Hello all;
Just wanted to display my 1st point to point wired amp.It was built because I had this transformer when rectified gave me +20-0-20 dc. This is the bottom of the voltage scale for this chip and it definitely works; has good volume.
Most likely about 20-25 watt/channel 8 ohm. With 10r accross the outputs and the inputs shorted I get 5.1,6.2 mv offset. The feedback resistor is 10k set by 428r to give a gain of about 24. The input caps are .47uf phillips[yellow caps]. I can say this is fun to do and it is playing "the nutcracker" as I type. Just using some old test speaks now.
The case itself is small; 8" long, 7" high,4.5" wide. The homemade stacked heatsink hardly gets warm at all; most likly due to the low power. This type of amp may be perfect for hi-eff. speakers.
will post an assembled pic later.
p.s. I want to give credit to Mick F.-his guide helped me a lot.
cheers
doggy
Just wanted to display my 1st point to point wired amp.It was built because I had this transformer when rectified gave me +20-0-20 dc. This is the bottom of the voltage scale for this chip and it definitely works; has good volume.
Most likely about 20-25 watt/channel 8 ohm. With 10r accross the outputs and the inputs shorted I get 5.1,6.2 mv offset. The feedback resistor is 10k set by 428r to give a gain of about 24. The input caps are .47uf phillips[yellow caps]. I can say this is fun to do and it is playing "the nutcracker" as I type. Just using some old test speaks now.
The case itself is small; 8" long, 7" high,4.5" wide. The homemade stacked heatsink hardly gets warm at all; most likly due to the low power. This type of amp may be perfect for hi-eff. speakers.
will post an assembled pic later.
p.s. I want to give credit to Mick F.-his guide helped me a lot.
cheers
doggy
Attachments
ship in a bottle
Thanks inguz, I really meant to build your amp but I sort of got side tracked and built this instead.But I can understand the satisfaction of trying something different; especially when you get lucky and it turned out better than could have been expected. This little amp belts out no lack of bass or dynamics. I am using a 95 db driver which is required with lower power. I boosted the capacitance to about 13,600 uf per side; it was all a tight fit, I had to measure all my available space. It's about the size of a kid's lunchbox. toal cost for this project was about $80. out of pocket.
listening to "grateful dead live"
cheers
doggy
Thanks inguz, I really meant to build your amp but I sort of got side tracked and built this instead.But I can understand the satisfaction of trying something different; especially when you get lucky and it turned out better than could have been expected. This little amp belts out no lack of bass or dynamics. I am using a 95 db driver which is required with lower power. I boosted the capacitance to about 13,600 uf per side; it was all a tight fit, I had to measure all my available space. It's about the size of a kid's lunchbox. toal cost for this project was about $80. out of pocket.
listening to "grateful dead live"
cheers
doggy
Attachments
sagarverma:
I guess I should say "mini enclosure' by my standards. It's all in there, no outboard power supply. Also some caps were not of the compact type. most likely it could be smaller. This was difficult enough for me to do and I had to shift some parts around to make it all fit.
The bonus is: again, to me it sounds dam good; I can only compare it to what else I have around. I have been burning it in with 10r 10 w resistors. I do have a scope but not in use.
I polished the bronze with some brasso and sealed it with some furn. wax.
cheers
doggy
I guess I should say "mini enclosure' by my standards. It's all in there, no outboard power supply. Also some caps were not of the compact type. most likely it could be smaller. This was difficult enough for me to do and I had to shift some parts around to make it all fit.
The bonus is: again, to me it sounds dam good; I can only compare it to what else I have around. I have been burning it in with 10r 10 w resistors. I do have a scope but not in use.
I polished the bronze with some brasso and sealed it with some furn. wax.
cheers
doggy
Attachments
plate
Well this was left over from some fabricated lighted enclosure for some expensive condos at Whistler B.C. I got this from Brenco Industries here in B.C. but I believe the supplier was Alaskan copper and brass. I would check out your local specialty alloy fab. shops; I am sure they could steer you right locally. this was a little less than 1/8" thick. It can be cut with a table saw, info. is on the Russ W. preamp thread.
cheers
doggy
Well this was left over from some fabricated lighted enclosure for some expensive condos at Whistler B.C. I got this from Brenco Industries here in B.C. but I believe the supplier was Alaskan copper and brass. I would check out your local specialty alloy fab. shops; I am sure they could steer you right locally. this was a little less than 1/8" thick. It can be cut with a table saw, info. is on the Russ W. preamp thread.
cheers
doggy
Thanks speaker, I strive to do unique work as best as I can. kerosene pot?...hmm, might make a nice novel case. I think I saw were somebody used a kid's metal lunchbox for a case, one of those older ones.
It's all about having fun with this hobby. I can say I have learned more lately by doing this p2p amp. I f you have access to a table saw, you can make precision cuts
I can say again that this 3886 chip works with lower voltage. I wanted to try this trafo. because it is tamradio which I suspect has some connection to tamura of japan-known for quality output trafos. for tube amps.
cheers
doggy
It's all about having fun with this hobby. I can say I have learned more lately by doing this p2p amp. I f you have access to a table saw, you can make precision cuts
I can say again that this 3886 chip works with lower voltage. I wanted to try this trafo. because it is tamradio which I suspect has some connection to tamura of japan-known for quality output trafos. for tube amps.
cheers
doggy
Attachments
turkey tonite!
Just wanted to post some observations: lower voltage works fine; I will try low voltage(within reason and good size va-400 for next project-most likely plitron. My view is that the ps is very important. In this amp I had a few different caps and the sequence was to feed 2- 220uf-450volt caps[from the total cap. supply] feeding the 100uf caps on the pins,by-passed with10nf-200v each. Call it luck, call it synergy but it works very well. Also a lot has to be said for p2p style construction which allows short paths. pcbs are neater but perhaps a smd version would have some benefits-if the difficulty of soldering smd can be mastered. Also some experimentation with the feedbck circuit and values. The home-made heatsink works great.
cheers
doggy
Just wanted to post some observations: lower voltage works fine; I will try low voltage(within reason and good size va-400 for next project-most likely plitron. My view is that the ps is very important. In this amp I had a few different caps and the sequence was to feed 2- 220uf-450volt caps[from the total cap. supply] feeding the 100uf caps on the pins,by-passed with10nf-200v each. Call it luck, call it synergy but it works very well. Also a lot has to be said for p2p style construction which allows short paths. pcbs are neater but perhaps a smd version would have some benefits-if the difficulty of soldering smd can be mastered. Also some experimentation with the feedbck circuit and values. The home-made heatsink works great.
cheers
doggy
Attachments
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