Class T Audio Amplifiers - Page 4 - diyAudio
Go Back   Home > Forums > Commercial Sector > Vendor Forums > Inactive Vendor Forums > Connexelectronic

Connexelectronic Commercial Vendors large & small hawking their wares

 
 
Thread Tools Search this Thread
Old 19th July 2010, 09:56 AM   #31
diyAudio Member
 
Join Date: Apr 2008
V4 looks interesting.

But I have a question about theTA2022 amp. I'd like to get better quality coils. Cristi, can you point me into any direction. Their value is 10H, correct?

I also have a question regarding TA3020V2: I ordered the board for a friend of mine - he replaced some caps - and whenever the board is powered on I get smoke coming from one of the output resistors. Any idea what one can do?

Thanks in advance for answering.
Cheers,
Wolfram
 
Old 19th July 2010, 11:02 AM   #32
Cristi is offline Cristi  Europe
diyAudio Member
 
Join Date: Dec 2008
Location: Dortmund+Shenzhen
For the TA2022 amplifier the output inductors have 11uH (10-12uH) 11uH and the capacitor 220nF. I don't recommend to replace them since they are already made on one of the best core material which is also recommended by tripath in their application notes. to get better performances, you can increase the order of the filter, now is second order, can be increased at 4-th order by adding one more filter stage. but this should be done carefully using good quality cores and capacitors. air core inductors seems to be better but they radiate a looot of EMI unless they are shielded. they also must use thin stranded wire instead of single wire otherwise they will get very hot due to proximity effect.

The smoke coming out from Zobel resistors indicate that there is a high frequency oscillation and the reactance of capacitor from the zobel network connected in series with this resistors, allow the hi-freq current to pass through this resistors and they dissipate a significant power.
need to check carefully which capacitors were changed and their value. a wrong cap or mounted wrong can damage the amp. for example, if the cap value from the low pass filter is not within range (0.1-0.47uF) can get the same result. do not leave the board to work in this conditions, otherwise something will be damaged !!

As a general advice for all the enthusiast which wants to reach perfection, please, try to not change the components, since this can lead to malfunction. the board has already proper and selected components and there will be no significant positive changes in the sound, or at least does not worthed the risk to fry the board for that. sometimes i saw that some ppls trying to improve the sound, they replaced some components with others which even if they were more expensive and good to be used in some particular stages, they were not suitable to be used where they installed them. for example huge size film capacitors which might improve the sound on a class AB amp as input capacitors, were installed on a class D or T, under the board, and very close to the switching node, where high amplitude and high currents are switched very fast. the cap itself act like an antenna which capture a looooot of noise from the power stage and the end result is much worse than with the original caps plus the risk of damaging the amp to to excessive parasitic coupling.
__________________
www.connexelectronic.com complete assembled amplifier and SMPS
 
Old 26th July 2010, 11:56 AM   #33
zog666 is offline zog666  Australia
diyAudio Member
 
Join Date: May 2009
Quote:
Originally Posted by Cristi View Post
As a general advice for all the enthusiast which wants to reach perfection, please, try to not change the components, since this can lead to malfunction. the board has already proper and selected components and there will be no significant positive changes in the sound, or at least does not worthed the risk to fry the board for that.
I just learned that lesson the hard way! Tried to add some larger coupling capacitors and messed it up. My fault! Well on the positive side I'm interested to hear what differences the IRFP4228 fet option makes, as that was available after I purchased my TA3020 v3c.
 
Old 27th July 2010, 06:46 AM   #34
Cristi is offline Cristi  Europe
diyAudio Member
 
Join Date: Dec 2008
Location: Dortmund+Shenzhen
What's hapent ? what are the symptoms now ? is not working at all or one channel only ? if you can't fix-it you can send me back and i will solve-it for you. i also can replace the MOS-FET's with IRFP4228 if you want to try them.
__________________
www.connexelectronic.com complete assembled amplifier and SMPS
 
Old 27th July 2010, 11:35 AM   #35
zog666 is offline zog666  Australia
diyAudio Member
 
Join Date: May 2009
Quote:
Originally Posted by Cristi View Post
What's hapent ? what are the symptoms now ? is not working at all or one channel only ?
I replaced the 1uF input coupling capacitors with some Metallised / Polypropylene 2.2uF capacitors. These are quite large units with larger leads so took a bit of effort to get them into the holes from where the existing capacitors are.
I decided to wire them with the line in direct onto the capacitors so I didn't have to connect the other lead back into board (not enough room). Of course, though I didnt notice at the time, this excludes the 100K resistors across the input from the circuit. Possibly this blew the TA3020? (direct line in without the 100K resistors?) I disconnected and traced the circuit more carefully after this and added in 100K resistors across the inputs but it still doesn't appear to work. I suspect leaving out the 100K resistor may have overloaded the input?

Symptoms:
-> The unit is completely silent.. i.e. no faint white noise when ear up against tweeter, on either channel. It sounds like it is off, when powered up.
-> Heat sink doesnt warm up at all, before it got a little bit warm when powered on.
-> I can measure -50v DC + 50v DC at the outputs of the rectifier bridge, and the 38VAC - 0 - 38V AC on the AC input so the power appears OK.


Quote:
Originally Posted by Cristi View Post
if you can't fix-it you can send me back and i will solve-it for you. i also can replace the MOS-FET's with IRFP4228 if you want to try them.
Still thinking about this! My first thought was just to just order another one of your web site straight away.. of all the amps I have, this is by far the best, and the one miss the most having it non functional. Don't want to spend too much time without my Connex TA3020.
 
Old 12th August 2010, 11:48 PM   #36
col is offline col  Australia
diyAudio Member
 
col's Avatar
 
Join Date: Feb 2008
Location: Melbourne, Victoria, Australia
Default TA2022 scratchy distortion

My 1RU rack case implementation of the ConnexElectronic TA2022 has developed a scratchy distortion noise that I can't seem to cure. It may have been there from the start but wasn't discovered until later as it is a bit sporadic and only seems to occur on some music, it almost sounds like a loose wire being wiggled but it isn't. I have tried replacing all connections.

I'm wondering if it has anything to do with the input impedance setting resistors or the gain structure? Reading the Connex TA2022 manual it mentions that the impedance is set by 2 resistors R15-R17. Mine have the numbers "473" on them and I'm using them with 8ohm speakers? Or could it be the gain is to low? the resistors R8-R9 are "203". What would I change them to?

There is some photos here:

MINIRIG Minirig Symetrix 420 ConnexElectronic TA2022

cheers,
col.
__________________
http://www.minirig.org.au
 
Old 13th August 2010, 07:10 AM   #37
Cristi is offline Cristi  Europe
diyAudio Member
 
Join Date: Dec 2008
Location: Dortmund+Shenzhen
At which volume the distortion occur ? is just at high volume or even at low volume ? which frequencies are the most affected ? low or high ? is there any kind of noise when signal is not present ? what is the supply voltage ?
the described symptoms can have many causes, they can occur when either the supply voltage is too low, and the amplifier enter in premature clipping, the input signal has too high crest factor, there is an oscillation on the amp due to inpropper wiring and GND return path or the output inductor saturate, but this should not be the case, especially with 8R speakers.
if the R15-17 resistors are lower, the gain is higher. the simplest way to increase their value without replace or solder anything on the board is to connect in series with the input another resistors, then the total value of the equivalent resistors will be the sum of the existing resistor from the board plus the external one.
__________________
www.connexelectronic.com complete assembled amplifier and SMPS
 
Old 14th August 2010, 02:35 AM   #38
col is offline col  Australia
diyAudio Member
 
col's Avatar
 
Join Date: Feb 2008
Location: Melbourne, Victoria, Australia
Quote:
Originally Posted by Cristi View Post
At which volume the distortion occur ? is just at high volume or even at low volume ?.
it starts at a fairly low volume and extends through the volume range.

Quote:
Originally Posted by Cristi View Post
which frequencies are the most affected ? low or high ?
worse around 150-200hz

Quote:
Originally Posted by Cristi View Post
is there any kind of noise when signal is not present ?
No.

Quote:
Originally Posted by Cristi View Post
what is the supply voltage ?
30v

Quote:
Originally Posted by Cristi View Post
the described symptoms can have many causes, they can occur when either the supply voltage is too low, and the amplifier enter in premature clipping, the input signal has too high crest factor, there is an oscillation on the amp due to inpropper wiring and GND return path or the output inductor saturate, but this should not be the case, especially with 8R speakers.
if the R15-17 resistors are lower, the gain is higher. the simplest way to increase their value without replace or solder anything on the board is to connect in series with the input another resistors, then the total value of the equivalent resistors will be the sum of the existing resistor from the board plus the external one.
what would be a good resistor value to start with?

cheers,
col.
__________________
http://www.minirig.org.au
 
Old 16th August 2010, 04:54 AM   #39
Cristi is offline Cristi  Europe
diyAudio Member
 
Join Date: Dec 2008
Location: Dortmund+Shenzhen
Col,

where is connected the case to the GND ? check to see if there is no loop (again )
the resistors which you connect is series should have 10-22K. try to use a scope to see the output without input signal. there should be a clean sine wave at 600-700KHz with amplitude around 1-2Vpp.
__________________
www.connexelectronic.com complete assembled amplifier and SMPS
 
Old 16th August 2010, 11:10 AM   #40
col is offline col  Australia
diyAudio Member
 
col's Avatar
 
Join Date: Feb 2008
Location: Melbourne, Victoria, Australia
Quote:
Originally Posted by Cristi View Post
Col,

where is connected the case to the GND ? check to see if there is no loop (again )
the resistors which you connect is series should have 10-22K. try to use a scope to see the output without input signal. there should be a clean sine wave at 600-700KHz with amplitude around 1-2Vpp.
The wiring is connected exactly the same as your diagram:

Click the image to open in full size.

There is no screw between the middle screw hole of the TA2022 module and the case , the GND terminal of the TA2022 module connects into the SMPS250 which connects to the case. This is the only GND connection apart from the one that goes through the speaker protection module.

I connected my scope to the output. Without input the sinewave is thin and slightly wobbly. When I applied 640hz signal at 1.5Vpp to the input the sinewave is thick black and not stable but moving across the screen.

Will try with resistors.

col.
__________________
http://www.minirig.org.au
 

 


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
non surface mount class D mono audio power amplifiers Conor Digital Source 10 4th October 2013 07:38 PM
Single-Ended Class-A Audio Amplifiers shaan Everything Else 32 4th September 2009 02:42 AM
Class A vs. IC amplifiers for PC audio Beggar Solid State 15 26th July 2002 11:58 AM


New To Site? Need Help?

All times are GMT. The time now is 12:15 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2