[MitchV]

I am *not* an electronics wiz by any means, but I was hoping I could get some general advice on my PC speaker amplifier. I've received a lot of good advice in these forums.

Around the year 2000 I bought a Cambridge Soundworks speaker system DTT3500. I know it's not for audiophiles, but I still feel like it's one of the best $300 purchases I have ever made... I've really enjoyed the setup.

One of the nice features is that the amplifier accepts so many inputs and you can change between them with the press of a button or two. This is cool because the little box is MUCH smaller (and less powerful) than a stereo receiver.

If I could find something similar to this now, I would buy it.... maybe that is what I need to do. It accepts Optical in, Co-Ax in, Soundblaster digital DIN, standard front/back PC inputs.... and it outputs to a 5.1 speaker setup with a minimal amount of clutter.


Anyway... the unit now seems to need to "warm up." When I cut it on, the sound is at first inaudible and later becomes terribly broken. After 3-5 minutes it seems to fix itself. Is there a general diagnosis that might be the cause of this... would it be someting a n00b might have a prayer of fixing?

Thanks in advance!

[MitchV]

Not knowing what I am doing, I actually cracked open the box to see what I could see...

#1 It was a bit dusty, but no more than I would expect from this kind of device after 5-7 years of use. I blew it out with canned air.

#2 It looks like it must have been involved in a drink spill in the past. This equipment STAYS in my office and I never spilled anything on it. It makes me suspicious of the wife and kids.... but a lot of drink spills go unreported around here. /sigh

#3 I used a paper towel and alcohol to clean up any drink residue I could find. I tried to be careful. I was cleaning the bottom of the main board, and the capacitors and resistors were on the other side of the board and appeared to be unaffected by the spill.

#4 I did notice a single trace where there appeared to be exposed copper. I tried to clean this with alcohol really good.


I tested the unit again and got the same results.

Not being a person who knows anything about electronics, it would seem that there is likely a capacitor or some other component that must take too long before it builds an adequate charge... thus the crappy to non-performance when I first turn on the unit... and eventually it starts working as expected.

If my observations are true, should I attempt anything else with this thing? How the heck would I know which capacitor or whatever to replace... I have a multimeter, but I do NOT feel comfortable poking around testing things while this unit it on. I like it but I'm not gonna fry for it!!!

Thanks in advance again!

Mitch

[Skeith]

sounds like a bad capacitor, A leaky electrolyte will do this, Ive had this happen so many times on tube amps that I repair. Not very common on newer amplifiers since the capacitors arent ususaly old enough to dry up or become leaky, unless the are cheap capacitors to begin with.

Look for capacitors with odd discolourations and or bulges. Meethinks on the powersupply or output coupling capacitors. The ceramic and mica caps usualy dont go bad as such.

[Per Hansson]

Had to register to post this, sorry for reviving a really old thread but it gets high on the google rankings...

I can confirm it's bad capacitors in the DTT3500 causing the issue you describe, a friends system had the exact same symptoms, it first threw me off tho because gently hitting the PCB in question with a plastic object caused the sound to go out; so i thought it was a bad solder joint...

But then finally I gave that up; I removed the faraday cage covering the Dolby Digital sound processor and replaced the 3 capacitors feeding it with power with ones from an old Audigy2 that was off for the dump anyway

Instantly when I powered on the system from being cold the Dolby Digital signal light that previously just blinked for like 5 minutes before becoming somewhat stable was dead steady on!

I'm using a 3.5mm Mono > RCA adapter in the digital out of a Creative X-Fi XtremeMusic for sound output, and have bought the Dolby Digital Live license so I encode the sound I play to Dolby Digital so I get real 5.1 sound...

I will buy new caps for the card, since reusing old ones isn't a good idea
Elfa in Sweden has suitable ones with these part numbers;
67-002-98
67-002-72
67-002-56

I will post a picture once I replace the caps with the good ones I buy from Elfa...

[ComicDom1]

Originally Posted by Per Hansson

Had to register to post this, sorry for reviving a really old thread but it gets high on the google rankings...

I can confirm it's bad capacitors in the DTT3500 causing the issue you describe, a friends system had the exact same symptoms, it first threw me off tho because gently hitting the PCB in question with a plastic object caused the sound to go out; so i thought it was a bad solder joint...

But then finally I gave that up; I removed the faraday cage covering the Dolby Digital sound processor and replaced the 3 capacitors feeding it with power with ones from an old Audigy2 that was off for the dump anyway

Instantly when I powered on the system from being cold the Dolby Digital signal light that previously just blinked for like 5 minutes before becoming somewhat stable was dead steady on!

I'm using a 3.5mm Mono > RCA adapter in the digital out of a Creative X-Fi XtremeMusic for sound output, and have bought the Dolby Digital Live license so I encode the sound I play to Dolby Digital so I get real 5.1 sound...

I will buy new caps for the card, since reusing old ones isn't a good idea
Elfa in Sweden has suitable ones with these part numbers;
67-002-98
67-002-72
67-002-56

I will post a picture once I replace the caps with the good ones I buy from Elfa...

Well I for one and glad you did. I wish I knew more about electronic repair. I started having problems getting sound out of my optical ports.

When I called Creative to seek repair or replacement because it was still under warranty at the time, they told me that they could not repair it and it was discontinued. I really loved the DTT3500 and the sound out of it was amazing to me. I asked about a different decoder, but I was told the speakers were digital and would blow if I hooked them up to a regular stereo. So I boxed up my DTT3500 and it has been sitting in the garage ever since. I would be thrilled if I could get it repaired. I even think I still have my digital din cable as well.

Creative them mentioned the DTTS-100 which was new at the time. So I bought one of those and they game me a set of inspire speakers they told me were equal to my DTT 3500 speakers. The newer speakers are ok, but I do not think the sound quality is the same. I probably should invest in the Giga Watt speakers but this would be a moot point if I can get the DTT 3500 repaired. Then I could use the DTT 3500 for my HTPC system and run my sound out optical for Blue Ray playback.

If parts are available that would be great. Do you think a local audio and tv type repair shop would be able to possibly fix this?

Let me know any idea's you might have.

You can email me at ComicDom1@aol.com

Thanks,
Jason

[Super Nade]

Originally Posted by Per Hansson

Had to register to post this, sorry for reviving a really old thread but it gets high on the google rankings...

I can confirm it's bad capacitors in the DTT3500 causing the issue you describe, a friends system had the exact same symptoms, it first threw me off tho because gently hitting the PCB in question with a plastic object caused the sound to go out; so i thought it was a bad solder joint...

But then finally I gave that up; I removed the faraday cage covering the Dolby Digital sound processor and replaced the 3 capacitors feeding it with power with ones from an old Audigy2 that was off for the dump anyway

Instantly when I powered on the system from being cold the Dolby Digital signal light that previously just blinked for like 5 minutes before becoming somewhat stable was dead steady on!

I'm using a 3.5mm Mono > RCA adapter in the digital out of a Creative X-Fi XtremeMusic for sound output, and have bought the Dolby Digital Live license so I encode the sound I play to Dolby Digital so I get real 5.1 sound...

I will buy new caps for the card, since reusing old ones isn't a good idea
Elfa in Sweden has suitable ones with these part numbers;
67-002-98
67-002-72
67-002-56

I will post a picture once I replace the caps with the good ones I buy from Elfa...

Hey man, welcome to ocf. How are you?

What caps did you use?

[Per Hansson]

Originally Posted by Super Nade

Hey man, welcome to ocf. How are you?

What caps did you use?

Thanks Nade, I used Jamicon SS series caps (same as original)
I first tried LOW ESR Sanyo MV-WX caps but that did not work so I guess it needs to be general purpose caps...
Pretty odd tho since it seems to be just for a power circuit...

Hopefully I will get the new caps I ordered from Elfa this Friday so I can remove the caps I scavenged off that Audigy2
Then I'll post some pics too, might even drop by over at Badcaps

ComicDom1; Yea, a TV Repair shop should be able to do this, it's allot of deassembly necessary tho, so might cost a bit...
Wait till I post the pics that will give you a better idea...

[Per Hansson]

First I have to apologize for the poor image quality, I forgot my SLR so had to use my Nokia N82...
The first image shows the system with only back and topcover removed, 2 screws in back and four in topcover

In the second pic some cables have been removed and the PCB lifted up.
The metal faraday cage must be removed for the caps we are looking for.
First unscrew the PCB with the metal faraday cage on it, there are 3 brass screws on the back holding it, desolder the cage carefully at the four points it is attached to the PCB with...

The next picture shows the 3 caps you need to change. (Next to the Zoran Dolby Digital chip) All are 16v one is 100µF, the other 47µF and the last one is 22µF... The big ones are Jamicon SS series and the 22µF is a Wincap R85SM(M)
Desolder these 3 caps and _gently_ push a small needle through the holes while heating them with the soldering iron, let the solder cool a second or two then gently pull the needle out so you have a free hole for the new capacitor (you do this because capacitors are very heat sensitive)
Now put the new caps in and solder them in place.

The last pic shows the replaced caps, after this mod the Dolby Digital light became lit permanently, and the sound produced with the X-fi XtremeMusic and Dolby Digital Live addon in Crysis Warhead was very emmersing in all it's 5.1 glory

[ComicDom1]

Originally Posted by Per Hansson

First I have to apologize for the poor image quality, I forgot my SLR so had to use my Nokia N82...
The first image shows the system with only back and topcover removed, 2 screws in back and four in topcover

In the second pic some cables have been removed and the PCB lifted up.
The metal faraday cage must be removed for the caps we are looking for.
First unscrew the PCB with the metal faraday cage on it, there are 3 brass screws on the back holding it, desolder the cage carefully at the four points it is attached to the PCB with...

The next picture shows the 3 caps you need to change. (Next to the Zoran Dolby Digital chip) All are 16v one is 100µF, the other 47µF and the last one is 22µF... The big ones are Jamicon SS series and the 22µF is a Wincap R85SM(M)
Desolder these 3 caps and _gently_ push a small needle through the holes while heating them with the soldering iron, let the solder cool a second or two then gently pull the needle out so you have a free hole for the new capacitor (you do this because capacitors are very heat sensitive)
Now put the new caps in and solder them in place.

The last pic shows the replaced caps, after this mod the Dolby Digital light became lit permanently, and the sound produced with the X-fi XtremeMusic and Dolby Digital Live addon in Crysis Warhead was very emmersing in all it's 5.1 glory

Why did you want the Dolby Digital light to be constantly lit? Didn't that take away some functionality of your DTT3500?

I have disassembled my unit before but not to the extent that you have. Your pictures and steps will be very helpful.

My issue maybe different. My sony type optical port stopped working and the round one was sporadic behavior with some scratchy type sounds coming through the speakers.

I still have all my speakers and the original sound card that takes the Digital Din plug. They are all boxed up in my garage.

Jason
ComicDom1@aol.com

[Per Hansson]

I want it to be lit constantly else when you play a sound, like the ding in Windows, the DD signal must get detected and then enabled on the receiver, which takes time and thus you only hear a small bit of the "ding" sound... (and any other sound, i.e. you miss the first 500ms or so of it..)

This is entirely a driver problem (if it exists)

[pmatil]

Hi all!

My DTT3500 stopped working yesterday. The subwoofer made a "poff"-sound and then nothing. All other speakers were dead except center which makes a silent "pop" every 500 ms or so. The real audio can be heard with every pop but only from the center speaker.

So I started searching if anyone had the same fault. I found this thread and replaced the mentioned caps. Didin't help. Then I measured the voltages on the main and on the control board. Today I noticed that at power-on the control board's 3.3 V regulators do NOT get +5 V in, and hence no 3.3 V out. After some more measuring it turned out that the part marked U13 was broken. This IC (or transistor or whatever) is supposed to connect +5 V to the regulators after the power switch is pressed. I removed the part and connected +5 V (red wire from the main board) to the closest 3.3 V regulator (type BA033). It works! I have to make a better solution because just connecting 5 volts to the regulators results in higher stand-by current consumption. Not much but a little.


Oh, before this happened I had occasionally problems with dolby digital sounds. I used the coaxial digital input. Sometimes the digital sound was nothing but hissing, whistling and random noise. The real audio could be heard in the background. I have to test whether it works again, I'll post the results later.

I hope this helps others with their faulty DTT3500s. I just love it, I use it with my home theatre.

regards,

Petteri

[Diogynes]

My DTT3500 started the crackling noises. At first, it was just a quick "pop" in the rear speakers every few minutes but it progressed into a serious "rice crispy" loud crackling from all speakers. I was a bit skeptical, but I replaced the three capacitors as shown and it completely fixed the problem.

I found the required caps on an older Creative card. The caps are physically short to fit under the shield and the ones from the Audigy and SB Live cards fit perfectly. You will need one each 22 uF, 47 uF, and 100 uF at 16v. It's an easy fix as long as you are comfortable with removing solder without damaging the circuit board traces.

[Frider]

big thanks from Moscow! %) i'm happy, after replace three capacitors my DTT3500 is OK! %))

[paul_ee]

The last time I hooked mine up for DD5.1 was when the audigy 5.1 came out. I tried to hook it up for 5.1 on a ps2 when they were new and just figured it was a codec problem making it crackle in and out of 5.1 so I have just been using them for HIdef stereo on my laptop since. Got a new ps3 slim and wanted to try again since playing MW3 on a 42" screen with narrow stereo sucks. Same thing cracking in and out of DD5.1 with the light blinking.. then it would almost work like it should. Now that I am into my junior year of electrical engineering i dug back into it and replaced every capacitor on the board with some better quality ones and it is good as new.... Guns and bombs have never sounded so good! Glad I could breath some life back into this thing, even if the 5.1 never worked again it has been worth everything i paid for it...

Just a note for anyone, i don't remember if it was this thread or another... there is no such thing as a digital speaker, only a digital amplifier. If you take these DTT3500 speakers and impedance match them to a reciever you should get excellent sound quality.... they are not the loudest, but when you have the clarity across the spectrum you shouldn't have to turn them up as loud to get them to sound good.

[lanset]

Originally Posted by Diogynes

My DTT3500 started the crackling noises. At first, it was just a quick "pop" in the rear speakers every few minutes but it progressed into a serious "rice crispy" loud crackling from all speakers. I was a bit skeptical, but I replaced the three capacitors as shown and it completely fixed the problem.

I found the required caps on an older Creative card. The caps are physically short to fit under the shield and the ones from the Audigy and SB Live cards fit perfectly. You will need one each 22 uF, 47 uF, and 100 uF at 16v. It's an easy fix as long as you are comfortable with removing solder without damaging the circuit board traces.

I got same problems as others with my amplifier Creative Cambridge
SoundWorks DTT3500.There is no new capacitors mention here in my region but I can get few older creative soundcards. Could anyone tell me from which model of sound card I can take off the capacitors and where they are on it? These are the cards that I can get:


I prefer Live! cards because I can get them chipper than Audigys.

Creative SB Live! (CT4670)
Creative SB Live! CT4830
Creative SB Live! SB0100
Creative SB Live! SB0220

Creative SB Audigy SB0090
Creative SB Audigy SB0570

Regards Alex

[przemas]

Originally Posted by lanset

There is no new capacitors mention here in my region but I can get few older creative soundcards.

I know it may be hard to buy these capacitors (you need them to be at most 7mm high to fit under the Faraday's cage, I had real problems finding the 100uF one), but it's really your best bet. Capacitors degrade over time and there's a chance you'll degrade them further during desoldering, so it's really better to buy them online instead of gettting old ones from a used component... I paid like 10c for the capacitors and $8 for shipment.
I don't know how problematic it would be to run without the cage, or a cage soldered 4mm higher (or maybe with holes cut out for the caps?), but if it can be done, you could even fit full height caps there.

BTW, thanks for the advice Per, my amplifier now works perfectly! You rock!

[przemas]

Some advice for people trying this without having much experience in PCB soldering:
- take photos during disassembly, just in case, maybe even make a list of detached connectors/ribbons
- use a small flat screwdriver to detach snap-in connectors, do not force them out
- during reassembly, make sure you insert the ribbon cable in the proper direction ;-) All other cables fit only in the proper direction.
- You need to buy 7mm capacitors, otherwise they won't fit under the cage. I've used Hitano caps (the only ones I could easily find with that height)
- I found desoldering pump to be helpful during Faraday's cage removal. Don't force the cage out, you will damage the PCB. You should be able to lift it side by side with your hand. The flat (copper?) piece under the cage is soldered AND glued to the PCB. If you heat up the solder, just pull it, the glue will let go.
- For desoldering caps, it's better to use the needle method Per has described (but you can give the pump a go as well).
- before resoldering the caps look at the PCB (take photo) to make sure you understand where the solder should and where it should not go
- don't use a soldering iron more powerful than 40W
- you really only need to replace the three caps. Replacing the rest is an overkill ;-)

[MattB247]

Hi

I too have a problem with my DTT3500. I use it for music in my study and connect either my laptop or mp3 player via the front analogue line in. Sound from the four satellites is fine (I haven't bothered connecting the front/centre satellite as I'm just using it for music) but the subwoofer output seems quite abrupt and crackly. I've tried lowering the output / bass etc from both the mp3 player and laptop and varying the volume and bass/tone, and also let it warm up for a while before use, but the subwoofer output is sometimes non existent or quite sudden and almost a few ms late as if the initial signal is lost before the sub kicks in. When it does play it's very deep and rumbly but a bit crackly. Has anybody seen anything like this? I'm not an electronics expert and I'm reluctant to take it to a TV/audio repair centre without having a rough idea of what may possibly be wrong with it as I don't want to have to pay a fortune to get a repair.

Any help or advice you could offer would be greatly appreciated!

Regards

Matt

[BloodlustNL]

I am simply gonna have to try the replacement capacitor trick but then again i have another problem will this fix the dts signals? because those stopped working years ago


i found all three capacitors needed on an old soundblaster awe 64 wich was heading for the scrapheap so here's hopin this will all work out like it should first i gotta get the buggers out of the old one

[nikop7]

First i'd like to thank Per Hansonn for this fabulous " how to " renew the DTT3500 !

I was trying to keep my kit alive till all of my speakers got the crackling disease ...
It began years ago with the optical input, then my coaxial went off too, and finally after loosing it all in "line in" mode i used your troubleshoot (today ^^) and changed the 3 capacitors.

Now it's like i just the kit out of the box anew ! Everything is working from line in to Digital ( coaxial mode) and 5.1 . Sound as clear as it could be ! I'm so happy ! Thanks a lot !

And for those who want to get a go, you got nothing to loose just do it, or ask a friend because the electronic part is not that easy !

Cheers !