I have a pair of bookshelf speakers currently being driven with a miniDSP crossover and a pair of ACA amps. The amps are moving on to my main speaker project and I need 4 channels of amplification for this system. The ACA amp is more than sufficient in terms of power (10w) and fidelity. I'd like to avoid a design that has high power consumption during idle times - i.e. I assume all Class A designs.
Following the instructions and putting the ACA together was not hard for me, but I can't say I have proven that my skills and knowledge are much more advanced than that.
If there is some sort of DYI/kit that could achieve my goal here I'd like another project.
Thanks for any thoughts.
Following the instructions and putting the ACA together was not hard for me, but I can't say I have proven that my skills and knowledge are much more advanced than that.
If there is some sort of DYI/kit that could achieve my goal here I'd like another project.
Thanks for any thoughts.
What impedance drivers are you using?
Currently I have a favorite cheap class B, the LJM MX50SE (I have 3 pairs at the moment). Can be built as a kit or purchased ready built. Works best for 8ohm woofers.
LJM audio MX50 SE Power amp kit Stero Amplifier kit DIY | eBay
Ok for tweeters too, but for tweeters I would recommend the version with (fake?) Sanken output transistors, it sounds nicer in the treble, but costs more.
Assembeld LJM MX50 SE Amplifier Board 2SA1295 2SC3264 100W+100W ( 2 Channle AMP) | eBay
No big heat sinks needed for these, especially if you are not using a lot of power. They need very low idle current.
I'm sure there are a lot of kits, including class D (no heat).
Currently I have a favorite cheap class B, the LJM MX50SE (I have 3 pairs at the moment). Can be built as a kit or purchased ready built. Works best for 8ohm woofers.
LJM audio MX50 SE Power amp kit Stero Amplifier kit DIY | eBay
Ok for tweeters too, but for tweeters I would recommend the version with (fake?) Sanken output transistors, it sounds nicer in the treble, but costs more.
Assembeld LJM MX50 SE Amplifier Board 2SA1295 2SC3264 100W+100W ( 2 Channle AMP) | eBay
No big heat sinks needed for these, especially if you are not using a lot of power. They need very low idle current.
I'm sure there are a lot of kits, including class D (no heat).
Ok, that's a great starting poiint, thank you. Seems like quite a few comments on these forums about those devices.
The speakers are the Dennis Murphy version of the OkaraII i.e. the OkaraOW1. The tweeter is the Hiquphon OW1 and Vifa P13WH the tweeter is listed as 8 ohms and I am pretty sure the P13 is as well. The original passive crossover is gone of course.
The speakers are the Dennis Murphy version of the OkaraII i.e. the OkaraOW1. The tweeter is the Hiquphon OW1 and Vifa P13WH the tweeter is listed as 8 ohms and I am pretty sure the P13 is as well. The original passive crossover is gone of course.
I'm planning to use four of these to drive 4pcs 6,5" Vifa C17 woofers in MTM speakers. They sounded great for bass with them, and also great with some simple 8 ohm 8" speakers I have in the workshop. The real surprise was when I first connected them to the workshop speakers to test the amps, I never heard the speakers sound so good. Made me think I should do something more with them.
For treble I'm looking to use something class A, and for the subwoofers I still don't have a definite candidate.
Conclusion: for bass I would definitely recommend them, for treble you could probably find better candidates, but they are ok with some nicer output transistors. I even tried paralleled output transistors, and that made treble sound smoother IMO. You should add bias adjust. Maybe some more people will come with more suggestions too.
Have fun with the project!
For treble I'm looking to use something class A, and for the subwoofers I still don't have a definite candidate.
Conclusion: for bass I would definitely recommend them, for treble you could probably find better candidates, but they are ok with some nicer output transistors. I even tried paralleled output transistors, and that made treble sound smoother IMO. You should add bias adjust. Maybe some more people will come with more suggestions too.
Have fun with the project!
There is a superbly sounding class B amp (12W/8R) called "Micro Mite" by G.Randy Slone described in his book "The Audiophile's Project Sourcebook". It is a descretely built design, output stage being complementary feedback employing a good short circuit protection network. I have built one and used for quite some time without any issues. Additionally there is also a separate circuit for turn-on delay, dc protection with led indication to make sure an accidental fault does not fry the speakers. Power supply demand is +/-18Vdc, two 2,200uF of filter caps for one channel and some scrap piece of aluminum to act as a heatsink.This project suggestion is good for acquiring experience in fabricating your own pcb's and drawing them also. I recommend Express PCB.
Thank you Lojzek. That looks like an interesting and for me, challenging option. I have to admit feeling a bit like a fraud when I tell people I built the ACA amps since I really have little idea of the practical implementation. I mean I understand the basics of electricity, components, amplification as a concept but zero ideal why we use a cap with this value here and that resister there etc.
I'll look into that book and decide if its something I could realistically take on.
I'll look into that book and decide if its something I could realistically take on.
May want to look into the TI EVM's, not sure if they've had another sale on them (look around?) but you can get 4 channels from one for a very reasonable cost and something from the 32xx series will provide you a *lot* for not much $$. Definitely a bit more powerful than what you need but their idle power is hard to beat.
3244 is one of the lower power, but I don't think it necessarily has lower gain, I'd probably recommend the 3251 if paying the same price. Add one quality 36V SMPS and desolder the bypass tabs for the cap coupling and use it as a 4x SE board. (All of this is in the EVM manual, and ask if you need help)
http://www.ti.com/tool/TPA3244EVM#buy
3244 is one of the lower power, but I don't think it necessarily has lower gain, I'd probably recommend the 3251 if paying the same price. Add one quality 36V SMPS and desolder the bypass tabs for the cap coupling and use it as a 4x SE board. (All of this is in the EVM manual, and ask if you need help)
http://www.ti.com/tool/TPA3244EVM#buy
Simple answer is for the same price and same gain (G= 20 db = 10x) and EVM cost, the 3251 is capable of more power, and, more importantly, staying further away from where its distortion starts to rise. Lastly, should your needs change later, "more power" is always great for a subwoofer amp.
I believe the 3244, 3245 and 3251 are more similar than different albeit with increasing power, whereas there were some different compromises made for the 3255, which is the high power boy. I've only listened to the 3255's which I'm happy with for whatever it's worth.
I believe the 3244, 3245 and 3251 are more similar than different albeit with increasing power, whereas there were some different compromises made for the 3255, which is the high power boy. I've only listened to the 3255's which I'm happy with for whatever it's worth.
Oh wow, thanks for waking my memory up. I just salvaged some Hypex UcD180 modules. Honestly, I didn't even really know what they were till I looked them up just now. Looks like I already had my project and I didn't even know it!
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