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PostPosted: 01 Aug 2017, 03:47 
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Joined: 09 Oct 2012, 19:43
Posts: 290
Location: Vancouver Canada
Certainly there are sockets that will do what you ask. Here is the data sheet for the UAC3552A.
http://www.datasheetcatalog.com/datashe ... 552A.shtml

Page 27 of 29 shows the sch for a typical setup. It shows how the 3.5mm socket is wired to switch from digital to analogue when a jack is plugged into the socket.
There are more than one reason i mentioned using a switch.
1- Using a switch allows the addition of more than one analogue source. One switch (perhaps toggle) would select analogue / digital
and then a rotary switch to select different analogue sources. (Comp, CD, TV, Tape, etc)
2- I have not had much luck with the selection of 3.5mm sockets in the market. There are many different types/styles sold but only a few really stand the test of time. When they start going bad having the dig/anlog switching as part of it's function is just an added pain.
3- Having the switching done automatically when a source is plugged into the socket is cool and all but i just prefer to have control over what is going on myself. (Call me old fashioned)
4- Using a switch allows for more than one type of socket to be used for the source input. 3.5mm is common now days but so is RCA, and 1/4" phone jacks.

Have a look on some of the bigger company's sights for 3.5mm jacks and sockets. They come in many configurations from no switches to 1, 2 and sometimes 3 or 4 switches engaging when the plug is inserted. Companies like Digi-Key, Mouser, have a good selection of these at reasonable prices.

It's all just personal preference.


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PostPosted: 03 Aug 2017, 00:48 
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Joined: 18 Jul 2017, 05:14
Posts: 9
Thank you Laurie for your detailed replies! I too like having more control than "automation", and I like the idea of having multiple inputs, something that I hadn't thought of myself.

In a non UAC3552A related issue, I purchased this power adapter from Amazon, having read that other customers have had issues, to try for myself since I can sent it back for a refund. There is a very audible, high pitched sound coming out of both the woofer and satellites when plugged in. I will be sending back the adaptor, but I need to find a solution to power the speakers. Does anyone have any information on a power adapter that might be better? I have seen others that buy the plug and wire it to a laptop adapter for example. Is there anything that I should look out for?


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PostPosted: 03 Aug 2017, 22:23 
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Joined: 09 Oct 2012, 19:43
Posts: 290
Location: Vancouver Canada
The wine from your power supplies is coming from the type of power supply you are using. In the old days !&$#$#&&*%* a power supply was a transformer, (to reduce the 120vAC down to 5, 12, or whatever voltage is desired). Then a bridge rectifier to change the AC (alternating current) into DC (direct current). Then a capacitor to smooth the DC ripple out so it was as pure DC as could be achieved. Like a battery. That is what is most desired << pure DC >>, ""especially for audio"".
Lately however, a new type of power supply called a "high-speed switching power-supply" has become very popular. This PS is much more efficient at changing the voltage from 120vAC to a lower voltage, usually 5V. It is popular because of it being the main voltage for USB devices, cell phones etc. It is good to have standards. Anyways,,, these supplies are much cooler and much smaller/lighter since they do not require a transformer to scale the 120V down to 5, 12, 24v etc. They do this by rectifying the AC into DC then into a switching circuit which turns on and off to fill the output capacitors to the desired voltage. Monitor circuits are also present to monitor the output voltage and adjust the switching SPEED to regulate (hold) the voltage at exactly the stated voltage. eg: 5v. They do however suffer one common problem and that is the switching on and off is done at a very high speed. This switching gets into the output supply lines and is "heard" especially when used to power AUDIO circuits. Having said this, not all switching power supplies suffer from this problem but certainly most of the cheaper ones bought on eflay and imizon do. For digital processors and circuitry, this buzz is mostly ignored, but, for audio it can be a nightmare making the quietest audio amp sound like it is going to explode at any moment.
I will mention that the old pwr spply's start with a ripple of 60Hz (low) and the newer hssp's have higher ripple speed of anything from 20,000Hz and up. That is why it sounds like a high pitch wine.
There is a way to quieten this buzz by putting more capacitance in the output of the supply but this presents another problem as these supplies must conform to standards which dictate that anything the supply is driving must not create a surge (demand) of more than 100mA when first plugged in. (or the supply will shut off) This limits the size of capacitance that can be used at the output. At 5v this means 100uF capacitance would be about all that can be added. (( if an HSSP can take more than 100uF load at startup I would be suspicious of it's ability to operate properly at all, driving expensive equipment!! )). The buzz can be heard (ears), seen (oscilloscopes), and filtered out by using inductors, bypass caps, ferrite beeds, and other rf filters, but this takes experience that comes with an engineering degree and then some experimenting.
The solution is to look for a regular type of power supply that uses transformer, diode bridge rectification, and capacitors to filter the ripple (noise, buzz, etc) out of the supply. This type of supply will give you a clean quiet DC supply voltage like a battery. And if there is any buzz present it can be filtered out by adding a large cap at the output without worrying about it shutting off due to the turn-on surge being too much. These older supplies are popular and come in many more voltages than the HSSP's and since they are mostly being phased out of existence, are cheep. Most second hand stores have a box of them on the floor somewhere in the store and would sell for pennies. You will need to be aware of 3 things when looking. 1- An output equal to what you are needing, (5vDC). 2- it must be capable of supplying enough current to your device. (500mA / 750mA / 1000mA etc). 3- the plug on the end to plug into your device must match.
What you have is a " high speed switching power supply ".
What you want is a "mechanical power supply" also called linear supplies.
There are millions of schs for both supplies on the net and good explanations of how they work etc, but you get the general pic.

I hope this helps and if you have any more questions do not be scared to ask.
Laurie

P.S. I should add before i am shot down in flames by people having equipment running (audio) which does use HSSP's that those are "Dedicated circuits" designed and built for that circuit and not ones which are bought cheeply on the market.
There are other reasons for PS wine to get into the output of HSSP supplies having to do with floating output stages and thus ground loops etc but i won't even get into these as your problem is mostly what i have stated. I see the supply you have shown is running at 16vDC. Any linear supply of around 12, 15, 16 volts will work.


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PostPosted: 04 Aug 2017, 03:39 
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Joined: 18 Jul 2017, 05:14
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This helps alot! Thank you once again! My guess is that I will purchase the Power DIN 3 pin plug, wire it to a standard 5.5mm DC Power socket for example, take that to the a local electronics store where they sell a multitude of power supplies, tell them what I need and test before purchasing. As the main reason for not purchasing locally was that no one had this plug in stock.


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PostPosted: 04 Aug 2017, 12:58 
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Joined: 09 Oct 2012, 19:43
Posts: 290
Location: Vancouver Canada
Sounds good. As long as you get a linear power supply. Then the wine goes away. AS for the voltage i have looked again and the UAC is wanting 5-volts so there must be a 5 volt regulator on the PCB for it. Therefore i would say the full 16 volts are being used to drive the power amps for the spkrs. I don't know which amp is on the board for the spkrs but this means even though you are needing 16 volts for an input you could get away with using a more popular (more readily available) 12, or 15 volt supplies (linear supplies). I would not go any higher in voltage however than what is asked for without further looking into the tolerance of all the chips on the PCB.
Most power supplies will come with 2.5 mm barrel plug.
If you can see what the number is on the amp IC package then we get the data sheet and see what the voltage range of those chips is, and, you may be able to get an 18 volt supply, which is the next common value up (but over the 16 specified). It would also be good to know which regulator IC is being used for the 5-volt supply. That would give info on what it's range of input tolerance is.


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PostPosted: 05 Aug 2017, 10:23 
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Joined: 18 Jul 2017, 05:14
Posts: 9
There is a picture of the the PCB here if its of help. On the image it says that it is a TDA8510J.


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PostPosted: 06 Aug 2017, 02:47 
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Joined: 09 Oct 2012, 19:43
Posts: 290
Location: Vancouver Canada
A quick google search says Digikey has them. Well good news and bad news. They are available for replacement if ever you need. Now for the bad news. The spec sheet says max voltage is 18v. From looking at the board i see an inductor and caps for filtering the power rails, the inductor would bring the voltage down a bit not enough to feel safe supplying any more than the 16volt suggested. So i would say go for 15 or 16 volt linear power supply.


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PostPosted: 06 Aug 2017, 03:56 
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Joined: 18 Jul 2017, 05:14
Posts: 9
Good to know! I will go ahead and order the plug then.


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PostPosted: 08 Oct 2017, 12:41 
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Joined: 08 Oct 2017, 12:21
Posts: 1
Hello everyone,
gotoid did you get through with the analog input hack?
I wonder if UAC3552A pin 33 is directly connected to ground or by means of a resistor.
Looking at PCB pictures looks like it is connected by means of a R.
Did you get a chance of checking it?

I'm going to try the hack as well trying to save the USB functionality.


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PostPosted: 12 Oct 2017, 08:15 
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Joined: 18 Jul 2017, 05:14
Posts: 9
I haven't completed it, other projects got in the way.
Unfortunately I don't know about pin 33. Sorry I wasn't able to assist.


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