My design L20D IRS2092+IRFI4020H 200W8R

[Mayday]

In the ebay listing I bought mine from, a year or two back(still not in a case), it said +/-72Vdc.
Maybe that is a different version of the L20 digital amp modules?

 

[Hofmann]

SF14 must be used. D669 must be used
1N4004 cannot be used.

Why not?
My L25D modules have '4004' printed on the pcb where the diodes go.

I can not get SF14 locally, but I can get 1N400x.

 

[ljm_ljm]

In the ebay listing I bought mine from, a year or two back(still not in a case), it said +/-72Vdc.
Maybe that is a different version of the L20 digital amp modules?

The l20d can use a wide range of voltages.
For example, + - 60V, or + - 70V, 72V can also be used.
Because the manufacturer's components will also change. So sometimes I change some components.
But basically it won't change much.

 

[ljm_ljm]

Why not?
My L25D modules have '4004' printed on the pcb where the diodes go.

I can not get SF14 locally, but I can get 1N400x.

Printed on PCB refers to UF4004. Fast recovery diode.
Not 1n 4004, ordinary diode.
So SF14 or her104 or UF4004 is generally used. Or mur120

 

[Mayday]

The l20d can use a wide range of voltages.
For example, + - 60V, or + - 70V, 72V can also be used.
Because the manufacturer's components will also change. So sometimes I change some components.
But basically it won't change much.

I did put in higher voltage capacitors, and I swapped the big resistors for higher rated brand name ones.
It's just sitting there waiting for me to either go with the +/-72Vdc SMPS or an "audio grade" toroidal transformer from toroidy and some 4x6800uF/100V Epcos capacitors(per rail).
In case of the latter, I'd have to get a new/used bigger enclosure.

 

[Wieslaw Lipowski]

I've got "Toroidy" 300W/2x45VAC and a board of electrolytics as per the photo. The DC voltage is 2x63V and that's enough for my L25D.

 

[Mayday]

Wow, I've looked at those "a ton of caps" boards.
I went the other way big cans that you bolt to the chassis and connect via screwterminals.

Edit: They were 4700uF/100V 4pcs/rail.

 

[ljm_ljm]

I did put in higher voltage capacitors, and I swapped the big resistors for higher rated brand name ones.
It's just sitting there waiting for me to either go with the +/-72Vdc SMPS or an "audio grade" toroidal transformer from toroidy and some 4x6800uF/100V Epcos capacitors(per rail).
In case of the latter, I'd have to get a new/used bigger enclosure.

I don't recommend SMPS.
It is used in general in the family. Actually, it only needs a small transformer.
For example, ac36-0-36 200va. About $20.
It's good to use l15d or l15dsmd.
There may be many problems with SMPS. And its power, does not judge the real power.

 

[Mayday]

I do have the 600VA 0-?VAC + 0-?VAC.
I do remember it's ordered to be about +/-70Vdc after the rectifier bridge.

I have the Epcos cans, so might as well use them when I get around to wiring it up and putting it in a case, that's all that's left.

I've got a soft start ready for it as well.

 

[ljm_ljm]

I think the MOSFET produced by irfb4020 IR company has always had a big error recently.
Different places of origin differ too much. It mainly refers to the temperature.
So I'm going to modify the MOSFET. Refer to iraudamp9.
I changed to irfb4227 MOSFET. Irfi4227 is also used. Basically the same.

 

[nigelwright7557]

I changed to irfb4227 MOSFET. Irfi4227 is also used. Basically the same.

The 4227 has a larger gate capacitance so needs driving harder.
I found I needed gate drivers to make it work well.

 

[Wieslaw Lipowski]

New ljm amp

A message to jlm_jlm

I would like to buy from you a class-d amplifier for my 4-ohm speakers.

Now I own your L25D 8-ohm amplifier, which is very good and reliable.

Your mail box is full so I can't post anything there.

 

[ljm_ljm]

The 4227 has a larger gate capacitance so needs driving harder.
I found I needed gate drivers to make it work well.

yes. It's very simple.
Please refer to iraudamp9
These are off the shelf solutions. We don't need to change it.

 

[ljm_ljm]

A message to jlm_jlm

I would like to buy from you a class-d amplifier for my 4-ohm speakers.

Now I own your L25D 8-ohm amplifier, which is very good and reliable.

Your mail box is full so I can't post anything there.

yea i know my PM box is 100% full
But I don't know where to empty the mailbox.
I'm very slow to access the website here. I don't know what's going on. The success rate of opening a web page is about 50%. And it takes two minutes.
If you have any questions, please email me ljm_ljm@foxmail.com

 

[Hofmann]

I still have 2 L25D modules that have blown up. I've been wanting to repair them, and I think I would be wise to change the IRFB4020 to 4227 while I'm at it.
What commonly available transistors could I use for the gate driver?

 

[Mayday]

I am thinking of putting my two Dayton 15" IB's in an W-baffle.
The two L20D boards I have should drive the Woofers quite nicely. I'll do dipole compensation either via a DCX2496 or one of my FreeDSP Classic boards.
My preamp, a BCL clone headamp w raised bias, should have no problem driving driving a poweramp and whatever DSP I wind up using(followed by the L20D's) in parallel.
I've done similar in the past when using a passive x-over for mids/highs and active x-over for the woofers.

 

[Mayday]

I just checked, and I have a 500VA 0-48VAC 0-48VAC Audio transformer from Toroidy along with a bunch of 100V/4700uF Epcos caps.

That should be plenty to drive two L20D boards?

 

[Wieslaw Lipowski]

Yes, it should be fine.

I use a 300VA 45VAC-0-45VAC from Toroidy with my two L25D amps with no problem at all.

 

[Mayday]

Yes, it should be fine.

Great

That only leaves the DSP design for using my Dayton 15" IB in a W-baffle.

 

[Mayday]

SQ in comparison?

I've not gotten this up and running yet due to my chronic pain.
I was just curious if anyone has compare the L20D to UcD400 or IcePower ASP500?
I'm asking as I've heard those, I regret selling a very well built UcD400 with a linear PSU with RIFA PEH169(IIRC) 22000uF/rail, and I'm curious to how those having heard these in comparison to the L20D rate them SQ-wise.