Any chance to save my mini-stereo?

[Muse]

Oh, so the laptop is already plugged into the minisystem's Aux jack? Then no worries! Just leave it plugged in, and run the cord from the minisystem's headphone jack to the new amp/receiver, as decided previously. You will still be able to select "Aux" on the minisystem and have the laptop sounds come out the headphone jack. Sure, there might be a tiny bit of degradation by passing the signal through the minisystem on its way to the amp, but the convenience offered by switching solely through the minisystem surely makes up for it, IMO.

Yeah, on this system it's actually called the Game input. In fact there's another one called Video! It's pretty flexible. I could use either of those but I decided on Game for some reason playing stuff from the laptop, which has access to it's own HD and wirelessly to the server machine's USB 2TB drive, where my basic stash of MP3s resides.

I'm wondering if I can get an opinion of this for an amp:

Lepai Tripath Class-T Hi-Fi Audio Mini Amplifier with Power Supply -- $25 shipped at Amazon

It has a lot of pretty decent reviews at Amazon, is certainly cheap, is pretty small (a benefit in this environment) is also T class and seems to have more power than the one linked in the 2nd or 3rd post in this thread (20 watts/channel, the other 15), the Dayton at Parts Express. Realize that this system is in my kitchen, not a big room, and is a louder environment than a living room and such with a sofa and chairs and such. Would that amp provide adequate volume without clipping? It also has treble/bass controls, which I like. TBH, having a wall wart for power doesn't please me, but if it doesn't draw significant power when not in use, I don't really care. I think maybe the ones they're making nowadays don't.

Another thing I'm wondering is whether it makes a difference how I use the minisystem's volume control vs the one on the amp. Is the amp less likely to clip if the signals sent to it are boosted somewhat? Or is the volume coming out of the speakers going to determine that by itself?

 

[slashbinslashbash]

I am honestly not experienced with any of the Class T amplifiers linked in this thread (or any Class T amps at all, actually) so I can't really comment there. I have heard great things about them, and for the size/weight/price, AFAIK they can't really be beat. But again, I have never had one myself.

With the the volume controls on the minisystem vs. the amp... As far as I know (based on similar, but not the same, situations) your goal should be to leave the volume control on the minisystem set at a certain level all the time, and control the overall volume with the amp's volume control. You would need to experiment to find the proper level for the headphone output; go as high as you can without distorting. (I believe that it's possible that you could pump up the signal high enough to distort the inputs on the amp.) I would shoot for around 1/2 to 2/3 volume control on the minisystem, for starters, and adjust it up or down depending on whether I can hear distortion at normal volumes. You don't want the input getting clipped.

 

[vshah]

i haven't personally tried either the dayton or the lepai, i do have a different class T amp (they all use the same brand of amplifiers made by tripath, although different chips have different power handling abilities.)

i have the topping tp21 http://www.parts-express.com/pe/showdetl.cfm?Partnumber=310-310

which is a bit more powerful than the dayton or lepai, but drives my bookshelves (which are less efficient than your yamahas) plenty loud.

if you post over at avsforum, i'm sure a lot of people will have opinions/advice on the dayton and lepai, they are quite popular.

 

[Muse]

I am honestly not experienced with any of the Class T amplifiers linked in this thread (or any Class T amps at all, actually) so I can't really comment there. I have heard great things about them, and for the size/weight/price, AFAIK they can't really be beat. But again, I have never had one myself.

With the the volume controls on the minisystem vs. the amp... As far as I know (based on similar, but not the same, situations) your goal should be to leave the volume control on the minisystem set at a certain level all the time, and control the overall volume with the amp's volume control. You would need to experiment to find the proper level for the headphone output; go as high as you can without distorting. (I believe that it's possible that you could pump up the signal high enough to distort the inputs on the amp.) I would shoot for around 1/2 to 2/3 volume control on the minisystem, for starters, and adjust it up or down depending on whether I can hear distortion at normal volumes. You don't want the input getting clipped.

Yeah, I was thinking similarly. I think the volume on the minisystem goes up to 30. It increments in integers on the front panel display from 0 up to 30. The volume knob on the unit stopped functioning properly several years ago and nowadays I have to control the volume with the remote, which I keep velcroed to the side of the refrigerator! It works. At 18 or so the volume is nice and loud but not too loud, not so loud that it would distort. I think I'll leave it there or so.

I'm a little worried that the amp being blown like it is (one channel) will cause the minisystem to draw more current than it normally does. Is that possible? I think I wrote down some figures in a notebook (I have to find) that tells me how many watts the minisystem (and a lot of my other stuff) draws when in use, when idle but on, when in standby, stuff like that. I could compare with the way it behaves now if I can find that notebook!

Here's a page at Amazon showing a big variety of T Class amps. I'm thinking I should maybe dig a little deeper in my pocket and get one that is higher rated in terms of watts/channel. They might be about the same at ordinary listening volumes but if and when I want to crank it up (and that will happen occasionally), I don't want it to distort (and I figure the lower powered ones will distory), and I don't want it to go on the fritz. I know less than you do about T class amps, I'm sure!

T amps at Amazon Note that the first one is the one I asked about. There are many others!

Thanks for the help!!!

 

[Muse]

i haven't personally tried either the dayton or the lepai, i do have a different class T amp (they all use the same brand of amplifiers made by tripath, although different chips have different power handling abilities.)

i have the topping tp21 http://www.parts-express.com/pe/showdetl.cfm?Partnumber=310-310

which is a bit more powerful than the dayton or lepai, but drives my bookshelves (which are less efficient than your yamahas) plenty loud.

if you post over at avsforum, i'm sure a lot of people will have opinions/advice on the dayton and lepai, they are quite popular.

I did post at AVS Forums, but have gotten very sparce response so far. Just one guy suggesting a small receiver (a Sherwood) and another who linked me to the Amazon search for T Amp which I included in my last post here. Here's the AVS Forum thread:

I need a simple stereo amp It's in this AVS forum:

AVS Forum > Audio Related > AMPs, Receivers, and Processors

Maybe if I'm persistent or start another thread there I can get some feedback on specific T amps. Thanks for the suggestion.

 

[slashbinslashbash]

Yeah, I was thinking similarly. I think the volume on the minisystem goes up to 30. It increments in integers on the front panel display from 0 up to 30. The volume knob on the unit stopped functioning properly several years ago and nowadays I have to control the volume with the remote, which I keep velcroed to the side of the refrigerator! It works. At 18 or so the volume is nice and loud but not too loud, not so loud that it would distort. I think I'll leave it there or so.

I'm a little worried that the amp being blown like it is (one channel) will cause the minisystem to draw more current than it normally does. Is that possible? I think I wrote down some figures in a notebook (I have to find) that tells me how many watts the minisystem (and a lot of my other stuff) draws when in use, when idle but on, when in standby, stuff like that. I could compare with the way it behaves now if I can find that notebook!

Here's a page at Amazon showing a big variety of T Class amps. I'm thinking I should maybe dig a little deeper in my pocket and get one that is higher rated in terms of watts/channel. They might be about the same at ordinary listening volumes but if and when I want to crank it up (and that will happen occasionally), I don't want it to distort (and I figure the lower powered ones will distory), and I don't want it to go on the fritz. I know less than you do about T class amps, I'm sure!

T amps at Amazon Note that the first one is the one I asked about. There are many others!

Thanks for the help!!!

I think that if you have the speakers unplugged, the amps can't use much, if any, power, even if something is wrong with them. For that matter, having the headphones plugged in *should* disable the amplifier. I doubt that the current draw will be much to worry about.

About the T Amps, I just don't know, man. I have been tempted by those T amps before, but every time I look at them, I'm just not convinced that they meet my needs. I have bought a couple of very nice, older home theater receivers (Dolby Pro Logic) from pawnshops or Craigslist, and I just can't see the reason for something small when I can have something nice, conventionally sized, with a nice display, plenty of inputs and tons of power for like $50-$100. I'm talking like Pioneer Elite, Sony ES, nice Onkyos and Yamahas and H/Ks, etc. Once they become obsolete (was- no Dolby Digital, now- no HDMI) the prices drop like a rock, but the amps and preamps are still top-notch. I think I have 4 extra HT receivers, beyond my main Onkyo, one of which is in use in my office, and the other 3 are just sitting around until the day that I find a use for them (whole-house setup, most likely).

I mean, I look at that Amazon link, and my eye drifts automatically to the AudioSource 100W amp for $91. That's the kind of stuff I'm used to, aesthetically. I know that the Class T amps are great, but I basically just don't like the looks of most of them (they look like gaudy car stereo amps). It is a weird and biased thing to say, but when I see an A/V component that's not in the 17" form factor, my brain automatically recoils a bit. I just can't quite take it seriously. I have no need for the smaller form factor, and I can find something just as good in a full-size form factor for the same price, so that's what I gravitate towards.

As far as I know, the Class T amps are all pretty much the same internally. Pick the one that meets your needs the best with respect to inputs, etc. If I had to pick one, I'd probably go with the Dayton Audio DTA-100a. You may want to try the Lepal or another one with tone knobs, however, since you need to boost your treble.

In any case, it's not really worth agonizing over, IMO. You could buy any one of those amps, and only be out a small amount of money. If you don't like it, you could easily turn around and sell it on the FS/FT forums for close to what you paid for it. They are popular little amps, and there is always a demand for them.

 

[Muse]

That's a good idea scouting for used quality "obsolete" HT receivers, and I will do that, because I have need of one downstairs. The one I had down there is being used for my HT headphones upstairs nowadays.

I think I'm going to get that cheap Lepai Tripath TA2020 Class-T Hi-Fi Audio Amp w/Power Supply for 25 bucks. The most compelling reason to get that one is the small form factor. In this instance there's not a lot of room in the kitchen and this one accommodates being screwed to a surface and I figure to turn it upside down and put it on the bottom of a shelf. The sound should be OK if I don't crank it up too high, which is something I don't do a lot, only occasionally. It never crossed my mind that I could damage the minisystem doing that. One reviewer of the Lepai says that the power supply isn't strong enough to reach that kind of level, maybe true, maybe not, but there's only $25 at risk!

Who knows how long that minisystem is going to last? When I bought it I read one review by a guy who said they can be expected to last 5 years and then poof, they're not usable. He didn't elaborate, but I figured he meant that the CD player didn't work any more. I've had this 10.5 years, so I have to figure I'm on house money here. I've always kept that guy's post in mind, don't use the CD player a ton, but I've sure used it when I wanted to, the tape transports and recording quite a bit too, knock on wood, they still work. Once in a while I experience problems playing a tape but I think it's because a particular cassette isn't working properly, has excess friction, resistance of some kind. Others work OK. You can even program this thing to turn itself on at a certain time of day and record an FM broadcast onto cassette. I used to use that functionality a fair bit. I should maybe use the speakers it came with rather than the Yamahas, it might be better for the Lepai amp, but hey, I can always get another amp!

 

[Muse]

Over at Parts Express there are 144 reviews for this Lepai. One says this:
- - - -
September 22, 2011
These are even better if you use one Lepai for each channel.
I think a lot of people would be floored if they new just how hi the level of sound can come from these amps. If hooked up to good sources and wires and speakers, these will astound. They can, if properly set up; embarrass many a audiophile amp, and I have a few around to compare.
- - - -

I was thinking that to myself, what if I use two of these, I'd get more volume for the same level, escape distortion, not stress the amp. I'd have to split each channel into two, combine the speaker out wires at the speaker for each channel. $50 for a pair of these.

 

[ericlp]

http://www.ebay.com/sch/i.html?_nkw=muse+t-amp

check out these? Do you see a connection?

T-amps are the way to go. You won't be disappointed I own a few.

 

[Muse]

http://www.ebay.com/sch/i.html?_nkw=muse+t-amp

check out these? Do you see a connection?

T-amps are the way to go. You won't be disappointed I own a few.

There's a ton to choose from, they look OK. I figure that a 50W/ch would be more than sufficient. Evidently they don't come with power adapters. I still am thinking the 15w/ch Lepai, cause it does come with adapter, is small, if I am not satisfied with it, I can get something more robust, use the Lepai bye and bye with something else, playing MP3s off my laptops or portable MP3 players.

 

[vshah]

get one with a ta2021, should be fine

 

[Muse]

get one with a ta2021, should be fine

As cheap as $36 shipped, but I'd need to buy a power supply, an adapter for it.

I think I may go with the one that slashbinslashbash said he'd gravitate towards:

I mean, I look at that Amazon link, and my eye drifts automatically to the AudioSource 100W amp for $91.

AudioSource AMP-100 Stereo Power Amplifier

Reason is it has auto-on/off. I presume that means I can leave it on all the time, that's a big plus for me. Probably has adequate power. Another big plus for this amp is the A/B speaker switching. I could run wires into my dining room and power the speakers in there, they're the ones that came with the mini-system. I've wanted to do something like that for a long time, even bought an elaborate terminal laden gismo from a local electronics store in order to do that but never got around to it. With this amp it would be a few snaps to have that going.

Edit: Alas, the auto power on probably is useless for me. The following snip from the most helpful Amazon review makes it clear that it will turn off if a music passage is too quiet:

- - - -
There is an autopower feature as well. If left on it will cause the same problems with the amp cutting out during quiet passages as the autoinput switching. However it can be disabled by a selector switch on the back of the unit. This is clearly explained in the manual. The intent is to allow the unit to be powered on remotely when used with a distributed music system. If you want a standalone system disable this feature and turn it on and off manually.
- - - -

That's too bad. I dislike the idea of having to turn the amp on or off manually every time I turn music on or off in my kitchen.

 

[SithSolo1]

The AMP-100 should be fine. Its a nice budget unit.

 

[Muse]

The AMP-100 should be fine. Its a nice budget unit.

Well, it has a couple of problems for me:

1. It's kind of big, about 16.5" x 8.25" x 2.8" It's so big that it's difficult for me to find a place for it where it's quite as accessible to me as the little Lepai TA2020 amp.

2. The auto-on/off wasn't designed well from my perspective, see the quotation in my last post by a reviewer who disables this feature because the amp turns off in quiet musical passages. I'd buy it and leave it on all the time if I thought that it didn't draw significant power when it wasn't fed a source signal, but I suspect otherwise.

I just had a thought. Since one channel of the minisystem seems to be working OK (left channel), why not run the left Yamaha speaker off the minisystem and run the right minisystem headphone channel into both inputs of the Lepai? Both channels of the Lepai would power just the right Yamaha speaker and I'd get less distortion at higher volumes. I could place the Lepai's volume control at the point where both speakers have approximately the same volume (i.e. with monophonic source), and then control volume with the minisystem's volume control. Would this work out?

 

[vshah]

Well, it has a couple of problems for me:

1. It's kind of big, about 16.5" x 8.25" x 2.8" It's so big that it's difficult for me to find a place for it where it's quite as accessible to me as the little Lepai TA2020 amp.

2. The auto-on/off wasn't designed well from my perspective, see the quotation in my previous post by a reviewer who disables this feature because the amp turns off in quiet musical passages. I'd buy it and leave it on all the time if I thought that it didn't draw significant power when it wasn't fed a source signal, but I suspect otherwise.

I just had a thought. Since one channel of the minisystem seems to be working OK (left channel), why not run the left Yamaha speaker off the minisystem and run the right minisystem headphone channel into both inputs of the Lepai? Both channels of the Lepai would power just the right Yamaha speaker and I'd get less distortion at higher volumes. I could place the Lepai's volume control at the point where both speakers have approximately the same volume (i.e. with monophonic source), and then control volume with the minisystem's volume control. Would this work out?

Only if your Yamaha support biamping/biwiring

I wouldn't recommend it though. You'll hear a difference between the amps.

 

[Muse]

Only if your Yamaha support biamping/biwiring

I wouldn't recommend it though. You'll hear a difference between the amps.

Oh, OK, thanks!

I wouldn't know about biamping/biwiring. I just figured it would work, never done anything like that, but if the sound would be so disparate, I guess it's a bad idea.

Could I try it and see how it works? Is there any danger in doing so? If I don't like how the little Lepai works in the kitchen I could use it as a headphone amp using line out from my blu-ray player. It might do a better job than my Airhead headphone amplifier, which doesn't have tone controls. Or I could use it for other light duty amplification duty such as with headphone out from a laptop or from a portable MP3 player even.

 

[Muse]

I went ahead and ordered the Lepai Tripath Class-T Hi-Fi Audio Mini Amplifier with Power Supply for $24.49 shipped, includes power supply. I'll try it, see how I like it. If I'm not completely satisfied (I don't expect to be), I'll move it upstairs and use it as a headphone amp. I may or may not like it for that (probably depends on how I like the tone controls, since I want a boost in treble to compensate for my ~50% hearing loss at 3000 hertz and higher). Meantime I'll have a better idea what I'd like with the minisystem. I figure one of the more powerful T class amps (2021 or stronger), or the AudioSource AMP-100 Stereo Power Amplifier might be my ultimate choice. I'm trying to figure out whether or not I'll be turning the amp on/off each time I use it or will just leave it on. That's a big part of the decision making process. Which amp I ultimately use dictates its placement based to size/space/convenience issues.

 

[Muse]

Did you unplug and re-plug everything? You can get weird noises sometimes if there's a wire loose. I've been embarrassed to troubleshoot something for quite a while, then check the back and find that one of the wires was slightly pulled out.... could also be an internal connection to the speaker wires (if they're permanently attached) or terminals on the back of the minisystem. It might be worth your time to open up the back of the unit and look for something obvious like the terminal coming unsoldered, or a bulging or busted capacitor.

Today, after not having the speakers attached for an entire week and only being on occasionally with headphones attached, I reconnected the speakers and then removed the headphones from their jack to see what would happen. I was fully prepared to turn it off in a flash if again I heard screeching loud noise coming from the right channel. However, the unit has functioned apparently normally now for over 4 hours.

I do not trust it, at least not enough to leave it on and leave the house as I have done for several years. When it was going crazy a week ago the sound from it was enough to alarm my neighbors, I'm sure. I will hopefully remember to turn it off before I leave the house and "monitor" the situation. It's hard to imagine the problem will not resurface. I've run it at normal volumes except I did turn it up fairly loud for 20 seconds or so to see it it would trigger an episode, which it didn't.

 

[Muse]

At first everything seemed fine when I connected the headphone out to the Lepai 20w/ch T class amp I ordered from Amazon. Good sound, plenty volume, everything seemed peachy. But problems developed after about a week. The stereo main body is on a shelf system and if I plopped something down on a shelf (i.e. jostled the stereo body a little) some noise was heard in the right channel (the same one that was a problem before). Turning the volume down to zero and then back up on the Lepai amp stopped the noise, which sounds like rough static.

This problem got worse over the next week (this last week) until it's at the point where a very tiny bump causes noise. It's easier to turn down volume with the external amp than it was with the mini-stereo because the only way of doing that (since the volume knob stopped functioning a few years ago) is to do it with the remote, which is slow.

Well, it's not really usable like this. I have the service manual in PDF form. I figure to at least take off the cover and see if I can find a problem of some kind, poke around, hopefully not electrocuting myself. I'm not optimistic. The problem can't be in the amp section, I figure, because it's in the right channel headphone output, so it could be in the preamp section, where ever that is. It happens with tuner, cassette, CD play as well.

It's interesting that turning down the volume and then back up stops the noise. I think this means that something is going on in there that when brought to a low enough volume (approaching zero), is stopped. It's like a recursive signal, like feedback, in that regard. I'm thinking maybe a bad solder joint. Needle in a haystack, most likely.

Assuming I can't fix it, I'll have to toss it and probably use my Panasonic 5CD mini-system instead in the kitchen. Use the Lepai for a headphone amp in my home theater.

 

[slashbinslashbash]

Make sure to use lots of canned air and clean everything out in there. Also some DeOxit to clean the potentiometers (volume control knob, etc.) and other contacts (switches, etc.) would be a good idea.

Also, it would be worth a shot to try the optical output on the CD transport to see if at least that part can be salvaged, since that seems to be the main component of the unit that you like to use. Run the optical to an appropriate amp/receiver and see if the noise happens there. I'm betting that it won't. It would be very strange for that kind of noise to enter the digital signal path.

 

[Muse]

Make sure to use lots of canned air and clean everything out in there. Also some DeOxit to clean the potentiometers (volume control knob, etc.) and other contacts (switches, etc.) would be a good idea.

Also, it would be worth a shot to try the optical output on the CD transport to see if at least that part can be salvaged, since that seems to be the main component of the unit that you like to use. Run the optical to an appropriate amp/receiver and see if the noise happens there. I'm betting that it won't. It would be very strange for that kind of noise to enter the digital signal path.

I took the cover off yesterday, had it on a table out in the sun in the back yard, so I could get a real good look at things. Had a flashlight too. I have a portable vacuum that's real strong and you can reverse the hose so it blows (way stronger than canned air), and I used that to blow dust out of the unit. Brushed the circuit boards with a 2" paint brush, too. I hadn't seen your post (saw it just now), and I didn't use DeOxit (I have a can). I had a golden chance to poke around and try and ascertain some ideas about what's going on in there. It wasn't too clear. Slight taps anywhere were causing a momentary short burst of noise in the right channel (I was using headphones from the headphone jack only, the Lepai was still in the kitchen). I had FM (an antenna attached), and a CD in there. The sound source is evidently immaterial.

I tap, tap, tapped all over trying to get an idea where the problem might be, assuming it was coming from a _location_.

Now, some things were eyebrow raisers. For one thing, the volume (adjusted with the unit's remote) had no effect on the volume of the noise in the headphones. However, when the volume was at minimum ("Min" appears on the LCD display), the noise was way quieter, but still there.

Somehow, the propensity for the noise varied. I jiggled wires, wire bunches, connections of wire bunches at circuit boards hoping that the noise was engendered at one of those connections, but it didn't seem to be the case.

After poking around all over and being unable to get any idea of a hot point that was more likely to cause noise compared to others I got the idea that a certain circuit board was more sensitive, however this could have been momentary or illusory (earlier tapping didn't give me that idea). That circuit board is held down by two screws, and I loosened those screws a few turns, taking tension off the board. The problem seemed much ameliorated. In fact it seemed gone, could have been a coincidence, because the problem has not always been there or at the same sensitivity. I did get a squack in the right channel with a tap on the machine after loosening those screws, but I have heard no squacks since. I put the cover back on the machine and put it back in the kitchen, connected everything back up and right now it seems to be behaving OK. So, there appears to be hope, but I have to figure the problem will return. Maybe not, maybe taking tension off that circuit board will turn out to be a key. I think I could have taken the back off the unit, but didn't go further than taking the main cover off. The back might be trickier. The service manual has a flow chart for taking the thing apart. I printed out the first 15 pages (it's 75 pages), which includes that flow chart. I suppose I could actually remove that circuit board, don't know. Might be pretty hairy.