Frank,
I need to fill in what I did yesterday, I have been off and on the PC, I'm not worried about the supply, the slight hum I hear when no music is playing is easily corrected with a CLC arrangement as ABRAX suggested but is not intruding when music is playing.
The mushing is gone and the mid peaking remains, less obstructing and cleaner and tends to reside with more hours playing music but still there.
Caps are lousy and haven’t done much on the chip feeding the satellites. I will explain later what I did thou you already have bits and pieces from the later posts.
Antonio
I need to fill in what I did yesterday, I have been off and on the PC, I'm not worried about the supply, the slight hum I hear when no music is playing is easily corrected with a CLC arrangement as ABRAX suggested but is not intruding when music is playing.
The mushing is gone and the mid peaking remains, less obstructing and cleaner and tends to reside with more hours playing music but still there.
Caps are lousy and haven’t done much on the chip feeding the satellites. I will explain later what I did thou you already have bits and pieces from the later posts.
Antonio
Interesting, if you google the part number without pleomax preceding it you get something completely different! Actually you get a few different sets of PC speakers.
Have you any idea what drivers Samsung use? I know logitech use tang band in some of their speakers.
Have you any idea what drivers Samsung use? I know logitech use tang band in some of their speakers.
Thanks, what my test was about is that the current demand by the subwoofer working strongly highly likely causes too much modulation of the voltage rails elsewhere on the board, overwhelming the satellites' circuitry's ability to reject this as a negative influence - and doing the test will show how bad it is.
In the meantime, everything you do to clean up the supplies will help - nurse those chips as if they are new born babes ... 😀
In the meantime, everything you do to clean up the supplies will help - nurse those chips as if they are new born babes ... 😀
I got the point. I can snip or desolder the cables to the LF speaker and replace it with a 20 Ohm resistor and test the satellites, this way I won’t leave the LF chip flapping.
Yes, need to get to the small chip and clean the area replace all suspect caps, to do this need to desolder most of the cables coming to the plate, all possible only takes time to do it nicely. Lots of hotmelt on those places.
Yes, need to get to the small chip and clean the area replace all suspect caps, to do this need to desolder most of the cables coming to the plate, all possible only takes time to do it nicely. Lots of hotmelt on those places.
If you go that way I would use a much higher resistance, at least 200R say; 20R is still too close to voice coil resistance - I would snip the power feed to the woofer area, say, or the input signal - if you can work out a clean way of doing it.
Strongly recommend not losing the benefit of the hotmelt, after fiddling secure everything down even better than before, if possible.
Strongly recommend not losing the benefit of the hotmelt, after fiddling secure everything down even better than before, if possible.
What I did yesterday was to replace the main dc smoothing filter with the same value (2.2mf) Pana HFS and took away the bypass I had added, the big chip was fed directly from this cap which was about an inch away and the chip did not have the recommended decoupling cap so added a biggy FC 220u with the shortest leads possible directly at the chip pins, this cleared all problems on the low end.
Now pedal notes from the Widor piece are outstanding even when they are played simultaneously they are distinct and full quite amazing for the little woofer, not even my 15 incher from the main system can play them this good (getting carried away? but no), they are two different system, one is near field capable of vibrating the table and the other rattles windows.
The other thing I did was to replace two lytics near the signal input which called my attention for their low value 0.22u (don’t know their function) and manage to replace them with Wimas MKP’s of the same value. That was all, besides staring at the circuit trying to understand it.
All caps look crapy (did I say that before?), would like to change them all if I could.
Antonio
Now pedal notes from the Widor piece are outstanding even when they are played simultaneously they are distinct and full quite amazing for the little woofer, not even my 15 incher from the main system can play them this good (getting carried away? but no), they are two different system, one is near field capable of vibrating the table and the other rattles windows.
The other thing I did was to replace two lytics near the signal input which called my attention for their low value 0.22u (don’t know their function) and manage to replace them with Wimas MKP’s of the same value. That was all, besides staring at the circuit trying to understand it.
All caps look crapy (did I say that before?), would like to change them all if I could.
Antonio
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That's excellent - the first time you experience good quality bass notes coming from a 'nondescript' speaker it does seem remarkable, but, yes, this is all about power supplies - just ask abraxalito! 😀
What I would then typically do is see how far I could push the volume before there was a loss of quality of that bass, and try substantially increasing the 2.2mF figure to see if that improved headroom.
How are the satellites connected to the main box - with plugin connectors, or what? If not hardwired I would suggest trying that.
The satellites seem to have fairly insubstantial footings - I would try Blu Tacking them to the surface, very firmly, so they feel "glued" to the table.
Personally, I would not replace the caps until other things were looked at - I've managed to get very decent sound with pretty junky cap's everywhere, to me it's a secondary consideration.
I will test to double filtering values maybe needing a separate pcb for that (transformer is rather small to add filtering, 20 or so VA), but really not trying to replace the main system 😀 looking to a good near field sys, thou now I’m hearing at a higher vol to these 2Cello guys in concert in Croatia (Arena Pula), 8 hours ago I couldn’t hear to cellos because they sounded like violins on the upper registers, not that much now.
Haven’t mention this but I would like a system that sounds good after 15 min, is that asking too much?
Haven’t mention this but I would like a system that sounds good after 15 min, is that asking too much?
Depends on everything, 😀. I go by very aggressive, driving R&R, this tends to need more "bedding" in time - classical can hit the spot almost straight away, if the right things have been dealt with. Typically, if high current draws are needed - say, recent, highly compressed pop music - this will take the longest time to stabilise, 🙂.
I decided to try again with active speakers.
I chose my very old Videotone MiniMax with perished surrounds on the bass/mid units.
New surrounds fitted.
These are just one step up from PC speakers.
They replay full range reasonably well, if not pushed using a conventional ClassAB power amp.
I decided to make them a mid and treble part of a 3way active.
First guess at 150Hz to 2700Hz for the bass mid unit and >2700Hz for the treble unit.
Chose a pair of low gain 3886 chip amps as the integrated amplifiers.
Moxlite as the LR4 active filter, no EQ as yet.
DC protection on the mid and capacitor coupling on the treble.
First playing on music is showing promise.
Adding a bass only channel makes for a very good music replay as mono only, till I decide if it's worth building the second one for use as desktop monitors.
Making each driver handle ONLY the frequencies it is capable of replaying well seemed the obvious way to maximise performance.
I chose my very old Videotone MiniMax with perished surrounds on the bass/mid units.
New surrounds fitted.
These are just one step up from PC speakers.
They replay full range reasonably well, if not pushed using a conventional ClassAB power amp.
I decided to make them a mid and treble part of a 3way active.
First guess at 150Hz to 2700Hz for the bass mid unit and >2700Hz for the treble unit.
Chose a pair of low gain 3886 chip amps as the integrated amplifiers.
Moxlite as the LR4 active filter, no EQ as yet.
DC protection on the mid and capacitor coupling on the treble.
First playing on music is showing promise.
Adding a bass only channel makes for a very good music replay as mono only, till I decide if it's worth building the second one for use as desktop monitors.
Making each driver handle ONLY the frequencies it is capable of replaying well seemed the obvious way to maximise performance.
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Ohhh, you should try Reason 😉
The syntethisers are very funny...I cannot compose music and with the mouse it's very difficult, but the sounds coming out are...fun!
BTW mine it was just rethoric ! It is obvious that with a recorded medium you can play and re-play a lot of times.
The syntethisers are very funny...I cannot compose music and with the mouse it's very difficult, but the sounds coming out are...fun!
BTW mine it was just rethoric ! It is obvious that with a recorded medium you can play and re-play a lot of times.
https://www.parts-express.com/vifa-tc9fd-18-08-3-1-2-full-range-paper-cone-woofer--264-1062
pair of these as satellites is good enough, ~ 5 liter closed box will go down to round 120 hz or so. 22 usd is a good price for 2 of them.
HTTP 301 This page has been moved
refer to the datasheet, you can bridge 2 channels for sub, and use the other 2 for them satellites.
the chip costs at worse no more than 7 usd.
apart from that it needs some caps and its ready to go.
refer to the datasheet for a delayd turn on circuit, one circuit is needed to delay the amp turn on, the other to drive a relay and delay the power to the chip to make sure the switch on surge of computer psu does not kill the IC.
most probably the satellites alone would provide decent sound for tipical pc uses.
but, wanna go fancy?
https://www.parts-express.com/pyramid-wx85x-8-white-poly-woofer--290-272
40 liter, tuned to 40 hz will give something roughly ~38-40 hz at -3dBL, probably far superior in bass than 90% of computer speakers.
integration with the vifa satellites is a piece of cake, as those roll off them self around 120 hz.
a simple cap paralell to the subwoofer input chanel will make you a sorthof passive line level crossover network that way.
presto you got ~40 hz to 20 khz band, enough power to give reasonable SPL levels.
12 usd for the pyramid drivers. not so bad i guess.
with some scavanging, you can do the 2.1 set for roughly 40 euro.
the samsung system pointed out costs 27 euro.
the difference is, you will spend money on the samsung and end up with something far less than building my suggestion.
allow me to mention, that components where selected in roughly 5 minutes.
probably with a bit more effort one can find a better deal.
or even, instead of a 2.1 system find parts for an alternative stereo bookshelf set.
or just find a suitable fullrange driver to use.
endless number of choices, all far better than a factory made stripped down thing.
pair of these as satellites is good enough, ~ 5 liter closed box will go down to round 120 hz or so. 22 usd is a good price for 2 of them.
HTTP 301 This page has been moved
refer to the datasheet, you can bridge 2 channels for sub, and use the other 2 for them satellites.
the chip costs at worse no more than 7 usd.
apart from that it needs some caps and its ready to go.
refer to the datasheet for a delayd turn on circuit, one circuit is needed to delay the amp turn on, the other to drive a relay and delay the power to the chip to make sure the switch on surge of computer psu does not kill the IC.
most probably the satellites alone would provide decent sound for tipical pc uses.
but, wanna go fancy?
https://www.parts-express.com/pyramid-wx85x-8-white-poly-woofer--290-272
40 liter, tuned to 40 hz will give something roughly ~38-40 hz at -3dBL, probably far superior in bass than 90% of computer speakers.
integration with the vifa satellites is a piece of cake, as those roll off them self around 120 hz.
a simple cap paralell to the subwoofer input chanel will make you a sorthof passive line level crossover network that way.
presto you got ~40 hz to 20 khz band, enough power to give reasonable SPL levels.
12 usd for the pyramid drivers. not so bad i guess.
with some scavanging, you can do the 2.1 set for roughly 40 euro.
the samsung system pointed out costs 27 euro.
the difference is, you will spend money on the samsung and end up with something far less than building my suggestion.
allow me to mention, that components where selected in roughly 5 minutes.
probably with a bit more effort one can find a better deal.
or even, instead of a 2.1 system find parts for an alternative stereo bookshelf set.
or just find a suitable fullrange driver to use.
endless number of choices, all far better than a factory made stripped down thing.
Just finished second round and can tell its sounding pretty good since powering up, not even giving time for caps settle so things will be getting even better.
Today things were centered on the small chip which powers the satellites.
I got the spec sheet for the TDA2822M that matches the pinout so was easier to work. I clipped away two tiny ceramics which were at the rail at both sides of the jumper with the ferrite which is the trace that feeds the small chip and there was a third ceramic, same small size, acting as a decoupling cap at the chip I was laughing. Instead for decoupling I added an FC 100u.
Changed also the output caps for Pana FC 220u, same value as the originals.
Sound now is very focused and nicely integrated, so far not a trace of grittiness or the peaking at mids but need to test other music material to be sure.
Antonio
Today things were centered on the small chip which powers the satellites.
I got the spec sheet for the TDA2822M that matches the pinout so was easier to work. I clipped away two tiny ceramics which were at the rail at both sides of the jumper with the ferrite which is the trace that feeds the small chip and there was a third ceramic, same small size, acting as a decoupling cap at the chip I was laughing. Instead for decoupling I added an FC 100u.
Changed also the output caps for Pana FC 220u, same value as the originals.
Sound now is very focused and nicely integrated, so far not a trace of grittiness or the peaking at mids but need to test other music material to be sure.
Antonio
Oh! We were talking about those DIP amplifiers...I lllllove them!😛
About 1 W in SE and 3 W in BTL configuration.
Strange, I found one which had some strange flat panels as the speakers.
Kynio brand ! I found two minuscule transformers at the output, after the 33uF coupling cap; then I put to service my 32Ω Philips speakers.
The tiny 33uF cap was substituted with a NP one, 47 uF. As well as re-routing the supply PCB traces and letting the new external one (12V@1A woooah)
insert where the suction is, the subwoofer chip.
The sub is still in the making (....) and when I tried the whole system I just
put a 4" in front of a TL line 😎
The lowpass is RCRC so no Op-Amps and the sub driver I put it with the magnet in sight, to limit a little midrange emission (the basket might help).
About 1 W in SE and 3 W in BTL configuration.
Strange, I found one which had some strange flat panels as the speakers.
Kynio brand ! I found two minuscule transformers at the output, after the 33uF coupling cap; then I put to service my 32Ω Philips speakers.
The tiny 33uF cap was substituted with a NP one, 47 uF. As well as re-routing the supply PCB traces and letting the new external one (12V@1A woooah)
insert where the suction is, the subwoofer chip.
The sub is still in the making (....) and when I tried the whole system I just
put a 4" in front of a TL line 😎
The lowpass is RCRC so no Op-Amps and the sub driver I put it with the magnet in sight, to limit a little midrange emission (the basket might help).
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