My design L20D IRS2092+IRFI4020H 200W8R

[Mayday]

"What, exactly, is your modding?"
* osc freq 400kHz
* Dead Time = 25ns
* 12R base stoppers, 1N4148 parallel to them
* fast diodes UF4007
* doubled output capacitor

Can these mods be done on the L20D modules?

 

[LKA]

You have changed the Fc of the outputfilter. Is the frequency response seriously affected?

for 8R leave 0.47u

 

[Piersma]

Mods

@Mayday

I think the modus can be applied without issues on the L20.

 

[Mayday]

@Mayday

I think the modus can be applied without issues on the L20.

I have the parts needed to mod the L20D boards I have.
I only need to know that the modifications will work on the L20D as they do on the L15D.

 

[Piersma]

All the mods LKA proposed.
I would only modify the output capacitor, when your load is 4 Ohms.

 

[Wieslaw Lipowski]

You mean C12?

What value do you recommend for 4R load?

 

[Mayday]

My outputload will be 8R.
A pair of DAyton 15" IB's driven by one L20D each.

 

[Piersma]

I would follow LKA's advise and proposal and use 1uF//22uH for the LC output filter and a load of 4 Ohms.

 

[Mayday]

I would follow LKA's advise and proposal and use 1uF//22uH for the LC output filter and a load of 4 Ohms.

Put Dayton 15" IB's in paralell?

 

[Piersma]

You could indeed put the Daytons in parallel, otherwise leave the LC as is, and use 8 Ohms load. The stock LC-filter is intended for 8 Ohms.

 

[ljm_ljm]

Do you offer any amp boards which use this IRF6645? I had a look on Taobao and only saw evaluation modules priced sky-high (upwards of 2500RMB).

I'm playing with your L15DSMD at the moment and I'd like to say it was a very good move to use those TIP41C and TIP42C transistors to power the front end OTA inside the IRS2092. I haven't seen any other boards on Taobao doing this but subjectively its so much better than using the internal zeners.

I don't have an irf6645. I mean it's going to be stronger. Good performance.
This is a theoretical direction. It's not that you have to make it.
It can draw conclusions. Higher voltage. More power. It's not the best direction.
Irfi4019 is second only to irf6645

 

[Wieslaw Lipowski]

CP1 importance

I'd like to ask whether the CP1 22uF input capacitor is a part od the negative feedback circuit?

If the answer is yes, CP1 mustn't be shorted even if there is no Vdc at the input.

I think the answer is YES.

 

[Mayday]

A question as I am, at least mentally, getting ready to test the L20D modules. At first with a +/-72Vdc SMPS(I'll see if I can lower the output of the SMPS with a few volts using the pot next to the terminals).

To my question;
I know some digital amps go *pooff* if not connected to any load. Is this the case with this design?

And, not being very familiar with switch mode power supplies, is the pot there for the purpose of adjusting output voltage? If not, I'd think they wouldn't make it easily accessible?

 

[chienmort]

What model/manufacturer is your power supply?

 

[Mayday]

What model/manufacturer is your power supply?

I don't know to be honest.
I had it confused with another powersupply I have, the "boxed in" type.

This is the information I have on it(and a few pics)

Switch Mode Power Supply (500VA) +/-70Vdc, +/-15Vdc 1A, +12Vdc 0.5A

Transformers: 0.1mm*100 Multistrand OCC enameled wire.

Efficiency: 90%

Dimensions: 100*133*50mm

 

[Mayday]

SMPS Supply is out, atleast for the L20D

It's labeled +/-70Vdc, but powered up my DMM climbed to +/-74Vdc before I decided I didn't need to measure how far it would climb(this was in 10-15 seconds at the most) as it was already over the +/-72Vdc I read is the roof for the L20D modules. The switch mode supply was not loaded by anything while I measured this.

I may get one (for subwoofer, two Dayton 15" IB, connected in parallel in a W-baffle giving a 4ohm load) more powerful amp board based on the same concept, preferably a board that can handle a +/-80Vdc supply or more driving a 4Ohm load.

Any suggestions for such a board would be greatly appreciated.

 

[ghitus]

Hypex UcD700, +-85V, 700wrms on 4ohms

 

[Mayday]

Hypex UcD700, +-85V, 700wrms on 4ohms

I'd love to, but unfortunately those are out of my price range.

 

[ghitus]

Check the Hypex site, they lowered the price some time ago. May be you can afford them now...

Gaetano.

 

[ljm_ljm]

How about the L15D, is it using the g23a ?

I like l15d. I think l15d is better than l20d.
Because it has a lower voltage. L15d or l15dsmd
Use + - 50V. It will have less heat.
So it uses 7g17a. Because it's enough. It's not very hot.
L20d l25d uses 7g23a