Andypairo said:
I can't but agree.
I always smiled when reading people's complaints about those SMD parts being so tiny... until I got my 41Hz Amp3 kits.
Now I'm a bit scared
Will let you know how things go.
Cheers
Andrea
My AMP2 should be comming in soon, I wonder how much work can be done in the oven.
SMD are small but, are really workable.
If I have been able to do it, complete newbe, anyone can do it!
I even used a basic gun type 30W soldering iron, but very fine tip,
no soldering station or anything fancy.
Another tool needed is just a tweezer, without which no amp3.
By the way Nuuk, thanks for the link for stepped attenuator.
The only thing is to find metal resistors. Remember I'm in mauritius.
If I have been able to do it, complete newbe, anyone can do it!
I even used a basic gun type 30W soldering iron, but very fine tip,
no soldering station or anything fancy.
Another tool needed is just a tweezer, without which no amp3.
By the way Nuuk, thanks for the link for stepped attenuator.
The only thing is to find metal resistors. Remember I'm in mauritius.
Nuuk said:Hi MrDodo,
The cost of real ebony over here would be more than the cost of the amp!But it looks very good.
How about making a stepped attenuator. If you made that AMP-3 kit, making an attenuator will seem easy in comparison! You can read how to make one here .
Some info here too.
http://www.goldpt.com/compare.html
http://home.comcast.net/~0fficeboy/attenuator/photos/photo_3.html
Nuuk said:
I'm certainly no expert in these matters so wouldn't like to say. As you read on my page, I did use four of the 8080's to get 24 volt rails for the GC.
Could you get a 48v SMPS? I'm sure they must make them.
I already have a few 48V SMPS, I just don't know whether a different one would also work like that or not. Seems like I need to pull PS out of my old computers and just try them out.
I've put many different SMPS's in series, most of which came from old PC's. The most important thing to to remember is you MUST disconnect the AC ground from the ground of the supply or things will quickly turn nasty. Also, if theres a pot to adjust the voltage, try and get the supplies as closely matched as possible before putting them in series.
I think using two 48v SMPS's to make a 48-0-48 supply is an awsome idea for the AMP2.
I think using two 48v SMPS's to make a 48-0-48 supply is an awsome idea for the AMP2.
Andypairo said:
I can't but agree.
I always smiled when reading people's complaints about those SMD parts being so tiny... until I got my 41Hz Amp3 kits.
Now I'm a bit scared
Will let you know how things go.
Cheers
Andrea
After a afternoon dedicated to smd soldering (with some difficulties on the Tripath chip because of the too big iron tip) my 1st AMP3 is now playing some music.
Will soon make a shootout with my regulated, OPA627 buffered GC and with my just completed Mauro Penasa "ref" amp.
Cheers
Andrea
Just finished my Amp 1B kit and wanted to rave about the sound a bit. I am blown away. Dynamic, open, transparent and excellent soundstaging are some words that come to mind.
As far as the kits are concerned: I was very impressed by the speed with which I received my kit. I am also impressed by the very professional way that the kit was packaged and the components were marked. Anyone with a moderate amount of soldering experience would be able to build this kit without to much difficulty.
Regards
Dirk
As far as the kits are concerned: I was very impressed by the speed with which I received my kit. I am also impressed by the very professional way that the kit was packaged and the components were marked. Anyone with a moderate amount of soldering experience would be able to build this kit without to much difficulty.
Regards
Dirk
Flux is the Key
I started modding one of the Sonic Impacts I have lying around for use as a kick-around integrated amp.
As I was replacing the SMD feedback resistors, I kept on having a problem with the solder flowing too thickly and balling up at the ends of the resistors and even dragging the resistors off kilter when the iron was removed. This was with the ultra-thin rosin core Radio Shack silver bearing solder and an ultra-fine Hakko tip.
I had this problem with another SI (my first experience soldering SMD), and I was afraid I'd end up struggling, again, and spending a lot of time fiddling about just to get a questionable joint.
Then I recalled a suggestion on the board that suggested that flux was required, even with flux core solder.
I pulled out my tube of paste flux and dabbed a tiny bit on the SMD resistor contacts. The solder flowed much easier and soldering was actually pretty easy!
Well, I never had this problem with through-hole sized components, as the solder surface tension was low enough for this, so these trials with soldering SMDs are like baby steps for me.
Thanks to all who posted suggestions. I now feel much more confident that I could build the AMP3 without too many disasters.
Best,
KT
I started modding one of the Sonic Impacts I have lying around for use as a kick-around integrated amp.
As I was replacing the SMD feedback resistors, I kept on having a problem with the solder flowing too thickly and balling up at the ends of the resistors and even dragging the resistors off kilter when the iron was removed. This was with the ultra-thin rosin core Radio Shack silver bearing solder and an ultra-fine Hakko tip.
I had this problem with another SI (my first experience soldering SMD), and I was afraid I'd end up struggling, again, and spending a lot of time fiddling about just to get a questionable joint.
Then I recalled a suggestion on the board that suggested that flux was required, even with flux core solder.
I pulled out my tube of paste flux and dabbed a tiny bit on the SMD resistor contacts. The solder flowed much easier and soldering was actually pretty easy!
Well, I never had this problem with through-hole sized components, as the solder surface tension was low enough for this, so these trials with soldering SMDs are like baby steps for me.
Thanks to all who posted suggestions. I now feel much more confident that I could build the AMP3 without too many disasters.
Best,
KT
I have just finished an Amp 3 over the weekend, before that i did a fair bit of modding a SI. The Amp3 is easilt worth thr effort, in my opinion it is cleary in it unbroken in state better than my modded Sonic Impact. I can also say that while no where near as easy as saying building a BrianGT chipamp kit it is doable. I have only really been into the whole diy audio scene for abotu 5 months and of course this was the biggest challege i have coem across so far. Go the whole thing together in a maybe 4-5 hrs. One thing to say is absolutely do no try and solder the indivdual lead on the chip. This is close to impossible. The trick is to use plenty of flux, i use a pen, solder to opposing cornersto align the chip. Then just solder all the legs on one side in one go. then using so braid which you have coated in flux remove almost all the solder.
Another thign i found was to use plenty of heat, if not with all those pins and pads and solder you will be on the pads too long and heat up the chip. Try to get the iron hot, i used my 50wat iron on the max setting, and did the desoldering in stages letting the chip cool down between it. Eventually you end up with what look like really clean solder joint, now is the time to get out a magnifiying glass a terbble check all the legs before giveing the thing any juice.
On my first attempt i had one pins non connected, it was the 5v lead out so the amps was dead, thought i had killed it with too much heat, 20 mins later and much prodding with a multimeter and i found the duff lead.
Anyway sorry gone on a bit, the amp3 is greta in stock form and i will have to do a few mods on the capacitors.
Do it!!
Another thign i found was to use plenty of heat, if not with all those pins and pads and solder you will be on the pads too long and heat up the chip. Try to get the iron hot, i used my 50wat iron on the max setting, and did the desoldering in stages letting the chip cool down between it. Eventually you end up with what look like really clean solder joint, now is the time to get out a magnifiying glass a terbble check all the legs before giveing the thing any juice.
On my first attempt i had one pins non connected, it was the 5v lead out so the amps was dead, thought i had killed it with too much heat, 20 mins later and much prodding with a multimeter and i found the duff lead.
Anyway sorry gone on a bit, the amp3 is greta in stock form and i will have to do a few mods on the capacitors.
Do it!!
Hi Nuuk,
How goes, yeah i have the amp3 running in my main setup at the moment using your buffer/PSU design in my preamp. Sounds really good and its only got some cheap maplin caps in for the 20,000uf (recommend somwhere) caps. Since i couldnt get any good one in the centre of london and was in a hurry i tired using 18*1000uf slashed together using some mains cable. It works fine but I am thinking about getting somthing better in there, they are just maplin stndard caps which are BC 037 series.
What have you used, and what do you think might be a good choice for some premium(ish) caps, to me in england unless you are willing to pay about £30 on starget from farnell or even more for black gates from hifi collective or audio com there seems little choice. The only really cheapish options seems and array of Panasonic FC since they are so cheap and everyone seems to thinking they are pretty good. Any other ideas?
What voltage are you using your at, my SMPS it set at 12.1v but i can see a trim pot near where the wire come out so i might try adgusting up to around 14v
Take care anyway and hope you are enjoying the amp3 as much as i am, thinking with a little tweaking it could be the amp i settle on.
Oh my ofset was nearly identical to yours, 115mv one side and 20ish the other, any ideas if this might be a problem long term?
Phil
How goes, yeah i have the amp3 running in my main setup at the moment using your buffer/PSU design in my preamp. Sounds really good and its only got some cheap maplin caps in for the 20,000uf (recommend somwhere) caps. Since i couldnt get any good one in the centre of london and was in a hurry i tired using 18*1000uf slashed together using some mains cable. It works fine but I am thinking about getting somthing better in there, they are just maplin stndard caps which are BC 037 series.
What have you used, and what do you think might be a good choice for some premium(ish) caps, to me in england unless you are willing to pay about £30 on starget from farnell or even more for black gates from hifi collective or audio com there seems little choice. The only really cheapish options seems and array of Panasonic FC since they are so cheap and everyone seems to thinking they are pretty good. Any other ideas?
What voltage are you using your at, my SMPS it set at 12.1v but i can see a trim pot near where the wire come out so i might try adgusting up to around 14v
Take care anyway and hope you are enjoying the amp3 as much as i am, thinking with a little tweaking it could be the amp i settle on.
Oh my ofset was nearly identical to yours, 115mv one side and 20ish the other, any ideas if this might be a problem long term?
Phil
Phil, you may not want to hear this, but after all your hard work on the pre-amp, I think that the class-T amps sound better with just a volume control! 
I'm using mine with a single SMPS with (snubbered) 10K cap across the output. One of the guys that bought the same SMPS from me says he finds the sound better with no cap on the output!
So your question on caps may be irrelevant. But FWIW, I don't think Starget are anything to write home about, BG's (for me) don't justifiy the expence, FC's are good for the money and if I was going for top PSU caps, I would use DNM Slitfoils. In fact, I'm that busy at present that I hadn't even thought to try one of my Slitfoils on the SMPS!
Interesting that you had the same offset figures as I did. I am also wondering about using an amp with so much offset long-term so perhaps one of the 'experts' can advise us on that point!
I'm nearly ready to make comparisons between all the class-T amps that I have here but after my initial reservations, I think that one of them will take over duties from the GC!
I'm using mine with a single SMPS with (snubbered) 10K cap across the output. One of the guys that bought the same SMPS from me says he finds the sound better with no cap on the output!
So your question on caps may be irrelevant. But FWIW, I don't think Starget are anything to write home about, BG's (for me) don't justifiy the expence, FC's are good for the money and if I was going for top PSU caps, I would use DNM Slitfoils. In fact, I'm that busy at present that I hadn't even thought to try one of my Slitfoils on the SMPS!
Interesting that you had the same offset figures as I did. I am also wondering about using an amp with so much offset long-term so perhaps one of the 'experts' can advise us on that point!
I'm nearly ready to make comparisons between all the class-T amps that I have here but after my initial reservations, I think that one of them will take over duties from the GC!
Interesting,
Yeah i was starting to suspect the same myself, i had been testing my various T-amps with just some coda 7 and either a old cd67 or a ipod in my spare room, before finally sticking them into the main system and something did sound quite as good sound stage wise with my larger floor standers. The sound stage seems a little smaller using the preamp compared to without. Your right though my preamp took me longer than any of the other amps to build and tweak so yeah a bit gutting, and to build another without, well my heart just sinks at the prospect. At least the PSU can be used for a phone amp at some point!!
Ok i will go with some FC's then i think, for starter, i am not using full range speakers so i have a feeling the extra capacitance might help.
What value of snubber are you using after your 10.000uf cap?
Be very interested to read your final assement of the kits available, might leave of my modding and pre-amps type stuff till after since i will inevitable end up trying what you suggest.
Take care
phil
Yeah i was starting to suspect the same myself, i had been testing my various T-amps with just some coda 7 and either a old cd67 or a ipod in my spare room, before finally sticking them into the main system and something did sound quite as good sound stage wise with my larger floor standers. The sound stage seems a little smaller using the preamp compared to without. Your right though my preamp took me longer than any of the other amps to build and tweak so yeah a bit gutting, and to build another without, well my heart just sinks at the prospect. At least the PSU can be used for a phone amp at some point!!
Ok i will go with some FC's then i think, for starter, i am not using full range speakers so i have a feeling the extra capacitance might help.
What value of snubber are you using after your 10.000uf cap?
Be very interested to read your final assement of the kits available, might leave of my modding and pre-amps type stuff till after since i will inevitable end up trying what you suggest.
Take care
phil
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