Hi eveverybody,
I Just finished my first amp.
Much to me relief, it worked first time I powered up!
All the boards are by ESP (http://sound.westhost.com). I wanted to go for a proven design on my first attempt.
It consists of:
P3a power boards, at 35V for approx 60W 8ohm
P97 preamp, with OPA2134 op-amps
300va toroid, 20400 uf per rail.
Chassis is my own work. Uses conrad heatsinks. Obligitory blue LED.
I'm very happy so far, sounds great to me.
Here are a few pics:
Top:
Even my GF is happy, although that is probably because she finlly gets the kitchen table back....
Mark
I Just finished my first amp.
Much to me relief, it worked first time I powered up!
All the boards are by ESP (http://sound.westhost.com). I wanted to go for a proven design on my first attempt.
It consists of:
P3a power boards, at 35V for approx 60W 8ohm
P97 preamp, with OPA2134 op-amps
300va toroid, 20400 uf per rail.
Chassis is my own work. Uses conrad heatsinks. Obligitory blue LED.
I'm very happy so far, sounds great to me.
Here are a few pics:
Top:
An externally hosted image should be here but it was not working when we last tested it.
Even my GF is happy, although that is probably because she finlly gets the kitchen table back....
Mark
Back:
An externally hosted image should be here but it was not working when we last tested it.
Front:
An externally hosted image should be here but it was not working when we last tested it.
Last and importantly, inside:
Comments welcome!
Mark
An externally hosted image should be here but it was not working when we last tested it.
Comments welcome!
Mark
Thanks guys, I'm pretty wrapped for my first effort. Of course, there are so many things I would change next time...
I learned a lot about building a chassis. I thought that the electronics would be the hard part and the box would be easy. HA! not...
Majord: Knobs from Jaycar, yes?
Darkhorse: Does "ss" mean stainless steel? Yikes
I thought building my box out of aluminium was hard enough. I'd hate to try the same thing in stainless! You're a braver person than me. 
cheers,
Mark
I learned a lot about building a chassis. I thought that the electronics would be the hard part and the box would be easy. HA! not...
Majord: Knobs from Jaycar, yes?
Darkhorse: Does "ss" mean stainless steel? Yikes
I thought building my box out of aluminium was hard enough. I'd hate to try the same thing in stainless! You're a braver person than me. cheers,
Mark
mAJORD: No, filter caps are 80v 6800uf From Wes components. Not chassis mount, just stuck into a crude pcb.
DarkHorse: How is ss as a heatsink? Aluminium is supposed to be quite good because it spreads the heat out well.
Nothing really wrong with your english. I went to school with people who write a lot worse....
Cheers,
Mark
DarkHorse: How is ss as a heatsink? Aluminium is supposed to be quite good because it spreads the heat out well.
Nothing really wrong with your english. I went to school with people who write a lot worse....
Cheers,
Mark
Hi,
Excellent job! I just ordered the exact boards from Rod to try my hand at as a first project. I am impressed with your case design. I haven't put any thought into this as yet but now I certainly have some direction. Just a couple of questions:-
- Did you have any trouble sourcing components (Pretty much only have Jaycar around here)?
- Most imprtantly, how does it sound?
Cheers,
Jeff
Excellent job! I just ordered the exact boards from Rod to try my hand at as a first project. I am impressed with your case design. I haven't put any thought into this as yet but now I certainly have some direction. Just a couple of questions:-
- Did you have any trouble sourcing components (Pretty much only have Jaycar around here)?
- Most imprtantly, how does it sound?
Cheers,
Jeff
Bikeman that looks really good!
My first am was a Quad 405 and it looked like a gutted case with an amp botched inside hehe.
I would check your output with a scope though and put a signal generator in to check you are not hurting your speakers.
I thought my Quad worked but when i looked at the waveform it had oscillations on it and was triangulatedat high output levels!
Your amp probably is fine but i would check.
Craig
My first am was a Quad 405 and it looked like a gutted case with an amp botched inside hehe.
I would check your output with a scope though and put a signal generator in to check you are not hurting your speakers.
I thought my Quad worked but when i looked at the waveform it had oscillations on it and was triangulatedat high output levels!
Your amp probably is fine but i would check.
Craig
Hi jgrigg,
Not too much trouble getting stuff. The heatsinks are Conrad:
http://www.conradheatsinks.com/welcome.htm
Actually bought on sale at Dick Smith.
The transformer is from Radio Parts:
http://www.radioparts.com.au
I got it from there 'cause it was cheap, but it hums quite a lot. For my next project I might try Altronics:
http://www.altronics.com.au
The filter caps and 500V ceramics were from WES:
http://www.wescomponents.com/
Bad website, and you have to email or call for prices, but they have lots of stuff.
Case was made from Al bought from Capral:
http://www.capral.com.au
If you are lucky they may have offcuts, so they won't have to cut up big pieces from scratch. If you are nice, they might even cut the bits to size.
Most of the rest was from Jaycar, who seem to stock less components (especially decent speaker drivers) and more crap each year.
Wish Australia had something like parts express.
Edit: I can't even say crap (cr@p)? Geez...
As to how it sounds. Well, pretty good to me, although I'm not one of the golden ear brigade!
It was a gift to my younger brother, so he is the only one who has listened long term.
A couple of tips: The preamp has way more gain than you will need, I don't turn the volume past about a third.
I probably wouldn't bother with the fancy op-amps next time, as the little buggers overshoot anyway.
Edit: ...pretty aggresive profanity filter! Think bug, then gers.
Let us know how you get on.
Mark
Not too much trouble getting stuff. The heatsinks are Conrad:
http://www.conradheatsinks.com/welcome.htm
Actually bought on sale at Dick Smith.
The transformer is from Radio Parts:
http://www.radioparts.com.au
I got it from there 'cause it was cheap, but it hums quite a lot. For my next project I might try Altronics:
http://www.altronics.com.au
The filter caps and 500V ceramics were from WES:
http://www.wescomponents.com/
Bad website, and you have to email or call for prices, but they have lots of stuff.
Case was made from Al bought from Capral:
http://www.capral.com.au
If you are lucky they may have offcuts, so they won't have to cut up big pieces from scratch. If you are nice, they might even cut the bits to size.
Most of the rest was from Jaycar, who seem to stock less components (especially decent speaker drivers) and more crap each year.
Wish Australia had something like parts express.
Edit: I can't even say crap (cr@p)? Geez...
As to how it sounds. Well, pretty good to me, although I'm not one of the golden ear brigade!
It was a gift to my younger brother, so he is the only one who has listened long term.
A couple of tips: The preamp has way more gain than you will need, I don't turn the volume past about a third.
I probably wouldn't bother with the fancy op-amps next time, as the little buggers overshoot anyway.
Edit: ...pretty aggresive profanity filter! Think bug, then gers.
Let us know how you get on.
Mark
Craig405:
Yeah, chucked it on a scope. Got some noticable ringing at 10Khz square wave, but no real high frequency runaway. Certainly nothing I would think could damage speakers. Ehh, close enough.
If I get really motivated one day I'll chuck some extra bypass caps directly on the op-amp pins.
Anyway, it will be my brothers speakers that get damaged, not mine.
I forgot to mention in my last post. They had a power surge at my brothers place a while ago, due to lightning strike. So I went over to check things out,
Everything fine. Still less than 10mV offset on both channels after more than 6 months.
Guess there might be something in keeping it simple and overengineering...
Regards,
Mark
Yeah, chucked it on a scope. Got some noticable ringing at 10Khz square wave, but no real high frequency runaway. Certainly nothing I would think could damage speakers. Ehh, close enough.
If I get really motivated one day I'll chuck some extra bypass caps directly on the op-amp pins.
Anyway, it will be my brothers speakers that get damaged, not mine.
I forgot to mention in my last post. They had a power surge at my brothers place a while ago, due to lightning strike. So I went over to check things out,
Everything fine. Still less than 10mV offset on both channels after more than 6 months.
Guess there might be something in keeping it simple and overengineering...
Regards,
Mark
Hi Mark,
Nice job. I chose ESP for my first amp as well. I built the P101. I went three channels, and two of the three channels worked first try. The other had a bad transistor. Easy fix.
I always recommend Rod's amps to first timers. They go together well and sound good to my ears.
I used Conrads for my amp as well. Sure made building the case easier. I just attached all of the other pieces to them like you did. The shipping makes them a little expensive for me or I would use them for all of my projects. They are very nice indeed.
You mentioned the transformer hums. Is it a mechanical hum or heard through the speakers? Have you tried rotating it a little? Helped with my amp.
Blessings, Terry
Nice job. I chose ESP for my first amp as well. I built the P101. I went three channels, and two of the three channels worked first try. The other had a bad transistor. Easy fix.
I always recommend Rod's amps to first timers. They go together well and sound good to my ears.
I used Conrads for my amp as well. Sure made building the case easier. I just attached all of the other pieces to them like you did. The shipping makes them a little expensive for me or I would use them for all of my projects. They are very nice indeed.
You mentioned the transformer hums. Is it a mechanical hum or heard through the speakers? Have you tried rotating it a little? Helped with my amp.
Blessings, Terry
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