Author Topic: duelund caps issues  (Read 15418 times)

tuyen

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Re: duelund caps issues
« Reply #40 on: October 13, 2010, 05:37:40 PM »
Can't agree more with your post 3bm.

I'm no electronics wiz either, so I'm truly enjoying the learning aspect of all this DIY stuff and when constructive input and advice is given from anyone.    I always try to help others whenever and whereever I can though. That's what I kind of enjoy about the the DIY scene. Everyone seems to try help each other out when possible?

Make peace, not war.  Enjoy your systems and remember to share the love!(when appropriate)

 ;D
« Last Edit: October 13, 2010, 05:39:53 PM by tuyen »

Offline stevenvalve

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Re: duelund caps issues
« Reply #41 on: October 13, 2010, 07:57:15 PM »
I can not undersatnd why my posting can turn people against each other .My B+ is mutch lower than others and I feel in my dac that this is not a problem but for others with higher voltage is the only reason that I posted it.
       Please stop fighting and enjoy you systems.
                                                                  Paul
Guys. We (Paul Terry Steven) have known for years that there is a surge on start up in the DAC, but its well within spec of this cap, i have used 30+ of these caps, and they have been running for years. and only 1 of these has failed and that was in the first hour. So there is no real need to get the 400V cap unless for reliability, That is why allmost all the DACs i have made have a heater switch, and disable the B+ on startup.  And if yours does not, put one on.  I will get some anyway, Duelund 400V mainly the see how they sound, and if they cut it, i will let you know.    
« Last Edit: October 13, 2010, 08:18:52 PM by stevenvalve »

Offline lenehanaudio

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Re: duelund caps issues
« Reply #42 on: October 13, 2010, 11:07:59 PM »
Hasnt this place been a flurry of activity since yesterday.  I was the one who emailed duelund.  I was concerned you people were tarnishing his reputation with your acts of stupidity.  Amazing how everyone here was so quick to blame the capacitors before even looking at your half arsed circuit.  If it wasnt for me and omodo you guys would still be blowing caps and blaming duelund. I also wanted to make sure if he got any returns from misused caps he knew why.  Dont see why Frederick or Lenehan should bare any cost from your mistakes.  Im not hiding. and Im not posting here anymore, there is honestly no point.  Ive had my vent over on diyaudio, now my life will exist as though there is no such thing as a killerdac, and it will be a state of wonderful oblivious ignorance (just how the dac is built).
i know of 3 caps failing in killer dacs caps will be replaced seems their is a quality control issue with the caps or a manufacturing fault.

I would just like to comment on Avians email to Duelund !  I certainly will not be divulging the text ! I would like to say however that it was vindictive and contextually destructive. Very transparently so if fact and contained three significant inaccuracies.

Unfortunately this is whats not good about forums today ! people sit in front of their computers  and can't wait to take someone down.

 I'm a loudspeaker designer so only have basic chops re electronics ! I'm don't fully understand whether the product was being used correctly or not but Frederik explained to me on the telephone last night that to be safe he would use the 400v versions of the VSF.

His comment was that the lower voltage version would probably be ok but if there was enough thermal variation re external ambient temperatures the caps voltage rating could be lowered by around 10%.

Perhaps we've all learnt something here !                 Regards Mike Lenehan   LenehanAudio



« Last Edit: October 14, 2010, 08:08:31 PM by ozmillsy »

Offline flemo

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duelands
« Reply #43 on: October 13, 2010, 11:38:25 PM »
The observations made on the other DIY forum "may" have held some technical merit and even worthy of some robust debate or conversation. However the general comments and insults aimed personally at members or "minions" on this forum were IMO unprovoked, gutless and just plain nasty.  :P

Offline stevenvalve

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Re: duelund caps issues
« Reply #44 on: October 14, 2010, 01:13:52 AM »
I would just like to comment on Avians email to Duelund !  I certainly will not be divulging the text ! I would like to say however that it was vindictive and contextually destructive. Very transparently so if fact and contained three significant inaccuracies.

Unfortunately this is whats not good about forums today ! people sit in front of their computers  and can't wait to take someone down.

 I'm a loudspeaker designer so only have basic chops re electronics ! I'm don't fully understand whether the product was being used correctly or not but Frederik explained to me on the telephone last night that to be safe he would use the 400v versions of the VSF.

His comment was that the lower voltage version would probably be ok but if there was enough thermal variation re external ambient temperatures the caps voltage rating could be lowered by around 10%.

Perhaps we've all learnt something here !                 Regards Mike Lenehan   LenehanAudio



 I agree with Frederik, to save any possible problems it may be wise to use the 400V version. Heat seems to be an issue, i do not run a lid on mine and they run cold. Do the 400V models sound great, well that is the question. I will be the guinea pig
« Last Edit: October 14, 2010, 08:09:16 PM by ozmillsy »

Offline ozmillsy

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Re: duelund caps issues
« Reply #45 on: October 14, 2010, 08:11:01 PM »
edited mike's/stevens posts to correct the quotations......
It's all about the music,, not the equipment.

Offline Hens

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Re: duelund caps issues
« Reply #46 on: October 14, 2010, 11:50:23 PM »
My Cast Pios are running fine.
Hopefully those other vsfs dont die on me haha.

Offline stevenvalve

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Re: duelund caps issues
« Reply #47 on: October 15, 2010, 04:14:05 AM »
My Cast Pios are running fine.
Hopefully those other vsfs dont die on me haha.
Just for interest Mario checked the voltage start up peak on richards DAC, and it was under 85V DC Well within Spec of this cap. As i said i have been checking this for 8 years on and off and find no real problem. But if its a problem or worry for you change to the 400V.

Offline zenelectro

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Re: duelund caps issues
« Reply #48 on: October 15, 2010, 09:44:54 AM »
Guys,

The start up peak (when it happens) is a result of the rectifier tube heating up and conducting
current slightly faster than the OP tube does. When this occurs, the B+ builds up voltage before the OP tube
'sucks' it back down through the load resistor. Kind of like a delayed wave effect.

As such it is dependent on the individual tubes warm up to conduction times, ie; it will vary depending
what tubes you run.

The downside of the design is that if you have a fault in the OP tube, or in fact turn the DAC on without OP tube
plugged in, full B+ will be across the cap - not a good thing!

Generally speaking a good design should have caps rated for full B+ operation or otherwise have some form
of protection for the cap.

My recommendation is:

- if you are using a valve amplifier or have a standby switch all should be OK
- if you are using a SS amp or active speakers and do not have a standby switch, it's a good idea to use the voltage clamp I have shown above.

I'll knock up a few and we can evaluate them on Steve's system in the next week or so to make sure they don't affect sound in any way.

cheers

Terry

« Last Edit: October 15, 2010, 09:50:42 AM by zenelectro »

Offline omodo

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Re: duelund caps issues
« Reply #49 on: October 15, 2010, 10:59:41 AM »
The downside of the design is that if you have a fault in the OP tube, or in fact turn the DAC on without OP tube
plugged in, full B+ will be across the cap - not a good thing!

Generally speaking a good design should have caps rated for full B+ operation or otherwise have some form
of protection for the cap.

Hi, I took a step back from this thread for a few days due to the direction it was heading, which was partly my fault, I apologise for any angst my posts may have caused.

The above point made by zenelectro is a very important, and further illustrates the need to choose a capacitor rating that is suitable for all possible scenarios of your circuits operation.

In addition to the solutions offered in this thread, and if you wanted to keep using the 200v rated duelunds,  another option would be to reduce the B+ to below the capacitor rating, and use an active plate load/CCS (such as a cascoded IXYS 10M45S, DN2540N5, etc). This would avoid the need for a large plate load resistor (and thus the high B+ to allow for the drop across the resistor). This is very simple to do, basically 2 depletion mode mosfets, gate/grid stopper resistor, and a source resistor to set the ccs current, 4 parts per channel. And at the currents required for your circuit heatsinking would not be required. Another side benefit would be a reduction in output impedance for the stage.

edit: although I expect a ccs plate load, and/or the zener string/clamp, will both have a large effect on the sound/voicing of this dac that Steven et. al have worked so hard to achieve. But, still an interesting experiment to try - if the ccs load hasn't been tried before, it may have been.
« Last Edit: October 15, 2010, 11:40:32 AM by omodo »

Offline zenelectro

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Re: duelund caps issues
« Reply #50 on: October 15, 2010, 12:09:58 PM »

edit: although I expect a ccs plate load, and/or the zener string/clamp, will both have a large effect on the sound/voicing of this dac that Steven et. al have worked so hard to achieve. But, still an interesting experiment to try - if the ccs load hasn't been tried before, it may have been.

WRT the voltage clamp - the design criteria was:

a) Not to change the DAC design - it was painstakingly derived over a long period of careful listening tests.
b) Offer protection of the existing design -without- changing the sonics at all (if possible)

- Changing the design to an active load, particularly FET based CCS would almost certainly change the sonics.

- The clamp I have design should not change the sonics. It was carefully thought out and then simulated.
The zeners are only used as a voltage reference and so their noise and capacitive modulation is out of
the signal path. We will verify this.

cheers

Terry

 





 

Offline omodo

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Re: duelund caps issues
« Reply #51 on: October 15, 2010, 12:19:18 PM »
thanks for the info. I most certainly agree the ccs load will change the sound - by a lot, and pretty much put you back to square one, so - not the best solution, but you get to "easily" keep the duelunds! :) I'm interested to know how much the 200v vsf contribute to the final sound/voicing (I've only heard the DAC with duelunds), there has been talk to changing to cast pio, vsf black, 400v vsf, all of which will most likely have a large impact.

I'm looking forward to hearing the results of the clamp listening tests, if there is no impact to the sound it sounds like a perfect solution/fix

tuyen

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Re: duelund caps issues
« Reply #52 on: October 15, 2010, 12:22:17 PM »
Patiently await the results Terry. Thanks :)

I installed a pair of CAST PIO on one of hen's dacs. Hopefully he can chime in on his thoughts compared to his other dac which uses the standard VSF.


Offline stevenvalve

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Re: duelund caps issues
« Reply #53 on: October 15, 2010, 03:08:54 PM »
Patiently await the results Terry. Thanks :)

I installed a pair of CAST PIO on one of hen's dacs. Hopefully he can chime in on his thoughts compared to his other dac which uses the standard VSF.


As for the new cap types from duelund, they will change the sound. some will like these changes others not. basically (the DACs) are hand tuned by you, if you change parts, all the changes in vintage chokes valves rectifiers Deuland dubilier plessey caps types, you put in, make it a new ball game. I will try the 400V duelunds before any mod, because LESS is MORE. The only thing that will stop me is if they do not sound as good. To me sound is first, I what magic i will not put up with any drop in performance.  
« Last Edit: October 15, 2010, 03:24:06 PM by stevenvalve »

Offline stevenvalve

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Re: duelund caps issues
« Reply #54 on: October 15, 2010, 03:20:06 PM »

edit: although I expect a ccs plate load, and/or the zener string/clamp, will both have a large effect on the sound/voicing of this dac that Steven et. al have worked so hard to achieve. But, still an interesting experiment to try - if the ccs load hasn't been tried before, it may have been.

WRT the voltage clamp - the design criteria was:

a) Not to change the DAC design - it was painstakingly derived over a long period of careful listening tests.
b) Offer protection of the existing design -without- changing the sonics at all (if possible)

- Changing the design to an active load, particularly FET based CCS would almost certainly change the sonics.

- The clamp I have design should not change the sonics. It was carefully thought out and then simulated.
The zeners are only used as a voltage reference and so their noise and capacitive modulation is out of
the signal path. We will verify this.

cheers

Terry

 





 
Terry, has helped in what you see today (DAC) for longer than i can remember, his imput has been priceless, and we will (with his help) only go forward. And of couse not forgetting Pauls wonderfully designed and built digital boards.
« Last Edit: October 15, 2010, 03:22:22 PM by stevenvalve »

Offline stevenvalve

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Re: duelund caps issues
« Reply #55 on: October 15, 2010, 05:34:23 PM »
The downside of the design is that if you have a fault in the OP tube, or in fact turn the DAC on without OP tube
plugged in, full B+ will be across the cap - not a good thing!

Generally speaking a good design should have caps rated for full B+ operation or otherwise have some form
of protection for the cap.

Hi, I took a step back from this thread for a few days due to the direction it was heading, which was partly my fault, I apologise for any angst my posts may have caused.

The above point made by zenelectro is a very important, and further illustrates the need to choose a capacitor rating that is suitable for all possible scenarios of your circuits operation.

In addition to the solutions offered in this thread, and if you wanted to keep using the 200v rated duelunds,  another option would be to reduce the B+ to below the capacitor rating, and use an active plate load/CCS (such as a cascoded IXYS 10M45S, DN2540N5, etc). This would avoid the need for a large plate load resistor (and thus the high B+ to allow for the drop across the resistor). This is very simple to do, basically 2 depletion mode mosfets, gate/grid stopper resistor, and a source resistor to set the ccs current, 4 parts per channel. And at the currents required for your circuit heatsinking would not be required. Another side benefit would be a reduction in output impedance for the stage.

edit: although I expect a ccs plate load, and/or the zener string/clamp, will both have a large effect on the sound/voicing of this dac that Steven et. al have worked so hard to achieve. But, still an interesting experiment to try - if the ccs load hasn't been tried before, it may have been.
Omodo. your input will always be welcome. In the long run i think you are right.  The 400v model was not available until recently, that is why they where not used originally. The 100V Dc model was by far the best cap of any, (by a wide margin), at that time, So it was the only game in town.
« Last Edit: October 18, 2010, 12:42:52 PM by stevenvalve »

tubeguy

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Re: duelund caps issues
« Reply #56 on: November 04, 2010, 11:19:50 AM »
Hasnt this place been a flurry of activity since yesterday.  I was the one who emailed duelund.  I was concerned you people were tarnishing his reputation with your acts of stupidity.  Amazing how everyone here was so quick to blame the capacitors before even looking at your half arsed circuit.  If it wasnt for me and omodo you guys would still be blowing caps and blaming duelund. I also wanted to make sure if he got any returns from misused caps he knew why.  Dont see why Frederick or Lenehan should bare any cost from your mistakes.  Im not hiding. and Im not posting here anymore, there is honestly no point.  Ive had my vent over on diyaudio, now my life will exist as though there is no such thing as a killerdac, and it will be a state of wonderful oblivious ignorance (just how the dac is built).
i know of 3 caps failing in killer dacs caps will be replaced seems their is a quality control issue with the caps or a manufacturing fault.

I would just like to comment on Avians email to Duelund !  I certainly will not be divulging the text ! I would like to say however that it was vindictive and contextually destructive. Very transparently so if fact and contained three significant inaccuracies.

Unfortunately this is whats not good about forums today ! people sit in front of their computers  and can't wait to take someone down.

 I'm a loudspeaker designer so only have basic chops re electronics ! I'm don't fully understand whether the product was being used correctly or not but Frederik explained to me on the telephone last night that to be safe he would use the 400v versions of the VSF.

His comment was that the lower voltage version would probably be ok but if there was enough thermal variation re external ambient temperatures the caps voltage rating could be lowered by around 10%.

Perhaps we've all learnt something here !                 Regards Mike Lenehan   LenehanAudio

















Good points, that's why if you plan to build something posted on the net, it's best to use a design done by someone who knows and fully understands what they are doing.

Now imagine for a moment if you happen to have a cap fail, in your quest to locate the fault you remove the suspect channel IC. Whilst inavertantly holding it you flick the power switch on, B+ at the tip of the RCA plug for 10~30 seconds. Enough to kill most people.

There are too many circuit designs floating around the web that are very dangerous and could inflict serious injury, or even death in the worst case.

TG

Offline stevenvalve

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Re: duelund caps issues
« Reply #57 on: November 04, 2010, 03:24:51 PM »
There is a lot of people modifying equipment out there, including the KDAC . There is a lot fun in making your own sound, from an already great dac. We have a lot of tech people out there that think you may kill yourself, and they are right. I guess it is the because some modifiers are untrained amateurs and there is always that possibility, so be care full. If any of you guys do kill yourself, please leave me all your TDA1541A Double Crowns.
« Last Edit: November 04, 2010, 03:29:56 PM by stevenvalve »

crazikid

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Re: duelund caps issues
« Reply #58 on: November 04, 2010, 06:24:15 PM »
hehe.. very funny..

Offline zenelectro

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Re: duelund caps issues
« Reply #59 on: November 04, 2010, 07:53:58 PM »

Good points, that's why if you plan to build something posted on the net, it's best to use a design done by someone who knows and fully understands what they are doing.

Now imagine for a moment if you happen to have a cap fail, in your quest to locate the fault you remove the suspect channel IC. Whilst inavertantly holding it you flick the power switch on, B+ at the tip of the RCA plug for 10~30 seconds. Enough to kill most people.

There are too many circuit designs floating around the web that are very dangerous and could inflict serious injury, or even death in the worst case.

TG

TG,

Your points are noted.

If you do some research, lethal current is generally considered well above 10mA and that would have to pass in one
arm and out the other. Once you factor the bodies resistance in series with the plate resistor of DAC and the available HT
supplying that resistor, it's unlikely you would get 'hit' with more than a few mA, even if you jumped straight out of a wet shower
with the sudden urge to unplug your interconnects after a cap failure.

However safety and reliability are always of prime concern, refer to my previous post of OP voltage clamps. I made up a
couple shown below and we will evaluate them.  

cheers

Terry










« Last Edit: November 04, 2010, 07:56:50 PM by zenelectro »