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Jaycar amp

post #1 of 63
1/20/09 at 4:33am
Thread Starter 
Just finished a jaycar amp, it sounds wonderful. It was quite a surprise to find that this crazy best bang for your buck amp competes with some really respected amps. Here are my amps in order of most preferred to my ears driving my HD650’s:

1) M^3 Balanced
2) Jaycar
3) Darkvoice 337
4) Mini3

or

Mini3 > Darkvoice 337 > Jaycar >>> M^3 Balanced

Cost was:
$30 amp
$18 psu
$22 transformer
and around $30 for chassis

That’s $100AUD well spent, and represents great, great value. I initially took this on wanting something cheap to build and to learn from. I really didn’t expect such great sonics to boot. I know a lot of people will be turned off by the cheap price, that’s really too bad.

The support from the Rockgrotto community was fabulous, once again thanks sandyk and robertkd.

Here’s some pics...
LL
LL
LL
LL
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post #2 of 63
1/20/09 at 5:00am
Was the lens flare necessary? lol.
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post #3 of 63
1/20/09 at 5:05am
And the real beauty of it is now you can kick off the modification phase...

I made the following mods:
- replaced input caps with 10uF film caps from Jaycar
- replaced output transistors with 2SC3422/2SA1359 combo (just to be different)
- Increased the bias through the output transistors to 60mA (I think)
- Removed the inductors on the output

Unfortunately, it didn't really play all that well with my y1 and Sextetts (not overly sure why, bass was a bit disappointing) so it lost out to my recently completed MiniMAX for the work rig title (I'm a sucker for tubes). I'll take it home and play around with it, see if it likes the Grados a little more.
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post #4 of 63
1/20/09 at 5:13am
2001 An Amp Odyssey
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post #5 of 63
1/20/09 at 5:26am
Thread Starter 
Quote:
Originally Posted by iareConfusE View Post
Was the lens flare necessary? lol.
Yes definitely as well as considerably retouching to hide scratches I made on the chassis.
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post #6 of 63
1/20/09 at 5:39am
Nice work John, i will be starting to populate the psu and amp section tomorrow. I'm going straight for Alex's tweaked version, patient enough to wait to buy the odds and sods needed for the modded version but too impatient to tweak myself.

ps- greetings from the base of the Blue Mountains
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post #7 of 63
1/20/09 at 5:49am
Thread Starter 
Quote:
Originally Posted by nickyboyo View Post
ps- greetings from the base of the Blue Mountains
Hey nickyboyo, I’m Blaxland... sort of still base as well and you?
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post #8 of 63
1/20/09 at 6:17am
Quote:
Originally Posted by Daveze View Post
And the real beauty of it is now you can kick off the modification phase...

I made the following mods:
- replaced input caps with 10uF film caps from Jaycar
- replaced output transistors with 2SC3422/2SA1359 combo (just to be different)
- Increased the bias through the output transistors to 60mA (I think)
- Removed the inductors on the output

Unfortunately, it didn't really play all that well with my y1 and Sextetts (not overly sure why, bass was a bit disappointing) so it lost out to my recently completed MiniMAX for the work rig title (I'm a sucker for tubes). I'll take it home and play around with it, see if it likes the Grados a little more.
u have to mod the psu first, change the diode and put a cap at the ac input like what sandyk suggested. i did the same mistake as you, did most of the mod before mod the psu, modding the psu really drop the noise floor and making the rest of my other mod become more obvious. also if u want more bass, try the 4.7uf banana cap from jaycar sandyk suggested, this really bring out the bottom end, at first i thought it's too boomy, but after some burn in it really settle down nicely.
my experience taught me about the important role of low noise psu play in audio. i am pretty sure the jlh ( a shunt regulator ) can bring this thing to another level. still waiting for mine i ordered from uk, it's been more then a month now, hopefully oneday it will turn up.
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post #9 of 63
1/20/09 at 6:29am
Sunny Richmond here, just down the road mate. If it is ok with John, when i actually get round to finishing the build, you could do a stock to modded jaycar comparison, along with a comparison to some of your past and present amps. My range of listening with various types and different manufacturers pieces of equipment is very limited.
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post #10 of 63
1/20/09 at 7:16am
Hi nickyboyo


Did you track down a source for the 2SC5171 & 2SA1930 transistors?

I'm just going to wait until I have all the parts and build up the modded one.

Cheers
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post #11 of 63
1/20/09 at 8:04am
Oh, I forgot to mention that I had changed the diodes in the PSU. I haven't added the caps on the AC lines, I completely forgot about that phase of the modification. I have the 10uF version of the banana caps, bypassed by something small and black (can't remember what though).
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post #12 of 63
1/20/09 at 8:05am
Thread Starter 
Quote:
Originally Posted by nickyboyo View Post
Sunny Richmond here, just down the road mate. If it is ok with John, when i actually get round to finishing the build, you could do a stock to modded jaycar comparison, along with a comparison to some of your past and present amps. My range of listening with various types and different manufacturers pieces of equipment is very limited.
Definitely interested in hearing a fully modded jaycar, although mine isn’t purely stock. Mods on the psu minus the cap at the ac input have been done. The stock OPA2134 has been replaced with LM4562. Mate when your builds complete well do some comparisons, your welcome to come up for a session anytime. Make sure you pm me when your done well sort out a time.
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post #13 of 63
1/20/09 at 8:07am
I have a quote at work from WES for the 2SC5171 and 2SA1930, I only received it about a week ago so I assume its still valid.
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post #14 of 63
1/20/09 at 9:05am
Very nice, John. Where's the chassis from? One of the Jaycar ones?
I'd really like to build one, but I'll have to hold off until I finish everything else half done Perhaps I'll look at ordering parts to do the tweaks and stuff recommended at rockgrotto so that they'll arrive by the time I have some time to go it.
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post #15 of 63
1/20/09 at 9:13am
Quote:
Originally Posted by Daveze View Post
I have a quote at work from WES for the 2SC5171 and 2SA1930, I only received it about a week ago so I assume its still valid.
Any idea how much they were? (ballpark figure is fine)
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