I consider the sanwu 3118 a hot candidate to make my 0.53x Karlsonator with dual Vifas an active speaker.
For a single 8 Ohm driver you should consider the sanwu TDA8932.
That thing sounds fantastic costs half a 3118.
Freies verschiffen! Digitale platinenmodul 35 watt mono verstrkermodul High power TDA8932 geringer stromverbrauch in Bekanntmachung: die neue Tracking-Nummer fr china post gewhnliche kleine Paket plusnur verfolgen sie wurden schiff aus aus Andere
Thanks, same question for them, would it be enough with a pot between them and the source for volume control?
It's not like I don't have enough amps but you had to show us this so now I have to buy some. How can you pass up a Sanwu amp for $3.22? Is Sanwu the new name on quality nice sounding low cost board amps? The 3118 I have is very nicely made.
TPA3118D2
I don't get the calculation.
(And you edited your post)
(For 9k go for a 5k pot, gives 2k5 in center postition in parallel to 9k. -> ~2k that needs to be driven worst case. With 100R output impedance from a modern source I don't see problems here. Modern portable media-players are made for loads down to 16R (8-32R). Of course, "older" equipment might have trouble but normally don't need 36db of gain.
I don't get the calculation.
(And you edited your post)
(For 9k go for a 5k pot, gives 2k5 in center postition in parallel to 9k. -> ~2k that needs to be driven worst case. With 100R output impedance from a modern source I don't see problems here. Modern portable media-players are made for loads down to 16R (8-32R). Of course, "older" equipment might have trouble but normally don't need 36db of gain.
Last edited:
TPA3118D2
Do I? Still not understanding that sentence.
1/4, right.
Factor 10-20 is 90-180k, do you meant fraction?
Pots:
http://www.diyaudio.com/forums/anal...osing-potentiometer-passive-preamplifier.html
Do I? Still not understanding that sentence.
1/4, right.
Factor 10-20 is 90-180k, do you meant fraction?
Pots:
http://www.diyaudio.com/forums/anal...osing-potentiometer-passive-preamplifier.html
Last edited:
Using my Sanwu TDA8932 boards in a hot-rodded version of the Swan D1010 to drive the (4ohm) bass/mid, dynamics are to die for all tricked out. Even though that's below the recommended impedance in BTL, this chip delivers in spades. Supply is nominal 20V unreg.
I also have a few 3118 boards on order to compare.
Attachments
Last edited:
You bet, I also have a plan to use multiple boards with output transformers to get more power.... The idea being since output transformers provide isolation, why not stack multiple secondaries in series to get more power? I'll probably kick off with 4 boards and see where I get to.
Look forward to hearing how they work for you.
The heatsink is just being used for mechanical mounting, I've not done anything about the thermals yet. That's because its not yet put back in its case. If I encounter overheating then, I may experiment with thermal washers. The heatsink is there because the original bass/mid amps in this speaker are D1875 (a Chinese LM1875 clone) and they get way too hot because the heatsink is entirely internal. So fitting the classDs kills two birds very neatly with one stone.
I've done a lot of component changes to the active XO board. About the only thing I've not changed is the TL084 opamps, they're still there. But I multiply up the impedances of all the RC networks doing the filtering. For example there was a peaking 2nd order high pass filter using 100nFs, they're down to 2n2s (NP0 SMT ceramics) now, with the corresponding resistor values about 45X larger. This does wonders for dynamics, I'm amazed that el-cheapo TL084s can sound this good.
I also think the fact that the volume control is just 47k is limiting the dynamics of my sources so I'm working on an input buffer (discrete transistor).
I've improved the decoupling on the tweeter amp - you can see some of the additional ceramics underneath the PCB if you look carefully. That amp's a TEA2025 and runs from a separately regulated 12V, the regulator's using the main heatsink.
Last edited:
Basic questions on the TDA8932 mono amp
Hello:
1) I notice on this board that the "input" connections have no provision for ground. My question is where to attach a ground wire which would normally run from the two RCA's to the input on a board.
2) I have been reading a bit about this "master"/"slave" stuff, but I don't fully understand it or how to implement it. Assuming a power supply for each board, is it mandatory to make one board the master and the other a slave? Or, can I just ignore this ...hook up normally?
3) It would be nice to only use one power supply but I am not certain how that would wire up either. Danielwritesbac was indicating some sort of diode setup. Could anyone possibly sketch out a diagram of that?
Thanks everyone,
Mark
[I said:
Hello:
1) I notice on this board that the "input" connections have no provision for ground. My question is where to attach a ground wire which would normally run from the two RCA's to the input on a board.
2) I have been reading a bit about this "master"/"slave" stuff, but I don't fully understand it or how to implement it. Assuming a power supply for each board, is it mandatory to make one board the master and the other a slave? Or, can I just ignore this ...hook up normally?
3) It would be nice to only use one power supply but I am not certain how that would wire up either. Danielwritesbac was indicating some sort of diode setup. Could anyone possibly sketch out a diagram of that?
Thanks everyone,
Mark
Got two Sanwu TPA3118 blue amps today, and tried them immediately - a simple "dual mono" configuration, using a stereo pot on the input, powered by a single 19V brick SMPS...
Nice.... very nice...
I also added a 1500uF electrolytics to each module, and got some "fattening" of the bass (or at least it seems to me...).
Listening to various types of music, to get a feel for the sound.
All in all, I'm quite happy with these.
BUT (there's always a "but"...) - I'm getting pronounced hiss in the middle third of the pot travel - it's pronounced most in the very middle of pot volume (50K stereo blue Alps).
Now, this is not the first TPA31xx amp that does this - I've had the same experience lately with "dual chip" TPA3116...
Unfortunately, I only have 50K pots, but will try with a 20K one, as I recall that drmord said it might alleviate this problem.
So, the first third of the pot travel (volume) is hiss-free, the middle third has hiss, and the last third (up to the max. volume) is again his-free. I tried several pots (all 50K), and it's the same...
I even connected each Sanwu module to its own SMPS, but no dice - hiss is a bit less pronounced, but it's still there...
Also, I do get some turn-on pop.... Since I intend to put these in separate enclosures - as pure monoblocks - I'll probably have to either use the provided "mute" contacts or try to find out how to implement the "Giancarlo mod" (electrolytic cap + resistor).... which won't be easy - those are all SMD parts, and VERY small
But, to sum it up - it sounds really nice, and with some added electrolytics on the power input (just across the power contacts, 1500 uF), it has plenty of bass when needed.... I might even add some more (2200 or even 3300 uF total), to see if this changes anything...
Nice.... very nice...
I also added a 1500uF electrolytics to each module, and got some "fattening" of the bass (or at least it seems to me...).
Listening to various types of music, to get a feel for the sound.
All in all, I'm quite happy with these.
BUT (there's always a "but"...) - I'm getting pronounced hiss in the middle third of the pot travel - it's pronounced most in the very middle of pot volume (50K stereo blue Alps).
Now, this is not the first TPA31xx amp that does this - I've had the same experience lately with "dual chip" TPA3116...
Unfortunately, I only have 50K pots, but will try with a 20K one, as I recall that drmord said it might alleviate this problem.
So, the first third of the pot travel (volume) is hiss-free, the middle third has hiss, and the last third (up to the max. volume) is again his-free. I tried several pots (all 50K), and it's the same...
I even connected each Sanwu module to its own SMPS, but no dice - hiss is a bit less pronounced, but it's still there...
Also, I do get some turn-on pop.... Since I intend to put these in separate enclosures - as pure monoblocks - I'll probably have to either use the provided "mute" contacts or try to find out how to implement the "Giancarlo mod" (electrolytic cap + resistor).... which won't be easy - those are all SMD parts, and VERY small
But, to sum it up - it sounds really nice, and with some added electrolytics on the power input (just across the power contacts, 1500 uF), it has plenty of bass when needed.... I might even add some more (2200 or even 3300 uF total), to see if this changes anything...