Suggestions for a Mini Stereo Amp?

[sulretal]

Hey All,

So, I picked up 4 up 4 Klipsch RSX-3 speakers from a local good will for dirt cheap. Here is the link to the speakers: http://www.klipsch.com/rsx-3-bookshelf-speaker

I also have the subwoofer from the Klipsch iFi sound system, but the entire set requires the iDock to control power and function and I do not want to take the risk on the subwoofer not working. The iDock I find on ebay and the internet for around 80 dollars, and it seems a bit too much to risk.

With that said, I have two questions:

1) Does anyone have any suggestions for a nice little mini stereo amplifer? I'm not looking for tons of options, just input and the ability to hook up my speakers. This mini amplifer has really strong reviews, and I am leaning towards this http://www.amazon.com/LP-2020A-Lepa...348968423&sr=1-2&keywords=mini+audio+receiver

Has anyone had any experience with mini amps? This seems like a good one for the price, but I am not sure if it will work with my rsx-3 speakers. Also, the downfall is I have 4 rsx-3 speakers, and this mini amp is only 2 channels (left, right).

Perhaps I could just sell the other two rsx-3 speakers on ebay with the ifi subwoofer (With a return policy of course, I wouldn't want to rip anyone off).

2) Might there be any other way to control the power and volume on this old Klipsch iFi system without the idock? http://www.klipsch.com/ifi-ipod-speaker-system If there is a way to control the volume and turn it on without the control deck, I'd definitely consider keeping the woofer.

I tested all the speakers at a friends house, they sound really good, so I know they function. I don't really need a subwoofer. My apartment is small and I live in a quiet neighborhood, so I'm not trying to have house rattling bass anyway. Was going to use them on my computer.

Sorry for the long winded post. I believe I clarified everything that I needed to. For the TLDR crowd, any suggestions for a mini-amp?


Thank you so much.

 

[givmedew]

Hi, I have owned a custom T-Amp since 2006-2007 I bought the one that had all the rave reviews back then and then gutted it like many did and built my own chassis, psu, matched resistors instead of a volume pot etc.

They sound amazing and only have 1 draw back. Low power. For computer speakers they are PERFECT!!! I power 4Ohm Vienna Acoustics Haydn's which require a ton of power and 4Ohms is very hard on stereo equipment.

According to amazon that thing has a higher wattage than my chip but... that doesn't really mean anything since watts don't exist without a @THD rating so who actually knows what the wattage is with it having the THD rating behind it.

Either way at the distance you will have these speakers I believe that amp will be AMAZING and you will be shocked. Mine creates clear crisp deep bass but when the speakers are only a few feet from your ears it doesn't take a lot of power.

Also the power supply and caps are part of the bass response. If you are good at soldering you can tear that thing apart in a few years and upgrade it if you want to.

 

[Evilsizer]

Check out parts express.com they have some per built amp boards for decent prices. Add a case and power supply with some cabling. They have a 2x100w class d amp for 39.99 then get the volume pot that goes with for 9.99. IMO is a great deal for some thing like that if you don't mind doing the rest of the work. Making your own case has endless possibilities, some like to make their own wood cases for amps for example.

 

[givmedew]

Hey... just did some research on that amp and it is actually more like 7w per channel. Which is plenty. I know it doesn't sound like a lot but most people don't actually have a clue how watts matter. 7w @ 0.01THD vs 14w @10% lol. 20 watts would horrible.

I believe that is the same wattage as my chip was rated at so I think it may be the same chip. It is the same brand.

I do not recommend the D-Class amp though no offense to evilsizer I am sure he knows what he is talking about but a tripath t class chip is going to sound much better. If you where looking to power a subwoofer then I would say have at it.

T-Class amps are d-class but there are differences that make them much better. There are amazing D-Class amps out there and I have no idea wether the one evilsizer recommended is good or not.

What I can tell you is that there are plenty of reviews of TP2020 based T-Amps that are done by audiophile magazines that have plenty good to say about them. Like I said I think it is the same chip that started all the rave and craze when they first came out. They disappeared off the market for a while. I bought mine right when tripath stopped making the or slowed the production of the chips. Since then they have started making them again.

I would def buy that amp you will probably love it.

My amp is beautiful wood box that I found at a thrift store for $10. They create no heat and require so little power that they where originally designed to run off batteries.

 

[Evilsizer]

Well I have never listened to class d or class t amps. I have like the sound I get from chip amps using briangt kits, if I remember correctly the lm3886 ic is a class ab amp. I really do like the quality of sound and found no need to listen to others right now. I only talked about those class d at partsexpress because the seemed like a deal.

Going a chip amp route might be something for you if you can solder.

 

[givmedew]

To the OP are you interested in building this yourself? I didn't think so and for that case the amp you where looking at is great. It also has down the road value if you ever decide you want to build an amp because you can start bye taking that one apart and replacing the cheap parts on it.

If you actually like the idea of building from scratch I would have to say that for computer speakers or any speakers that will be driven from less than 3-4FT you are going to get considerably better sound from that T amp than any other amp 2-3x its price that is not based off a T amp. They provide near Class A only quality at a significantly low power. The bass can be missing on bigger less efficient speakers but thats not the case with your tiny Klipsch speakers. Klipsch is well known for high efficiency although the main reason is for using horns which those don't have but they still claim to be high efficiency. I would like to see the actual number because IMO high efficiency doesn't start till 90DB. The power requirements for efficient compared to non efficient is exponential so if you ever replace those with higher end bookshelves just make sure you are getting 90db or better if you are looking to use with that T amp. Like I said though my speakers are not efficient and my T amp delivers great sound and great bass but the parts that allow the bass to fall off first have been replaced (power supply and capacitors).

At $20 if you buy it and don't like it I will buy it from you for $15 you can just throw it in a bubble envelope LOL. But joking aside that product is actually refundable on Amazon with NO restock fee.

So at least give it a try.

Just remember that with that amp as the power goes up it will quickly encounter the DANGER ZONE! Which is square waves (clipping) and possible damage to speakers.

The bottom line is if it sounds like crap turn it down! If it sounds clear you can turn it up. Set your speakers as small in windows if that is an option for stereo. Not sure if it is or not.

Good luck!

 

[sulretal]

Hey thanks givemedew and EvilSizer! I really appreciate the input. I went ahead and ordered the mini amp I originally looked at. Your advice and all the rave reviews on the unit on the internet made the low price point made most sense!

And you are correct givmedew, I am interested in eventually customizing my own set up, but just wanted something to hold me over/get those speakers I have working.

When in doubt turn it down! Shouldn't be much of a problem for me!

I'll let you know how the product is when I get it Friday!

 

[voodoo do'er]

well if you don't mind rewiring them look into a cmoy or fiio amp

the fiio A1 should do fine
http://www.fiio.com.cn/product/index.aspx?ID=27&MenuID=020301

 

[givmedew]

Hey thanks givemedew and EvilSizer! I really appreciate the input. I went ahead and ordered the mini amp I originally looked at. Your advice and all the rave reviews on the unit on the internet made the low price point made most sense!

And you are correct givmedew, I am interested in eventually customizing my own set up, but just wanted something to hold me over/get those speakers I have working.

When in doubt turn it down! Shouldn't be much of a problem for me!

I'll let you know how the product is when I get it Friday!

Let us know when you get it how it sounds and how you like it. Do a nice little review for us. Also what voltage does it run off of? Is it 12v? If so you should make a connector to go from your PC psu to the amp. The PSU that comes with those things are usually garbage and cause a severe drop in decent bass.

One other thing also if you decide that you do not want the volume knob and want to control the volume from your computer then just turn the volume to the lowest setting that is loud enough disconnect the volume knob leads. Measure the resistance and shoot me a PM I will give you a pair of closely matched resistors.

When I bypassed my volume knob I went through about 100 resistors looking for 2 that where almost identical.

 

[sulretal]

Hey All,

The amp and cords came in thursday, but I just got my internet set up. I'll take pictures and everything in a day or so but I wanted to give a quick review now.


They're very functional! The design is pretty solid for such a cheap device. It is very light(there are holes from screws to hold it in place, which I thought was kind of cool.

I have them powering my Klipsch RSX-3 speakers, and the sound is great. I'm not sure why (maybe it is because my speakers might require more power than the amp can supply), but when I turn the volume knob to max the amp will start turning off and on rapidly. I just assume that the amp can't take the demand. I can turn the volume about 3/4ths of the way to max volume. Which is fine really, because it gets LOUD. Well, relative to my small apartment.

I'll put up pictures if you want later on, and anything else that could sway a buyer from buying or dismissing this little unit. Let me know what you want!

 

[Evilsizer]

Could be not a big enough power supply or the built in protection kicking in trying to save the amp,as far as it powering on/off.

 

[givmedew]

Lower the volume on the computer source and then turn the knob to the max. If it is still turning off it is a problem with the potentiometer or the maybe the pot is fine but the amp chip cant handle that low of a resistance on that side. I do not know if volume pots can send out a direct short or if they are even supposed to I never checked but if they are not supposed to and they do that is a problem. Because if I remember correctly you can not just remove the pot and short that stage you still have to have some sort of resistor.

This is why to me if this behaviors continues with the volume on the computer reduced the problem is probably the pot is creating a direct short or near direct short when it is not supposed to.

Someone who actually knows the exact rules (an electrical engineer) might chime in.

Besides that the other person would likely be correct except I did not know that there was any protection on that amp.

 

[givmedew]

What voltage and amperage is the power supply. Should be a block style not wall wort. Unless its a huge wall wart.

I wanna say that chip is made for 12v if your powr supply agrees you could just wire it into your pc. The original company who distributed these chips made one that went in a blank pci slot and plugged into the 12v supply on a 4pin molex then I just had a 3.5 in and out.

 

[Evilsizer]

going over the data sheet for the amp ic(TA2020) used, it only has overvoltage/undervoltage and overload protection. in the first two instances it would be distorting and in the last the mute would be enabled. which leads me to think it is a psu not having enough current/power for the higher volume.

there are no other types of protection built into the amp ic that would cause it to power down.

 

[givmedew]

going over the data sheet for the amp ic(TA2020) used, it only has overvoltage/undervoltage and overload protection. in the first two instances it would be distorting and in the last the mute would be enabled. which leads me to think it is a psu not having enough current/power for the higher volume.

there are no other types of protection built into the amp ic that would cause it to power down.

Thanks, I thought not, what about the voltage? I think it was originally designed for 8 double a batteries so 12 volts. I am not at home and I am not sure that I have the same model chip as his.

As far as amperage goes as far as this thing is concerned your PSU has unlimited power so if your chip is the 12-14 chip then I would get your power from the PC. Like I mentioned before the original distributor
made one for inside the PC the other was for batteries but came with a 3a PSU (I think). If my PSU is compatible with yours you can have t for the cost of shipping (if I can find it) I built my own years ago.


Edit:

If the supply is not providing enough amperage could it be going into under voltage protection and then coming out of it almost instantly because the voltage comes bacask to range as soon as the draw goes down?

Edit again... I looked up some specs I have a 2024 I don't know the diff maybe it's just older. It is designed for 12v both the 2020 and 2024. A technical review explains without a voltage regulator or a very high output (5a) the voltage drop and the tiny input stage capacitor will cause the bass to fall off quickly after 50hz. 1a is all you need but with a cheap 1a you looses few volts at load. Also something I did not know is that at 4ohms the amp provides 2x the power the speakers I have used where 4 for the jamo's and 6ohm for the Vienna's so if you ever decide to buy new speakers look for 6ohm to play it safer 4ohm if you know for sure you will never connect the speakers to a low or middle end home receiver (not 4ohm stable).

I hope that helps some... If you feel up to it there are 3 capacitors that could use replacements 1 is easy 2 of them may be dangerous to perform (soldering directly to an smd).

Let us know tomorrow how it goes.

 

[Evilsizer]

without knowing the specs of the included powersupply, my first thought is the power supply. if the included one is a 12v x 2amp, that would be 24watts max, meaning each channel would be doing something around 10watts.

yes the amp would go into undervoltage protection if the power supply does not have enough current. when the power supply runs out of current voltage will drop, if it drops enough it should shut off.
http://www.e-ele.net/DataSheet/TA2020.pdf

Protection Ci r c u i t s
The TA2020-020 is guarded against over-temperature and over-current conditions. When the device goes
into an over-temperature or over-current state, the FAULT pin goes to a logic HIGH state indicating a fault
condition. When this occurs, the amplifier is muted, all outputs are TRI-STATED, and will float to 1/2 of
VDD.

Over-temperature Protection
An over-temperature fault occurs if the junction temperature of the part exceeds approximately 155°C. The
thermal hysteresis of the part is approximately 45°C, therefore the fault will automatically clear when the
junction temperature drops below 110°C.

O v e r - c u r r e n t P r o t e c t i o n
An over-current fault occurs if more than approximately 7 amps of current flows from any of the amplifier
output pins. This can occur if the speaker wires are shorted together or if one side of the speaker is
shorted to ground. An over-current fault sets an internal latch that can only be cleared if the MUTE pin is
toggled or if the part is powered down. Alternately, if the MUTE pin is connected to the FAULT pin, the
HIGH output of the FAULT pin will toggle the MUTE pin and automatically reset the fault condition.

Overload
The OVERLOADB pin is a 5V logic output. When low, it indicates that the level of the input signal has
overloaded the amplifier resulting in increased distortion at the output. The OVERLOADB signal can be
used to control a distortion indicator light or LED through a simple buffer circuit.

 

[givmedew]

Well I think you hit it on the head with the PSU. Again to the OP my PSU works and I believe is 3a or more so if you want it just pay shipping. BUT! I still recommend going off your computers PSU or if you have a 12-14v high current power supply from something else then use that. Just make sure you don't wire the plug backwards!

 

[sulretal]

Problem is my primary computer is my laptop. Though! Your suggestions to lower the computer volume (I have been keeping it at 25), and using the volume knob on the amp is working wonderfully. The sound is much crisper and I can turn the knob to max volume.

 

[givmedew]

Problem is my primary computer is my laptop. Though! Your suggestions to lower the computer volume (I have been keeping it at 25), and using the volume knob on the amp is working wonderfully. The sound is much crisper and I can turn the knob to max volume.

Oh I was just mentioning that as a trouble shooting thing. I don't actually recommend that you do that because you will be amplifying noise. You want your computer volume near max to have the highest amount of voltage going through the inputs.