This thread is so huge ! I tried searching a while and gave up. Its so painful on the eye. I am sry if i am asking this question again.
I have some questions regarding grounding.
1) Do I connect the earth wire from the IEC inlet to the chassis ?
2) The ucd 400 manual has 2 grnd connections one on the secondary of the transformer and one on the capacitors. Do I join these 2 and wire them to the chassis ?
Thankz.
I have some questions regarding grounding.
1) Do I connect the earth wire from the IEC inlet to the chassis ?
2) The ucd 400 manual has 2 grnd connections one on the secondary of the transformer and one on the capacitors. Do I join these 2 and wire them to the chassis ?
Thankz.
I built a couple of UCD180HGs. For safety, I grounded the mains earth (the green cable in the US) to the chassis, and everything else is not connected to the chassis.
There is no "earth" in the transformer (at least the toroids I've used). There are two primaries and one or two pairs of secondaries. Wired correctly to the power supply, you will get a positive rail, a negative rail and a ground. This ground connects to the UCD ground pin
Then there is signal ground. This ground wire from your signal source connects to the signal ground pin in the UCD and is it isolated from the chassis.
In summary, the chassis is only connected to the earth gnd and nothing else.
(I think the Hypex documentation recommends floating the chassis and connecting the signal ground to the chassis to avoid hum but I think it is not as safe and you will have to read up on double isolation standards for your power wires and power supply)
There is no "earth" in the transformer (at least the toroids I've used). There are two primaries and one or two pairs of secondaries. Wired correctly to the power supply, you will get a positive rail, a negative rail and a ground. This ground connects to the UCD ground pin
Then there is signal ground. This ground wire from your signal source connects to the signal ground pin in the UCD and is it isolated from the chassis.
In summary, the chassis is only connected to the earth gnd and nothing else.
(I think the Hypex documentation recommends floating the chassis and connecting the signal ground to the chassis to avoid hum but I think it is not as safe and you will have to read up on double isolation standards for your power wires and power supply)
Thankz glt. Is this how it should be ?
An externally hosted image should be here but it was not working when we last tested it.
The UCD module has separate connectors for the supply gnd and the + and - connectors from the speakers. There is no need to make any additional gnd connection
UCD400AD and E.A.R tube preamp - deadly combination!
Hi all
I have tried my UCD amps together with a certain tube preamp.
At turn on there was a loud pumping noise from the speakers and smoke came out of both UCD amps!
I have measured the output of the tube preamp, and noticed a slow-oscilating voltage (effectively DC) at its output during the first 20 seconds of operation.
My question: how can I increase the turn-on delay time of the UCD-400 to 30 seconds so as to overcome the transients of the preamp at turn-on (for example when both come back after mains power failue)?
Thanks
Yair
Hi all
I have tried my UCD amps together with a certain tube preamp.
At turn on there was a loud pumping noise from the speakers and smoke came out of both UCD amps!
I have measured the output of the tube preamp, and noticed a slow-oscilating voltage (effectively DC) at its output during the first 20 seconds of operation.
My question: how can I increase the turn-on delay time of the UCD-400 to 30 seconds so as to overcome the transients of the preamp at turn-on (for example when both come back after mains power failue)?
Thanks
Yair
Re: UCD400AD and E.A.R tube preamp - deadly combination!
From the Hypex Faq:
"Q: Do UcD amplifiers work well with tube preamps?
A: Fundamentally there is no problem of course. However, most tube preamplifiers are designed alongside tube power amplifiers which are always AC coupled. As a result, many tube preamplifiers lack precautions against turn-on/turnoff transients. Some are liable to produce the full anode voltage at their outputs during turn-on and turn-off. We find that a large proportion of repairs are due to tube preamplifiers discharging their output caps into the UcD’s input circuit. Note that most solid state amps dislike such treatment, not just UcD."
You might instead look into a proper power on/off mute circuit for your pre amp, it will give you something to do while your modules are off being repaired.
yairf said:
From the Hypex Faq:
"Q: Do UcD amplifiers work well with tube preamps?
A: Fundamentally there is no problem of course. However, most tube preamplifiers are designed alongside tube power amplifiers which are always AC coupled. As a result, many tube preamplifiers lack precautions against turn-on/turnoff transients. Some are liable to produce the full anode voltage at their outputs during turn-on and turn-off. We find that a large proportion of repairs are due to tube preamplifiers discharging their output caps into the UcD’s input circuit. Note that most solid state amps dislike such treatment, not just UcD."
You might instead look into a proper power on/off mute circuit for your pre amp, it will give you something to do while your modules are off being repaired.
Re: Re: UCD400AD and E.A.R tube preamp - deadly combination!
Hi classdphile
Thanks for your reply, I wouldnt like to make any mods or changes to the preamp.
Any ideas how do I increase turn-on delay of UCD-400 to 30 seconds?
Thanks
Yair
classdphile said:
Hi classdphile
Thanks for your reply, I wouldnt like to make any mods or changes to the preamp.
Any ideas how do I increase turn-on delay of UCD-400 to 30 seconds?
Thanks
Yair
Re: Re: Re: UCD400AD and E.A.R tube preamp - deadly combination!
It isn't feasible to modify the module for such a delay, further doing so would do nothing for shutdown transients.
You obviously are in control of the /en pin, you could control it manually to test your theory but I tend to think it more sound to protect the amp from such absurd transients to begin with. You could do that with the same power on/off mute circuit as mentioned before, only put it at the input of your amp instead of the output of your pre amp, just place it in the box with your preamp though because that's where it makes sense to have it.
Google for "mute" and "soft start" and you'll get a schematic or two. You could also run a /trigger from that to your amp as well.
yairf said:
It isn't feasible to modify the module for such a delay, further doing so would do nothing for shutdown transients.
You obviously are in control of the /en pin, you could control it manually to test your theory but I tend to think it more sound to protect the amp from such absurd transients to begin with. You could do that with the same power on/off mute circuit as mentioned before, only put it at the input of your amp instead of the output of your pre amp, just place it in the box with your preamp though because that's where it makes sense to have it.
Google for "mute" and "soft start" and you'll get a schematic or two. You could also run a /trigger from that to your amp as well.
Hi ! I connected up the transformer and the fast recovery diodes for the bridge rectifier and switched it on. Then I saw smoke in the bridge rectifier. Everything is wired correctly but I dunno why the diodes had smoke and is like a little melted.
The diode i used is VISHAY SEMICONDUCTOR
BYV27-200-TR. Have I used the wrong one ? Pls I am in desperate need of help. Thankz.
The diode i used is VISHAY SEMICONDUCTOR
BYV27-200-TR. Have I used the wrong one ? Pls I am in desperate need of help. Thankz.
BTW the manual that came with the ucd400 i bought shows a fuse rating of 8AF for the supply rail but the manual on the website shows a rating of 4AF. Which one is correct ?
Hi Buzzy
Your diode has reverse voltage of 200V, which is borderline, and forward current of 2A, which is not enough - the inrush current of the transformer is much higher. try looking at 16A diodes.
Regards
Yair
Your diode has reverse voltage of 200V, which is borderline, and forward current of 2A, which is not enough - the inrush current of the transformer is much higher. try looking at 16A diodes.
Regards
Yair
I saw somewhere in this thread that a potentiometer can be used as a volume control. May i know what rating must it be and where to connect it ?
hi all
im just about to finnish my build of 2x stereo ucd400hg amps
im going to be using them to run some active 2way speakers using a manger transducer for mid and high and a eton 12" hexacone for bass
id prefer not to use loudspeaker protection if possible ,but im a little concerned about damaging the drivers if something goes wrong .(they are very expensive) any advice?
each amp has 1x 1000va nuvotem toroid and one of aussie amps ps3 powersupply,s with 60,000mf capacitance
is it better to use one amp for bass (both channels) and one amp for mid/high.(both channels)
or use one amp for bass and mid/high left channel and the other amp for bass /mid/high on the right channel
im just about to finnish my build of 2x stereo ucd400hg amps
im going to be using them to run some active 2way speakers using a manger transducer for mid and high and a eton 12" hexacone for bass
id prefer not to use loudspeaker protection if possible ,but im a little concerned about damaging the drivers if something goes wrong .(they are very expensive) any advice?
each amp has 1x 1000va nuvotem toroid and one of aussie amps ps3 powersupply,s with 60,000mf capacitance
is it better to use one amp for bass (both channels) and one amp for mid/high.(both channels)
or use one amp for bass and mid/high left channel and the other amp for bass /mid/high on the right channel
I'm using UcD180HG modules to drive my Mangers and didn't experience the slightest problem so far. I think the modules are safe and reliable to operate and I wouldn't bother about additional protection. Btw the Manger driver is further protected by the high-pass filter and you would most probably only blow the low freq driver.
Not sure but channel separation might be better if you use one amp per channel. I would go for the second option.
hi mate
thanks for the reply
im going to use my mangers in an active 2way with a dbx 260 for the crossover so the amps will hook straight into the drivers without any crossover ,this is why im a little concerned
im also leaning towards option 2 for the amps (one amp for high and low on each side ) for the exact reason you mentioned ,channel seperation ,i feel like you that it would be better
im very interested in your manger setup ,are the hypex modules a good match ? some people say they are very amplifier fussy and it had me a little concerned
thanks for the reply
im going to use my mangers in an active 2way with a dbx 260 for the crossover so the amps will hook straight into the drivers without any crossover ,this is why im a little concerned
im also leaning towards option 2 for the amps (one amp for high and low on each side ) for the exact reason you mentioned ,channel seperation ,i feel like you that it would be better
im very interested in your manger setup ,are the hypex modules a good match ? some people say they are very amplifier fussy and it had me a little concerned