I will try some caps on the RCA'S.
Does the hiss from my right channel when the RCA'S are disconnected indicate anything?
Does the hiss from my right channel when the RCA'S are disconnected indicate anything?
I have the cheater cord made. What I did was pick up caps at 10uf 10v and cut the RCA cord and soldered the center wire. I striped back the outer wires tied them and moved them out of the way. I have the directional arrow on the caps toward my amp in. When I turned the power on my amp it scared the $*?% out of me. The buzz that came from my speakers sounded like full power. What did I do wrong?
hello again ,
you have the cap in the signal center wire?? and the shield should have continuity from end to end being careful not to touch
signal with shield...btw use a non polar or film cap.
good luck as i try to find my weirdness in my Hafler DH200.
Elwood
you have the cap in the signal center wire?? and the shield should have continuity from end to end being careful not to touch
signal with shield...btw use a non polar or film cap.
good luck as i try to find my weirdness in my Hafler DH200.
Elwood
Thanks. I guess I did two things wrong. I used a polar cap, and I did not join the shield when I did the splice. I will fix and report back.
Ok, I tried the caps and the click is completey gone. But, the big question is NOW WHAT? Should I take this pre amp back (only two weeks old) or am I going to get the same thing in return? Or can I add blocking caps to the amp without sacrficing the sound? OR OR OR?
Thanks so far guys.
Thanks so far guys.
It was pretty much a forgone conclusion that it was the preamp. The amp doesn't 'know' that the preamp is switching from one program to another--it can only do what it's told. Ergo, if the sound happens only when the preamp switches, then it's the preamp. There's no other means of communication between the two than the interconnects.
As to what to do...the preamp is clearly defective. Take it back. If another one does the same thing, buy something else; the manufacturer clearly has quality control problems and there's no telling what else you'll face later on.
You should never have to resort to DC blocking caps to keep an unruly piece of equipment from throwing your woofer cones across the room. If the equipment is known to have DC at the output (like, for instance, tube preamps) then the manufacturer should have designed them in. If it's supposed to be DC-coupled, then you shouldn't be responsible for DC offset problems arising from improperly assembled or broken equipment. The fact that it's only one channel pretty much tells the tale--the unit is defective.
Grey
As to what to do...the preamp is clearly defective. Take it back. If another one does the same thing, buy something else; the manufacturer clearly has quality control problems and there's no telling what else you'll face later on.
You should never have to resort to DC blocking caps to keep an unruly piece of equipment from throwing your woofer cones across the room. If the equipment is known to have DC at the output (like, for instance, tube preamps) then the manufacturer should have designed them in. If it's supposed to be DC-coupled, then you shouldn't be responsible for DC offset problems arising from improperly assembled or broken equipment. The fact that it's only one channel pretty much tells the tale--the unit is defective.
Grey
Thanks. One thing that still does not make sense to me is that when I reverse the rca's from left to right the click does not move to the opposite channel. I talked to my dealer and they cannot understand why ether. They are going to give me a new pre amp (Marantz 8002 by the way) to try. If it still does it I will change models and try that.
hello...
Grey is right if the caps fixed it it's in the pre amp take it back get another(BTW what brand is it??) maybe change brands.. Probe the home theatre crowd and see what's popular with the separate amp and preamp guys...
Good luck, Elwood
Grey is right if the caps fixed it it's in the pre amp take it back get another(BTW what brand is it??) maybe change brands.. Probe the home theatre crowd and see what's popular with the separate amp and preamp guys...
Good luck, Elwood
That's why I hate debugging stuff over the web...there's always some little detail that got overlooked on page 3. Sixteen pages later, the guys says, "Oh, I thought you meant the other other one! You meant the first other one," or some such and the problem becomes clear...as a simple breakdown in communication. Since I'm perpetually pressed for time and have spent the last week or so playing host to a horde of vagabond germs that decided I looked like home (which threw me even more behind on my to-do list...bummer), I'm hoping that this really does manage to come to a happy conclusion in a mere two pages.
You didn't say whether you were switching the preamp while you were reading the input voltage. Checking for DC while everything is normal is good as a confirmation, but if the problem only appears when you're switching sources, then that's when you need to measure for a pulse of DC at the input. Incidentally, if you suspect a really massive amount of DC (regardless of where it comes from), it's best to buy some cheap 8 Ohm load resistors rather than risk frying your voice coils by leaving your speakers hooked up as guinea pigs whilst you debug the problems upstream. They're a lot cheaper and easier to replace than your speakers.
By the way, you weren't also switching the speaker cables when you switched the inputs, were you?
Grey
You didn't say whether you were switching the preamp while you were reading the input voltage. Checking for DC while everything is normal is good as a confirmation, but if the problem only appears when you're switching sources, then that's when you need to measure for a pulse of DC at the input. Incidentally, if you suspect a really massive amount of DC (regardless of where it comes from), it's best to buy some cheap 8 Ohm load resistors rather than risk frying your voice coils by leaving your speakers hooked up as guinea pigs whilst you debug the problems upstream. They're a lot cheaper and easier to replace than your speakers.
By the way, you weren't also switching the speaker cables when you switched the inputs, were you?
Grey
OK... if you like the way it sounds even if the new pre has the same symptom and you are not put off by caps in the signal path put them in relax have a cold beer or your beverage of choice put in your favorite movie and enjoy...
If it makes you happy it tickles me plum to death..
Elwood
If it makes you happy it tickles me plum to death..
Elwood
I would say you have a problem with the Fet pair on the input of the Threshold, because as you said with nothing attached to the input you had one channel giving a lot of hiss and the other not, I think what's happening when something is attached the faulty fet goes nuts and changes it's operating parameters.
Is the channel that has the louder hiss the same as the one that makes the speaker move 1/2"? or is it the other?
Cheers George
Is the channel that has the louder hiss the same as the one that makes the speaker move 1/2"? or is it the other?
Cheers George
OK, I will try to answer some questions.
Quote,
"You didn't say whether you were switching the preamp while you were reading the input voltage"
I did not check this. Someone said to add the blocking caps as a check.
Quote,
"By the way, you weren't also switching the speaker cables when you switched the inputs, were you?"
I did both. I switched at the input first and the click stayed in the right channel. Then I switched the speaker cables and the sound went to the left channel.
Quote,
Is the channel that has the louder hiss the same as the one that makes the speaker move 1/2"? or is it the other?
Yes, it is the same channel. The hiss is not audible from 5 FT away. You have to walk up to the speaker to here it. But the left channel is silent.
Quote,
"You didn't say whether you were switching the preamp while you were reading the input voltage"
I did not check this. Someone said to add the blocking caps as a check.
Quote,
"By the way, you weren't also switching the speaker cables when you switched the inputs, were you?"
I did both. I switched at the input first and the click stayed in the right channel. Then I switched the speaker cables and the sound went to the left channel.
Quote,
Is the channel that has the louder hiss the same as the one that makes the speaker move 1/2"? or is it the other?
Yes, it is the same channel. The hiss is not audible from 5 FT away. You have to walk up to the speaker to here it. But the left channel is silent.
Update:
Went back to the dealer and they replaced the original amp. Still clicks R/H channel only. We replaced that with a Yamaha 3800 still clicks R/H channel. Finally replaced that with an Onkyo 905 still clicks R/H channel. This has to be a problem with the power amp.
George, you mentioned something about the FET. Anything I can check?
Went back to the dealer and they replaced the original amp. Still clicks R/H channel only. We replaced that with a Yamaha 3800 still clicks R/H channel. Finally replaced that with an Onkyo 905 still clicks R/H channel. This has to be a problem with the power amp.
George, you mentioned something about the FET. Anything I can check?
This thread has "something else is wrong" written all over it. Given that the amp only makes noise when the preamp is switched and the DC blocking cap Elwood suggested seemed to fix it, then...oh damn, I just knew diagnosis in a mere two pages was too good to be true. Somebody fetch me a drink...and it better be a single malt Scotch or a pretty decent wine. Beer won't do for this sort of problem.
The thing about the bad input device proposition is that it doesn't explain what appears to be gross DC offset at the input.
I gather that the amp didn't exhibit this problem until you hooked up the new preamp. That's also disturbing.
Here's an idea: The preamps are all DC coupled and the source is passing DC on its right channel only. It pops when you switch to that source and pops again as you switch away from it. Try a different source. Doesn't have to be elegant or cool, just something other than what you're already using.
Any chance that your previous preamp was cap-coupled?
Grey
The thing about the bad input device proposition is that it doesn't explain what appears to be gross DC offset at the input.
I gather that the amp didn't exhibit this problem until you hooked up the new preamp. That's also disturbing.
Here's an idea: The preamps are all DC coupled and the source is passing DC on its right channel only. It pops when you switch to that source and pops again as you switch away from it. Try a different source. Doesn't have to be elegant or cool, just something other than what you're already using.
Any chance that your previous preamp was cap-coupled?
Grey
Dpeters said:
Send a PM to Nelson, to read this thread before it gets too confused, I'm sure he will, and he will nut it out, sounds to me still that it's the input tranies.
Cheers George
Dpeters said:
Yes, the one and only.
http://www.diyaudio.com/forums/member.php?s=&action=getinfo&userid=177
Cheers George
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