another 3886 build question

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wendelltate

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Joined 2008
#1
Hi all,
I am thinking about building a 3886 amp to see what all of the fuss is about.

I have been reading through various build threads and my head is spinning.

Would a good place to start be to just buy the PE Yuan Jing 3886 and maybe mod if needed?

Also, would the PE closeout Abletec switch mode power supply work with this? Or does it work better with something else?
Thanks!!!
 
#4
batteries are a good option

when I built my first gainclone I had problems with hum/grounding. I ended up trying batteries and was happy. I series connected several batteries and used two capacitors 1000uf and two resisters 4.7k in voltage dividing network. the network gave me a positive, negative and ground.

G Luck dwayne
PS I was a total nooby then, Now I only feel that way most of the time😉
 
#6
Arty said:
you can purchase 4 piece of 9v dry cells.
http://www.klu.com/images/articles/aade761e8e0287a1d7d8f49c7470240e_5.jpg
like thisone.
it is easy to chain them up to get a pretty nice 18-0-18 dc test supply.
Click to expand...

I always use 9v batteries for testing if I can get away with it. You're less likely to burn something up than if you hooked it up to a power supply.

You should have an idea how fast the batteries should drop for your circuit; if you watch the voltage drop, you can get a clue if something's amiss without burning up expen$sive parts. Just two days ago I was performing preliminary DC checks on a new construction when I noticed that the voltage was dropping fast. The DC voltages were close. I thought the circuit was oscillating, but I had merely forgotten to short the input for the test. I figured this out with a VOM that you could buy at Menards. The circuit works great and I'm working on the input board and fitting everything into the small case.
 
#8
aye, i like battery powered amps too.
pre-amps i have all use rechargeable batteries with a floating charger connected when they are not in use. a simple relay solves the automatic charging problem.
less noise i have thisway.
 
#9
The LM3886 amps are very sensitive to passive components. A Chinese amp with cheapo parts is probably not the best way to exploit what this chip has to offer. If built with good parts, there really is no need for a tube preamp to get smooth, spacious sound. I would be wary of one of questionable quality. You get what you pay for. Depends on what you intend to do with it.

There are plenty of 3886 kits available to build from scratch, using good parts instead of hacking away at a cheap PCB that will probably lose pads with the touch of an iron. Look closely at the MyRef series, an excellent design which goes a step further and is a bit more complex but pays huge sonic rewards. There are boards available right now in the Swap Meet, and documentation here is excellent.

Peace,
Tom E
 
#10
Many hum problems can be combatted by using a differential input. I suggest looking at the Jensen JT-11 transformers or the THAT1200 IC. Not only do the transformers/ICs get rid of the obvious hum, they also get rid of the hum-induced IMD or "fuzz" in the sound.

Tom
 
#11
AndrewT said:
Do you already have a suitable smps or transformer that you can use?
Get the amp working and then decide what final PSU would be suitable.
Click to expand...
Buy a dual secondary transformer.
Any of the following are suitable for a 3886 build.

20Vac + 20Vac for 4ohms, 6ohms and 8ohms duty
22Vac + 22Vac for 6ohms and 8ohms duty
25Vac + 25Vac for 8ohms duty

I do not recommend an smps for a first time builder.
 
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