topic Re: Amplifier advice please in Tech Help - Software/Hardware etc

Amplifier advice please

shutter — Tue, 04 Feb 2025 11:41:25 GMT

MY ASUS ROG laptop, has an output impedence rating tht can be changed using the ASUS software ( apparently ! ) . two settings are available... 64 ohms.. to give a range of 64ohms to 150ohms or 150 ohms to give a range of 150 to 300 ohms..

I would like to get a pair of "old style" wooden cabinet stereo speakers ( ex stereogram/stereo system ) like these

eBay item number:205216990742

as you can see, they are rated at 4 ohms.

From doing a google about this, I think I will need an amplifier to plug in to the earphone socket, and then plug in/wire up/connect the speakers to the amplifier.

Otherwise, I am likely to damage the sound card on the laptop.

I do not want huge amounts of volume, just would like to listen to quality sound in the lounge, rather than having to walk around iwth bluetooth or RF headphones on.

Can anyone suggest a reasonably low cost amplifier that would suit this application.... the ASUS output impedence would remain, "as is" at 64 ohms. so that, presumably, would be the "input" impedence to the amplifier.

Re: Amplifier advice please

HPsauce — Tue, 04 Feb 2025 11:53:29 GMT

I would expect your laptop output to effectively be designed to drive headphones, and fairly lightweight ones at that.

Any old HiFi amplifier that has a "phono" level input (typically labelled AUX) will almost certainly do the job, just don't use the turntable input if it has one as that's designed for much tinier signals from a vinyl cartridge.

You can also buy very cheap Bluetooth devices that plug into such an amplifier input (I have a tiny little rechargeable USB-powered one) so any source with a Bluetooth connection can play through it with needing cables.

Re: Amplifier advice please

MisterW — Tue, 04 Feb 2025 12:22:27 GMT

@shutter something like this https://www.richersounds.com/fosi-audio-bt10a-black/#tab-description

Similar price on Amazon but I'm sure you could find similar (cheaper) items on ebay

Re: Amplifier advice please

shutter — Tue, 04 Feb 2025 12:42:58 GMT

@HPsauce OK... don`t want to have a big old stereo unit lurking somewhere !...but you suggest you know of a cheap bluetooth unit, that I could plug in...I have bluetooth output on the ASUS laptop.. so I am assuming you are saying the bluetooth is a "receiver" and "amplifier with output connections to "external speakers"... BUT would that be capable of driving ( say ) a pair of 6ohm 6inch speakers ?

@MisterW Thanks for your suggestion.. and the linky... looks like a nice unit.. Maybe that is the sort of thing that @HPsauce is referring to ? ? ?

Thanks to both.

Re: Amplifier advice please

MisterW — Tue, 04 Feb 2025 12:49:59 GMT

@shutter it is, except that it has Bluetooth built-in as well as the AUX input

Re: Amplifier advice please

shutter — Tue, 04 Feb 2025 13:01:31 GMT

@MisterW ok... SO ... I could wire it direct on the AUX input from the phones output socket.. OR use bluetooth, which makes it more "flexible" in the location of the amplifier.

I used to mess about with Crystal sets, and low voltage valve radio construction, and I think I might have an old Maplin 3.5 watt amplifier module that runs off a 9v battery... but not sure if that would be powerful enough for a PAIR of speakers on either 4 o4r 6 ohms impedence. I moved recently and left most of my "junk" behind !.. so can`t remember if I still have it...

I presume that if the output is 3.5watts then that would only be 1.75watts to each speaker of a pair connected to it in parallel ?

I`ll do some more googling on that idea, and see if I can find the unit, or another more powerful output. and report back !

Thanks

Re: Amplifier advice please

HPsauce — Tue, 04 Feb 2025 13:19:44 GMT

@shutter @MisterW nice little unit that, does the job and is flexible.

FYI I was thinking of a second-hand amplifier (cheap as chips) and separate tiny Bluetooth unit, but that device looks ideal if you want something small. 👍

Re: Amplifier advice please

shutter — Tue, 04 Feb 2025 13:27:11 GMT

@HPsauce Thanks... Just wanted something "discrete" !..Still looking on google to find the amp, or similar !.

cheers

Re: Amplifier advice please

Dan_the_Van — Tue, 04 Feb 2025 13:37:18 GMT

@shutter

Have you looked at Bluetooth speakers?

Re: Amplifier advice please

MisterW — Tue, 04 Feb 2025 13:38:03 GMT

There's similar units on the bay from about £10 upwards. Most are 12v power so can be used in car or at home, but check if a psu is included ?

This https://www.amazon.co.uk/LiNKFOR-Amplifier-Bluetooth-Receiver-Amplifiers/dp/B0932B6VX6 at £40 additionally has USB and Sd slot so will play mp3 via usb stick or sd card. Also has a remote.

Re: Amplifier advice please

HPsauce — Tue, 04 Feb 2025 13:49:51 GMT

Yes @shutter as @Dan_the_Van mentioned there are fairly good Bluetooth speakers too, unless you're wedded to using those already shown.

We have a neat rechargeable little stereo unit (made by Lugulake) that doubles as an iPad/iPhone stand but packs a decent punch. SWMBO often uses it to play her music while having a soak in the bath! It's about the size of a 500ml beer can.

Re: Amplifier advice please

shutter — Tue, 04 Feb 2025 14:34:06 GMT

Hello, to all !..

OK... so. thanks for the "Bluetooth" option... So far, I have not been impressed with Bluetooth headphones.. compared to my wired headphones, for music quality.... I also have some "small" plasic boxes with small speakers in them, which are wired and powered via usb... in to the phones socket.. but again.. I am not impressed with the sound quality.

I am almost deaf without my hearing aids in !.. but when I watch my music videos on my laptop via wired head phones, I remove the hearing aids, use my ONEODIO wired head phones, and have the volume up 100% and I have a really good experience of all the sounds of all the instruments ( mostly backing bands for Latino/Mex female artistes ) which has a big complement of BASS sounds... which give the music its appeal for me.....(like being in the middle of the band on stage ) ! ! ! .. the sound emitted by the bluetooth phones and speakers is terrible comparatively..mostly top end, and losing the bass and middle frequencies, so I am looking for some Large Speaker cones ( 6 to 8 inch ) as was provided with the stereo systems of the 70`s and 80`s. with wooden casings that help to give quality sound to the music. I would be looking for them in charity shops or might even go for them on Ebay... hence my inquiry about the need for an amplifier to drive the big speakers..rather than just taking pot luck and plugging them in to the laptop, and killing off the sound card !

Still scouring google for the amp ! .

Re: Amplifier advice please

Protech — Tue, 04 Feb 2025 16:10:02 GMT

This little amp ( and many similar Class D amps ) are quite compact and have built in bluetooth

https://www.amazon.co.uk/Fosi-Audio-Bluetooth-Amplifier-Integrated/dp/B076XSBCCL/ref=asc_df_B076XSBCCL?mcid=2a27c6f702f33d06aca8cf466ca02fb7&tag=googshopuk-21&linkCode=df0&hvadid=696452133737&hvpos=&hvnetw=g&hvrand=6406179030243363465&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9045597&hvtargid=pla-569659243362&psc=1&gad_source=1

I've been using a similar amp ( non bluetooth ) for a couple of years now and the sound quality is surprisingly good

Re: Amplifier advice please

shutter — Tue, 04 Feb 2025 16:32:09 GMT

@Protech Thanks for your input... ( and research! ) . MisterW already mentioned that amplifier in post 10 above !

Re: Amplifier advice please

HPsauce — Tue, 04 Feb 2025 18:03:35 GMT

My only thoughts about your audio needs @shutter is that if you're after "old school" speakers an "old school" amplifier might be needed to give the bass output you're after.

Many modern amplifier systems are built assuming a separate and separately-powered single bass unit.

Re: Amplifier advice please

shutter — Tue, 04 Feb 2025 18:15:08 GMT

@HPsauce I get what you are saying.... and might well be true... however... my laptop soundcard gives an excellent level of Bass on my wired headphones... so I think that the big speakers will also produce a similar level of excellence ... due to the size of the cone(s)...

Yes the speakers in the headphones are small(ish) actually 40mm diameter.. they give a really good bass sound.

whereas the little speakers in the plastic boxes give a very weak sound due to their size, and the enclosure.

Re: Amplifier advice please

RobPN — Tue, 04 Feb 2025 21:31:30 GMT

As background noise was mentioned on another thread it might be worth pointing out that, depending on protection features built in to an amp, running speakers on an under-powered amp will likely cause background noise to be reduced - due to speakers being blown!

A little knowledge can be a dangerous thing ...

Re: Amplifier advice please

HPsauce — Tue, 04 Feb 2025 21:50:33 GMT

@shutter I'll let you do your own research; I'm no expert but I do have a fair amount of 1970s HiFi and know a lot of other people similarly equipped.

Under-powered or more modern amplifiers do seem to be not well regarded when it comes to sound quality across the frequency range, bass in particular needs a lot of power and amplifiers that have a lot of "headroom" to deliver it undistorted.

Generating bass in a headphone sealed to your ear/skull is so much easier.

And for speakers 50 watts per channel (depending how measured/specified) is not that much....

My main amplifier, nominally around that range, has some very serious heat sinks on the power transistors and they get HOT! The units linked look good on paper but I see no sign of dealing with the inevitable heat they could/should/would generate driving serious speakers!

Re: Amplifier advice please

outcast — Wed, 05 Feb 2025 00:00:33 GMT

@shutter wrote:

... have the volume up 100% and I have a really good experience of all the sounds of all the instruments ( mostly backing bands for Latino/Mex female artistes ) which has a big complement of BASS sounds... which give the music its appeal for me.....(like being in the middle of the band on stage ) ! ! !

Here is a good thumping bass song when "the volume up 100%" and the Latino girl turns her voice up to '11' ! - Sara Loera

OMG !

Re: Amplifier advice please

Baldrick1 — Wed, 05 Feb 2025 14:45:17 GMT

@RobPN wrote:

.... depending on protection features built in to an amp, running speakers on an under-powered amp will likely cause background noise to be reduced - due to speakers being blown!

I can understand that loading on amplifer designed to feed high impedance speakers could damage the amplifier if connected to low impedance speakers. Also, a very powerful amplifier designed to feed low impedance speakers could destroy low impedance low power speakers through shear overload.

Hower, logic suggests to me that there is no way that a low power amplifier could destroy speakers. To do this the amplifier has to have the capability to provide a high current, indicating that it has been designed to feed a low impedance speaker.

@HPsauce

Class D amplifiers are generally about 90% efficient and do not get excessively hot, as was the case with analogue class A (cooks!), B and C variants.