ac1308 has 1uF in outputfilter, YJ copy has 680nF, PSU chipdecoupling is different too, both too far from chip, ac1308 little higher nF's. But YJ is famous for putting different values on pcb, so who knows, ac1308 comes with fake brand electrolytics too
Thanks irribeo for that good info. I was going to order a couple of the YJ ac1308 boards, but think I'll hold of until after I hear the HiAmp Ultimate. The YJ's are on sale BTW - Maybe they are closing them out so they can sell a new improved (copy) version.
Any idea what I would lose if I ran an AudioBah green board on 8 ohm speakers? I'll be using these on my super efficient HF horns in an active setup. If I only lose some power I could live with that. Losing sound quality would not be good!
Cheers,
Rod
Any idea what I would lose if I ran an AudioBah green board on 8 ohm speakers? I'll be using these on my super efficient HF horns in an active setup. If I only lose some power I could live with that. Losing sound quality would not be good!
Cheers,
Rod
@nwboater: If you use a mismatched inductor value / speaker impedance combination, the result is a non-linear frequency response.
YJ has sale all the time, browse few hundred/thousand posts in this thread😀
Outputfilter will peak a little sooner and a little more with higher impedances, because ac1308 has very low filterfrequency that will boost below 20khz too.
Outputfilter will peak a little sooner and a little more with higher impedances, because ac1308 has very low filterfrequency that will boost below 20khz too.
Ok thanks for info on Inductor affect. Guess I will for sure forget Audiobah board - darn it!
Cheers,
Rod
Cheers,
Rod
it is actually the 1uF capacitor that lowers ideal impedance and cutoff frequency, not the inductor, the 22uH could be good choice
I used the Audiobah green board with my nominally 8 ohm speaker and it worked fine. The original YJ red board utilzes 22 uH inductors and I preferred the sound of Audiobah. Personally I do not think the difference between 22 and 10 uH inductors matters that much in real world. Your speakers probably dominate the sound character of the whole system.
Regards,
And the plot thickens!
Thanks for that. It seemed odd that there are so many people using the Audibah board that some are probably using them with 8 ohm speakers.
My speakers use Active EQ in our HTPC and this amp will be used for the HF horns. I already calibrate our system to the room using REW and the DSP in JRiver Media Center. If there is some minor frequency response aberration it should just get adjusted out when I calibrate.
So along with ordering the HiAmp board I will order an Audiobah green board. These amps are all so cheap compared to traditional stuff that it's really possible and fun to do some experimenting. I'll then be able to compare a Blue YJ, the HiAmp Ultimate and the Audiobah green all unmodded. Will report the results here.
Cheers,
Rod
Neat to see an amp that claims the bootstrap snubber mod as a key feature. The price on the HiAmp is kind of steep for a board only. I think a fully boxed SMSL 36a pro is a better value and has bootstrap snubber. It is only 25watts but that is fine for most uses.
For a lot of people the SMSL is a great bargain. In our case their volume control would present a problem. When you power up their amp the volume sets itself at a low level - not where you last used it. I am using it in our 5.1 system with 3 of the speakers as 2 way with Active EQ. So each time I powered up I would have to reset the volume on several amps. Not a workable scheme. Les H pointed this out earlier in this thread. It's a real shame they chose that volume scheme!
Cheers,
Rod
You're talking about the SMSL SA-60 which uses the TPA3116 chip and has the IC-based volume control.
The SMSL SA-36 Pro uses the TPA3118 chip (hence the 25wpc rating), but features a straight forward potentiometer volume control.
audiobah with 8ohm speakers (in reality most of times 20 ohm for high frequencies) will lift treble from 5khz, filterfrequency for low volumelevels around 30khz, higher levels more towards 40khz, doesn't matter if you like the brighter sound, it just isn't your speakers sound, its the amplifiers behavior with impedances like your speaker (Lo_Tse example)
so it works fine, just a little brighter🙂
so it works fine, just a little brighter🙂
I think that volume knob problem is the TPA3116 version, not the TPA3118 model which is the 36A Pro - just a a basic pot and not rotary encoder like the 3116. Am I mistaken?
Here is image of 3118 - looks like a standard pot - and lack of an op amp for volume control:
Here is image of 3116 - obviously a rotary encoder for volume:
Btw, has anyone seen this amp on Amazon, what variant is this? I like ordering from Amazon if possible.
http://www.amazon.com/SMAKN%C2%AE-TPA3116-Amplifier-Board-Class/dp/B00KCEHS54/ref=sr_1_1?ie=UTF8&qid=1419956186&sr=8-1&keywords=tpa3116d2
Seems like a nice compact board with candydrop tantalums on the LC filter, and film caps on inputs, SMD ceramics on bootstraps.
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Is this board any good? The schematic posted by Perceval is the standard (non-EVM) one used by 95% of manufacturers - meaning no bootstrap snubber circuit.