Need help diagnosing a problem in my set up

[Will2225]

Today I bought a new audio rack and after changing all of my equipment out I noticed a problem. The woofers on my recently refoamed Wilson watt puppy 3.2 speakers are moving in and out. I believe it might be my d sachs model 3 tube pre amp. I tried swapping cords (interconnects, power cords etc) and eventually plugged my dac straight into the power amp and the problem seems to have stopped.

To give more information about my set up I'm using a d sachs 3 tube pre amp into a mcintosh 2105 power amp with a topping dac and Wilson audio speakers.

It's unusually hot today where I am and I'm wondering if that might be causing the tube pre amp to malfunction. Any advice on fixing this? Am I right in assuming that it's the tube pre amp?

The woofers move when there's no music playing and the tube pre amp and power amp are connected and on etc. I tried swapping tubes in the pre amp and it didn't help the problem.

Any advice on trouble shooting this and getting it fixed would be appreciated. The only other two things I should mention are that I plugged an ac into the same wall socket and that's when I first noticed the issue. Also the input jacks on the 2105 are most likely very tarnished and the sound sometimes cuts out if the cable isn't positioned just perfectly. Rotating the cable fixes the issue once it makes a good connection. I'm hoping that it's just the heat 90+ f that's making the tube pre amp malfunction, hopefully I won't need to get it repaired as it's relatively new.

 

[xero-D-hero]

The only other two things I should mention are that I plugged an ac into the same wall socket and that's when I first noticed the issue.

Putting any electronics on the same circuit as an A/C unit is just asking for problems.
So I'd suspect that long before I'd suspect the preamp or power amp.

Also the input jacks on the 2105 are most likely very tarnished and the sound sometimes cuts out if the cable isn't positioned just perfectly.

I kinda doubt that's the issue,that amp draws like 450 watts "all out".
That's only like 3.75 amps or so if my math serves me right.
And at idle it draws like 90 watts,which is like next to nothing.
So it's not even what I'd consider a "heavy draw" compared to some amps.

The "heavy draw" is gonna be that A/C unit,that's what's gonna stress all those sensitive electronics gear.
So I ask,what happens to the "issue" when the A/C unit is unplugged from that socket w/all the stereo gear hooked up ???

Bret P.

 

[Ds2000]

Second the AC on a separate circuit.

 

[Will2225]

Putting any electronics on the same circuit as an A/C unit is just asking for problems.
So I'd suspect that long before I'd suspect the preamp or power amp.

I kinda doubt that's the issue,that amp draws like 450 watts "all out".
That's only like 3.75 amps or so if my math serves me right.
And at idle it draws like 90 watts,which is like next to nothing.
So it's not even what I'd consider a "heavy draw" compared to some amps.

The "heavy draw" is gonna be that A/C unit,that's what's gonna stress all those sensitive electronics gear.
So I ask,what happens to the "issue" when the A/C unit is unplugged from that socket w/all the stereo gear hooked up ???

Bret P.

Thanks for your detailed reply, it's very helpful.

With the ac unit unplugged the same issue was happening unfortunately. The good news is that I think I figured out the problem. I believe it was due to a lack of space and poor ventilation for the tubes in the pre amp. I repositioned the pre amp a bit so that there's more room above the tubes and also put a fan on facing the audio rack and the problem seems to have gone away. The temperature where I am is in the mid 90s which is way hotter than normal, so I think it's probably the heat that caused the issue.

I probably won't run the ac while running my stereo set up just in case though.

Anyways, thanks again for the helpful and detailed response.

 

[markd51]

I'd clean up those RCA Inputs on the 2105 as well. At minimum, 91% Alcohol will work, and to get inside those jacks a Pipe Cleaner will suffice. Of course do this with the Amp unplugged, and don't shove the Pipe Cleaner in far.

If that doesn't cure the issue, then there's bigger problems to cure with those input jacks

 

[Will2225]

I'd clean up those RCA Inputs on the 2105 as well. At minimum, 91% Alcohol will work, and to get inside those jacks a Pipe Cleaner will suffice. Of course do this with the Amp unplugged, and don't shove the Pipe Cleaner in far.

If that doesn't cure the issue, then there's bigger problems to cure with those input jacks

Thank you, I'll get on this soon. I have the rubbing alcohol, might even still have deoxit gold as well. Just need to buy some pipe cleaners.

I'm still a bit confused on the issue with the pre amp. Im 90 percent sure it's a heat issue due to the intense heat in new england right now. I tried plugging the ac in with a fan also on in the direction of the pre amp and the problem happened again. With the ac unplugged and no fan on the issue also happens. With the ac off and a fan directed at the pre amp the issue seems to have gone away.

So most likely a heat/ventilation issue but maybe the ac causes a separate problem as well.

 

[xero-D-hero]

With the ac unit unplugged the same issue was happening unfortunately. The good news is that I think I figured out the problem. I believe it was due to a lack of space and poor ventilation for the tubes in the pre amp. I repositioned the pre amp a bit so that there's more room above the tubes and also put a fan on facing the audio rack and the problem seems to have gone away. The temperature where I am is in the mid 90s which is way hotter than normal, so I think it's probably the heat that caused the issue.

Ok,no A/C on that circuit and it happens.
Add a fan the problem seemingly clears up.
Obviously w/o the A/C the ambient temps get hotter...
Adding the fan (and repositioning the preamp) improves that situation the problem goes away.
But remember the A/C unit is STILL outta the picture here !!!
A common house fan would'nt be a heavy draw either,but it definitely could generate some EMI / RFI.
But that does'nt seem to be a problem here so far.

I'm still a bit confused on the issue with the pre amp. Im 90 percent sure it's a heat issue due to the intense heat in new england right now. I tried plugging the ac in with a fan also on in the direction of the pre amp and the problem happened again. With the ac unplugged and no fan on the issue also happens. With the ac off and a fan directed at the pre amp the issue seems to have gone away.

Ok,,,we're back to square one...
This is more-or-less just what you said earlier.
Add the A/C unit and BAM it happens again.
Except this time it's WITH the fan as well as the A/C unit.
Well that seems perfectly logical,,,does it not ???

So w/o a doubt having the A/C on that circuit is'nt helping the situation @ all.
And adding a fan seems to help keep the preamp a bit cooler which seems to help...

Now care to elaborate on the current arrangement of these components ?
Is the preamp in a somewhat confined space or something of that sort ??
Maybe a bit close to that power amp which could be contributing to increased ambient temps as well ???
Maybe too much direct sunlight ????

Some clear well lit pics would really help us visualize what you're working with here.



Bret P.

 

[the skipper]

what's your source?

 

[Will2225]

I'm fairly confident it's the heat. I've never ran this set up in temperatures anywhere close to the 90 degrees until today and yesterday.

I also noticed that when the pre amp was positioned underneath the wood portion of the audio rack, and not underneath the glass portion where there's more ventilation, the problem is much more persistent. What I mean is the woofers moving happened more often and at more frequent intervals.

I'm attaching photos to this post to try to see if that clarifies anything.

I have been playing the system for a few hours today and with the ac off and a fan on a high setting facing the pre amp it seems completely fine and back to normal. Must be a heat issue with the pre amp that's being exacerbated by the lack of vertical space above the tubes and the very high temperature. I think I'll know for sure when it cools down in a few days and if the problem goes away without a fan.

Still the rack is open on all sides, so it's a bit of a bummer that the pre amp has this issue even with good ventilation.

The audio rack is a soundations audio rack that I just bought second hand with glass shelves.

 

[Will2225]

what's your source?

Ive only been using a topping E30 dac for source but when the dac is plugged directly into the power amp the problem goes away completely. I did leave the pre amp on a different input with nothing playing and on the other input the problem still happened etc.

 

[Will2225]

More photos.

 

[Will2225]

What he is saying is the A/C on the same circuit - meaning the plugs are wired together - may be the issue.

I understand. I tried the ac on another outlet and the problem stayed the same. I think it might be the same circuit though as the main outlet I use.

 

[Will2225]

I think so too. Can I make a crazy suggestion? Use a long outdoor extension cord for the air conditioner and plug it into another room to see if that changes anything.

That's not all that crazy, I was thinking of doing the exact same thing haha.


Unfortunately my problems persisted into new problems and I think it's all because of the heat and less ventilation in the new rack.

The back left tube in the pre amp failed. Makes sense considering this one is the closest distance to the top wooden part and has less ventilation. Plus my phono cable ground connection inside the din connector must have come loose and I have to open it up again to fix it.

It's all very frustrating. I think I'm just going to take the equipment out. Lower the shelf so there's more ventilation for the pre amp and then not listen to it until it cools off outside. Might have to invest in a solid state pre amp for the summer months unfortunately or go back to my old audio rack and keep the pre amp on the very top where it has room to breathe.

 

[xero-D-hero]

Unfortunately my problems persisted into new problems and I think it's all because of the heat and less ventilation in the new rack.

Ahhhh,see this is the first I recall hearing that all the gear is in a "new" rack,but I admit I could've missed that bit.
But no doubt it could be at least a small part of the larger problem.

The back left tube in the pre amp failed. Makes sense considering this one is the closest distance to the top wooden part and has less ventilation.

Yeah could be the tube was slowly dying this whole time and that was the main issue from the get-go.
And looking at that preamp in that pretty wood case I cant help but think it has absolutely zero ventilation provisions.
I guess that may be why lots of tube gear fans run their gear "sans case" or "topless" to avoid these sorta heat related issues.

It's all very frustrating.

We totally get this part.
And all of us have likely BTDT @ one point or another.
But the AK community is here for you and we're doing what we can to help figure it all out.
Turth be told though this might've been a post better suited for the tube forum ???

I think I'm just going to take the equipment out. Lower the shelf so there's more ventilation for the pre amp and then not listen to it until it cools off outside. Might have to invest in a solid state pre amp for the summer months unfortunately or go back to my old audio rack and keep the pre amp on the very top where it has room to breathe.

Those would definitely all be options,any of which all you could do is try 'em and see if any does the trick.

And if adjusting shelves is possible...
There are purpose specific fan units on the market that could likely be adapted to work with that rack as well.
So maybe look into that as an option too.

Good luck here.

HTH

Bret P.

 

[Will2225]

Ahhhh,see this is the first I recall hearing that all the gear is in a "new" rack,but I admit I could've missed that bit.
But no doubt it could be at least a small part of the larger problem.

Yeah could be the tube was slowly dying this whole time and that was the main issue from the get-go.
And looking at that preamp in that pretty wood case I cant help but think it has absolutely zero ventilation provisions.
I guess that may be why lots of tube gear fans run their gear "sans case" or "topless" to avoid these sorta heat related issues.

We totally get this part.
And all of us have likely BTDT @ one point or another.
But the AK community is here for you and we're doing what we can to help figure it all out.
Turth be told though this might've been a post better suited for the tube forum ???

Those would definitely all be options,any of which all you could do is try 'em and see if any does the trick.

And if adjusting shelves is possible...
There are purpose specific fan units on the market that could likely be adapted to work with that rack as well.
So maybe look into that as an option too.

Good luck here.

HTH

Bret P.

Haha all good points and very true. I did mention the new audio rack but no worries about missing that part.

The pre amp has ventilation on both sides but no where else. Never had a problem before but always used it on the top of an audio rack where it had more room to breathe.

Also thanks! I love the AK community it's the best. You're probably right about it being posted in the tube forum but at the time I didn't know whether it was the pre amp or the solid state amp that was causing issues.

Oh well such is life, I just had a turn of very good luck recently related to all this so its not the end of the world to run into some issues.

I'll report back in a few days when it's colder out and hopefully that resolves the issue. It probably will. All signs seem to point to heat being the culprit haha

 

[rothwellaudio]

Woofers moving? At what kind of frequency?
It seems unlikely to me that a valve preamp running in a warm environment would produce any more movement in the woofers than if it was in a cooler environment. Does the air conditioner have some kind of fan in it? Is it possible the woofers are simply reacting to air movement in the room?

 

[wmgwizard]

You might want to check the bias when the unit is hot. I suspect as the tubes get hot the bias is drifting(probably what killed the one tube you mentioned).

 

[Will2225]

Woofers moving? At what kind of frequency?
It seems unlikely to me that a valve preamp running in a warm environment would produce any more movement in the woofers than if it was in a cooler environment. Does the air conditioner have some kind of fan in it? Is it possible the woofers are simply reacting to air movement in the room?

I don't think it's the fan moving the woofers. It seems like a small sudden pulse of DC going to the speakers.

I wonder if it's because I refoamed the speakers myself and maybe it's caused by some debris on the spiders. I know the was a little bit left over from the old foam, tiny bits. I cleaned it off well on the second speaker but didn't really do a good job getting it off on the first speaker.

I don't know if this is super likely though as it didn't happen at all when I used my dac as a pre amp.

I adjusted the shelves and am using the ac now and it doesn't seem to be affected by the ac. It's much cooler in my apartment now and not as hot. It only seems to happen very rarely in the left speaker where the woofers will pulse very quickly for a short burst. Nothing audible and I only notice if I pay close attention.

I think it's still most likely the pre amp but it's possible something I did during the refoaming of the four woofers is causing it. I think I did a good job on aligning the voice coil as I used a test tone and there's zero rub by feel. Maybe debris on the spiders could cause this but I'm not sure.

 

[rothwellaudio]

I wonder if it's because I refoamed the speakers myself and maybe it's caused by some debris on the spiders.
...it's possible something I did during the refoaming of the four woofers is causing it.

Seems highly unlikely to me.

What you're describing sounds a little bit like shot noise or popcorn noise. It used to be fairly common that carbon composition resistors used as anode loads would go dodgy and cause strange noises. It's a lot less common with modern metal film resistors. I don't know what kind of resistors you have in your preamp.

 

[maxhifi]

I'm curious what woofers moving means. Is it all the time, or is it during warm up or shut down? Do they slowly pump in and out, or is it when you listen to music? Is it the same on digital and analog sources?