Class T-amps

[MartinT]

however if the error amplifier input is fed AC rather than the 2.5V DC from the voltage reference it'll generate an AC output

Clever!

[Reid Malenfant]

Clever!

Perhaps i should have added that the voltage reference is 5V DC & the error amp is normally fed by a resistor divider network to get the 2.5V DC.

Yes it's pretty amazing what you can do with SMPS ICs, i developed a circuit using an industry standard SG3524 to regenerate mains 240V using a transformer back in about 1991 It worked beautifully but was restricted power wise by the transformer.

Thankfully i never forgot what i learned

I reckon a simple OP amp circuit added on can set the DC offset to just about zero & as long as i use AC feedback i can get distortion to incredibly low levels. Less than 0.1% at any rate which compared to normal mains is vanishingly small.

I also have far more than enough of some cracking power mosfets that would do the job admirably, well over rated @ 45A/550V STW45NM50

Apologies, looks like a few clicks are needed to access the info as with the UC1876 Ah well, at least you might get the picture..

[MartinT]

I reckon a simple OP amp circuit added on can set the DC offset to just about zero & as long as i use AC feedback i can get distortion to incredibly low levels. Less than 0.1% at any rate which compared to normal mains is vanishingly small.

I was thinking about the zero DC output problem, guess this would be the makings of a servo amp. All the better for dissipation, too. Wish I had time to tinker as I used to, although my area of strength used to be class AB push/pull amps - I used to breadboard and prototype like mad. JLH was my hero. All lost in the misty past now

[Alex_UK]

Best laid plans and all that - my "new" Spendors haven't left the living room, so my Acoustic Energy Aegis Evo 3's have ended up in the dining room, where my Roku Soundbridge is patiently awaiting a "mates rates" set of active mini-monitors. Space is limited, so I'm thinking a stop-gap might be a "T" amp... I'm keen to give one of these a whirl out of interest anyway. So far, I'm preferring the Topping TP21 on the basis of the headphone option which could be useful if/when the monitors arrive, as oposed to the Mini T - the speakers are pretty efficient (90.5 db efficiency) and only ever likely to be used for "dinner jazz" background music - so which one would people recommend, or any alternatives around the £50-60 mark? Pretty much discounted the Muse on the basis of Will's woes, and I would prefer a UK seller. Waddya reckon?

[John]

I only heard the Mini T a real bargin nice clean fast sound, to be honest I think for your needs either will do, if I was in your shoes I probarly go for the Topping as has the headphone option

[Alex_UK]

Thanks John, that's what I'm leaning towards as a little cheaper and the headphone option would make it more flexible if/when the little actives arrive. Mind you, I'm not sure I really need a 5th system (6th if you count the little Myryad in the kitchen) but since when did "need" mean much with this hobby?

[WAD62]

Pretty much discounted the Muse on the basis of Will's woes, and I would prefer a UK seller. Waddya reckon?

Thankfully the Muse's power supply has been resurrected and improved, and in combination with the M21 amp sounds great, but I have to agree that buying from China is a slightly risky business...along with the 'smuggling' aspect

Strangely enough my mate recently acquired a Mini-T from the same supplier as mine, it looked slightly different (the speaker terminals are now banana plug only, very similar to the muse)...after about 2 weeks it blew up with an audible pop!

However to his credit the UK supplier replaced it within a week, no questions asked.

A UK supplier has to be the way to go with these amps, unless you're more proficient with a soldering iron than I am

[Alex_UK]

Thanks for that Will, pretty much only going to go with a UK supplier, savings are minimal anyway and I just don't need the hassle for such a small purchase.

[Tarzan]

Alex, l am going to sound like a broken record here but the Mini-T for the monet is a remarkable sounding amplifier for the money.... but no headphone socket

[John]

Thanks John, that's what I'm leaning towards as a little cheaper and the headphone option would make it more flexible if/when the little actives arrive. Mind you, I'm not sure I really need a 5th system (6th if you count the little Myryad in the kitchen) but since when did "need" mean much with this hobby?

Now that just being greedy