My 6 ch Gainclone

[DeanP]

Well I finally completed my 6 ch Gainclone! I have trouble getting extra parts as I live in a small town and electronics isn't part of this red neck town.

I got this kit from AudioSector back in Jan and the 2-400va 25v + 25v trannies off of E-bay and other parts from Apex Jr. It is the 4780 kit with snubbers. I must say that it was definitely was a learning experience! :T
As for sound, it is excellent! It is replacing my 6 ch Rotel(which will be for sale in the Pawn shop). When I went to separates with the Rotel, it was definitely an improvement in clarity and power, now it is even much more clearer.

EDIT: I posted the new mods down below in another post...

[TacoD]

Wow, nice project. I think those chipamps are great value for money!

[dynamowhum]

Looks like a great project. How many watts per channel and how much did it cost?

[Mazeroth]

Looks like a great project. How many watts per channel and how much did it cost?

Ditto!

[DeanP]

It is about 60w per ch into 8 ohms and if I hook up a 4 ohm speaker it would be about well over 70w but it could over heat as my supply voltage is to much. The supply voltage should be about 25v vice the 30v I have. I lost track of how much it cost, but approx. $350.

[Hdale85]

350 thats cheap......hmmmmmmm

[Inu_Yasha]

It is about 60w per ch into 8 ohms and if I hook up a 4 ohm speaker it would be about well over 70w but it could over heat as my supply voltage is to much. The supply voltage should be about 25v vice the 30v I have. I lost track of how much it cost, but approx. $350.

What type of speakers are you using? 70w into 4 ohms sounds kinda low... Or is this some type of my effieient power?

[DeanP]

I could be under estimating the 4 ohm rating, it is what I interpet from National Semiconductor's site on the Lm4780 data.
I'm using the Audax ht system here.My thread for Audax

[Dennis H]

350 thats cheap......hmmmmmmm

Not really. That's about a buck an 8-ohm-watt. You can get similar watts/buck with the Outlaw (ATI) amps and you don't need to build them.

http://www.outlawaudio.com/products/index.html

[mrogowski]

Not really. That's about a buck an 8-ohm-watt. You can get similar watts/buck with the Outlaw (ATI) amps and you don't need to build them.

http://www.outlawaudio.com/products/index.html

Certainly true, but what sound quality would you be getting? A buddy of my lent me his GainClone for awhile and it sounded better than my Luxman power amp which was a fair chunk of change at the time.

Best,
Mark

[Dennis H]

Certainly true, but what sound quality would you be getting?

I don't think there is anything special about gainclones other than marketing and high price for the original namebearer. When dissected, they are just chip amps using circuits designed by the chip manufacturer. SL uses chip amps for some of his designs and ATI amps for others and I trust his judgement that neither is particularly better than the other except power rating and convenience.

[mrogowski]

But that's the magic about them - there *isn't* anything special about it. Its a simple design, and if you use quality parts around the core, you can achieve some very good results.

Best,
Mark

[Hdale85]

Thats whats fun about it though? Is building it. I've been looking at different DIY amp designs and been thinking about building one.

[Inu_Yasha]

So is this gainclone enough to drive say, the WMTW and TMWW set or would that be asking too much out of it?

[Hdale85]

It would all depend on how loud you need it to be I would bet. Has anyone figured out the sensativity of the TMWW's?

[jonathanb3478]

I remember someone posting that the DM Seas version of the RS TMWW was ~87dB. I do not recall who posted that, and I might not be remembering that correctly. I typically have a good memory for numbers though

Take it for what it is worth.

[DeanP]

Since I created this in summer '06, I had planned to improve it somewhat.
Well this past summer I did. I added two extra channels for bass bins. They are LM4780s but each of the new ones are built in parallel config to drive a 4 ohm load. So now I still have 6 inputs but each of the mains are passed through a Marchand XM-1 x-over @ 250Hz and then split off to their own chip. I also cleared up a ground loop that I had before and now the amp is dead quite.
Since I had to keep the bass bins small, I just used some 8" drivers in a small vented box. My Audax mains, each sit on top of one. It sure made a difference in the bass department; its a "go between" for my dual Shivas. :T

[dragonrage]

You can bridge LM4780s. That'll drive basically whatever you want other than big subwoofers.

[BobEllis]

I wouldn't bridge into 4 ohm loads unless you also parallel another bridged pair. The built in protection will keep the chips alove, but what it does to sound quality is :frypan: - much like too small heatsinks.

[kevmurray]

DIY perspective on amps

One of the greatest benefits of the gainclone in my opinion is the price and versatility. A DIY'er can build a small stereo amp for fun and then for very little extra cash, can add extra channels as required. I'm going to build a 6 channel one soon for driving a pair of 3 way speakers. It will have a DIY active crossover integrated in a chassis I built with parts scrounged from local recyclers. The 1kVA transformer was $40 and 10,000uF caps were $2 each. I have future plans to add more channels since the speakers have dual woofers (more power good :twisted: ) and this will be easy and cheap. Oh and the heat sinks were from a recycler too. Gainclones may not measure as well as descrete amps but the price and built-in protection is hard to beat from a DIY perspective. This is a DIY forum right?

DeanP: Way to go, cool project! :T

[Habs4life]

I'm using a pair of LM 3875's to drive the Vifa 2ways on my computer rig and am quite pleased with the SQ considering the low cost to build.


btw Dean ,that sweater in your sig should have a gold metal on it.

[Hdale85]

I'm using 3875's to power my Lineup Maxx's. But I have issues with noise from my computer PSU. Probably going to be building a more expensive power amp based on mosfets soon though. Probably be something like twice the price of the chipamp.

[dragonrage]

If you want more expensive, try UcD180 (www.hypex.nl or www.diycable.com) or get a kit from 41Hz.com

[Hdale85]

No going to build a Class A/B amp thats not quite as expensive as the UCD modules. And the goal wasn't to pick a more expensive design but a better design Going to build a 2 channel Aussie Amp. The NX150's just waiting for him to get them back in stock which he says should be any day now.