1st Gainclone

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A

AndrewGM

Member
Joined 2008
Ok, I've read enough, drooled over the pics and I'm going to have a go.
I have good soldering skills and fiddle around with HI FI
having had a few lessons from very clever engineers at a Hi Fi shop where I worked for years part time.

My understanding of electronics is limited to recognising polarity,
replacing resistors, smoothing caps, transistors, wiring and stripping rebuilding - the really easy simple stuff..
I'm careful, have a big bench power supply and test meter
to assist me with my anorak moments.

For me to make a gainclone from scratch I'd need close up pictures of point to point as my understanding of schematics
is poor.
I can easily copy something but not with diagrams !

Clearly you guys are all experienced electronics hobbyists or engineers and I fall a long way behind - apologioes in advance !

Any clear close ups of what goes where would be great.

Is there a better way ?

Any help from patient people would be great !!

Many thanks Andrew
 
A

A Sanchez

Member
Joined 2008
Also check dogbreath.de Simple designs with very detailed photographs and explanations and clear schematics. You could try his copy of the original gaincard.

He has even simpler designs but you have to be careful because they do not offer protection against DC offset and your speakers could be at risk if you do not know what you are doing.

Regards
 
DC Dave

DC Dave

Member
Joined 2004
Copying from a picture might work, but what will you learn from that.

Learning to read a schematic is your best bet. It is not difficult. A chipamp schematic is a great place to start as there are only a few components to deal with. Just some resistors and capacitors. Make sure you download the data sheet for whichever chip you use. If you get confused, google, go to the data sheet or come back here and ask.

Shown is a very simple circuit for the LM1875. Only 6 components plus the chip.
 

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A

AndrewGM

Member
Joined 2008
! st Gainclone - reply

Thanks to Andrew T, CPK Builder, D Dave and A Sanchez
for the excellent response.
OK I'll buy a book and learn some stuff first !!
If I bake a cake there's still things I need to read.

I'm buying two output boards and a power supply board from
E Bay - pre done boards, nicestuff ( no compnents )
Checked with a guy in Belgium who bought same who said they were excellent

£ 5.00 + £ 4.00 carriage.
Can't argue with that !

It should be a little safer in the first instance though I'll definately try a point to point as my understanding of what I'm doing increases - not ashamed - I want to learn !

Can I add a stepped attenuator easily in the same box and with an lm 3886 based GC would 25 K or 50 K stereo be OK ?

Thanks again - much appreciated

Andrew
 
A

AndrewGM

Member
Joined 2008
Mad About Sound - J Blackburn

John Thanks.

Useful site and maybe some after sales service too !!

A new and enjoyable dilemma - I like those.

Dual mono too !
OMG - what to do ?
I'm sure I can build these things but it's getting like a swimming pool. ' shallow end or deep end '

I got my schematic info today too so hopefully I won't disgrace myself too much with stupid questions - well maybe some !

Thanks

Andrew
 
J

john blackburn

Member
Joined 2006
AndrewGM

I was lucky to have done my LM3875 a couple of years ago when Vikash kept the Chipamp.com kits in stock. Chipamp kit, suitable heatsinks, volume pot, FR125 speakers and suitable transformer all from one supplier. It made it much simpler for a beginner, but I bet it generated an awful lot of email questions! The service is superb as well.

If you take your time, triple check everything and use the series light bulb tester when you power anything up you will have something that sounds better than anything you thought you could put together yourself, and a grin from ear to ear!

Be warned though, you cant stop at one chipamp, just one more then I'll quit........

John

PS Vikash as well as being a moderator here has a non comercial site you may not have seen yet........

http://www.vikash.info/audio/
 
A

AndrewGM

Member
Joined 2008
Last..... 1 st Gainclone

Another inspiring site - thanks.

I think you may be right about how many get built.
' i'll do it this way next time '

Just how good are they - any big differences between 3875 and 3886 ?.
Tell me what the Gainclones sound like if you can - it's a big ask - I know !

Don't understand and can't see what snubberised is .
I'm of course checking schematics now - because I can - Ha !

I'm waiting for some bits to come from RS so I could be posting some pics and grinning faces soon or maybe loads of stupid questions !


Thanks for your input + a group if good guys all in one place
at the same time !

Regards

A

How do I attach the ' funny faces ' in the right places.
 
J

john blackburn

Member
Joined 2006
AndrewGM

Wikipedia has a bit about snubbers here........
http://en.wikipedia.org/wiki/Snubber

This site has a lot of info, from basic to headfrying that may answer a few questions for you....
http://www.allaboutcircuits.com/
and
http://www.kpsec.freeuk.com/study.htm

I dont think you will be disappointed whichever chip you go for, both have their fans though I've never heard any other than the 3875.
I was in the same boat when I put mine together, I had never heard one but had been tempted by all I had read.
I have no experience of high end stuff to rate it against, the best I had until the chipamp was a Denon PMA250 and a pair of old Bose speakers.
When I finally got the chipamp and preamp playing with the FR125s I turned it on just to see that it sounded OK, I reluctantly tore myself away several hours later a very happy camper!

John
 
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