessing that TC means thermal cutoff.

the suggested solutions by me as well as kroyin are debatable as after reaching 75 on heatsink mains fuse was rendered useless. What is left to save in amp?

I didn't get what has been highlighted. Could you kindly elaborate?

Why not to add all these to one document which will ensure topics - before starting build, how to build, before power on and after power on.

Please pm me your thoughts.

Great idea Mishraji. :clapping:

 

[pdhanwada]

I for all practical purposes am not bothered about amp blowing ..small parts that can be sourced & replaced .... am I bothered about what happens to my speakers after the amp blows, so rather than looking at soft start I should be looking at spk protection.
But its just me (not ordering spk protection) what's life without a little risk

kroyin or anybody

Do you have any speaker protection suggestions.

Thanks
Pandu

 

[kroyin]

You can get spk protection & soft start boards from diyaudio

 

[omishra]

Mishraji sorry for the noob questions. What is the full form of 'NTC' I'm guessing that TC means thermal cutoff.

I didn't get what has been highlighted. Could you kindly elaborate?

NTC (thermistor) means Negative Thermal Coefficient thermistor. Thermistor is resistor whose resistance value changes with its operating temperature. NTC means resistance decreases with increase in temperature and vice verse. There is PTC thermistor also.

If somehow your heatsink reach 75C then MOSFETs are already cooked and burnt. That will draw massive current and main fuse should blow if used moderate value. Still damage is done.

 

[quad]

Ebay has several upc1237 based boards.

Looks like lot of folks on diyaudio build the Dr Bora OMNI circuit -

redesign of leach amp pcb for integrated TO-247 output devices - Page 31 - diyAudio

redesign of leach amp pcb for integrated TO-247 output devices - Page 28 - diyAudio

 

[kroyin]

Om 75c on heatsink does not mean the mosfets are gone . They breakdown temp of mosfet is usually 100-150c.
So prolonged operation above 70 odd degrees is not desireable.

The thermostatic switch is a part of aleph amps.

 

[captrajesh]

we have incorporated thermal drift by means of NTC on board Amp PCB.

If somehow your heatsink reach 75C then MOSFETs are already cooked and burnt. That will draw massive current and main fuse should blow if used moderate value. Still damage is done.

Om 75c on heatsink does not mean the mosfets are gone . They breakdown temp of mosfet is usually 100-150c. So prolonged operation above 70 odd degrees is not desireable.

The thermostatic switch is a part of aleph amps.

The tech talk is going beyond my head. Does our circuit have temperature protection? If yes, is it sufficient to safeguard the amp and/or (importantly) speakers? Coz repairing my speakers exceeds the cost of the whole amp.:annoyed:

What is the optimum temperature for smooth functioning of the MOSFETs? Can't we have a thermostat to shut the amp off beyond this temperature.

 

[cmsajith]

This is the image from the post.

I felt it will bounce back one temperature declined below 75. I am using this board which will need hard power reset after thermal cutoff. No affiliation with seller.

Class A Power Delay Soft Start Temperature Protection Board 110V 220V | eBay

Along with this, i feel its better we use a normal thermal switch to just get a warning beep when the temp reaches nearby 75 (say ~65) so that we can switch off the amp or alternative cooling option can be used.

 

[pdhanwada]

Captrajesh,

What kroyin suggested is temperature protection. But it does not guarentee the speaker protection because of DC. I just checked out diyaudio for speaker protection boards. It is going to turn out to be another F5 project to create the protection boards.

But my guess, Speaker protection is not done by many in diy audio as I remember. Mostly it is temperature protection.

The idea is to stabilize your amplifier using smaller or inexpensive speakers. After being comfortable with the smaller one then hook up your expensive speakers.

Thanks
pandu

 

[omishra]

The tech talk is going beyond my head. Does our circuit have temperature protection? If yes, is it sufficient to safeguard the amp and/or (importantly) speakers? Coz repairing my speakers exceeds the cost of the whole amp.:annoyed:

What is the optimum temperature for smooth functioning of the MOSFETs? Can't we have a thermostat to shut the amp off beyond this temperature.

Captain, I never heard anybody blown there speaker or burnt F5 amp after successful biasing and initial 1 week observation of heatsink temperature in actual use case. Once your heatsinks are stable at 55C then its life long (as per NP). So invest into heatsink and take absolute slow approach while increasing the bias to the amp. Once you reach to 10sec temperature test of heatsink, stop further increase of bias. Your amp's limit is reached.
10 sec heatsink test means with bear hand able to touch hot heatsink for more than 10 sec.