Mini Stereo amp in New Astro City

[NASguy]

Would this work in a NAC?

http://www.amazon.com/PCA2-40-Watt-Ster ... B001P2VV50"

I'm thinking of wiring up the mono sound off Jamma into two RCA jacks, and then plugging the Astro's speaker wires directly into this thing. I'm guessing it will be better quality than stock. Then all I have to do for CPS2 titles and such, is plug in the RCA jacks from the board directly.

It's listed as 40 W of power on each channel at 4 ohms, is this suitable for Jamma and the Astro's speakers?

Can anyone comment if they've already done this? And if so, share the amp they used?

Thanks

[NASguy]

BTW does anyone know what kind of connectors (and where to get them) that the New Astro uses for the speakers?

They're the plastic 4 pronged kind (in a cube). I can't upload images currently or I'd post a pic.

[Cageman]

The NAC uses AMP UP (or AMP type B) connectors for sound. First check to see if your NAC doesn't already have an AMP fitted (beneath the PSU):



Be aware: you cannot just connect a JAMMA output to an amplifier that uses Line-level inputs. JAMMA audio is amplified; each standard JAMMA PCB has an onboard amplifier.

[NASguy]

The NAC uses AMP UP (or AMP type B) connectors for sound. First check to see if your NAC doesn't already have an AMP fitted (beneath the PSU):



Be aware: you cannot just connect a JAMMA output to an amplifier that uses Line-level inputs. JAMMA audio is amplified; each standard JAMMA PCB has an onboard amplifier.

Yeah I don't have that amp in my cab.

Ah, I understand now, so using the stereo amp for non-stereo jamma boards is usless. I'll have to get a spare AMP UP connector to make a stereo adaptor for, and just unplug the one connected to the Jamma harness for stereo games.

[FrancoB]

I have the same cab/PSU as you and I posted a similar thread [here] which you will probably see as its just been bumped to the top

I'm going to try to use that small 12v amp I have for it. I was going to run it off the 12v from the PSU but I noticed it only outputs 1.5a @12V and I'm not sure how much 12v amperage Jamma boards use and if there will be enough left over for the amp. I do have a small mains powered 12v PSU which I may use instead.

In regards to the AMP connector I presume you are talking about this one under the CP:



I have been looking for a female four pin AMP connector myself but without much luck. When taking that photo just now I realised that I/we could use a 12 pin AMP connector and just populate the 4 pins in the middle.



Do you have the tools to crimp the AMP pins? If not I could ship a populated connector over with your Negatron.

[NASguy]

I have the same cab/PSU as you and I posted a similar thread [here] which you will probably see as its just been bumped to the top

I'm going to try to use that small 12v amp I have for it. I was going to run it off the 12v from the PSU but I noticed it only outputs 1.5a @12V and I'm not sure how much 12v amperage Jamma boards use and if there will be enough left over for the amp. I do have a small mains powered 12v PSU which I may use instead.

In regards to the AMP connector I presume you are talking about this one under the CP:



I have been looking for a female four pin AMP connector myself but without much luck. When taking that photo just now I realised that I/we could use a 12 pin AMP connector and just populate the 4 pins in the middle.



Do you have the tools to crimp the AMP pins? If not I could ship a populated connector over with your Negatron.

I sourced the AMP connectors our cabs have for the speakers/stereo. Akihabarashop sells them, and the pins. No clue what you'd use to crimp, though. Good question.

I am going to put that on the backburner for now as I don't actually own any stereo PCBs at the moment... Was going to order a CPS2 recently, but it fell through.

I have a 2.1 stereo amp I use for my 360, and I just plug that into the wall or back of the cab.

[Cageman]

In regards to the AMP connector I presume you are talking about this one under the CP

What I meant was using a 4-pin AMP connector to connect the amplifier (existing or new one ) to the speakers of the NAC. It is then just a matter of disconnecting the JAMMA output, and connecting the Amplifier output to the connection Akuma is holding is in hand right here: http://forum.arcadeotaku.com/download/f ... &mode=view"

[Cageman]

I sourced the AMP connectors our cabs have for the speakers/stereo. Akihabarashop sells them, and the pins. No clue what you'd use to crimp, though. Good question.

For people in Europe: starcab.net sells them as well: http://www.starcab.net/index.php?cPath=90_201".

About crimping: I just use pliers, and solder the wire to the pin.

[FrancoB]

In regards to the AMP connector I presume you are talking about this one under the CP

What I meant was using a 4-pin AMP connector to connect the amplifier (existing or new one ) to the speakers of the NAC. It is then just a matter of disconnecting the JAMMA output, and connecting the Amplifier output to the connection Akuma is holding is in hand right here: http://forum.arcadeotaku.com/download/f ... &mode=view"

I was talking to NASguy but that does appear to be the better connector to use, rather than the one in the CP, thanks

I sourced the AMP connectors our cabs have for the speakers/stereo. Akihabarashop sells them, and the pins. No clue what you'd use to crimp, though. Good question.

For people in Europe: starcab.net sells them as well: http://www.starcab.net/index.php?cPath=90_201".

About crimping: I just use pliers, and solder the wire to the pin.

I just added the bits to the cart. The order comes to about three euros, shipping is over 13 euros I think just get a 12pin one from Andy or Craig.

I got the P-706 crimp tool from Akishop. It's ridiculously overpriced for what it is but it does crimp very well. I have used it on AMP pins, JST RA pins and AMP Mini Mate-N-Lok pins with [borat]great sucess[/borat].

[NASguy]

A little update on the solution I found. I ended up using this:

http://www.pyleaudio.com/itemdetail.asp?model=PCA1"

It seemed like a smart solution since it outputs stereo at 4ohms, the same as the New Astro City speakers.

I got it to use with CPS2, and the unit has male RCA connections with about a foot of length coming off the back (for the audio input, instead of traditional female ones), so it plugs right into the CPS2 A board with no additional cable needed. The whole unit fits on top of the Astro PSU and for the moment have it plugged into the back of the cab. I have plans to wire this into the 100v AC connector coming off my Astro PSU, since it's for the sega audio amp I don't have anyway.

All in all, it sounds great on the New Astro, and I don't know what else you could want, was less than 30 dollars.

Perfect little solution.

[Sobriquet]

Interestingly I'm about to tackle this same issue after a hiatus of over a year. I have the AMP connectors, pins and a crimper.
What I lack is an amp for my mini-ITX PC -> J-PAC (actually the sound will probably go nowhere near the J-PAC since I want stereo).

I was just planning to hackup a pair of amplified PC speakers, but if I can find a suitable small amp that would be preferable. My NAC definitely doesn't have the stereo amp underneath the regular PSU Anyone know if it can simply be added?

[NASguy]

Interestingly I'm about to tackle this same issue after a hiatus of over a year. I have the AMP connectors, pins and a crimper.
What I lack is an amp for my mini-ITX PC -> J-PAC (actually the sound will probably go nowhere near the J-PAC since I want stereo).

I was just planning to hackup a pair of amplified PC speakers, but if I can find a suitable small amp that would be preferable. My NAC definitely doesn't have the stereo amp underneath the regular PSU Anyone know if it can simply be added?

I wouldn't bother with that old sega stereo amp unless it was already there, it's so huge and it's from the 90s.

Just buy a better one.

[leonk]

I recently purchase a 40 watt class T amp from eBay for my NAC/Mame machine, here's what I did:

Since the original PSU is no longer working (turned off), I needed an AMP inside the machine to power the original speakers. I ordered a small TA2020 mini amp from eBay (~20$US + shipping from China + another 12$ for a high end power supply for it that looks like a laptop power adapter). This mini amp takes as input 8mm connector (same as what comes out of a PC sound card) and connects to Left/Right +/- speakers.

The PC side was easy, the speaker side is where it got "fun". Using the NAC schematics I was able to identify the left/right +/- speaker wires (the schematics include color codes!). Even though NAC has 2 speakers, there's a yellow molex connector inside the cab (not the one under the control panel!) that converts it into mono .. from the factory. I disconnected the connection here, and spliced back into stereo into the mini-amp.

Hope this helps.

[NASguy]

I recently purchase a 40 watt class T amp from eBay for my NAC/Mame machine, here's what I did:

Since the original PSU is no longer working (turned off), I needed an AMP inside the machine to power the original speakers. I ordered a small TA2020 mini amp from eBay (~20$US + shipping from China + another 12$ for a high end power supply for it that looks like a laptop power adapter). This mini amp takes as input 8mm connector (same as what comes out of a PC sound card) and connects to Left/Right +/- speakers.

The PC side was easy, the speaker side is where it got "fun". Using the NAC schematics I was able to identify the left/right +/- speaker wires (the schematics include color codes!). Even though NAC has 2 speakers, there's a yellow molex connector inside the cab (not the one under the control panel!) that converts it into mono .. from the factory. I disconnected the connection here, and spliced back into stereo into the mini-amp.

Hope this helps.

I would advise against using that Lepai Tripath TA2020 amp in the NAC, it is rated for 8ohms only, so you will fry that amp pretty fast since the NAC uses 4ohm speakers. I know this because people on parts express have reported it fries with 4ohm speakers.

You will need to wire the speakers into the amp "in series" to get around this, but you'll take a volume level hit.

Just use a 4ohm amp, all the Pyle Audio ones are 4ohm, and better than the Lepai I might add.

[Sobriquet]

You will need to wire the speakers into the amp "in series" to get around this, but you'll take a volume level hit.

And lose Stereo to boot...

[PrincessPrinPrin]

I would advise against using that Lepai Tripath TA2020 amp in the NAC, it is rated for 8ohms only, so you will fry that amp pretty fast since the NAC uses 4ohm speakers. I know this because people on parts express have reported it fries with 4ohm speakers.

You will need to wire the speakers into the amp "in series" to get around this, but you'll take a volume level hit.

The NAC wiring diagram shows the speakers are wired in series.

[Sobriquet]

The NAC wiring diagram shows the speakers are wired in series.

Well, they are with the default JAMMA harness - but if you want to get stereo you're going to need to change that. They're wired independently to the AMP plug though.

[NASguy]

I would advise against using that Lepai Tripath TA2020 amp in the NAC, it is rated for 8ohms only, so you will fry that amp pretty fast since the NAC uses 4ohm speakers. I know this because people on parts express have reported it fries with 4ohm speakers.

You will need to wire the speakers into the amp "in series" to get around this, but you'll take a volume level hit.

The NAC wiring diagram shows the speakers are wired in series.

Only for mono.

You don't wire stereo speakers to an amp in series unless you're trying to match ohms.

The NAC is one 8ohm load for mono to both speakers, and two 4ohm loads for stereo (obviously). If you run those speakers on a cheap 8ohm stereo amp you'll fry it with the quickness.

[leonk]

I would advise against using that Lepai Tripath TA2020 amp in the NAC, it is rated for 8ohms only, so you will fry that amp pretty fast since the NAC uses 4ohm speakers. I know this because people on parts express have reported it fries with 4ohm speakers.

Maybe it's a problem with the parts express amps (not known to have the highest quality around, even though I purchase items from them sometimes).

If you look at the actual specs of the TA2020:

Tripath TA2020-20
Output Power 2 x 20W @ 4ohm, 2 x 12W @ 8ohm
Signal-to-Noise Ratio (SNR) 98dB
Dynamic Range 98dB
IHF-IM Distortion 0.1% @ 1W, 4ohm
THD Distortion
0.03% @ 9W, 4ohm
0.1% @ 10W 4ohm
0.1% @ 6W 8ohm
10% @ 23W 4ohm
10% @ 13W 8ohm
Power Efficiency 81% @ 20W, 4ohm, 88% @ 12W, 8ohm
...

you will notice that it is rated for 4ohm, and tested at 4ohm. I've been playing with it for a few weeks now, with no issues. The Tripath chip is only 5% of the equation, the other components, PCB design, parts quality all play a part to make/break an amp. I wouldn't worry about running the amp with 4 ohm speakers in stereo.

[NASguy]

That is interesting to know, sounds like it should be fine.

Not a fan of the cheap build quality and some other things I've heard about it, though. And running off 12v is a pain for wiring it into a cab.