New Amp 11 Hi-power kit [Archive]

View Full Version : New Amp 11 Hi-power kit

Scratchy

25-Aug-08, 01:48

As per the latest news post form Jan, I did some searching on this STA516B chip and found the following:

It seems there was a production run of these for Philips, but perhaps they are no longer made due to the hissing problem as discussed in this forum?
http://www.avforums.com/forums/showthread.php?t=657273

I also found the STA517B chip which is stocked by several suppliers:
http://www.sourceesb.com/ProdSearch.asp?part=STA517B13TR

It looks like it could be a direct substitute for the STA516B ?!?
http://pdf1.alldatasheet.com/datasheet-pdf/view/217134/STMICROELECTRONICS/STA517B13TR.html

I think this is a really great kit for hi-powered mobile applications and would love to see Jan produce more of these.

***If it was easy, everyone would be doing it***

gupsta

25-Aug-08, 04:29

Does the LV version now come with air core inductors ?

Cheap +/-50vdc smps here http://cgi.ebay.co.uk/NEW-UNUSED-50V-DC-POWER-SUPPLY-9-9A-BY-MINEBEA_W0QQitemZ280181270070QQcmdZViewItem?hash=i tem280181270070dunno if it would be suitable.

gupsta

25-Aug-08, 04:29

Scratchy

25-Aug-08, 06:53

quote:Originally posted by gupsta

Does the LV version now come with air core inductors ?

Cheap +/-50vdc smps here http://cgi.ebay.co.uk/NEW-UNUSED-50V-DC-POWER-SUPPLY-9-9A-BY-MINEBEA_W0QQitemZ280181270070QQcmdZViewItem?hash=i tem280181270070dunno if it would be suitable.

Amp11 uses a single ended supply, hence my reference to mobile applications.
A simple 12V to 48V DC to DC converter can be used for a 300W stereo Amp.

***If it was easy, everyone would be doing it***

Scratchy

25-Aug-08, 06:53

Jan

25-Aug-08, 09:21

Hi and thanks for the feedback!

STA516B /STA517B; I have asked ST several times about the difference between them but got no reply. I compared the datasheets for both and to me the datasheets seem identical to the last letter, except the "6" or "7". Both are listed as in "Evaluation" status, ie not in regular production.

I will probe for the STA717B, if they really are available. If these perform like the STA508, but with more voltage / current, they should imo make exellent amps! I will aslo have my own AMP11-HV up and running in a few days.

Jan

25-Aug-08, 09:21

mazdapowered

25-Aug-08, 14:15

from the avfourms about the chip:
quote:I actually opened mine, it uses STA516B quad-amplifier. The 8 Ohm stages (subwoofer and central speaker) are connected with something like a "differential" filtered input whereas the other 4 (3Ohms stages) are connected relative to the ground. The ground connection should be very noisy/badly isolated, this is why you can "hear" some glitches related to the "digital" part (try pressing some keys on your remote).
From the above it is implying that the noise from the STA516B is being caused more from poor circuit/layout design than anything wrong with the STA516B, its self.

I've but in an order for the AMP11-HV and have a 50V power supply (nearly) ready so Ill try and go for a quick build to get some feed back on this.

Richard

mazdapowered

25-Aug-08, 14:15

Scratchy

26-Aug-08, 06:48

Let us know how the Amp sounds Mazdapowered.
It's strange that Phillips used these in their Amps, but there are none to be had on the market.

I did some more Googling for the STA517B.
It seems the only difference is in the power rating:
STA516B Dual 160W BTL class-D power audio amplifier output stage
STA517B Dual 175W BTL class-D power audio amplifier output stage
Although the datasheet indicates the 516B rating at 50V and the 517B rating at 54V.

This link showing quantities available seems quite promising:
http://www.hkinventory.com/public/OfferInventResult.asp?Order=1&pnums=sta517b+audio&crit1=&crit2=&category=&product=&keywords=&words=3&country=&postdate=&brand=&crit3=&crit4=0&datecode=

***If it was easy, everyone would be doing it***

mazdapowered

03-Sep-08, 23:07

The amp kits have arrived but I am tempted to wait for feed back from Jan about his build before I go ahead. Plus I'm supposed to be building speakers and a casing my previous amp11's.

Richard

col_s

08-Sep-08, 06:55

I just completed my Amp11-HV (using STA517B) and have it working. I can't comment on sound quality as I still have it on the bench using a test speaker. It certainly functions properly. I have sound coming out, and the DC offset is adjusted close to 0mV.

At the moment I am running it using only a 30V rail and power is via a PS3 using the amp11's on-board regulator for 5V. Modifications to the over/under voltage sense resistors and modulator feedback resistors are all that is really required to optimise it for different voltages.

I've only had it playing for a few minutes. I need to mount it onto a heatsink.

I'm also building a second amp11-HV. I guess it will be easier to evaluate the sound quality when I can listen to them in stereo.

mazdapowered

09-Sep-08, 00:23

Thanks col_s for the feedback on your build please keep us updated. Also thanks for the heads up on the modulator feedback resistors, I'd forgoten about them :).

Richard

col_s

09-Sep-08, 03:54

quote:Originally posted by mazdapowered

Thanks col_s for the feedback on your build please keep us updated. Also thanks for the heads up on the modulator feedback resistors, I'd forgoten about them :).

Richard

More about this from my own notes are below... please double check all of this for yourself as I may have made an error or incorrect assumption. At the moment I appear to be getting nasty distortion/clipping at medium volumes so I wonder if I have messed something up somewhere.

Colin

---

The modulator feedback should be set based upon the rail voltage. The formula from the data sheet (TK2050) is

Rfbc=(Vcc*Rfbb/2)-Rfbb

Rfbb is fixed to 1K. Supplied for Rfbc is a 10K+2.2K resistor in series, ie. 12.2K. These resistors are R3+R114 and R12+R103. Reworking the above equation, Vcc=(12200+1000)*2-1000 = 26.4V, so it is roughly optimised for a 24V supply.

For a 48V supply, it would be (48*1000/2)-1000 = 23Kohms required for Rfbc.

With the supplied voltage sense resistors (R52, R54) of 220K, I calculated it should turn off if the voltage exceeds appx 35V. To calculate the correct resistance for a particular upper voltage, divide the vppsense over voltage turn off current threshold of 162uA into the voltage.

eg. 35 V / 0.000162 A = 216049 ohms

For a 50V turn off, it works out around 309Kohms

The under voltage turn off point is also adjusted proportionally. The threshold current for under voltage turn off is 72uA. For 220K resistors, it will be 35/0.000072 = 16V. With the 309K resistor calculated above, the under voltage turn off would be about 22V

The AI says that the on-board 9V regulator that feeds into the 5V regulator is good for up to 32V, so changes would need to be made to use a higher rail voltage. I suppose if you are using PS3, that it would make sense to feed the output of the preregulator on PS3 in via R2 and disconnect R2 from the rail.

col_s

12-Sep-08, 05:25

The distortion with my first Amp11-HV was due to a bad solder joint on one of the VCC pins on the power chip. I got a buzzy sort of sound when the volume was turned up high. I fixed that and now it works perfectly. I pushed it right up to the maximum my source could give, through a dummy load and it was fine.

I also completed my second Amp11-HV and have given them a bit of a listen. I can't really fault the sound. As would be expected with dual-mono, the channel separation is fantastic. Noise is very low (tested with the "stuck my ear next to the tweeter" test). Heatsinks are almost cold.

I still have not tried it with a higher voltage, so I have not really pushed it past the specs of the standard Amp11.

mazdapowered

12-Sep-08, 09:33

Great news on your progress and BTW your calculations on the modulator feedback look sound.
No movement on my Amp11 HV's, I've been working on my bass cabs, no need for my high powered AMP 11 if there nothing to drive.

Richard

V-bro

12-Sep-08, 11:29

quote:Originally posted by col_s

The distortion with my first Amp11-HV was due to a bad solder joint on one of the VCC pins on the power chip.

I have had this on two of the eight AMP11 I've built. There are some PCB pads that need incredible amounts of heat to be soldered, even though it's just a 0805 component to be soldered there...

In general:
It's all due to the large and thick copper planes that are attached to these certain pads. It is VERY important to monitor that the solder really flows on the PCB and not only the component. It's also not a bad idea to first heat the PCB and than touch the component, otherwise you may overheat these components...And add small amounts of solder over and over until you see it flow on the PCB pad.

------X-max. can be several meters on any driver, too bad it can be done only once...------

longitude

30-Sep-08, 20:03

quote:Originally posted by V-bro

quote:Originally posted by col_s

The distortion with my first Amp11-HV was due to a bad solder joint on one of the VCC pins on the power chip.

I have had this on two of the eight AMP11 I've built. There are some PCB pads that need incredible amounts of heat to be soldered, even though it's just a 0805 component to be soldered there...

In general:
It's all due to the large and thick copper planes that are attached to these certain pads. It is VERY important to monitor that the solder really flows on the PCB and not only the component. It's also not a bad idea to first heat the PCB and than touch the component, otherwise you may overheat these components...And add small amounts of solder over and over until you see it flow on the PCB pad.

------X-max. can be several meters on any driver, too bad it can be done only once...------

I am interested in amp11-HV,
however, I can't find them in costumer shop anymore.
I remember I saw them last week...
:(
Are they out of stock?

V-bro

30-Sep-08, 21:23

Hi, I'm afraid it could be worse, they may not be there any more at all....

But you can order the standard kit and swap the electrolytic caps and order the STA.....chip yourself....

I'll ask Jan, keep you informed....

------X-max. can be several meters on any driver, too bad it can be done only once...------

Scratchy

01-Oct-08, 03:25

Have a look at this post in the Latest News section:
http://41hz.com/Forums/topic.asp?TOPIC_ID=2033

quote:
The bad news; this chip is not available . It has been listed under "Evaluation" status for almost two years and can not be bought. I got my hans on a small batch and I will sell these kits now as it makes no sense holding on to them forever. The deal is:

* You can only buy these kits on the Customer Shop page, ie only available to those of you who for those of you who are already customers.

***If it was easy, everyone would be doing it***

longitude

01-Oct-08, 17:17

quote:Originally posted by V-bro

Hi, I'm afraid it could be worse, they may not be there any more at all....

But you can order the standard kit and swap the electrolytic caps and order the STA.....chip yourself....

I'll ask Jan, keep you informed....

------X-max. can be several meters on any driver, too bad it can be done only once...------

Please!!!
I really want to have a pair of them (or even some pairs...)!

audiophool

01-Oct-08, 18:09

I may be able to get hold of some of these chips. If you want some, please post here about how many you want and what you are prepared to pay for them. I guess I would need to get a batch of at least 20.

Rgds.

V-bro

01-Oct-08, 18:42

Hi, I would like to get 20 pieces at least...

------X-max. can be several meters on any driver, too bad it can be done only once...------

audiophool

02-Oct-08, 02:10

If I find the ICs at an acceptable price, I will buy them immediately and not come back with a quote for further discussion/consideration. If you want some, please post here about how many you want and what you are prepared to pay for them. Please consider that there will also be the cost of shipping.

Rgds.

col_s

02-Oct-08, 03:08

quote:Originally posted by audiophool

If I find the ICs at an acceptable price, I will buy them immediately and not come back with a quote for further discussion/consideration. If you want some, please post here about how many you want and what you are prepared to pay for them. Please consider that there will also be the cost of shipping.

Rgds.

Thanks for offering to look into this. I would definitely buy 4, but maybe a batch of 10 if the cost is not high. I'm not sure of their value but I would be willing to pay reasonable costs for your trouble.

longitude

02-Oct-08, 03:21

I would like to buy 8 pieces,
If the cost is not high, I think I will buy 12 of them.

audiophool

02-Oct-08, 16:17

So we want 32 to 42 pieces on whether the price is reasonable or high. What price is reasonable and what price is high? I would be doing this as a favor for you guys.

Jan

02-Oct-08, 16:30

Hi,

My AMP11-HV worked without any problems, even if I have not put it under any high power or measurements yet.

Availablility; I do have a dozen more of the STA516B chip but was waiting for some reactions on the first STA517B batch, especially pushing it beyond what the original chip could handle.

IMO this is a very, very interesting chip and amp, if you can handle the surface mount issues.

dweekie

02-Oct-08, 16:48

I'd like to get 4 chips, maybe a few more. I'm not so sure about the pricing of these chips though. It seems like given the power ratings, a fairly high price would still make the Amp11HV attractive. Is there any estimates? The most expensive STA chips I see are $13 USD at Digikey, so anything around there sounds reasonable to me.

V-bro

02-Oct-08, 18:29

If I buy the batch I buy it for the company I work for and they need a receipt so to speak... Perhaps It's best if Jan orders "enough" of them, It'll draw customers for sure! I'd prefer to order them through 41hz.com myself...

------X-max. can be several meters on any driver, too bad it can be done only once...------

longitude

03-Oct-08, 04:34

quote:Originally posted by V-bro

Perhaps It's best if Jan orders "enough" of them, It'll draw customers for sure! I'd prefer to order them through 41hz.com myself...

------X-max. can be several meters on any driver, too bad it can be done only once...------

Me too...
So...Jan, PLEASE let us know when will amp11-HV be available.

audiophool

03-Oct-08, 13:13

OK then that's me done!

V-bro

03-Oct-08, 14:16

I don't know what Jan pays for them, maybe you can help Jan to tell him where you get them from Tim?

------X-max. can be several meters on any driver, too bad it can be done only once...------

audiophool

03-Oct-08, 15:00

Jan,

Please email me if you are interested.

Rgds.

Jan

04-Oct-08, 14:07

Hi,

We will put out another dozen kits, with the last chip I have, in the shop of the support site in the coming week. I will post here when they are available.

I also have to find more chip. I am searching.....

Jan

05-Oct-08, 16:49

Hi,

The AMP11-HV kits will be available, in a limited number, from noon (European time) tomorrow monday, in the shop on the support site.

mikechw

11-Dec-08, 15:51

Will these kits be available again ?

So which chip does the STA chip replace from the original ?

Can anyone comments on the audio quality of AMP11-HV compared with Truepath ?
Is building 2 AMP11 easier than building a Truepath ?

Thanks..
Michael

V-bro

11-Dec-08, 15:59

Hi, I haven't built mine yet, but all I can say is that I've always been very impressed with the sound quality of the AMP11 36Vdc version and the LV version as well... I have read somewhere that the HV version would have slightly more distortion so that would indeed make it somewhat more comparable to Truepath. But Truepath is much more powerful. I think that building two AMP11 comes very close to the amount of work it takes to build a Truepath and the difficulty level is pretty comparable...

------X-max. can be several meters on any driver, too bad it can be done only once...------

mikechw

14-Dec-08, 13:40

Thanks for the info,

I just ordered a few AMP11-LV and 2 Truepath kits.

mikechw

14-Dec-08, 16:19

If I have a pair of 6 ohm speakers, how do I calculated the max output from each AMP11-LV that I have. (assuming the supplied voltage is 24V)

What is the max currents that each speakers will experience ?

Thanks.

audiophool

14-Dec-08, 18:10

Mike,

TK2050 datasheet has a chart for for 6 ohms at 23.5V. It can supply approx 30W at low noise.

At 30W the current is (30/6)^0.5 = 2.2A RMS.

Rgds.

audiophool

14-Dec-08, 18:13

quote:Originally posted by V-bro

Hi, I haven't built mine yet, but all I can say is that I've always been very impressed with the sound quality of the AMP11 36Vdc version and the LV version as well... I have read somewhere that the HV version would have slightly more distortion so that would indeed make it somewhat more comparable to Truepath. But Truepath is much more powerful. I think that building two AMP11 comes very close to the amount of work it takes to build a Truepath and the difficulty level is pretty comparable...

------X-max. can be several meters on any driver, too bad it can be done only once...------

Hi V-bro,

I am interested to know what is the lowest THD+N level below which you would not be able to perceive any difference.

Rgds.

V-bro

14-Dec-08, 22:46

quote:Originally posted by audiophool

Hi V-bro,

I am interested to know what is the lowest THD+N level below which you would not be able to perceive any difference.

Rgds.

Well that's very interesting Tim as I've experienced something that proves THD is not very audible nor annoying.

I have had a demo day at VM (Van Medevoort). It's quite nearby where I live, it's a very small company where they make very decent high-end audio equipment, they are situated in Maarssen near Utrecht. They had a test setup with five amps all placed in similar looking black enclosures. They were configured* like this:

1. Single ended tube amp 8W/ch. with about ~5% THD, ~0,01% IMD. (intermodulation distortion)

Sound was very round smooth and warm, quite nice actually.

2. Push pull tube amp with 40W/ch. ~0,5% THD, ~0,01% IMD.

Sound was quite sophisticated, neutral.

3. 200W/ch. class B amp ~0,1% THD and ~3% IMD.

Basically a quite poor amplifier, powerful but dirty. It sounded terribly distorted in a very nasty way.

4. 100W/ch. class AB amplifier ~0,001% THD ~0,8% IMD.

Sounded reasonably good, good control and good with popular music. With voices and other "natural" sounds it didn't quite do the job, it had a slight dirty edge that spoiled the realism a little bit.

5. Class A 30W/ch. hybrid amp ~0,02%THD ~0,01% IMD.

Very natural fluent sound, smooth and entising. Good resolution and good behaviour with complicated signals like orchestral work.

First we had to listen before we knew what was in the boxes and we had to make up our opinions about what we thought we heard. We had to write our experiences down and then we would be introduced to what was in the boxes and what specs the amps would have.

Here's where I learnt that THD isn't much to worry about, it becomes audible when it reaches 5%, but it becomes really annoying when it exceeds 10%. IMD on the other hand becomes audible when it exceeds 1% and it becomes very annoying and even irritating when it exceeds 2%. IMD is the nasty and dirty sounding distortion where THD (the abbreviation reads "Harmonic" which already implies the distortion is in the harmonics, humans like the sound of harmonics) sound quite nice actually.

Tripath amps are best of both worlds, low THD and low IMD, that's why some find these amps sound a bit like tube amps, of course they don't, but it's low IMD they have in common.

* Specs I mention are from my organic memory banks and date from about eight years ago, but they are close enough to be able to make my point here...

------X-max. can be several meters on any driver, too bad it can be done only once...------

mikechw

15-Dec-08, 03:33

quote:Originally posted by audiophool

Mike,

TK2050 datasheet has a chart for for 6 ohms at 23.5V. It can supply approx 30W at low noise.

At 30W the current is (30/6)^0.5 = 2.2A RMS.

Rgds.

Does this mean I can assume TK2050 can output low noise if the current output from each channel is less than 2A ?

So if the output is parralleled, 2A * 2 ?
4A ?
4A^2 * 6ohm = 96 W ?

Does anyone know what is the max input voltage for AMP11-LV ?
Thanks..

col_s

15-Dec-08, 05:00

quote:Originally posted by mikechw

Does this mean I can assume TK2050 can output low noise if the current output from each channel is less than 2A ?

So if the output is parralleled, 2A * 2 ?
4A ?
4A^2 * 6ohm = 96 W ?

Does anyone know what is the max input voltage for AMP11-LV ?
Thanks..

Whether the output is paralleled or not, the load is still the same (ie. 6 ohm) so the power will be the same. To increase power, the load needs to be increased (eg. 4 ohm speakers) or the supply voltage.

The gain for AMP11's input stage can be adjusted over a wide range to match the maximum output voltage of your source. In addition to this you can adjust the amplifier gain (modulator gain) to match the power supply voltage that you use. These settings can allow you to tune the overall gain of the amplifier so that when the source is outputting full volume, the amplifier will be just below the clipping level (ie. before distortion rapidly rises).

mikechw

18-Feb-09, 17:51

quote:Originally posted by jan
If these perform like the STA508, but with more voltage / current, they should imo make exellent amps!

Can STA508 be used instead of TP2050 ??
Do they have the same power rating ??

col_s

18-Feb-09, 22:58

I think STA505 is equivalent to the TP2050, but STA508 looks like higher current version of STA505 and could also be used.

mikechw

19-Feb-09, 01:19

I need a replacement chip for my AMP11 :)

Looking for alternative replacements.
I see getting it from 41Hz is the cheapest option ...