AudioSector-chip amp kits, dacs, chassis

[Peter Daniel]

Those are FAL drivers from Japan. Bent Audio is the North American distributor: http://bentaudio.com/index2.html

 

[Peter Daniel]

if you want to built a complete pre, it is better then to put the buffer at the input, before a 10K attenuator?

That's what they usually do, but just for fun I configured it the other way and works very well. The main reason was safety. Since it's brand new and untested circuit, I wanted a potentiometer separating buffer from the amp. Later I will try it the other way.

Yep - that's until you do the next significant mod....

That is very true

MAT02 is better than SSM2210 though specs are the same.
I have tested both. MAT02 has higher Beta or HFe

Yes, it seems like. Levinson was also installing MAT in all reference equipmnent. MAT are available directly from AD at approx $15/pc

 

[Wynand]

Off the current topic...

Peter, I just bought a LM4870 kit from audiosector.

I'm wondering which configuration you would suggest, bridge or parallel?

Also, because I'm a very impatient person, how long do you usually take to ship orders?

Not to rush... I'm just very keen!!

 

[Wynand]

P.S.

I'll probably be running 4 ohm speakers

 

[Peter Daniel]

If you have balanced preamp, I would go with bridged configuration, however, with 4 ohm speakers it's not recommended (unless the speakers are highly efficient and enough heatsinking implemented with the chips). So probably parallel setup would be more practical option.

I will send it tomorrow, and normally for Europe, the package would be delivered middle of next week (for some locations it could be even Monday). I'm not sure how long it takes to your destnation, but I think it shouldn't take much longer than a week.

 

[Bas Horneman]

I'm not sure how long it takes to your destnation, but I think it shouldn't take much longer than a week.

Canada - Europe takes days. I reckon Canada - South Africa would taka around a month. Much less air traffic between those 2 countries.

 

[Peter Daniel]

I'm not sure about that. I sent to some less common destinations previously, like Papua New Guinea, and it didn't take longer than 2 weeks.

 

[karma]

Those are FAL drivers from Japan. Bent Audio is the North American distributor: http://bentaudio.com/index2.html

wow i would need to take out a small loan just for a set. hope thay sound as good as thay look

 

[randytsuch]

wow i would need to take out a small loan just for a set. hope thay sound as good as thay look

How much are they? I was going to email Bent, but it seems you already did.

Randy

 

[Peter Daniel]

When you read this thread, the price was indicated as $800/pc: http://www.audiocircle.com/circles/viewtopic.php?t=1805&highlight=fal

 

[karma]

yup thats what he Quoted me. im holding off till income tax time

 

[randytsuch]

When you read this thread, the price was indicated as $800/pc: http://www.audiocircle.com/circles/viewtopic.php?t=1805&highlight=fal

Well, I guess this is not my next driver, at least not unless I save up some money.

Randy

 

[safetyman]

LM4780 isolation

Peter or any of the guys who have built the LM4780, what would you suggest for isolation of the chip from the heatsink?

Are you confident that the Electrostactic Conductive bag that Russ White suggested will be able to do the job?

 

[Magsy]

http://cgi.ebay.com/2-Thermagon-905...ryZ46322QQssPageNameZWD1VQQrdZ1QQcmdZViewItem

Something like that, assuming it is non conductive.

 

[mikelm]

Electrostactic Conductive bags are conductive

check with DMM

 

[mikelm]

ps - the conductivity will rise with area so just checking with DMM probes could give misleading reading

I got about 300K ohm through the plastic at a small point. I would guess 5 - 10k for TO220 but for big chip less

You might get OK results if you use black anodised heat sinks with these bags - because the paint itself is an insulator so the bag will just stop the tranny from scratching through the paint.

 

[Magsy]

Is it acceptable to short the output of an LM3875 to ground for a few seconds? If so is there a recommended resistor?

I want to pull the outputs to ground for start up mute, say 2-3 secs max.

The pop it makes is only small, but I'd like to remove it if possible.

 

[jeff mai]

Is it acceptable to short the output of an LM3875 to ground for a few seconds?

Noooooooo!!!!

Why not use a relay to OPEN the output to the speaker for a few seconds after turn on?

 

[Magsy]

I don't want a relay in the signal path, although I admit that is probably the better option.

 

[Peter Daniel]

Is it acceptable to short the output of an LM3875 to ground for a few seconds? If so is there a recommended resistor?

I want to pull the outputs to ground for start up mute, say 2-3 secs max.

The pop it makes is only small, but I'd like to remove it if possible.

I had the output shorted for 30min and nothing happened (the amp run a bit warm though). The chip is protected against short and is protected in case one rail is off.

If the circuit is implemented correctly, there shouldn't be any pop at start up.