Reference DIY amplifiers

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lgreen

lgreen

Member
Joined 2003
troystg

troystg

Member
Joined 2004
Some of us can't speak one language very well so "hopefully" when we read international posts we give LOTS of room for interpretation, and we ALWAYS TRY to give the other person the benefit of the doubt. At least I do.

We are all different but here because we have a common bond. Different tastes and preferences, but over all the same passion.


Good posts like this will flesh out valuable information that will be benificial to many people down the road.
 
H

horus

Member
Joined 2005
pinkmouse, thanks for the kind words!:)

I was in a hurry rechecking the last 5 pages and it seems that it
isn't much to add. If someone sees that I've missed something please tell me. In the future I'll try to make the list more appealing
(colour it).

Please attach this part to my previous post for the moment.

Mod edit: Done! ;)
 
Z

Z33

Member
Joined 2006
horus said:

When I said "DIY reference amps" I was talking about amplifiers that are very popular around DIY builders, praised for their sound, and that can compete with high-end commercial ones(ML, Naim, Linn, Ayre, and others that are playing in this category)
Click to expand...
Great thread, Horus, and thanks for that clarification. If you don't care about politics, posturing or semantics, then the question becomes clearly one of performance. I went through the same sort of head-scratching when I found this site a few months back. Lots going on here, and it had been years since I'd built anything, so it naturally takes a while to sift through it all.

In the end, I took a shot at 3 very different but likely candidates, figuring that at least I was paying for some education, and would probably end up with something useful: the Hypex switching amp modules, Mauro Pensa's MyRef RevC, and Greg Ball's SKA. These are all out of the ordinary in their respective design realms, which is part of their attraction.

The MyRef is still unbuilt, because in the mean time I've also made some new speakers (Dan Wiggins' DDR dipole design) that need a bit more power, and the Hypex and Ball amps seem better suited; I'll get around to MyRef in due course. The Hypex were easiest to use, and required just a few simple mods to sound very, very good indeed. They are quite sensitive to PS quality, and I've found their HG a good investment also.

The real surprise was Greg Ball's design. Between my wiring errors and Greg's troubleshooting expertise, I learned a lot about his circuitry the hard way, but the results exceeded all my expectations: I've never heard a sweeter, more musical amp, at any price. IMHO, its performance reaches easily at least 2 orders of magnitude beyond its price point, and it does so with a robust simplicity that even my haste and carelessness in assembly couldn't completely destroy.

SKA: http://www.diyhifi.org/amplifierguru/guru_001.htm

I like my other amps, but I love my Balls. :D
 
lineup

lineup

Member
Joined 2005
Luke said:
anyone here built the JC3?
Looks like a simple diy type circuit form a well known designer
but I cant remember seeing anyone talking about it here.
Click to expand...


I was the one mentioning our member, John Curl JC-3 amplifier.
When I gave a hint about The Class-A Amplifier Site http://www.tcaas.btinternet.co.uk/


John Curl, if you read this, looks like a good CLASS A amplifier!
... but it is so old, that almost all transistors used
are obsolete or to be replaced by modern better ones!
;) It is high time for a JC-3-2007 updated version;) .

The basic concept is in my liking:
- JFET input
- Inverting amplifier
- Gain is low, ~8
- Supply +/-20 Volt
- Current bias in output: 2.0 Ampere
- Vbe multiplier uses a good alternative method

In short:
It is a very interesting amplifier, that could be updated and IMPROVED.
The power output, something like 15-30 Watt,
is more than we would want from a good Class-A Amplifier.

Here is schematic of John Curl's oldie Class A JC-3
;) http://www.tcaas.btinternet.co.uk/jc-3.gif ;)



Regards
lineup
 
lineup

lineup

Member
Joined 2005
Luke said:
Hi Lineup,

good idea about 2007 jc3, but ive got several projects on for now so I think 2007 is out for me. I would definitely follow any developments on this though. Good luck!

arthur
Click to expand...

Okay.
we see.
If not John Curl himself will respond,
I am sure someone would try to modernize this good old Class A amplifier.
And share this project in some new topic, for us.

lineup
 
lineup

lineup

Member
Joined 2005
Re: I am sure someone would try to modernize this good old Class A amplifier

loek said:
Maybe Mr. Lineup himself can give it a start?
Would be an other interesting DIY project i think.
Greetings, Loek
Click to expand...

I may be able to do this.
But I have rather newly started to use EWB MultiSim,
so my library of good audio transistors is very tiny.
I have added some models, but I have failed adding other.

What we need, I need, is
1 good suitable N-JFET pair ( a dual JFET in one package )
1 good dito P-JFET pair ( a dual package)
The input stage is important and to get this right with best possibly matched devices
is the best start of an amplifier!


Now, I know that Mr Curl have great knowledge about JFET.
He has used them since time began (the fet times)
and still prefer them in many amplifiers!
We must get some hints from him .... I say :)

... but if we can't get it from him
we will turn elsewhere. Who needs Curl :D
when there are so many clever persons with better knowledge of latest modern JFETs

To surpass the oldie John Curl, I am thinking of course 'bout
Suzy Jackson = our suzyj
This engineer sure has got a good hand with chips, circuits and FETs.
After all, this is a bit of what she does for living.


Good Day
lineup :cool: who will surpass and replace Mr Lineup, one day ........?
 
H

horus

Member
Joined 2005
Moderator edit:

Here is a list of projects and links compiled by Horus:


This is the list of Reference DIY amplifiers:

Leach amplifier: http://users.ece.gatech.edu/~mleach/audiothings.html

LM3886/LM4780 chip amplifiers(Briann GT / Peter's LM3875 Dual Mono Classic Kit / etc.)

PASS DIY AMPS:http://www.passdiy.com/

Krells KSA50 & KSA100MKII:
http://www.diyaudio.com/forums/show...t=&pagenumber=1
http://www.diyaudio.com/forums/show...t=&pagenumber=1

Rod Elliot P3A:http://sound.westhost.com/project3a.htm

MikeB'sSymasym: http://www.diyaudio.com/forums/show...0918&highlight=

ZEN Class A(Nelson Pass) & Aleph(many variations)

JLH:http://www.tcaas.btinternet.co.uk/index-1.htm

Geoff Moss's latest version of JLH:
http://www.members.shaw.ca/paul.r.b...f Moss JLH/

David Tilbrook's AEM6000:
http://www.littlefishbicycles.com/poweramp/poweramp.pdf

AKSA kits:http://www.aksaonline.com/products_2.html

Power amp under development:
http://www.diyaudio.com/forums/show...&threadid=43331

Death of Gain Clone:
http://www.diyaudio.com/forums/show...9782&highlight=

SKA amps kits:http://www.diyhifi.org/amplifierguru/guru_001.htm
Erno Borbely kits:http://www.borbelyaudio.com/products.asp
Anthony Holton http://www.aussieamplifiers.com/

Krell KSA 50 clone building guide
http://www.diyaudio.com/wiki/index....=Building+guide

Krell KSA 100 clone group buy and related info
http://www.diyaudio.com/wiki/index....n+the+group+buy

Aleph X (Pass Labs variant) building guide
http://www.diyaudio.com/wiki/index.php?page=Aleph-X

Jean Hiraga Class-A Amplifiers

http://www.tcaas.btinternet.co.uk/hiraga.htm

The JLH Class-A Amplifier
http://www.tcaas.btinternet.co.uk/index-1.htm

Other Class-A Amplifiers - for example John Curl's JC-3
http://www.tcaas.btinternet.co.uk/index-3.htm

Classic Class-B Schematics - like NAD 3020
http://www.tcaas.btinternet.co.uk/index-4.htm

The Class-A Amplifier Site
http://www.tcaas.btinternet.co.uk/

Tubes:
1.300b (or 2A3)single ended with various driver stages(JElabs is a classic 6sn7-300b)
2.Williamson type push-pull amp.
 
lineup

lineup

Member
Joined 2005
flg said:
Lineup, How about a MOSFET output version of the JC-3??? from what I've read lately, John might even use a MOSFET driver???
Just a thought:D :D :D
Click to expand...

You are giving me some ideas, flg :att'n:

Not often we see MOSFET used for drivers/VAS.
Actually I have been thinking doing such an amplifier.
With for example IRF610/9610 as VAS transistors.
There has to be some good ways to do this.

Still I myself prefer BJT Power for the final output.

Sooner ot later I may present my new version suggestion
for John Curl JC-3.
In some other topic.

Though, I would prefer John Curl would do this himself.
I have no great illusions anybody could do this better - than JC.


Regards
lineup
 
H

horus

Member
Joined 2005
Yes, the links are not corect because the forum streches them and I've copied the hole post in Notepad to edit it without realizing this until it was too late.
Here's the correct part:

Krells KSA50 & KSA100MKII:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=31077&perpage=10&highlight=&pagenumber=1
http://www.diyaudio.com/forums/showthread.php?s=&threadid=78129&perpage=10&highlight=&pagenumber=1

Death of Gain Clone:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=69782&highlight=
MikeB'sSymasym:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=60918&highlight=

Thanks Loek!
Pinkmouse I need your help again. Thank you!
Only if I had an edit button!
 
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