What is a Gain Clone exactly?

[peranders]

The advantage of LM3875, 3886 is the simplicity and all protection schemes. I think this is the main advantage.

Eventually I will make pcb's but so far I haven't heard a LM3886 live yet but I have no doubts that it's quite good. Technically it's also interesting because I believe it's the best monolithic non-class D power amp around. Apex is possibly better.

[zygibajt]

The biggest cost is transformer, but even using exotic components the total cost shouldn't exceed $150 (not including chassis

Peter how much does the Piltron transformer cost?
Let's say 400AV ,2*20V.
And where can they be bought (via internet)?

Bartek

[Peter Daniel]

A transformer like that cost $89,59 CAD (plus 15% taxes if bought locally). Shipping weight is 4kG. The lead time is probably 4 weeks. http://www.plitron.com/


There was a recent price increase, as I remember those were sold at around $ 70 previously.

[Morse]

Hi Peter;

>>>A transformer like that cost $89,59 CAD (plus 15% taxes if bought locally). Shipping weight is 4kG. The lead time is probably 4 weeks.<<<

How about the Avel Lindberg trafos? I see that Parts Express in the US has a 36vct, 250VA rated job for $42.26USD that's available without delay. Are the Plitrons really that much better (not stating an opinion, since I don't have one!), or could one "get away with" the Avel Lindberg toroidals?

Thanks in advance!
All the best,
Morse

[Peter Daniel]

I was buying 250VA transformers from Apex Jr for $25. They were pretty good and initially I thought they were even better than Plitron, but more tests shows 400VA Plitron was preffered.

I don't think Avel Lindberg would be a bad choice, it will work perfectly well in a GC. It's only if you want to gain tha last few percent of performance, you should become fussy about transformer chouces. I'm almost sure that 400VA vs 250VA toroid would be better.

I would assume that 400VA Lindberg converted to Canadian funds wouldn't much different regarding the price (comparing to Plitron). And then you add higher shipping cost when dealing with States vs local Canadian.

I would also assume that good quality R-core would be even better than toroid.

[Morse]

Thanks Peter;

Good point about currency conversion and shipping - 'course if the USD keeps dropping, you guys north of the border may be buying cheap US goods soon!

BTW, my TDA2030's and LM4766's have all shown up, so it's just a question of finding enough 'quality time' in my workshop to wire up a little chipamp.

Do you think that a 4"x6" sheet of 1/8" thick aluminium will suffice as a heatsink for a (approx) 12wpc chipamp? I'll need to use a mica spacer with these, so that will cut into heat transfer. My current plan is to use the top plate of the chassis to mount everything (so it's going to hang upside down in there) and use it as a heat sink. Then the bottom plate can just be some thin alloy sheet stock I have laying around. Good or bad idea?

Thanks in advance!
All the best,

[Peter Daniel]

I would say it should be enough. The amps usually run only slightly warm and only when you really push them they can become hot (but this also in a case when 40W pc is expected).

[ronc]

Good to see you trying a chip amp
Morse.If done right you wont be displeased.More like startled.
ron

[Morse]

Thanks Peter!

Sounds like it's a 'go' on my current chassis design....

BTW, IIRC I can freely use a 115VAC 60cps rated PS trafo for 100VAC 60cps, right? In which case I can expect a reduction in Vout from the thing, but so long as I stay above +/-10VDC on the rails the 4766 should be happy. I'd like it to work on either power standard, so if need be I could wire in a 6.3VAC trafo and use it as an autoformer with a DPDT switch to select between the two configurations.

Or is any of that wrong? Thanks in advance!

Hi Ron; you wouldn't happen to be "Ron" at the Fullrange Forum, would you? Anyway, yep, I'm looking forward to getting something up off the ground (pun intentional) - it's been too long since my last new amp was finished and I'm going through "DIY amp withdrawl"!

Thanks again!
All the best,
Morse

[ronc]

Yea the same ron here, OK i confess,LOL.
ron