WIRING HELP for a Super Duper Nice Girl ;)

[theAnonymous1]

Thanks for the correction; I don't know why I was thinking the ground sleeve is the same length on both.

 

[underwurlde]

No worries, like I said, I initially thought EXACTLY the same thing and like you, was about to post to say as much - then the penny (or cent) dropped.

A

 

[kittygirl]

Ok guys, I did a google search and came up with this pdf on how to wire stereo to mono. Seems like it would work to me, what do you think??

If the attachment doesn't work, here is a direct link

http://www.intelix.com/.../152_Athena_http://www.intelix.com/media/tech_notes/152_Athena_how_to_wire_stereo_to_mono.pdf

 

[theAnonymous1]

Ok guys, I did a google search and came up with this pdf on how to wire stereo to mono. Seems like it would work to me, what do you think??

That's showing how to passively sum two unbalanced signals using resistors and feed them into a balanced input. Not really what you're going for here.

Unless you rewire your guitar cord with a stereo plug like underworld suggested, there's no way to avoid using a switch if you want both stereo 1/8" and 1/4" mono inputs on the amp.

 

[russc]

I'd suggest you make a short patch lead, 1/4" mono female jack to 1/4" or 1/8" stereo male jack. Converts any standard guitar lead to use with your amp without hacking up your guitar lead ie you can still use guitar lead with any guitar amplifier.

 

[kittygirl]

That's showing how to passively sum two unbalanced signals using resistors and feed them into a balanced input. Not really what you're going for here.

Unless you rewire your guitar cord with a stereo plug like underworld suggested, there's no way to avoid using a switch if you want both stereo 1/8" and 1/4" mono inputs on the amp.

Thanks for clearing that up Anonymous1.

I am thinking I would like to try adding a switch. I did a google search and came up with a bunch of what I think is irrelevant info. Could you point me in the right direction where I could find a wiring diagram to accomplish this.

Thanks again!!!

 

[kittygirl]

Oh yeah, another quick question. This little amp requires a 12V 2A power supply.

I happen to have one on hand, however the input plug doesn't fit. My question, can I just cut of the adapter plug and solder the leads to the underside of the board? Basically bypassing the outlet on the board? Or should I unsolder the outlet and solder directly to board itself.

Thanks again,
K

 

[Mooly]

Oh yeah, another quick question. This little amp requires a 12V 2A power supply.

I happen to have one on hand, however the input plug doesn't fit. My question, can I just cut of the adapter plug and solder the leads to the underside of the board? Basically bypassing the outlet on the board? Or should I unsolder the outlet and solder directly to board itself.

Thanks again,
K

Either is fine. Make sure you get the polarity right and be sure to avoid any possibility of wire "whiskers" that can caue a short if the lead can move... or it's tears at bedtime

A dab of silicon sealer (not the quick cure that gives off acetic acid) can be usefull for securing leads and avoiding cable strain.

 

[kittygirl]

Thanks Mooly!

I just realized I have 2 power supplies, I don't want to cut both of them.....Sooooo, i am wondering which one I should use.

One says "Switching Power Supply"
One says "Class 2 transformer"

Any advantages/disadvantages to using one over the other?

How do I determine correct polarity?

Thanks

 

[underwurlde]

"Switching Power Supply" or Switched Mode Power Supply or SMPS uses a higher switching frequency than the mains frequency to transform mains voltages into a more useable voltage. Their advantage is that they are more efficient, smaller and lighter than their 'normal' counterparts that use a simple large transformer to do the same job. Their disadvantage is that due to the higher switching frequencies they employ produce more electrical noise (oh and they are more complicated and hence more to go wrong on them). Personally I love them.

The other "Transformer type II" is I guess a more traditional type set up: transformer > rectifier > regulator style: less electrical noise but at the expense of being heavier, bulkier and less efficient.

In the 'audio world', SMPS's are frowned upon because as I've mentioned above they produce more electrical noise due to faster switching frequencies, but one could argue that these frequencies far exceed the audible range our ears can hear.

Also, the amplifier you've chosen uses switching techniques so that in itself is another controversial 'thing' in the audiophile world: Personally I have no beef with these types of 'Class D' amps and use them myself along with a SMPS to provide power for it.

--------------

I will sketch something up for your question above, but in the mean time do you have a manufacturers part number for both the 1/4" and 1/8" jacks you intend to use?

Andy

 

[kittygirl]

Underwurlde, you are the best!!! Thanks for taking the time to explain that.



I had to read that like 3 times, LOL. I guess I will just try them both and report back.

Well I found these....... that seem like a great deal

http://www.taydaelectronics.com/3-5mm-mono-enclosed-socket.html

6.35mm 1/4" Mono Chassis Socket / Jack

Thank you, thank you, thank you!!!!!

 

[theAnonymous1]

Be careful with that type 2 power supply. It is most likely unregulated and rated for 12V at a specific current draw. The unloaded voltage can be much higher and you run the risk of frying that poor little chipamp.

 

[kittygirl]

Well that doesn't sound good. Is there a way to tell from the specs if this is safe to use on this little amp?

I just took a picture of the tag on the transformer and have attached it.

Here are the specs written out

GlobTek Inc.
Class 2 TRANSFORMER
CLASS 2 NOT WET. CLASS 3 WET
P/N WD1E2000S760K-N
MODEL : GT-357-12-2000D
INPUT: 120V AC 60Hz 35W
OUTPUT 12V DC 2000mA

UL US LISTED

Looks to be Center Positive

 

[underwurlde]

^ Just a warning from TheAnoymous1, just in case & he was quite correct to make you aware of that - lots of different ways to make a power supply: some good, some bad. That is not to say ALL "Type II Transformer" PSUs are inherently 'bad', BUT some could be!

----------

Anyway, it's far easier for you (IMHO) to change that mono jack plug on your guitar to a stereo one, but if you REALLY don't want to go this route then...

Hopefully I have this right:

You'll need now a DPDT (Double Throw, Double Throw) switch to do what you want.

Andy

PS, Hawaii??? Lucky, lucky!
"Summer" (I use the term lightly) here in the UK has so far consisted of 3 months of solid rain. Sunny today though, but at work

 

[kittygirl]

^ Just a warning from TheAnoymous1, just in case & he was quite correct to make you aware of that - lots of different ways to make a power supply: some good, some bad. That is not to say ALL "Type II Transformer" PSUs are inherently 'bad', BUT some could be!

----------

Anyway, it's far easier for you (IMHO) to change that mono jack plug on your guitar to a stereo one, but if you REALLY don't want to go this route then...

Hopefully I have this right:

You'll need now a DPDT (Double Throw, Double Throw) switch to do what you want.

Andy

PS, Hawaii??? Lucky, lucky!
"Summer" (I use the term lightly) here in the UK has so far consisted of 3 months of solid rain. Sunny today though, but at work

ANDY.......
Again, wow, you are so quick to respond, and again sooooo incredibly insightful and informative. Thank you for taking time out of your day to draw up this diagram. I can't thank you enough, I wouldn't have known where to begin.

A question.... so from your diagram I need a 1/4" STEREO jack
6.35mm 1/4" Stereo Chassis Socket / Jack 3 Terminals

Not a Mono jack like I was thinking
6.35mm 1/4" Mono Chassis Socket / Jack

Is that right?

I appreciate TheAnonymous1 warning me on the Class 2, I definitely don't want to fry the board.

Yup, I am an Island girl, born and raised. Aloooooha.

3 month of rain, then working on a sunny one, yuk. I am sending you some sunshine love from Hawaii!!

 

[underwurlde]

"Is that right?" Yes.

My thinking is for you to keep everything STEREO (and why not?) and ONLY when you plug your mono-forcing guitar mono jack plug in, then flick the switch to put it into mono enabled input mode, but with 'mono sounds' coming out of BOTH speakers.

Andy

 

[underwurlde]

And if using screened cable to wire this lot up, then:

Andy.

 

[chris661]

"Summer" (I use the term lightly) here in the UK has so far consisted of 3 months of solid rain. Sunny today though, but at work

We've had warm and humid for the past few days now. The rain's arrived and the air is starting to clear. Lovely.

About power supplies...

I have the same amplifier board as the one you're using. I found that using a 12v (can't remember if its transformer or switch mode) wall supply gave a high-pitched whistle sound from the speakers. I suspect the switching frequency of the amplifier was interacting with the power supply. Its worth measuring the output of the power supplies before plugging them in - I have a (different) 12v supply that's more like 19v off-load. This would make the amplifier very unhappy, and the magic smoke may come out.
If I had to bet on one of them, I'd go for the switch mode one - its more likely to be regulated.

I also use 7.2v remote controlled car batteries to power mine - no whistling sound, and one charge will give ~2 hours at rather loud levels. >4 hours if the volume's at a more sane level.

Another thing!
Watch your speaker impedances. My amplifier is driving a 4ohm speaker per channel, and (when cranked right up) cuts out when bass comes along: it detects too much current (or maybe heat), and shuts down.

Have fun, though - these are really cool boards to play with.

Chris

Edit

Wow! that's a great buy. Better buy two or more. At $7 a pop, the QA/QC dept won't be well funded.

Let us know how these amps rock.

They're decent enough. Get an off-the-shelf bookshelf speaker, put one of these in, add a decent battery and you've got a decent (plenty loud) portable speaker.

 

[Mooly]

Thanks Mooly!

I just realized I have 2 power supplies, I don't want to cut both of them.....Sooooo, i am wondering which one I should use.

One says "Switching Power Supply"
One says "Class 2 transformer"

Any advantages/disadvantages to using one over the other?

How do I determine correct polarity?

Thanks

You've had plenty of replies I see... some good advice there.

A meter (DVM on volts) will show the polarity. Always check polarity before powering up the amp by measuring the voltage with the PSU unconnected to the amp.

If the meter reads say 12.7 volts then the PSU lead that the Red meter lead goes to is positive. If the reading was -12.7 then the DVM is showing that the Black meter lead is connected to what is really the supply positive. Obviously make sure the meter leads are correctly fitted (right way round) first

A non technical way of determining the type of PSU is to go off its weight. A 12 volt 2amp SMPS will be light (like a laptop PSU) and a 12 volt "linear" type with conventional transformer will be much heavier.

An SMPS type is usually tightly regulated and the voltage is the same at no load or full load.

A linear type without regulator will show a higher voltage when no or little current is drawn.

 

[kittygirl]

The wiring diagram worked perfectly!!!!!! THANK YOU, THANK YOU, THANK YOU!!!

Ok, so i just received a few more of these little guys. I also have some leftover parts from Radio Shack because I couldnt wait to get started on this one.

I have 3.5mm jacks and wire. I don't have a prewired 3.5mm audio cable that I can cut like I did for the first one. So I have a couple of questions about wiring the 3.5mm 1/8" jack.

On this board is a mounted 3.5mm jack with 5 pins. Like this one

10 Pcs DIP PCB Mount 5 Pins Female 3.5mm Stereo Audio Jack Plug Socket | eBay

The ones I bought from Radio Shack are 3 pins. Like this one
Lot of 5 Stereo 3.5mm 1/8" Panel Mount Jack | eBay

I have wire and I can't seem to figure out which wires go to which pins to make it work on both channels.

I assume I would only have to hook up 3 wires. Or do I have to run jumpers to the remaining 2 pins to make it work?

Thanks in advance
Kianna