gainclone 3875

[southpaw]

My shiny kit from Peter at Audiosector arrived today

Que many hours staring at it wondering how to fix it all together.

I was originally planning on dual mono amps but one of my transformers has gone walkabouts. So on to my first question - will 100va be enough for both channels ?

I put some more pics up as soon as I find time to get started

[rickcr42]

Should be OK.

Gainclones are surprisingly good sounding amps for something so cheap and easy to build (even hard wired).My own uses the lower powered LM1875 and is my backup amp or utility amp or during the summer months when I entertain outside (nice way of saying when we piss off the neighbors with our rowdy gatherings ) is the amp I use to drive a pair of PA speakers.

Not my best amp but a keeper being my most versatile amp

[southpaw]

Cheers for that Rick, I best get on with building it then.

[PinkFloyd]

Looking good Southpaw

[southpaw]

admin said:

Looking good Southpaw

Thanks ! although it is still in pieces ;D

I ve put in the rapid order so will should have everything I need tomorrow or monday. Im still thinking about whether to build / buy cases for the amp and also dual mono or all in one box ?

[southpaw]

my bench (piece of wood in the hallway) has been busy this afternoon.




The boards are now done apart from the 3875 chips - got to workout how to put the nfb resistor on first.

Also made a cable for my headphone amp , Ive had bought some of the cable about 2 years ago - about time i did something with it really. Off to see if it makes any difference now.

[rickcr42]

my bench (piece of wood in the hallway) has been busy this afternoon.

hope you have a pair of these babies



soldering on your knees even with a carpet can get painful

[southpaw]

If I can't clear this desk im typing away on I might just get some. They'll allways come in handy for paintball! I like the way the man is using what looks like a fridge for cover...

[rickcr42]

I like the way the man is using what looks like a fridge for cover...

Take a shot...grab a beer from the fridge.....shoot the next guy dumb enough to come into range......have another brewskie.......

[southpaw]

got my bits from Rapid today so im almost set to make some music. What rating of transformer would I need if I wanted to go down the dual mono route?

[rickcr42]

Personally I would not (and have not actually ) go full dual mono since to me the returns in SQ or dynamics are not on the same curve as the additional cost incurrred with the power supply being THE expense when building a chip amp.

My take is the amps are great for what they do and will not shame your system but if stepping up to that cost bracket (dual mono) you get more bang for the buck with another design.

Just my opinion man

[southpaw]

Now I know this build has taken awhile ;D

I've finally ordered the transformers to finish this.

I'm decorating the room they were going in this weekend and thought I should get a system ready.

[xerxes]

I'll be interested to hear what you think. I ordered some gainclone boards, 4 actually, enough to make a 300wpc power amp: www.shine7.com/audio/bpa300.htm, cost around £35.00 shipped from Hong Kong. I priced up the project and I reckon it will cost around £400.00 to £500.00 to build the completed amp(s).

However, I'm not sure when I'm going to get around to building this, or if I ever will as I've just ordered all the parts to make a pair of 350wpc power amps using the Hypex UCD700HG modules. My speakers are rather low efficiency monitor types that apparently thrive on power, so I'm looking forward to hearing this when I've finished.

[southpaw]

Hi Xerxes,
My plan is just to make a cheap dual mono setup to run off my pc. It was a long time ago but I think my pair of boards with parts cost £30 ish and the rest of the parts should bring it up to around £100. What components are you using to bring the cost upto £400-£500 ?

Those hypex things look nice. Im going to concentrate on getting some sounds out of the 3875s first.

[xerxes]

Well the boards I bought use 6 paralleled LM3886s per channel, so 12 in total. Couple of 500VA transformers, 16x2,200uF 63v Nichicon caps, 4x15uF Solen axial polypropylene caps, plus 16x10,000uF electrolytics for two snubberized power supplies, big heatsinks and a couple of cases, it all adds up.

This is something of a hot-rodded Gainclone capable of delivering 300 watts into a 4ohm speaker, rather than the usual 30 to 50 watts of a single LM3886, or 25 to 40 watts of an LM3875.