Jump to content

These ads only show for users who are not registered or logged in


Photo

Geeky Hifi Amp Solution


  • Please log in to reply
32 replies to this topic

#1 friendly1_uk

friendly1_uk

    Spends way too much time on Nutz

  • Members
  • PipPipPipPipPipPipPipPipPip
  • 9,607 posts
  • Gender:Male
  • Location:Nottingham

Posted 17 October 2016 - 03:43 PM

In this post, I'm going to talk about the latest integrated circuit that satisfies both Audiophiles and the budget conscious that can wave a soldering iron. 

 

20 years ago we had the Tripath chips that dominated the market, and are well reviewed in TA2020 amps such the Lepai. A $20 headphone amp that musters maybe 5wrms per channel, though it's sold as 25w rms with no consideration for distortion.

More recently, the Texas Instruments tpa3100 range has taken the crown, and as of a few years back, 50w per channel amps that can bridge have been released. It's this tpa3116 that has my interest.

 

A quick search will reveal 1000 page long threads on this topic, hosted on DIY HiFi forums. This chip is satisfying. As is the £10 price tag on boards that deliver 100wrms X 2 with the right power source: http://www.ebay.com/...r-/281712272349

 

Like most, they want between 9v and 24v. With 12v we would see just a quarter of that power, but just £10 buys a 12v to 24v convertor. So hey presto, 100wrms X 2 for £20 http://www.ebay.co.u...=STRK:MEBIDX:IT

 

This would be quite rough. Like a midi system, not a hifi. That 100rms is 70rms if we are realistic about distortion. The input caps want swapping for metal film and two stages of simple capacitor based filtering is missing compared to the TI supplied diagrams. Some supply decoupling caps right by the chip are missing and It's hard to say if they configured the two amps as master and slave or as other Chinese boards, forgot and introduced noise. All this can be fixed though. 

 

I'm listening to one of these right now: http://www.ebay.co.u...=STRK:MEBIDX:IT

That is just a single chip, but just one stage of filtering is missing and the decoupling caps. All of which is in the post at £4. Running off a 12v 12w psu from an old router it's doing a fair job. A big warm sound with a midrange reminiscent of a valve amp, due to the fairly low damping factor of integrated amps. Unfortunately it gets muddled if I try and play lots of tracks all at the same time. The missing filtering lives between the chips output and the chokes, which will give the chokes less to do and is said to give much better separation. I don't see this amp ever competing with a £500 HiFi amp, but $500 headphone amps exist that revolve around the tpa3100 which was the first one made and rather low powered. 

 

I think anyone capable and interested could put together something rather special. The endless help online, and many youtube video's using serious test equipment should back this up as a viable project.

 

There are many tpa3116 based boards and boxes out there. Some with bluetooth. Others with tone controls. Many 2.1  50+50+100 designs. One or two can just be bought and used, but most need attention if your really serious about your sound.

 

The £20 starting point of this thread presumes the 24v convertor doesn't require work to cure noise. A smoothing cap perhaps. It's a simple solution for pushing some small subs about though. Accept it's £10 and run it off the 12v system to get maybe 25wrms per channel, which could feed these: http://www.richersou...0/pion-s-slw500

They're 12x43x36 so might hide behind a seat. It's a £20 project. An amp and two subs. Add the £10 12-24v convertor if it works, to release 4 times the power. The pio's claim they will take it. That 12cm is including the feet so they are fairly narrow.

 

 

 

 

While I'm having a waffle... The Mission cube subwoofer. Pair of 8s sharing under a cubic foot. Sealed. I paid £25 though people ask that per driver. It would make a small sub of well reviewed quality. It's a bit deep though for a real shallow box. I could measure if anyone wanted to know.


  • 0

89 Greddy. FMIC. EMB. LC-1. Gauge linearisation. Walbro+Relay. Racing Mazda ceramic downpipe with split mod. Silenced de-cat. FM duels. FM adjustable roll bars. FM rails. HD engine mounts. 1.8 Brakes with m/c brace. Later gearbox. Torsen LSD. Rokkor Mk2 coilovers. Weapon style bar. White wheels, White car, Black Hardtop. Sunglasses holder, footwell lights.


#2 LTurner1

LTurner1

    Code Monkey

  • Members
  • PipPipPipPipPipPipPipPip
  • 4,793 posts
  • Gender:Male
  • Location:Manchester/Wilmslow/Lytham St Annes/Romiley

Posted 17 October 2016 - 04:01 PM

Interesting!

 

I'd be into having a play with something like this, afterall I've ditched my head unit as things stand, and wouldn't mind a small discreet amp somewhere. I haven't fully decided whether I want radio yet though so I might just end up relocating a headunit to the glovebox or something. But if all I want is aux in from my ipod or phone then this might be a goer! 

 

It'd be nice to mount the amp itself somewhere in the dash, and then extend the wiring for the volume control and the actual aux in to be somewhere discreet. Maybe have the aux in, mounted in the centre console and the volume knob sticking off the dash somewhere sensible...


  • 0

MvVoNTxb.jpg NeeoQyFb.jpg Xh7xjZ8b.jpg  XbdiDtJb.jpg

Build Thread - http://www.mx5nutz.c...howtopic=105180

 


#3 HarryB

HarryB

    Nutz regular

  • Members
  • PipPipPipPip
  • 540 posts
  • Gender:Male
  • Location:Greece

Posted 17 October 2016 - 07:54 PM

Sensible is the cig lighter... As you can tell have been searching a similar project to go with my Nexus installation, albeit I would also love radio and BT connectivity.


  • 0

#4 dave65

dave65

    Nutz regular

  • Members
  • PipPipPip
  • 359 posts
  • Gender:Male
  • Location:durham

Posted 17 October 2016 - 08:15 PM

interesting i've been thinking of removing my head unit and having a mini amp.


  • 0

#5 friendly1_uk

friendly1_uk

    Spends way too much time on Nutz

  • Members
  • PipPipPipPipPipPipPipPipPip
  • 9,607 posts
  • Gender:Male
  • Location:Nottingham

Posted 18 October 2016 - 01:05 AM

If your using bluetooth for mp3's then a 3100 series chip is a bit overkill. A bluetooth amp with car stereo performance is about £7.50

http://www.ebay.co.u...sd=322214963570

Here is a video is it playing at distance:

 

There is a bluetooth+radio+memory card reader 'front end' for £4 that offers a hard wired option also: http://www.ebay.co.u...sd=381749145530

That would feed a separate amp of almost any type. This one is a little smarter, but it's £5.39 http://www.ebay.co.u...sd=191680263174

 

I'm not sure how the above front ends sound. They do come with amps attached from other vendors, but non I know of are that good. There is a whole load of so called mini amps to look at, but nearly all fall down when reviewed beside the favourites.

 

 

I thought somewhere sensible for the volume, would be right beside the ignition key. Power on. Volume up! :)

 

 

I keep listening to this little amp on my 12w power supply. With 90% efficiency it can't be far off 5w a side. Enough to find my rooms resonant frequencies and flex the windows though. I know I'm an audio snob. I will turn off most things as just noise. Lots of kit has been through my hands, much of which lasts literally seconds on the bench before I have heard enough. This sounds fat and heavy. Not muffed, just a bit too weighty. Which is something I have never said about an amp before. I can't wait to mod it further. Having so far just dropped the gain to reduce background hiss. It's meaty presentation is great with my Jungle, I just need to loosen the midrange a bit. Then I would put a big price ticket on it.


  • 0

89 Greddy. FMIC. EMB. LC-1. Gauge linearisation. Walbro+Relay. Racing Mazda ceramic downpipe with split mod. Silenced de-cat. FM duels. FM adjustable roll bars. FM rails. HD engine mounts. 1.8 Brakes with m/c brace. Later gearbox. Torsen LSD. Rokkor Mk2 coilovers. Weapon style bar. White wheels, White car, Black Hardtop. Sunglasses holder, footwell lights.


#6 tigerstyle

tigerstyle

    Nutz regular

  • Members
  • PipPipPip
  • 310 posts
  • Location:Bedford

Posted 18 October 2016 - 11:03 AM

Enjoying reading this! 


  • 0

#7 R3k1355

R3k1355

    Advanced Nutzer

  • Members
  • PipPipPipPipPipPipPip
  • 2,967 posts
  • Gender:Male
  • Location:Sheffield

Posted 19 October 2016 - 02:34 PM

If you were to use it to drive a sub, but didn't have a dedicated subwoofer signal for the amp could you install a low-pass filter before the amp and feed it a normal output?


  • 0

#8 friendly1_uk

friendly1_uk

    Spends way too much time on Nutz

  • Members
  • PipPipPipPipPipPipPipPipPip
  • 9,607 posts
  • Gender:Male
  • Location:Nottingham

Posted 19 October 2016 - 06:46 PM

Bass amps really need an adjustable crossover point to properly pair with what your door speakers can achieve. If you wanted stereo plus bass, the 2.1 amp looks ok, but I'm not sure that's for you. http://www.ebay.co.u...sid=p5731.m3795

That is just a random link, you can probably find it cheaper.

Bass needs a big dose of power. If your doors get 50 each a sub probably wants 200 if you play bass heavy stuff. I'm not sure what your building but with so many used car amps available that offer lots of adjustment and clout for the same money, I'm not sure I would get to involved with cost saving or getting the very best sound. I was a bit excited before when I suggested the £7 100+100 amp and some £5 richer sounds subs. For bass, I would just buy something used.

We do know the input impedance so could calculate the inductor value for the frequency you want, and a 10 pack would likely be 99p so you would have a few spares to sum some other values. It's not beyond reason, I just don't know if I would bother. This 3116 stuff is overkill on quality and not really beefy enough for a dedicated bass amp. 

 

 

 

I can't stop listening to the bugger. I have been benchmarking it against rated hifi amps and it's a contender in many respects. I can see why the hifi forums are abuzz with talk about them. It's got a big warm bass greater than Arcam or Audiolab, which really puts it out there. It's got a silky smoothness in the mids that just veils voice's a little, so may not suit screaming rock fans but takes the edge off in a way that will really suit £100 door speakers with that warmpth and fluidity. It's in the high frequencies it needs work. There is quite a bit of sibilance, making the Th in This into hissing somewhat. On a level with entry grade hifi. This follows on with big band stuff where symbols are not quite right, and the noise of bow on string is lost. The metallic sound of metal instruments resonating not there. Though the music from a tuba is wholly appreciated. The high frequencies are probably off because it's class D. Switching the power at 40khz to make a smooth waveform at perhaps 7khz won't happen. No amount of waveform shaping will enable a 20khz signal to be reproduced accurately from just two square waves. Most peoples hearing isn't right over 10khz though and by middle age we can't hear past 15khz so it's not the end of the world.

 

My components arrived today so it's time to mod and benchmark again :)


  • 0

89 Greddy. FMIC. EMB. LC-1. Gauge linearisation. Walbro+Relay. Racing Mazda ceramic downpipe with split mod. Silenced de-cat. FM duels. FM adjustable roll bars. FM rails. HD engine mounts. 1.8 Brakes with m/c brace. Later gearbox. Torsen LSD. Rokkor Mk2 coilovers. Weapon style bar. White wheels, White car, Black Hardtop. Sunglasses holder, footwell lights.


#9 friendly1_uk

friendly1_uk

    Spends way too much time on Nutz

  • Members
  • PipPipPipPipPipPipPipPipPip
  • 9,607 posts
  • Gender:Male
  • Location:Nottingham

Posted 19 October 2016 - 11:08 PM

Well I got the filters in. Certainly better but not night and day. I'm tripping it up playing Faithless Music Matters

It's processed to give an airy feel, using a bit of echo to boot. That's causing some problems on the female vocalist. At 1 min she starts, and some of the S noises are causing problems like she is lisping a bit. Later in the track some T's. I know my £500 amp can resolve this, but this £20 one just wants to get down and boogie. It's really great with his voice, but the effects on this track are making it sound bad. Like a Technics or Kenwood system might manage. Which is really being hard on it, because it's £20 and I'm pitting it against a few things 50 times the price. Plus I'm using metal dome tweeters which add sibilance at the slightest excuse. I'm sure most of you will hear just the same issue if you play the track on your own kit. It doesn't make it a bad amp. It's just not perfect. It really wants to get down and play some rhythm, not lay out a full orchestra in front of you or show all the hammers hitting the piano strings. Which will never happen in the car anyway. 

 

I'm not sure I can get the decoupling caps by the chip. It looked like hard work, and I wanted to try it again following the boot strap cap mod.

 

Edit: This mod has made it normal. The bass weight and smoothness has gone, leaving a more normal, lean sound. Nope... Boring. Too clinical, and it's really not transparent enough to be clinical. It's still good, but the character drawing people in has gone. I'm going to have to get my hands dirty and find a compromise. Though that lisping is much reduced with the soft domes Ive switched to. So I can see why this mod is recommended on the manufacturers data sheet.


  • 0

89 Greddy. FMIC. EMB. LC-1. Gauge linearisation. Walbro+Relay. Racing Mazda ceramic downpipe with split mod. Silenced de-cat. FM duels. FM adjustable roll bars. FM rails. HD engine mounts. 1.8 Brakes with m/c brace. Later gearbox. Torsen LSD. Rokkor Mk2 coilovers. Weapon style bar. White wheels, White car, Black Hardtop. Sunglasses holder, footwell lights.


#10 HypnoToad

HypnoToad

    Nutz regular

  • Members
  • PipPipPip
  • 107 posts
  • Gender:Male
  • Location:Bristol

Posted 28 October 2016 - 12:34 PM

I still run a few Tripath amps, TA2020's, you can get a little more out of them if you run them at 14v-15v, around 10-12W rms before the THD creeps in. It's amazing how something so small can make such a detailed sound.

 

I'll have to try some of the newer offerings, I've found the Meanwell power supplies for well for amps that need a higher input voltage, they give a clean power feed. :)


  • 0

#11 friendly1_uk

friendly1_uk

    Spends way too much time on Nutz

  • Members
  • PipPipPipPipPipPipPipPipPip
  • 9,607 posts
  • Gender:Male
  • Location:Nottingham

Posted 28 October 2016 - 04:10 PM

I have had my next update on hold. I messed up my testing. When I did the filter mod, I switched to different speakers without realising. Basically pulling the first ones apart for a makeover because a second set arrived, but it turns out this second set sound different to the first. Differences I wrongly attributed to the amp.

 

These test speakers are 100mm metal cones with metal tweeters in a metal enclosure, connected with silver cable. Everything about them says avoid bright sounding electronics. Even as a £1000 set the reviews point out you will need to partner them carefully. They are very revealing.

 

This amp sounds nice. The filter mod didn't loose any bass, and did clean the sound up a little. The decoupling capacitors gave further improvements. Each being definite upgrades. Then the psu was switched from the 12w transformer based one to a 90w 19v laptop charger and it also made things a step better. I imagine on battery it can only get better still. Like any 12v amp, it's not really getting past 16wrms or 20rms per channel if we allow marginal distortion. Just like a car stereo can supply. That might be enough for many though. There is always another 3db to be had from a bridged version, but thermal limitations from sharing the heatsink likely make it pointless.

 

It's a smooth performer. Not the most revealing amp in my collection, but as a hifi amp sat in a dealers, it's sound wouldn't be terrible at £300. Even without any modification it's a contender, not just midi system junk. Taming the metal speakers in a manner that shows it will help cheap car speakers to not become fatiguing

 

I think for anyone wanting an amp to just plug there phone into, to achieve car stereo volumes, this £20 offering can't be beaten. I might try a version with tone controls next


  • 0

89 Greddy. FMIC. EMB. LC-1. Gauge linearisation. Walbro+Relay. Racing Mazda ceramic downpipe with split mod. Silenced de-cat. FM duels. FM adjustable roll bars. FM rails. HD engine mounts. 1.8 Brakes with m/c brace. Later gearbox. Torsen LSD. Rokkor Mk2 coilovers. Weapon style bar. White wheels, White car, Black Hardtop. Sunglasses holder, footwell lights.


#12 HarryB

HarryB

    Nutz regular

  • Members
  • PipPipPipPip
  • 540 posts
  • Gender:Male
  • Location:Greece

Posted 28 October 2016 - 07:05 PM

Thanks a lot for posting all these up, definitely got me intrigued


  • 0

#13 friendly1_uk

friendly1_uk

    Spends way too much time on Nutz

  • Members
  • PipPipPipPipPipPipPipPipPip
  • 9,607 posts
  • Gender:Male
  • Location:Nottingham

Posted 28 October 2016 - 10:49 PM

There are quite a few youtube video's of these Chinese amps being tested. There are many based around other chips claiming 800w and such, but it's almost all lies. Only the older 2020 tripath such as the lepai and some of the 31** based units are hifi standard. I think the lepai is about £10 now. A real bargain for a connoisseur of such things, but I'm not sure it's loud enough for the car. The 3100 was no louder. It's as we got to the 3116 where we got a chip that can actually manage 50rms a channel in the right situation. That being 24v with 4ohm speakers and some special attention to cooling. 30rms per channel is about our limit or the tiny core gets close to 200c in a moment, and the amp has a chill out break. These figures are not bridged though. It seems using multiple chips correctly has as yet not been achieved in China. Though you can fix that by choosing master and slave, to stop the noisy argument they have otherwise.

 

 

I will be opening a Blaupunkt car amp soon. I'm quite sure it uses 24v rails, which is all I want from it. A nicely boxed psu with remote switching. I will ignore the amp half, and just pull the 24v I need off the smoothing caps. If needs be I can adjust it's voltage anyway. Each rail will be monitored via a voltage divider, so it's just a few resistors. I like these easy little projects. The Blau is no good as it is. The left and right don't even sound the same. It's a 'new in the box' door stop. About to find some use :)


  • 0

89 Greddy. FMIC. EMB. LC-1. Gauge linearisation. Walbro+Relay. Racing Mazda ceramic downpipe with split mod. Silenced de-cat. FM duels. FM adjustable roll bars. FM rails. HD engine mounts. 1.8 Brakes with m/c brace. Later gearbox. Torsen LSD. Rokkor Mk2 coilovers. Weapon style bar. White wheels, White car, Black Hardtop. Sunglasses holder, footwell lights.


#14 HypnoToad

HypnoToad

    Nutz regular

  • Members
  • PipPipPip
  • 107 posts
  • Gender:Male
  • Location:Bristol

Posted 28 October 2016 - 11:26 PM

Yep those PMPO figures need to be taken with more than a pinch on salt! The datasheets show the real (RMS) power and how much THD is at various power levels, but even these sometimes do not tell the whole story.

 

I did try a Lepai TA2020 in the car for a while when my headunit died, used a few Zener diodes to drop the voltage a little below 14v while the engine was running, it really didn't sound good as the power supply was just too noisy. I just use it in the house now, or from batteries for a small portable sound system, and it sounds a million times nicer.

 

Nice idea using an old car amp for it's SMPS, if you find the voltage rails are above 24v, it's easy enough to just unwind the toroid transformer a few turns in order to reduce the voltage a little :)


  • 0

#15 friendly1_uk

friendly1_uk

    Spends way too much time on Nutz

  • Members
  • PipPipPipPipPipPipPipPipPip
  • 9,607 posts
  • Gender:Male
  • Location:Nottingham

Posted 31 October 2016 - 02:00 AM

Interesting point about the noisy 12v in the car.

This 3116 is like duel mono, with each amp having it's own 12v connection. I have gone right up to the chip and fitted a 330uf Panasonic FC at each. The FC is their very low impedance capacitor for car use. Where a lot of noise is likely. This is something the datasheet shows but the Chinese omit. Well, the sheet shows decoupling caps (just caps to ground). It's the forums where the FC choice comes from. Though indoor use is on their mind. The amps input is 10 470uf caps, so I will switch the first two in the bank for FC's as I just put in an order with some spares. I'm making another.

If it's still an issue, I will measure up for a single 4700uf FC, or some way of summing it up nicely. It's quite tight in there. I had to pull out one of the 470's to get one of the 330's right in close. So reclaiming that 470 might be nice. Though I did gain 660 at the time. So I'm 200uf up. 

 

I guess I could always fit a farad externally lol Or more likely find a broken hifi amp to give up it's smoothing. Though that switchmode will change everything. I don't have scope, so may end up with a know voltage regulator circuit. A third idea in the mix. Though that's a project for another forum perhaps. Nobody is likely to copy what I do there. 


  • 0

89 Greddy. FMIC. EMB. LC-1. Gauge linearisation. Walbro+Relay. Racing Mazda ceramic downpipe with split mod. Silenced de-cat. FM duels. FM adjustable roll bars. FM rails. HD engine mounts. 1.8 Brakes with m/c brace. Later gearbox. Torsen LSD. Rokkor Mk2 coilovers. Weapon style bar. White wheels, White car, Black Hardtop. Sunglasses holder, footwell lights.


#16 R3k1355

R3k1355

    Advanced Nutzer

  • Members
  • PipPipPipPipPipPipPip
  • 2,967 posts
  • Gender:Male
  • Location:Sheffield

Posted 01 November 2016 - 11:48 AM

Are you going to make a build thread type thing so others can have a go?

 

I honestly don't really have a clue what you're talking about, but I'm fine doing some simple soldering and stuff to make a few nice improvements.


  • 0

#17 Quick Silver

Quick Silver

    Miss me?

  • Members
  • PipPipPipPipPipPipPipPip
  • 4,522 posts
  • Gender:Male
  • Location:North Wales

Posted 01 November 2016 - 12:23 PM

Are you going to make a build thread type thing so others can have a go?

 

I honestly don't really have a clue what you're talking about, but I'm fine doing some simple soldering and stuff to make a few nice improvements.

 

I'd second all the above

 

Vince.


  • 0
Meet%20Banner%20-%20Monthly.jpg

#18 friendly1_uk

friendly1_uk

    Spends way too much time on Nutz

  • Members
  • PipPipPipPipPipPipPipPipPip
  • 9,607 posts
  • Gender:Male
  • Location:Nottingham

Posted 01 November 2016 - 01:19 PM

I will try and go a bit slower and take some pics when the next one arrives. It's not particularly involved with the only surface mount work a part removal. In fairness though, the amp is ok and the mods only really show if your using some very expensive kit. It will be removing vehicle noise where the real work lies.

On my phone at the alignment center. Saving you a long post lol
  • 0

89 Greddy. FMIC. EMB. LC-1. Gauge linearisation. Walbro+Relay. Racing Mazda ceramic downpipe with split mod. Silenced de-cat. FM duels. FM adjustable roll bars. FM rails. HD engine mounts. 1.8 Brakes with m/c brace. Later gearbox. Torsen LSD. Rokkor Mk2 coilovers. Weapon style bar. White wheels, White car, Black Hardtop. Sunglasses holder, footwell lights.


#19 LTurner1

LTurner1

    Code Monkey

  • Members
  • PipPipPipPipPipPipPipPip
  • 4,793 posts
  • Gender:Male
  • Location:Manchester/Wilmslow/Lytham St Annes/Romiley

Posted 01 November 2016 - 02:34 PM

Also interested in a guide  :thumb-up:


  • 0

MvVoNTxb.jpg NeeoQyFb.jpg Xh7xjZ8b.jpg  XbdiDtJb.jpg

Build Thread - http://www.mx5nutz.c...howtopic=105180

 


#20 dave65

dave65

    Nutz regular

  • Members
  • PipPipPip
  • 359 posts
  • Gender:Male
  • Location:durham

Posted 01 November 2016 - 10:44 PM

would also be interested in a guide,


  • 0




0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users