Gainclone: 2 newbie questions...

Bassterror · 2nd April 2006, 04:50 PM

Hello

What do u recommend as highest Voltage for foolproof and SAVE operation with 4Ohm Loads?
18V Transformer seems to be OK, what about 22V?

And what happens, when a 3886 dies? Will it kill my speaker?
Possibly DC to the speakers?

nina · 2nd April 2006, 04:53 PM

I guess you means AC.

Though 22-0-22Vac should be fine provided you get big enough heatsink, the 18V-0-18Vac provide better margin of safty.

cpemma · 2nd April 2006, 09:33 PM

It also depends on whether you use the 3886T or 3886TF package, see the Overture Design spreadsheet for the NS recommended max DC rail limits, which means the quality of your thermal interface is also important when you're living near the edge.

Nordic · 2nd April 2006, 10:04 PM

Just about any amp can kill your speaker if it blows.

Bassterror · 2nd April 2006, 10:40 PM

@nina:
I mean AC.

@cpemma: I cant find any difference between T and TF in the sheet

RDV · 2nd April 2006, 10:55 PM

Quote:

Originally posted by Bassterror
@nina:
I mean AC.

@cpemma: I cant find any difference between T and TF in the sheet

The TF has an insulated case. The T carries the negative rail voltage on the case.

RDV

RDV · 2nd April 2006, 10:58 PM

For a 4 ohm load you will need a larger than normal heatsink also. I'm speaking from experience. Chipamps love 8 ohm loads and hate 4 ohm loads.

RDV

Bassterror · 3rd April 2006, 12:18 AM

Quote:

The TF has an insulated case. The T carries the negative rail voltage on the case.

Yes, I know. But does that affect the heat flux?

Quote:

For a 4 ohm load you will need a larger than normal heatsink also. I'm speaking from experience. Chipamps love 8 ohm loads and hate 4 ohm loads

Right now I've got 8 ohm speakers at my computer. But I want them to be capable of driving 4 Ohm loads. I want to be flexible.

Assuming I torture them with 4Ohm.

- Will this affect the sound seriously?
- What will happen when they get too hot?
Can I hear them suffer before it's to late?

Ed LaFontaine · 3rd April 2006, 01:14 AM

Bassterror asked:

Quote:

does that affect the heat flux?

Sort of, indirectly. If you use the "T" version, you must isolate the heatsink from other circuit elements, OR use an insulating washer to isolate the chip from the sink. Your choice (there are several options) of insulating washer will directly affect the heat flux.

If you use the "TF" version, no added washer is needed. You should use heat transfer paste with either version.

RDV · 3rd April 2006, 02:19 AM

Quote:

Originally posted by Bassterror

Assuming I torture them with 4Ohm. Yes, but with enough heatsinking and not too high supply voltage it will survive.

- Will this affect the sound seriously? No.
- What will happen when they get too hot? Thermal Shutdown until temp goes down below shutdown threshhold.
- Can I hear them suffer before it's to late? No.

2nd April 2006, 04:50 PM	#1
Bassterror diyAudio Member Join Date: Mar 2006 Location: Niedersachsen	Gainclone: 2 newbie questions... Hello What do u recommend as highest Voltage for foolproof and SAVE operation with 4Ohm Loads? 18V Transformer seems to be OK, what about 22V? And what happens, when a 3886 dies? Will it kill my speaker? Possibly DC to the speakers?

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2nd April 2006, 04:53 PM	#2
nina diyAudio Member Join Date: Apr 2005 Location: Earth	I guess you means AC. Though 22-0-22Vac should be fine provided you get big enough heatsink, the 18V-0-18Vac provide better margin of safty.

2nd April 2006, 09:33 PM	#3
cpemma diyAudio Member Join Date: Jul 2003 Location: S Yorkshire OK	It also depends on whether you use the 3886T or 3886TF package, see the Overture Design spreadsheet for the NS recommended max DC rail limits, which means the quality of your thermal interface is also important when you're living near the edge.

2nd April 2006, 10:04 PM	#4
Nordic diyAudio Member Join Date: Sep 2005	Just about any amp can kill your speaker if it blows.

2nd April 2006, 10:40 PM	#5
Bassterror diyAudio Member Join Date: Mar 2006 Location: Niedersachsen	@nina: I mean AC. @cpemma: I cant find any difference between T and TF in the sheet

2nd April 2006, 10:58 PM	#7
RDV diyAudio Member Join Date: Sep 2005	For a 4 ohm load you will need a larger than normal heatsink also. I'm speaking from experience. Chipamps love 8 ohm loads and hate 4 ohm loads. RDV

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