Sonic Impact 5066 Parts List & Modifications

Here's some data on what I've managed to pull from one of my Sonic Impact 5066 boards. This information should not be taken as gospel -- it's my best attempt to decipher the workings of the board.

-------------------------------------------------------------------------

Sonic Impact 5066 Parts Description, correlating to tripath datasheet
http://www.tripath.com/downloads/TA2024.pdf

This information is based on a Sonic Impact 5066 board with the date code of 2003.07.03

Parts with a (?) next to them indicate my best guess of this part's value and/or purpose. Many of the capacitors on the bottom side of the board, toward the speaker outputs, are most likely part of the output correction stuff on the datasheet. I was also unable to locate any schottky diodes on the output, as listed in the datasheet, but this may be my inability to decipher some of the surface mount parts.

=============
Connector #1:
=============

(from Left to Right):
V + Ro Lo G Li Ri

V = switch 12volt out
+ = switch 12volt in
Ro = to volume from right channel
Lo = to volume from left channel
G = ground
Li = from volume control to amp left channel
Ri = from volume control to amp right channel

The LED is mounted to bottom. Looking down from the top, the cathode (notched side) is on the left.

==================
Connector #2 (12V)
==================

Looking at the board from the top, with the wide side closest to you, the pins are as follows (front top to bottom):

Pin 1 (Top, Center): 12V in

Pin 2 (Middle, to the right): Ground disconnect for battery source. This pin opens the grounding between the battery and the rest of the board when a plug is inserted

Pin 3 (Bottom, Center): Ground


If you decide to remove the 12V jack, and don't care about destroying it, the easiest way I've found is to do as follows:

1) Using desoldering braid or a desoldering iron, remove as much solder from each of the pins as possible.
2) Using snips, cut the tabs off the bottom of the jack
3) Reheat the solder pad on pin3 and pull the connector from the back of the board towards the front. Then proceed in order through Pin2 and Pin 1.

=======================
Connector #3 (Audio in)
=======================

Looking at the board from the top, with the wide side closest to you, the pins are as follows (left to right):

Pin 1: Right channel in
Pin 2: Ground
Pin 3: Ground
Pin 4: Left channel in
Pin 5: Ground (located in the center of the connecter, below the other 4 pins)


==========
Resistors:
==========

t = top
b = bottom

Offboard:
---------
VR1 = 50k (volume control, measured 45k5)


Onboard:
--------

Top:
R01t = 10k (103), Right channel in, connected to ground
R1t = 1k5 (152), Current limiting resistor for LED
R2t = 20k (203), Ri - Inverting Input Resistor, Left Channel
R4t = 36k (363), Rf - Feedback Resistor, Right channel

Bottom:
R02b = 10k (103), Left channel in, connected to ground
R1b = 20k (203), Ri - Inverting Input Resistor, Right Channel
R3b = 8k2 (822), Rref - Reference Resistor to pin 6
R5b = 36k (363), Rf - Feedback Resistor, Left Channel
R8b = 10 (100), Output Zobel, Right Channel
R9b = 10 (100), Output Zobel, Left Channel


===========
Capacitors:
===========

Top:

C5t = 0.1uF?, Cs - Low Voltage Bypass, connects to pin 1, 4 and 9
C7t = 0.1uF?, Cd - Charge Pump input cap, pin 2-3
C10t = 330uF/16v, Csw - Supply Decoulping for H-bridge Supply Pins
(This cap supplies Vdd1 and Vdd2, as they are connected under the chip.)

Bottom:
C9b = 1uF, Cpump - Charge Pump Capacitor
C11b = 0.1uF?, Csw - Local supply decoulping for H-bridge
C12b = 0.1uF?, Csw - Local Supply decoupling for H-bridge
C17b = 0.22uF?, CDo - output zobel, right channel
C18b = 0.22uF?, CDo - Output zobel, left channel
C21-24 = 0.47uF?, Co - Output Capacitors


=========
Grounding
=========

The large solder blobs on the board are connected to the ground plane as far as I can tell. The grounding is connected to the bottom of the chip by a large number of vias underneath. This is similar to the Powerpad(?)-style mounting of a headphone amp chip from Texas Instruments.
 
Modification Suggestions

Here's my list of suggested modifications based on the datasheet and what I've seen other modders do:


1) Remove volume control and either wire it directly to your input jacks (dedicated amp) or wire it to a better one (integrated amp). Basically, get rid of the volume board.

2) Remove the power and audio input jacks. Wire your inputs directly to the pads described above. I wired the +12V in on mine directly to the switched 12v in, and the ground to pin 3 on the power jack.

3) Replace R4/R5 to 20k resistors. This sets it to the "ideal" 12V/V listed in the datasheet (Vinnie R states that he does this mod on his Clari-T mod of the Sonic Impact). Currently, the gain is set to 21, this mod would reduce it to 12 (I think.. I'm not an EE, so if this is incorrect, someone please let me know).

4) Replace C10. I replaced this with a Panasonic FC 16v cap that I had laying around. Vinnie R implies that he desolders C10, C11 and C12, and then solders "two" C10's of either 1500uF or 1800uF, one each directly to VDD1 and VDD2. These are then bypassed with 0.1uF surface mount caps on the caps.

I think this is unnecessary. C11 and C12 are already extremely close to the input pins. VDD1 and VDD2 are already interconnected underneath the chip (I dissected one SI board to confirm this!). Therefore, I think connecting a 1500uF or 1800uF cap directly to one of the pin sets would be sufficient. I can't see any harm in adding it to both pins, but I think you definitely run into the law of diminishing returns. For the ground path on this cap, just hook it into one of the giant solder blobs near the chip.

5) Replace R01t, R2t, R4t, R02b, R1b and R5b with better quality resistors. I don't think the ones on the board are of particularly high tolerences. 0.1% surface mount chips are extremely inexpensive, so this could be a good replacement.

6) Replace the input and output connectors. I think this one is pretty much a given. The spring clips for the speaker-outputs are pure ****. The input via 1/8" jack is fine for portable applications, but useless for home apps. I'm presently using jrsun's WBT-like RCA's and Binding posts.

7) New Case. I think this one is also a given. I'm presently using a Context Engineering case for mine (I'll try to post pictures later).

If anyone else has suggestions, please contribute! Hopefully with the parts list above it will help other folks come up with ideas for mods!


motherone
 
AC power supply possibilities

My current thought on an external, AC power supply on the cheap consists of the following:

2.4A, 15VAC wall transformer:
http://www.allelectronics.com/matrix/AC_Wall_Transformers.html

Digi01's Positive Regulator Board
http://www.diyaudio.com/forums/showthread.php?s=&threadid=39816

I'm outfitting the regulator board with a LM1085 voltage regulator set to 13V, along with a 12,000 uF 35v cap and MUR860 diodes.

I haven't completed mine yet, but I think that this is a pretty good set of suggestions. The total cost is probably $30, and I think it will beat the pants off any readily available regulated power supply near that price.

I'll let folks know how mine sounds once it's completed.
 

KT

Member
2003-10-11 4:37 pm
USA
Motherone,

Great post. Your research is very, very helpful!

I was also thinking of using digi1's regualtor board for the PS, but most likely for ones I'll be making for friends and family who don't want to deal with a battery.

Are you going to try CarlosFM's snubberized PS on the Sonic Impact? This was originally intoduced by Carlos for use with the gainclone amps. According to a members who's tried it, it works well for these digital amps, as well.

Apparently the snubberized design sounds just as good as a regulated supply (and even better according to Peter Daniel).

I like the snubberized supply because it alleviates the heat issues that sometimes regulated supplies have. I like this idea because the less heat, the better the longevity and reliability of the amp. And if it sound just as good or even better, well, hey!

Of course, the regulated supply will be somewhat smaller because it doesn't require as many large caps. With the results said to be equal or better, I like the passive solution better, myself.

Please let us know how your tests go.

Thanks!
KT
 
I use the SA to run my mids and Aurum Cantus 2si ribbon tweeter.

The sound is incredible, BUT I recently noticed that the highest highs such as cymbols lose their distinctive sounds and are more like a sizzle sound rather than brass being hit. Same for cowbells, the sound is a bit like a CD mistracking (exagerating a bit here...)

Now that I've note this it bugs me. I use a stock SA with a wall wart supply. Will any of these mods help this?

For bass I use my gainclone, so the weak bass doesn't affect me.
 
KT said:
Motherone,

Great post. Your research is very, very helpful!



Thank you. I was trying to find this information myself, but have yet to see anyone post anything like this. I think Vinne R might have this info, but since he's trying to create a commercial endeavor off of mods to the SI, it's probably not in his best interest to post this =)

KT said:
I was also thinking of using digi1's regualtor board for the PS, but most likely for ones I'll be making for friends and family who don't want to deal with a battery.

Are you going to try CarlosFM's snubberized PS on the Sonic Impact? This was originally intoduced by Carlos for use with the gainclone amps. According to a members who's tried it, it works well for these digital amps, as well.

Apparently the snubberized design sounds just as good as a regulated supply (and even better according to Peter Daniel).

I like the snubberized supply because it alleviates the heat issues that sometimes regulated supplies have. I like this idea because the less heat, the better the longevity and reliability of the amp. And if it sound just as good or even better, well, hey!

Of course, the regulated supply will be somewhat smaller because it doesn't require as many large caps. With the results said to be equal or better, I like the passive solution better, myself.

Please let us know how your tests go.

Thanks!
KT

I'm familiar with the snubberized power supply from Carlos. My thoughts are that I'll experiment and probably install the snubber before the regulator.

I'm definitely going to use a regulated PSU. The Gainclone has a pretty wide tolerence on what voltages it will handle, the Tripath chip doesn't. I'm setting my regulated PSUs to 13v dead even. Batteries usually sit at ~13.2v when fully charged.

Also, you only need 1 regulator for this chip. I'm using a 12,000 uF 35v Nichicon LS(M) before the regulator, and a 16v 470uF Nichicon HE(M) after the regulator. I may need to add a snubber/zobel(?) post-regulator to keep it stable -- I'm not sure if using the HE(M) will destabilize the regulator. The 35v 12,000uF caps are available from Apex Jr. (2 for $1!). Even if you just went with a snubberized version, you'd only be adding an additional cap and resistor to this.

Finally, as for the heat issues, if you go with one of the nice cases provided by AMT, you could probably just bolt the regulator to the case with a mica insulator and some heatsink goop with no problems. For $50 or so, I think his case is a fantastic bargain (I have to remember to e-mail him to buy a few!).


Variac said:
I use the SA to run my mids and Aurum Cantus 2si ribbon tweeter.

The sound is incredible, BUT I recently noticed that the highest highs such as cymbols lose their distinctive sounds and are more like a sizzle sound rather than brass being hit. Same for cowbells, the sound is a bit like a CD mistracking (exagerating a bit here...)

Now that I've note this it bugs me. I use a stock SA with a wall wart supply. Will any of these mods help this?

For bass I use my gainclone, so the weak bass doesn't affect me.


My lightly modded (new case, 10k noble volume pot and 680uF Panasonic FC in place of the original 330uF no-name cap) sounds absolutely fantastic. I'm still only powering it off the AA batteries. I'm using some Acoustic Research AR-17 speakers. These speakers have a Aluminum midbass coated with magnesium, and a titanium dome tweeter coated with diamond dust. Basically, it's unforgiving on badly recorded material and will show a spitty sound with bad electronics. I haven't noticed this at all with the SI, though.

My hunch is that your ribbons might be picking up some of the remnants of the high-frequency hash from the switching frequencies on the chip.

I'm in the process of picking up new parts from Digikey to finish up a newly modded one to compare against my lightly modded "benchmark". This list right here is only a list of the mods done to the board itself, not to the chassis/etc:

1) 4x 20k and 2x 10k 0603 surface mount resistors (0.1%):
http://www.digikey.com/scripts/DkSearch/dksus.dll?Detail?Ref=442911&Row=357674
http://www.digikey.com/scripts/DkSearch/dksus.dll?Detail?Ref=442911&Row=365300

The 20k resistors will replace R2t, R4t, R1b and R5b, while the 10k will replace R01t and R02b.

2) Removal of C4 on top and C3 on the bottom from the board. I'll bridge these traces and then mount the input caps offboard. I'll be using 5.1uF Solens for this.

3) Mount 1x 2200uF Panasonic FM cap as close as possible to the chip (probably to one of the pins), and removal of the 330uF cap in position C10t. The Panasonic FM cap is available here:

http://www.digikey.com/scripts/DkSearch/dksus.dll?Detail?Ref=443968&Row=360781

If you want to use something that fits in the original spot, the largest cap that will fit there is 8mm in diameter, so you're limited to a 680uF cap from panasonic. Nichicon's HE series might have something that fits there, though. Digikey's has the 680uF panasonic FM here:

http://www.digikey.com/scripts/DkSearch/dksus.dll?Detail?Ref=443968&Row=360808


4) Replace the 0.01uF output caps across the speaker terminals with 1% tolerance Polypropylene caps:

http://www.digikey.com/scripts/DkSearch/dksus.dll?Detail?Ref=444529&Row=368886

I think these mods will get the board a lot closer to it's full potential. After that, short of a redesign of the board itself, I don't think we'll be able to improve on it much more.

If anyone else has any suggestions, let me know -- I'll be placing my order with Digikey tomorrow. Good luck with your mods everyone!
 
motherone said:
Here's some data on what I've managed to pull from one of my Sonic Impact 5066 boards.... from Texas Instruments.


Motherone,
You have left out the input blocking capacitors. It has been suggested that they are limiting the low frequency response. They have to be connected to the 10K resistor setting the input impedance and connected to the input pins of the 2024.
This makes me think there is one on top and one on bottom. I am going to dig in and try and locate them. Bypassing them with a larger valur cap may flatten out the response below 200 Hz.

George
 
Panel,

Thanks for your reply. I agree with you that the input caps are most likely the source of low-frequency rolloff on the amp.

C3/4 in the post above are what I believe to be the input blocking capacitors. I'll be replacing those with Solen 5.1uF caps to see if it makes an appreciable difference.

On a side note, I placed my order with Digikey yesterday for the new resistors, caps and other parts. They shipped it this morning, so I should get it in the next few days.

I decided to go with Panasonic 1% resistors for the time being -- It's the same price for 50 of them versus 5 of the 0.1% resistors.

Hopefully this will bring good changes to the amp! To be honest, I really thought this SI stuff was a lot of hype until I put one on my little AR-17's.. I dare say it sounds better than my Panasonic Class-D amp.. It definitely seems to have more "punch" than the Panasonic at 1/20th the power.
 
Caps on speaker terminals

The film caps strapped across the speaker terminals in my SI are 0.15 ufd, not the 0.01 listed in the Tripath info. I think they made changes in the front, the circuit looks a lot simpler than the Tripath evaluation board.
The C3/C4 are the input caps. Polarity can be verified, the side that connects to the 20K resistor is the high voltage side.
I wonder is a high quality, 2.2 ufd is available. The ones listed in the Trpath data sheet are 2.2 ufd 10v ceramic X5R. The part number at DigiKey is PCC1868CT. These are multi layer type. They list them in larger values, but all look to be larger than the coupling caps used by SI. The one used by Tripath is larger than the SI.
Guess I need to make probes to fit my capacitance meter and check the value of the caps used by SI. I would be great to be able to extend the low end just by installing another cap here.

George
 
George,

Thanks for that piece of info! I totally missed that they spec'd it out on the datasheet. I think someone (Thorsten?) had posted in another thread that multilayer caps are terrible in signal chain due to smearing. I obviously have no idea on this, but it's food for thought.

I also agree that C3/4 look much too small to be 2.2uF. If you have a capacitence meter and can measure it, I'd be much obliged.

I'm hoping someone else can take a look at their boards and verify that my parts list above is correct. I'm guessing that if someone who has more experience at this type of stuff than I do can confirm it, it'll open modding these little guys up to even more people.

The one thing I still can find are the Schottky diodes mentioned on the datasheet. All the parts appear to be capacitors, resistors or coils, with no diodes in sight. Does anyone have any insight on this?

Thanks for your help!
 
The one thing I still can find are the Schottky diodes mentioned on the datasheet. All the parts appear to be capacitors, resistors or coils, with no diodes in sight. Does anyone have any insight on this?

Thanks for your help!

The clamping diodes are there. They are the large square blsck surface mount components. I put mine with me back into the new case, but they sais BEC or something. I do not think these are high quality. This may be a good swap also.
When I return home later this week I will try to measure C3/C4.

George
 
jkeny said:
Another area that impacts sound significantly is the inductors. What is the make/quality of these on the SI? Keep up the good work. I have two SI's on order and hope to see them in the next couple of weeks (by which time this thread will have become an opus)

Someone had posted the inductor manufacturer, but I can't seem to find that thread. I also can't remember if it was posted on here, or one of the other forums. This would be good info, and I'd be more than happy to purchase some inductors to swap out and see how ti goes and return the results to the group, IF someone can suggest a suitable (better!) replacement.


Panelhead said:


The clamping diodes are there. They are the large square blsck surface mount components. I put mine with me back into the new case, but they sais BEC or something. I do not think these are high quality. This may be a good swap also.
When I return home later this week I will try to measure C3/C4.

George

George,

Which ones? There should be 4 diodes on board, and I can't find anything close to the chip that would indicate they're on here. The only black chips on my board are for the resistors (R01, R1, R2 and R4 on top, R1, R3, R5 R8 and R9 on bottom). There's also what I assume to be two inductors on the board, labelled L1 (top) and L2 (bottom). Everything else is labelled with a "C" for surface mount parts, so I've assumed those to be capacitors. The remaining parts are the LED, the 330uF electrolytic cap, and the 4 inductors.

Thanks,

Mike
 
Here's a quick list of possible inductor replacements for L1-L4. I'm not sure if someone out there knows more about what type of inductor would offer improved performance over the existing ones, but I thought I'd take a shot and post the candidates that I've found so far:

JW Miller Magnetics:
--------------------------

Part# 6000-100k, 10uH @ 3.4 Amps, DCR of 0.045, SRF of 14Mhz ($1.51 each)
http://www.digikey.com/scripts/DkSearch/dksus.dll?Detail?Ref=273803&Row=323313


Toko America:
------------------

Part# 824MY-100K, 10uH @ 2.2 Amps, DCR of 0.052, SRF of 44Mhz ($5.57 each)
http://www.digikey.com/scripts/DkSearch/dksus.dll?Detail?Ref=273803&Row=455776&Site=US
 

Pano

Administrator
Paid Member
2004-10-07 6:05 am
Panama
Hi Guys,
Mike, you and George seem to be becoming real experts on these chips.

So of course I wanted to throw in my 2cents worth ;) and also ask a couple of questions.

The caps called C2 /C4 are indeed the DC blockng input caps, i found them while poking around the board today.
They are also the reason for the bass roll off. There is no low end loss in the signal path until it gets to the DC side of these caps. Then the attenuation is the same as I measured and graphed (see my site).

I don't know what the 2 SMDs labled L1 & L2 do, but they are certainly in the signal path. No DC on either side, as far as I can tell. Can't tell if they are in series or paralelle with the signal path but they get the same signal as c2/C4. Why would there be an LC filter at the input?

The ouput inductors sing. :att'n: If the amp is pushed hard (near max) the little chokes start to sing. You can quiet them down by placing a finger on them. Time for them to go.

Questions:
How are you ordering the Panasonic caps? I tried to follow the links posted but they had expired. I can find an in stock at Digikey, and minimums are 250~500.

Mike,
Did you get your Solen input caps in place yet? They should make a huge difference, if only in the bass. Have you also replaced the ouput filter?

I hope to make an seperate I/O board with better parts for the input and output filters. Also plan to bring the -3dB point of he output filter down an octave to about 35 kHz.

That's all for now.
Aloha
MM

My site: http://www.michael.mardis.com/sonic/
 
panomaniac said:
Hi Guys,
The caps called C2 /C4 are indeed the DC blockng input caps, i found them while poking around the board today.
They are also the reason for the bass roll off. There is no low end loss in the signal path until it gets to the DC side of these caps. Then the attenuation is the same as I measured and graphed (see my site).


Thanks for confirming this. I'll be bypassing these guys soon.


panomaniac said:

I don't know what the 2 SMDs labled L1 & L2 do, but they are certainly in the signal path. No DC on either side, as far as I can tell. Can't tell if they are in series or paralelle with the signal path but they get the same signal as c2/C4. Why would there be an LC filter at the input?


I believe they are in parallel. The via right next to L1 is connected to ground, while the other pin looks like it's in parallel with the input.

panomaniac said:

The ouput inductors sing. :att'n: If the amp is pushed hard (near max) the little chokes start to sing. You can quiet them down by placing a finger on them. Time for them to go.


Hmm. Maybe some physical dampening is in order? Either that, or some seriously better chokes should be put in. Perhaps the singing is caused by clipping?

panomaniac said:

Questions:
How are you ordering the Panasonic caps? I tried to follow the links posted but they had expired. I can find an in stock at Digikey, and minimums are 250~500.


Do a search for "Panasonic FM Capacitor" on digikey. Make sure you check the "In stock" button.

Here's the part numbers for a few of them:

Panasonic FM, 16v/680uF: P12377-ND
Panasonic FM, 16v/1000uF: P12366-ND
Panasonic FM, 16v/1200uF: P12367-ND
Panasonic FM, 16v/1500uF: P12368-ND

The 680uF should be a direct replacement for the existing electrolytic. It's the same size as the 680uF panasonic FC I'm using right now. The FM series is supposedly far superior to the FC series. Also, these are all available in quantities of 1, and the price ranges from $0.50 each to $0.76 each.

panomaniac said:

Mike,
Did you get your Solen input caps in place yet? They should make a huge difference, if only in the bass. Have you also replaced the ouput filter?


I'm waiting for my parts from digikey to arrive before starting on the next board. I'll probably throw this one in a wood enclosure for testing purposes and see how it goes. The parts from Digikey should arrive some time this week, so hopefully I'll be able to try it out this weekend.

panomaniac said:

I hope to make an seperate I/O board with better parts for the input and output filters. Also plan to bring the -3dB point of he output filter down an octave to about 35 kHz.


I plan on soldering the input caps directly to the back of the RCA jacks, and then hot-gluing or zip-tying them down in my enclosure.

As far as the output goes, I originally thought C21-24 were the output caps, but these are in fact the Schottky diodes mentioned on the datasheet. I whipped out the multimeter and confirmed it with it's diode testing function tonight.

R8b and C17 form the Right Channel Zobel, while R9b and C18 form the Left Channel Zobel. I think that the remaining caps on the bottom (C13, C14, C15, C16) and the two remaining ones on the top (C19 and C20) form the output network. I haven't had time to check the traces to figure out what's what. If you can measure these, we can probably just match them up to the datasheet.

Thanks for your input. I think we'll be getting pretty close to getting this board completely deciphered, which will make modding it even easier.
 

Pano

Administrator
Paid Member
2004-10-07 6:05 am
Panama
motherone said:
I believe they are in parallel. The via right next to L1 is connected to ground, while the other pin looks like it's in parallel with the input.

Hmmm.... I thought I saw signal on both sides of L1/L2. Will have to check again.

Maybe some physical dampening is in order? Either that, or some seriously better chokes should be put in. Perhaps the singing is caused by clipping?

It is, but some of the ringing just before clipping might be caused by the chokes. They need to go. Would we put inductors like this into our speaker projects? :whazzat: Let's hope not!

Here's the part numbers for a few of them:

Thanks a million.

I plan on soldering the input caps directly to the back of the RCA jacks, and then hot-gluing or zip-tying them down in my enclosure.

Sounds like a good plan. Simple and straight forward.

As far as the output goes, I originally thought C21-24 were the output caps, but these are in fact the Schottky diodes

Yes indeedy, they are. I took my switching waveforms from there.

R8b and C17 form the Right Channel Zobel, while R9b and C18 form the Left Channel Zobel. I think that the remaining caps<snip>

Good work! Nice to know where they are. We are getting close to figuring this thing out.
 

Pano

Administrator
Paid Member
2004-10-07 6:05 am
Panama
Input Schematic

Here is the input schenatic for the Sonic. A bit different from the Tripath app notes.

This should help in bypassing any or all of it.
 

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