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First One - mosFET amplifier module

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F

fluid

Member
Joined 2009
Bassivus said:
I'm making BOM to decide which way to go with the build.
I have decided to go with SMPS so I made excel table to compare Hypex with Cresnet. It's attached.
Also I have made a list of possible add on cap bank for Cresnet. This capacitors are what is available on Banzai music which is reliable and convenient source for Europe. It is nothing definitive...
I would like to hear your thoughts on what would you choose.
:cheers:
Click to expand...

My 2 cents from looking at your document.

You do not need a 5U chassis for a stereo amp. The 2U is about the right heatsink for a stereo module. The module is designed to run at a certain temperature based on the heatsinks thermal ability. The 5U will cause it to run cooler than designed.

The Hypex is a lot more expensive than the Cresnet and the Cresnet is a very good supply. It doesn't have as much peak power as the Hypex but it does have enough for a single module in my opinion. If you have a problem Cresnet will help you fix it yourself if you can. Hypex will have you send it back to them. One of my Hypex supplies had an issue, they fixed it without question but the postage to send it back to the Netherlands was more than the cost to buy a Cresnet module for me. YMMV.

Both supplies have inbuilt soft start circuits but it doesn't do any harm to have another. My Cresnet supply needed a single resistor added to start up with extra capacitance. The over-current protection kicked in as the very low ESR capacitors look just like a short until they get some charge on them.

For the capacitors look at the combined ESR to see if it is better to use multiple smaller caps in parallel. The Mundorf's are pretty good in this spec I used some Chemicon KYB as they were the lowest ESR good quality cap for the price. Of the ones listed I would probably go for the Mundorf's as they will be easier to mount.
 
Bassivus

Bassivus

Member
Joined 2004
fluid said:
My 2 cents from looking at your document.

You do not need a 5U chassis for a stereo amp. The 2U is about the right heatsink for a stereo module. The module is designed to run at a certain temperature based on the heatsinks thermal ability. The 5U will cause it to run cooler than designed.

The Hypex is a lot more expensive than the Cresnet and the Cresnet is a very good supply. It doesn't have as much peak power as the Hypex but it does have enough for a single module in my opinion. If you have a problem Cresnet will help you fix it yourself if you can. Hypex will have you send it back to them. One of my Hypex supplies had an issue, they fixed it without question but the postage to send it back to the Netherlands was more than the cost to buy a Cresnet module for me. YMMV.

Both supplies have inbuilt soft start circuits but it doesn't do any harm to have another. My Cresnet supply needed a single resistor added to start up with extra capacitance. The over-current protection kicked in as the very low ESR capacitors look just like a short until they get some charge on them.

For the capacitors look at the combined ESR to see if it is better to use multiple smaller caps in parallel. The Mundorf's are pretty good in this spec I used some Chemicon KYB as they were the lowest ESR good quality cap for the price. Of the ones listed I would probably go for the Mundorf's as they will be easier to mount.
Click to expand...

Fluid, thank you for taking time to look! I really appreciate that :)

I have put 5U chassis on the list when I considered building L modules:rolleyes: I agree, it is totally oversized for M modules. I'll change that to 3U, to have a bit more room.
It is obvious that going for Hypex almost doubles the build price, and I doubt it gives double the result. Anyways I have a limited budget so I believe this is OK compromise, otherwise I would have to give up my plan on building 3way spekers (Troels SBA10).

Things are a bit more complicated when trying to compare capacitors specs.
For example: Panasonic FC papers give ESR and ripple on 100kHZ, while others on 100HZ!
Some of caps from list compare this way(all given per rail!)


  • F+T SIH 36mOHM, Ripple 5

  • MLGO+ 48mOHM, Ripple 3.3

  • MLGO (2200x2) 32mOHM, Ripple 4.2

  • Pana FC 5.2mOHM, Ripple 6.5 @100kHZ
 
Bassivus

Bassivus

Member
Joined 2004
fluid said:
Fair point about comparing capacitors it is hard when the datasheets are not giving the specs you want.

Vishay has this information sheet which might help comparing some of them

https://www.vishay.com/docs/40057/ldacripp.pdf
Click to expand...

Thank you. I guess its a bit to much math for me at least on this matter :D
I guess I'll go with F+T SIH electrolytes. They seem like best bang for buck, and I can put them on PCBs from ebay.
 
E

edek44

Member
Joined 2013
Four questions...

Hello Everyone,

I'm trying to build FirstOne amp.
I'm not electrician and I do not have an experience with such equipment.
Can you help me and answer on my question written below?

Based on description about CAP bank:
“First One Cap Bank Positive or Negative module consisting of two four pin Mundorf MLytic 3,3 mF/100 V and two WIMA 0,22 uF/100
Using bypass caps is a choice of personal taste, but please be careful not to bring resonance oscillations to PSU, using damping resistors in series will help a lot.”
I would like to connect: SMPS --> with additional Cap (Mundorf MLytic AG 4700 uF 63VDC) together with “damping resisitor (WIMA 0,22 uF) ” --> with FirstOne.

My questions are:

1) How should I connect SMPS and extra caps with FO module? Please verify on my drawing attached below if my assumptions for connection SMPS <--> with CDE LX381 and additional capacitors <--> FirsOne are correct.

2) Do I need damping resistor (WIMA) in my configuration without bypass?

3) If my SMPS “faces 6800uf per rail without entering the protection mode”
What does it mean? Can I add one cap positive 4700uf and one cap negative 4700uf for each channel?

4) Should I use Mundorf MLytic AG 63VDC or Mundorf MLytic AG 100V (Like LazyCat did)?

I really appreciate any help you can provide
 

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