Gc with cheapo components

[rs1026]

I have seen lot of discussion on this forum on GC using premium components but has anyone built a GC with all cheap/scrap components without bothering too much about using only metal film resistors or balck gate capacitors. was just curious

[Igla]

I did.

[brianuk]

hi Igla,

Please comment on the results and whether you made a comparison to a commercial amp and/or a more expensive GC.

Thanks!

Brian

[BobEllis]

I did too - results

At least in its "on the cheap" incarnation the gainclone is not my cup of tea. Not terrible, but missing the detail of some more traditional designs. It's a decent starting point, perfectly suitable for less than super critical applications.

[Scribble]

ive built mine with el-cheapo components and it sound good to me. Very clear and detailed but only thing i dont like is the lack of bass.

But then again im proberly not as perdantic as some other members of the board

[psychosteve]

ive built tda 2030 chip amps with salvaged parts and that sounded fine to me. its ok if your sure of the values of components, a good multi meter, and preferably a capacitance meter. the trouble comes with resistors that look like 1watt, when they are only 0.2watt.

and what tollerance? 5%? 10%? 0.5%???? measure them, TWICE, then check again!!!

then run them as a dummy load, a simple battery circuit, with a volt and current meter to check they can handle the stress your putting on them.

see you later, steve.. ..

[Igla]

Well....I can try with my limited english.
I have used no-name metal film resistors which
I had in my junk box (22k / 1k).
For the power suply I've used Nippon Chemi-Con capacitors (1000uF)-cheap and the only brand available at that time in our
local shop and one cube-like big 25A/600V cheap diode bridge.
At the input cheap Piher pot and cheap film cap (Arcotronics;
the gray one, I think MMK).All wirings made point-to-point
of CAT 5 FTP cable.
This was my first LM3875 NIGC and I must say that it sonicaly beat the s..t out of my AIWA 950.It also replaced my ZEN amp.
The first big improvement was, when I removed the input cap.
Then I replaced Piher pot with Alps blue-much more expensive
but sonicaly quite an improvement.
The next step was MUR860 double bridge-smoother mids and more defined bass.Then I replaced double bridge with just one.
I can't say why I liked it more.
The last improvement is different schematic (and same parts)made by Stefanobilliani-
something like mix-mode current amp-look for the last scheme:
http://www.diyaudio.com/forums/showt...threadid=41189).
My parts have different values but the basics stays the same.
I am still testing it.All I can say is, that this is totaly different soud
comming out of my full range speakers.
Igla

[brianuk]

Thankyou for the comments.
Igla, your english is very good, much better than me trying ANY other language.

[Igla]

Thanks Brianuk...you don't want to hear me speaking
german.
I must say that my really first GC was inverted design
by Thorsten schematics.
After a while I just had to try non inverted design from
LM3875 datasheet.I found it somehow better sounding.
Then all the modifications followed.
A few weaks ago I found an article Mr.Pass wrote about
current amps and full range drivers.
So I just had to convert my GC to current amp; well, some
sort of mix mode amp.(check Rod Elliot page-variable
impedance).
Mr.Pass wrote that a full range driver hooked to a solid state amp
sounds more like a kitchen radio.
I can confirm that after the modification.
Hard to describe the difference in sound....more like the difference between my old computer monitor with washed-out colours to my brand new one.
The sound of NIGC on my full range loudspeakers is just
washed-out comparing to the mix mode amp.

[mateo88]

I've built several, all with very cheap components, and I do mean cheap. Just regular 10% carbon film resistors and some cheap 2200 uf capacitors. I've used both the lm3875 and lm3886, and I would strongly reccommend the lm3886 over the 3875. I just used the schematic from the data sheet, and there's much better bass response; it seems more detailed all around, as well. Really, I enjoy listening to my cheap gainclones with the lm3886 more than the one I have built using Brian's boards. You would be VERY surprised at what you can come up with for a few dollars.