Bottlehead Forum
Other Gear => Speakers => Topic started by: thdewitt on June 11, 2014, 05:08:33 PM
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I just received my Orca Deluxe and Dungeness today. I hooked them up to my Stereomour and my Submissive. I immediately got a pretty significant hum. Low hum in both the sub and speakers. I have the Stereomour at full volume and the submissive controlling the listening volume. Is this normal? Seems excessive. I have all the components, Sonos, Stereomour and Dugeness are all plugged in to same outlet. Any thoughts?
Thanks,
Tom
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Hello Tom,
Did you adjust the hum balance pots?
Is everything plugged into the same outlet?
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BP,
Thanks for the answer. I did adjust the balance pots. I followed the instructions in the manual and using my multimeter was able to adjust both sides to 0.
All the components are plugged in to the same outlet. I have a 4 port outlet and my sonos, Stereomor and sub are all plugged in to it.
thanks,
Tom
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Does the hum change level with the Stereomour level control?
Does the hum go away if you unplug both sub amps?
Is the hum still present with the Sonos not plugged in?
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OK, I did a little more checking. The hum seems to be just coming from the Subwoofer Amp. There steromour is dead silent. It gets louder if I turn the gain up. I normally have the gain on the sub set to about 11 o'clock and the hum is audible but not too bad. Gets worse as you turn up the gain.
The speaker wires go from Steromor to speaker then to sub. So both channels connect at the speaker binding posts. The speaker to the sub enters at the Amp in connections. Per the Bulmenstein Website instructions.
Tom
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Try the sub with inputs (from the speakers) disconnected and see if the hum changes.
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When I unhook the wires going to the speakers the hum goes away. If I hook just the sub up to the amp directly I get the hum. By adjusting the pots you can minimize the hum but it is still there audibly. If you increase the gain on the sub it goes up. The STereomour volume pot does not make a difference.
Tom
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You can measure the hum from the Stereomour with an AC voltmeter. If it has hum of 1mV rms or less it's operating normally. I use the Stereomour with Dungeness subs with no discernable hum issues, but if your setup measures within spec and you still find it unsatisfactory you can try running a pair of RCA cables from the Submissive to the Stereomour and a second pair of RCA cables from the Submissive to the RCA inputs of the sub, instead of using the speaker level inputs on the sub.
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I think my Stereomor is running in spec by the voltages I measured. On my fluke meter on the MV scale it bounces around between 2.1 and 0. It jumps directly from 2.1 to zero. no numbers in between. It will not hold a number whether I short the RCA or not. It is the exact same on both sides. If you turn the pots the numbers go up no matter which direction.
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you can try running a pair of RCA cables from the Submissive to the Stereomour and a second pair of RCA cables from the Submissive to the RCA inputs of the sub, instead of using the speaker level inputs on the sub.
Can you explain this to me. The submissive only has one set of RCA outs and 3 inputs. How would you accomplish running 2 pairs out. Are you suggesting rewiring one of the inputs to make another output?
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You could do that, or just by a y splitter for each channel.
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Thanks, do you think that the 2.1 reading that I am getting for the hum pots that erratically jumps to zero and back is normal.
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The jumpy reading most likely indicates a not-too-precise meter. Many meters have a hard time reading very low voltages and very low resistances. You can just listen to do the adjustment - it's harder to get the lowest reading but what you hear is what's really important anyhow. If you hear a clear minimum then you are almost certainly listening to the intrinsic filament hum and there are no other hum problems.
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Tom,
Just checking, are you measuring AC volts on your meter? BTW, both my 1980s and 1990s Flukes read down to 1mV AC reliably. Both autorange. The only mV setting is for DC. But when I get screwy readings from either of them it is time to change the battery.
Let's try something different, wire your left Dungeness to your right Orca and vice versa. I'm just thinking that there is a possible ground loop being created. This will rule out one channel of the Stereomour being missing a ground. If the same sub hums the Stereomour is fine. If the same channel hums it could be a lifted ground in that channel.
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Grainger,
You may be right. I was probably using the DC volts. But I had tried both. Here is a picture on the AC volts. It sticks at 000.
(https://dl.dropboxusercontent.com/u/38833957/2014-06-13%2009.00.59.jpg)
I hooked it up on the oscilloscope and couldn't get it as low.
(https://dl.dropboxusercontent.com/u/38833957/2014-06-13%2009.11.41.jpg)
(https://dl.dropboxusercontent.com/u/38833957/2014-06-13%2009.11.51.jpg)
Am I doing this right? I am still new to the electronics hobby.
I only have 1 sub. The hum actually comes out of the Orcas also but at a much higher pitch. When I turn the sub gain down to 10 O'clock it is minimized but still audible in the room.
Tom
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Try mV
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I would like to start by saying than you to everyone for their help. I am having so much fun with my Bottlehead projects. I will be buying some Paramounts and a Beepree soon.
Anyway, I love to post pictures. I am sure I have it right this time. When hooked up to the Fluke meter on the mV setting it jumps from 2.0 to zero. Here is a short movie of what happens.
https://dl.dropboxusercontent.com/u/38833957/2014-06-13%2010.07.56.mov
Here is what the readings are with the oscilloscope.
(https://dl.dropboxusercontent.com/u/38833957/2014-06-13%2010.06.03.jpg)
(https://dl.dropboxusercontent.com/u/38833957/2014-06-13%2010.06.27.jpg)
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The scope says 0.57mV rms of ripple. That is excellent. Up closer to 1mV is more common.
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Tom,
Ok, you have a good zero of the AC imbalance when your meter reads 0.000V AC. And we all agree this is not a normal situation.
Since the sub has extended response that the Orca doesn't at 60 Hz it will hum louder. What I was trying to check is if it is a ground loop in the Stereomour or in the Orca/Dungeness setup.
So we have that the Orcas hum a little and the Dungeness is louder.
One more thing, are you shorting the input of the Stereomour when making the hum balance adjustment?
When you use shorting plugs do you have the hum? If you get no hum this points to your Solos or the interconnects from it to the Stereomour.
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Tom, good catching up with you on the phone Friday and sorry to hear about the hum problem in your system. If you still have problems with it or have a hunch its somehow a malfunctioning amp in the dungeness then please let me know and I'll fix it for you.
Otherwise, I'm sure there are many people wondering: how's the sound of the stereomour/orcas?
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OK, First, thank you to Clark and Molly at Blumenstein Audio. They have been fantastic. From advice on the type of amp, to speaker placement, to just talking me through their offerings. Also, the craftsmanship and service are second to none. I absolutely love my new Orca Deluxe's and Dungeness sub. For me they are a piece or art that will live in my house as long as I do. My only concern now is what am I going to buy from them next. I see some great new products on the horizon. Probably will pick up a second Sub ASAP. Clark is currently working on my amp bases for my Crack, Stereomour, and Submissive in Chocolate Bamboo to match. They system will look sweet when they arrive and I will post some pictures.
BACK to MY QUESTIONS about hum on my Stereomour. I am a big dummy. I figured out that the probes on my Oscilloscope where set to 10X but my scope was set to 1X. After testing on both my scope and my Fluke Meter with the proper settings, i am getting readings of about 1.5 mV after adjusting the Hum pots.
Grainger and all. Is there something to look for that would cause this?
Answers to your questions:
I am sure I am testing AC mV on all the right settings.
I am shorting with RCA Plugs as recommended in one our your posts. (I cut up an old RCA twisted together and soldered.
I do have the hum when using shorting plugs.
Also, I do not get any hum in the sub when it is not connected to the Stereomor. When I connect one speaker side the hum starts, gets louder when second side is connected.
If I adjust the pots with the speakers connected I definitely get to a clear minimum as asked by Paul.
I have looked closely at all solder joints. I have reflowed any suspect joints. I have tested the continuity on all the grounds in the circuit and they seem to be fine.
Could there be a problem with the tubes?
Not sure if I should do anything else or just leave it alone and enjoy the amp/speakers with a slight hum.
Tom
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After testing on both my scope and my Fluke Meter with the proper settings, i am getting readings of about 1.5 mV after adjusting the Hum pots.
That sounds about right.
Have you set the levels on your sub amps? If they are up all the way, then the level of hum will appear to be artificially high.
-PB
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Another potential issue is that the subs may be sitting in a spot in the room that is accentuating the hum. You might try moving them around a little to see if you might be setting off a room mode where they are now. Usually moving them about a foot at a time is a reasonable.
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Have you set the levels on your sub amps? If they are up all the way, then the level of hum will appear to be artificially high.
-PB
Yes, When I adjust the sub gain to the 10 O'Clock position recommended by Clark the hum is minimized but still slightly audible.
When the system is first turned on, the hum starts very loud and then reduces for a few seconds to barely audible.
Tom
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Remember, the Stereomour has AC heaters. It will never be perfectly quiet. I have a pair of the discontinued Paramour II amps. The circuitry is similar and I even upgraded the iron to use the Stereomour/S.E.X. iron. I had 2A3's installed originally and later modified the amp for 45's. I always had a bit of hum that you could hear if you were right next to the speaker. Sitting in my listening position it was much less noticeable. And when music was playing you don’t hear the hum at all. I noticed that when I went from 2A3 to 45 the hum was lessened quite a bit. To me that would indicate too much gain. Additional padding in my pre-amp helped even more. In your case you are controlling the volume with the submissive. You could try dumping some of that gain with the pot on the Stereomour. Have tried hooking your source directly into the Stereomour? You might be introducing hum with your interconnects.
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Well, I hooked up the Orcas and Dungenus to two other amps and got zero hum even at 100% gain on the sub.
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Is the 1.5mV you measured on the scope peak to peak or rms? If it is peak to peak (Vpp) then you are well below the hum spec for the amp. If it is rms then the hum is slightly higher than average, but low enough that you would probably only get it lower by swapping out tubes until you find a particularly quiet set. The place to start might be the 12AT7.
You could also reduce the hum slightly by wiring the transformers for 4 ohms output rather than 8 ohms. However this will limit your headroom a bit.
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Thanks Doc, I am measuring RMS. I will take a look at the tube. Maybe wire the transformers for 4 ohms as well. I am in a small space.
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The 4 ohm thing would only be a liability if you run the system loud enough that it seems to run out of steam on loud passages. If you are not running that loud it should work fine. Also the hum may reduce a little as the tubes burn in. It's usually worth it to touch up the hum balance after a few hours play when you have new tubes.
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I am lucking for a replacement tube on ebay right now. Any suggestions. The stock one I got was pretty beat up. Pens a little bent so it may be suspect. Do you have a recommendation for a generally accepted high quality replacement. Cost is not a big issue.
Thanks,
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It's very subjective. I like the Mullard CV4024.
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Yes, When I adjust the sub gain to the 10 O'Clock position recommended by Clark the hum is minimized but still slightly audible.
How is that sub level when you listen? I would wonder if the level might be a little high for your space.
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How is that sub level when you listen? I would wonder if the level might be a little high for your space.
I think I have the sub level now in a good place. Slightly less than 10 O'clock. Sounds just right to me. Like I said, the hum is now only slightly audible and seems to be getting better. I have ordered a new pair of JJ 2a3-40 tubes and a mullard nos CV4024. I am hoping this may also help a little.
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OK, for those who are interested, my Blumenstein Dungeness Subwoofer is now absolutely quiet. I took DocB's advice and I changed my setup by modifying the submissive to have two RCA outputs. I hooked one up to the Sub and absolutely quiet even if I turn the gain up as fair as it will go on the sub. So now the Stereomour, Submissive, and Blemenstien Orca Deluxe/Dungeness are awesome.
I am not sure why, but the whole system sounds way better this way. The Orcas seem to sound better this way. Not sure what is going one but using the line level input seems to solve all my issues.
I am in Heaven.
Thanks everyone.
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You are no longer amplifying the residual noise floor of the Stereomour with the Dungeness amp.
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Yes, Doc, that is it!!!!! Also, today I received my new JJ 2a3's and my Mullard CV 4024. Man are these JJ's huge. The sound with everything is great. Looking forward to buying my next few items. Paramounts and a Beepree hopefully.
Thanks again,
Tom
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I'd give this a try with my setup but I might just lose my mind trying to dial in the Dungeness subs again.
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I'd give this a try with my setup but I might just lose my mind trying to dial in the Dungeness subs again.
Grainger, YMMV. I am not sure if everyone needs to hop off the bandwagon of the way we recommend hooking up the sub amps via speaker wire by switching their whole systems around to RCA hookups. Doc, Paul and I might differ on this one. While the RCA signal splitting solution helped out Tom's situation with his noisy stereomour, I've heard RCA splitting practices distort the sound in mine and others' systems, whenever the pre amp section is not up to the task.
For instance, the sound of the Fix kit inserted into my systems did not work for me and the Orcas, but other folks with other rooms and systems seemed to find more of an improvement. YMMV. So, similarly, RCA splitting should be chosen in accordance with personal priorities in performance.
I usually do not try to get my tube amps noise free, personally, I focus most system changes on trying to get better dynamics and natural tonality out of the speaker drivers and source as a raw, unadulturated ingredients. My Paramounts into Orcas on the desktop do have a little noise in them, for instance, but this is ok as soon as the music is playing. The SEX amp on the other hand, is truly hum/noise free btw, but uses a different kind of power triode thats less susceptible to all sorts of noise. I personally (perhaps esoterically) prefer the dynamics of the Paramounts into the Orcas even on the desktop so I put up with the truly miniscule hiss/hum and the potential risk of gently bottoming out the cone with the extra power. A very small trade off that's easy to deal with for me personally. But other folks might think differently and that's ok.
-Clark
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Clark, cool post. I can tell you for me, the difference is amazing.
If you are ever in San Diego and have a few minutes, you should come buy and take a listen. I would love to have you listen to this set up. You are right that these speakers in my 11x9 room is amazing. It seems to be getting better every day.
I dont understand your post though. If you output the signal directly to the subwoofer with the great volume control in the submissive, you basically have the signal going clean to the amplifier in the sub. Then you don't amplify the noise (if any) from the the Tube Amplifier for the bass signals.
How could it get any better through the Tube amplifier to be further amplified by the solid state amplifier in the Subwoofer??
Not trying to act like I know anything, because i don't, just wondering what your response is.
BTW, I keep you picture over the speakers in my office so I can tell everyone about your speakers when they ask
(https://dl.dropboxusercontent.com/u/38833957/2014-06-23%2017.47.20.jpg)
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Clark,
I might have been unclear about my comment. It was mainly tongue in cheek.
I am the weak link here. The Orcas and Dungeness are great products. I am compulsive and went wild dialing back and fourth on the level and crossover.
I ended up at your suggested settings after putting the Dungeness on the floor next to the Orca stands.
The flaw is in the user not the speakers.
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Tom, thanks man! I love the look of your system!
back to the sub hookups, I do get the theory of less distortion from not re-amplifying the amplifier's noise, but in practice, things can sometimes shake out differently.
In my opinion, debating RCA or speaker level hookup styles to avoid re-amplifying a noisy stereomour might just be...still ignoring the noisy stereomour. (Or dungeness amp?) who knows?
The reason I mention this is that usually, I notice very little difference between RCA hookups and speaker level hookups in most of my systems. Often, I ever so slightly prefer the speaker level hookups, or RCA's, or am somewhat indifferent. but the discrepancy between the two is usually not huge like you are saying about the RCA hookups in your system. Now, maybe the double outputted Submissive is just that good, and I'll try it out in my own system soon to confirm. But my stereomour on the other hand is dead dog quiet, which is why I am thinking it might be something different than the simple benefit of RCA or speaker level hookups. The "noise" might be the problem, not the amplification.
Generally, our company mantra is "speaker level" for a variety of reasons, practicality included. (Many of our customers are using integrated amps/receivers w/o any rca hookup potential). Practicality is important because we want to spread this gear (and therefore enjoyment of music) to an ever widening audience. And even in an increasing amount of "wireless" gear, wired still sounds arguably better, and is the only practical way of using physically microphonic tube amplifiers...outside of the speaker box! Its all easy to use, sounds great, and lasts a lifetime, and is never obsolete because its whole purpose is being fundamentally purist gear.
But back to the RCA splitting distortion I was discussing earlier: Bottlehead preamps with proper dual RCA outputs like the beepree, foreplay, and your properly modified submissive are a definite and huge step up over the typical rca "y splitters," from radio shack, but you can still sometimes hear a slight effect on the signal from the extra set of cables being hooked up, and other factors like different lengths/types of RCA cables also still seems to matter. In other words, there is probably no free lunch but the differences are minor when RCA level crossovers and such are properly set up
I should also say that our company structures are a little different. This is Bottlehead's forum. And we usually work out the troubleshooting on our products one on one by email or phone before it becomes a multi theoried forum thread. Information and misinformation about all this stuff can quickly become overwhelming for others, especially beginners, to read and perhaps get confused by all the seeming choices/quirks of tube equipment and single drivers. But it was impossible to see that potential complexity before posting so truly no worries.
Basically, Doc, PB, and I are all recommending different solutions to your problem. I don't have a problem with that, but people looking from the outside in, who might just be getting into this stuff, are probably more than a little confused by the jargon and conflicting theories by now.
While we do not "generally" recommend RCA hookups into Dungeness because of equal parts "it does not/should not matter much," assuming optimal health of components upstream, there is nothing expressly wrong with it. If it works it works. But speaker level hookups are often easier for folks to understand in terms of how to physically get the "mess of wires and drivers" to work. expanding this conversation's scope to the rest of the audio industry, everyone has their preferred method. That's part of the richness of this hobby!
So - I am not by any means "anti-RCA" level tone controls, crossovers, volume controls, etc. I am merely presenting them as potential variables to be assessed in terms of individual "component health" in the hollistic system you are troubleshooting.
I'd love to see more audiophile/minimalist/simple RCA line level 40-180hz crossover/biamplification products on the market, for instance. mmmmm... tube bass! But admittably, active crossovered, bi amped, SET tube will most often be for the purists (like us, who are regulars on this forum) who probably already have a few different tube amps around and are looking to put them to good use.
But in the same stroke we want to keep the product's presentation simple for the reason that for beginners, penetrating all the way through this mumbo jumbo audio lingo is tough and most folks just want to know that our speakers sound good, make bass, with Bottlehead gear. And as your data point and my data point, and other pleased folks on this forum confirm, that is the truth!
Thanks,
Clark