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-   -   Y148 AMP MODULE (http://www.diyaudio.com/forums/class-d/202411-y148-amp-module.html)

logotrikes 13th December 2011 09:28 AM

Y148 AMP MODULE
 
Hi Guys,

Anyone used the YDA148 module?

I got one from DealExtreme and it arrived today. Looks a well made little unit, though I looked in vain for any sign of imput caps or where they might fit in the scheme of things. I know nothing so I hardly know what I'm looking for, but it seems to me there should be some provision for them.

I read a couple of raves on the DealExtreme forum and this little module is highly praised. I'll hook it up over the next few days and report back.

Cheers for now, Martin

elevator 13th December 2011 10:58 AM

Martin,
you may want to chime in here
Cheers,
E

Peter Pan 9th February 2012 03:11 PM

I just happened to notice your post, and as time moves quickly in the DIY world you may no longer need assist. But I've worked with the board a it now and am very pleased with it, and have even done a few simple mods. Let me know if you're still seeking info.

logotrikes 9th February 2012 09:04 PM

Peter Pan,

Thanks for the reply. The y148 board still sits here on my desk untouched, I got sidetracked with other things, but sure, I would be interested to know what you've achieved with it...

Cheers, Martin

Peter Pan 10th February 2012 01:50 PM

Well I was looking for a class D board in the 10-20 watt range to build into a very small travel guitar along with a battery pack and speaker. Obviously anything battery powered will benefit from the high efficiency of class D, which also means no heat sync is needed so there is less bulk (and heat) to deal with. What I learned in the process is that there are many such boards available, most at around $10 or less. But I also learned that different boards have different features, as expected, and this one has so far been the winner. This board has some nice features to prevent (or at least limit) clipping distortion, which sounds particularly horrible with class-D, and can damage your speakers. I also found this board worked well doing something you're not supposed to do, unless you re-design the circuit. that is, paralleling the inputs and outputs in order to better drive a lower impedance (4 ohm) speaker, as a single 20W amplifier. I also found it was possible to alter the gain (and anti-clipping ) options, though it requires some very steady hands and good eyes to move / remove the 0-ohm resistors that control this.

But anyway, I'm rambling. My overall review is that this is not that absolute smallest board you can find, nor the absolute lowest quiescent current drain, but it does work well for me.

logotrikes 10th February 2012 04:53 PM

Ok, that's great Peter Pan...

I'm trying to put this board into a very small enclosure, currently trying to squeeze in all the required bits onto the small back panel, all in an effort to make the amp look as finished as possible. It wont be my main amp, I currently have several small Tripath amps from which to choose and most of my tinkering involves swapping these around some as I wait for parts from Ebay to finish the Y148.

I'm hoping for good things from the Y148, it easily looks and feels the best made of all the really tiny d class amp boards out there, and even if it does fall over, it's all part of the diy fun at chump change...what the hobby is all about I guess.

Cheers, Martin

Peter Pan 10th February 2012 05:19 PM

I've made a number of very tiny guitar amps so I feel your pain. There are some smaller boards out the you could look at, like this tiny one on ebay for just around $5.

Mini Amplifier Board 10W+10W Class D Amplifier DC 12V | eBay

If the plan is to amplify processed and likely normalized, limited, and compressed sound, like you'd get from an FM radio or MP3 player, then that might offer an option. If you're plan is to plug in a raw instrument like a guitar though, forget about it and use the Y148 board!

logotrikes 10th February 2012 08:49 PM

Yep, got that one...set it up temporarily, and it sounded quite good.

I'm using my old Adcom CD player through full range Fostex speakers in TQWT enclosures, very efficient, run on the smell of an oily rag type speakers, ideal for my 5w SET tube amp, or my current love affair, the T and D class midgets.

The y148 is just one of a few experiments on how to get the best sound out a handful of watts and as many dollars...

Cheers, Martin

pinobot 28th May 2012 09:30 PM

Anybody still working with those.
I got one and i think it's better than my TA2024.
One thing i notices is that the absolute phase is inverted, it sound a lot better with the polarity on both loudspeakers inverted.
as anybody tried removing the output coils? It's mentioned in the manual.
Quote:

In the following cases, use a speaker with an inductance of 20H or more (at around the switching frequency (fCKIN or fCK)).
1. Direct connection of a speaker to an output pin of the digital amplifier without an LC filter.
2. Connection of a speaker to a position after components of EMI measures such as ferrite beads etc. (filterless).
With an induction of les than 20uH, power loss in the speaker and this device may increase.


Peter Pan 29th May 2012 12:43 AM

I'm still messing with it and in fact intend to use it in at least one project I intend to market. The only mods I've attempted hava already been mentioned, changing the gain setting, and paralleling the inputs (and outputs) to make a mono block. Having messed with the gain settings though, I think I'll leave them unmodified for future use, adding any additional gain with a separate pre-amp. The lower (as shipped) on board gain setting also enables a kind of AGC, that does a good job preventing transient peaks from causing ugly sounding class D distortion. Were I concerned about the output being inverted, I'd add my own separate op-amp inverter stage. For my project, this isn't a problem.


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