Any type of 3W amplifier is a bit too small to use with many of the popular but usually inefficient , small hi-fi speakers available now. Unfortunately, to get audible levels of bass from small speakers, you have to sacrifice overall sensitivity which translates to more than 10W input power rating for typical speaker drivers. Have you also visited our members and friends at the Frugal-Phile support site for some inspiration and details for constructing low and very low power speaker systems? 'might be some good leads from member Planet 10 elsewhere here too. https://www.frugal-phile.com/
I have used a couple of old pairs of Celestion speakers for auditioning my low power projects (1-20W). The amplifiers are are mostly obsolete automotive chipamps, preassembled on dedicated PCBs - perhaps like those you are now considering. They seem to fit the bill, seldom have clipping issues when used with the right type of speakers and can be bought ready assembled - often complete with a control preamp, and quite cheap. This also brings me to the point of asking what speakers you have been using and prefer for your tests so far?
I have used a couple of old pairs of Celestion speakers for auditioning my low power projects (1-20W). The amplifiers are are mostly obsolete automotive chipamps, preassembled on dedicated PCBs - perhaps like those you are now considering. They seem to fit the bill, seldom have clipping issues when used with the right type of speakers and can be bought ready assembled - often complete with a control preamp, and quite cheap. This also brings me to the point of asking what speakers you have been using and prefer for your tests so far?
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How about old car cassette player?
Just connect a FM module output to the place where the head is connected, and put a switch, remove cassette mechanism.
Or take the Amp section out, put in a new cabinet.
May not be original idea, should work.
FM needs 5V, 7805 is enough from 12V line.
Speakers, again old car speakers are adequate.
Just connect a FM module output to the place where the head is connected, and put a switch, remove cassette mechanism.
Or take the Amp section out, put in a new cabinet.
May not be original idea, should work.
FM needs 5V, 7805 is enough from 12V line.
Speakers, again old car speakers are adequate.
I've been using different speakers with the PAM amp, some "packing case" speaker, using two 3 1/2 inch, 8 ohm drivers wired in series, "traffic light" speakers, using four 3 1/2 woven glass fibre, 6 ohm drivers wired in series/parallel, "quad cubes" four 3 1/2 paper 8ohm drivers wired in series/parallel, "BBC box" speakers, two 4 inch polypropylene duel come 4ohm drivers, wired in parallel with contour network, and "box in a box" two ways, based on 6 1/2 paper, 8ohm 85db drivers. The only ones that needed more power are the BBC boxes, and I've ordered some 2 ohm paper drivers to try in them. They work best with the box in a box speakers, I've just had "Lost dogs" (Pearl Jam) on, and Ed Vedder's voice sounded amazingly real. I do listen at quite low volume, and close to the drivers, 3 watt amps certainly won't be for everyone. Once I've finished some speakers based on 94db efficient drivers, I might make some active subs for them to stand on, hopefully giving good bass with the qualities of the 3 watt amp.
I still don't know if it's an amp running close to it's maximum output, or low voltage on the power rail, or less amplification stages that are responsible for the sound that I like.
If you are pushing the power and/or power supplies toward their limits, you may find that it's the increasing distortion or related effects that make some voices seem more clear or say, sustained notes and chords that sound most pleasant. The actual effects will depend on the amplifier design and the particular model speakers, but I think you may have realised there is a connection there.
Or it could just be good quality class-D. The datasheet probably takes away the guesswork, but it could be a high switching speed, and some of them forgo output inductors altogether, which could clean up the sound a bit.
Plus you never know what all their latest proprietary tricks are that they don't mention. The switching scheme could even vary the output impedance vs frequency, for all we know, eg. by mixing the 2 main 'up' or 'down' states with some well timed 'off' states.
And half the distance = 4x the amplitude or 8 times the power and less room interaction.
Plus you never know what all their latest proprietary tricks are that they don't mention. The switching scheme could even vary the output impedance vs frequency, for all we know, eg. by mixing the 2 main 'up' or 'down' states with some well timed 'off' states.
And half the distance = 4x the amplitude or 8 times the power and less room interaction.
I didn't like the thought of rf frequency through the speaker cables, so I used two ferite ring inductors in parallel for each connection. I think that 99% of listening is quite well below the level that it goes into distortion.
Bear in mind that the new amps are rated for 2 and even 1 ohm impedance, that will affect the playback quality over higher rated speakers.
I was browsing the tables on the (ST?) web site, and most of the Class D and car amps are with such ratings.
I was browsing the tables on the (ST?) web site, and most of the Class D and car amps are with such ratings.
Adding ferrite rings to the speaker leads raises more questions. The toroidal inductors so formed, are used to make lowpass filters with good linearity up to full power power levels but this isn't what happens if the more common ferrite materials are used, since they were probably intended for use in SMPS and related power control circuits designed to accommodate them.
Historically (probably mid to late 1970s) certain iron grades in large sizes were recommended in product reviews and hobby mags for EMI filtering of long speaker leads, usually at moderate power levels in multi-way systems. There were even kits of parts available for a boxed stereo speaker set, available from electronics hobby stores back in the day and many enthusiasts bought them. Generally, substituting common ferrite core inductors for the iron types was a bad idea though, as distortion increased markedly. This was backed up by some awful follow-up tests of available ferrite grades and substitutes - many simply to reduce costs.
Historically (probably mid to late 1970s) certain iron grades in large sizes were recommended in product reviews and hobby mags for EMI filtering of long speaker leads, usually at moderate power levels in multi-way systems. There were even kits of parts available for a boxed stereo speaker set, available from electronics hobby stores back in the day and many enthusiasts bought them. Generally, substituting common ferrite core inductors for the iron types was a bad idea though, as distortion increased markedly. This was backed up by some awful follow-up tests of available ferrite grades and substitutes - many simply to reduce costs.
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Good point, hadn't thought of that in the context of hifi but 'sag' is often desirable in guitar amps.
Actually just read a piece (sorry, forgot where) that suggests that the beloved character of the Fender Bassman is partly down to ripple on the supply as it sags. Which means that the same amp is going to sound different in USA and Europe, so to get that proper authentic Americana tone I need an inverter running at 60Hz...
Cable inductance by itself could be sufficient. There's also that issue of magnetic hysteresis. (The guys from Purifi did an eye-opening article on it, showing that magnetic memory can cause spurious voltage glitches across inductors with magnetic cores. Now, just imagine astrology getting vindicated as optical 'reversals' of the planets in the night sky create real glitches in the Earth's magnetic core, triggering earthquakes and confused migratory birds and stuff, but I digress 🙂 ).
If we're already modding class-D amps, maybe a set of air-core inductors could be a nice option? If the recommended value is in the 10 uH region, that seems like a few turns of copper on a pinkie diameter bobbin, depending on what the online calculator suggests.
If we're already modding class-D amps, maybe a set of air-core inductors could be a nice option? If the recommended value is in the 10 uH region, that seems like a few turns of copper on a pinkie diameter bobbin, depending on what the online calculator suggests.
The Bluetooth + PAM 8403 unit arrived and is working very nicely. Subdued mids I think:
Thread started.
https://www.diyaudio.com/community/threads/pam-8403-with-bluetooth-first-impressions.397207/
Thread started.
https://www.diyaudio.com/community/threads/pam-8403-with-bluetooth-first-impressions.397207/
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I'm well metered .... I usually listen at 70'ish DB (like right now). A few drinks I hit 100db+ with a 150W sub and 35W/ch HF drivers.
most of the source come out of the satellites , rarely over 30 watt's. With a 2.1 system , a little LM3886 powered by an SMPS is quite
sufficient. Some source material (club) , does need >100 W , but only under 80hz (my X-over).
most of the source come out of the satellites , rarely over 30 watt's. With a 2.1 system , a little LM3886 powered by an SMPS is quite
sufficient. Some source material (club) , does need >100 W , but only under 80hz (my X-over).
When you are at the point your amplifier is an improvement enough and you are looking for new music instead of amplifiers and speakers, that's when you have got what you wanted, for a few months anyway. That's where I am with my low powered stuff.
Anyone come across this problem with the PAM8403? I no longer plan to use it in 4 Ohm speakers.
I've used 4 ohm car speakers with no problem, I wonder if it is a power supply issue rather than a problem with the amp.
Low wattage amps can damage speakers if they clip, which they do. conversely high wattage amp ca drive low wattage speakers if driven at sensible levels
I think that that's a mix of truth and myth, which has been around forever...
The clipping can generate lots of high frequencies, which if combined with a passive crossover, can blow tweeters, which are only designed to handle a small fraction of the total power across the audible spectrum. But if you record some computer-generated fake clipping, does the same thing happen if the amplifier has even more power available? I would say yes.
The clipping can generate lots of high frequencies, which if combined with a passive crossover, can blow tweeters, which are only designed to handle a small fraction of the total power across the audible spectrum. But if you record some computer-generated fake clipping, does the same thing happen if the amplifier has even more power available? I would say yes.
Anyone run an amplifier off supercapacitors? Any dangers?
https://www.nationalgeographic.com/science/article/130821-supercapacitors
I have run a small electric motor off a supercapacitor and it runs for a few seconds, quite impressive.
Runs a drone for 10 seconds and has about 300 mAh
(Ebay)
Technical write up about using supercapacitors for backup of internet things.
This should do it: Zoxcell
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I do also like low powered amplifiers.
In fact I nearly always design for low power : 4 to 10 Watt.
Here is my present project. A 6 Watt amp.
https://www.diyaudio.com/community/...-amplifier-6-watt-with-low-distortion.397378/
It is so nice that even Mr Nelson Pass likes it 🙂
In fact I nearly always design for low power : 4 to 10 Watt.
Here is my present project. A 6 Watt amp.
https://www.diyaudio.com/community/...-amplifier-6-watt-with-low-distortion.397378/
It is so nice that even Mr Nelson Pass likes it 🙂