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Tube buffered 4870 gainclone kit

post #1 of 13
Thread Starter 
So I saw this while looking for other things.

LM4780 Olympic Edition Amplifier Kit [LM4780TDA] - $99.00 : hifidiy.net


I know that the tube is a china junk and was wondering what to replace it with. Also does anyone know what powers it? It seems to have +-18v and +-25v in.
post #2 of 13
Cheaper here: HIFI AMP KIT valve 6N11 + LM4780(2*60W) - eBay (item 180449856016 end time Jan-26-10 23:28:55 PST)


/U.
post #3 of 13
Thread Starter 
Aw that is so tempting. Any clue on what the va might be on the 18 and 9v sources? I assume 160va min for the 24-0-24 like a standard issue gain clone.
post #4 of 13
Wouldn't know without seeing the schematic, but if it is laid out like I think it is I would expect 9V/10-15VA (filaments) and 2x18V/20-30VA (tubes) and 2x24V/120VA+ (LM4780) should do it. To be honest I have looked at this kit and a couple of others like it before and the only thing that's kept me is the need for all these different voltages so if you do try it, please post your impressions.


/U.
post #5 of 13
Thread Starter 
well i got some info from the seller.

9V 5~VA
2*18V 30~VA

your pretty much on the money. He gave me the diagram too (no cap values). Its dc from input to the tubes, 1 cap then dc out to the speakers. Its also inverting since the signal goes to the negative in and the positive in is grounded. Sounds pretty good.
post #6 of 13
I have a sneaky feeling that tube is rather undervolted.
post #7 of 13
I am not so sure but again, I haven't seen the schematic. Many of these designs use a voltage doubler which in this case means you could have a B+ of nearly 100V. AFAIK there are plenty of low-power triodes that will sound fine with that.

/U.
post #8 of 13
I just pulled the plug on this. I bought it from here btw.
post #9 of 13
Let us know how it works

/U.
post #10 of 13
not a bad price at all.


I was thinking about making a 5687 buffered gainclone, but the parts cost alone adds up to over $300, a bit too much for a "fun" project.
post #11 of 13

Hey,

 

Nice purchase! Slightly hesitant on buying the whole amp until i've heard some real user feedback.

 

As a proud owner what is the score on this interesting amp?

 

Worth the money?

 

I'm planning to use it on a home made line array - so wanted the clarity that Gainclones give.

 

Any comments welcome.

 

Thanks

 

 

Ed.

post #12 of 13

Hi Eddiefish20,

 

Just curious. Are you the famous eddiefish20 (yeah, like how many people would pick an identical moniker) who solved the (in)famous Creative Gigaworks 550W relay problem of 2008-2009?

 

Cheers,

 

hpmaniac

post #13 of 13

I have this kit, I threw away the crapptacular china tube and replaced it with an electro harmonix cryo treated russian tube, DAY and NIGHT I tell you! I also replaced several cheap components with my choice of caps, transistor and resistors. I have zero hum maxed out. I can put my ear on the driver and it is dead silent. I used mundorf supreme eutectic solder for the entire board. I have a 10 inch aluminum radiator on the LM4780 chip and it still runs hot! I recommend active cooling.


Edited by RadiatedAnt - 9/22/13 at 2:26pm
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