Anyone run into this with SDA SRS Speakers
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Wnite
Posts: 12
I bough my SDA SRS speakers in 1987 right out of college (with a company car I was making speaker payments instead of car payments) and now they are the foundation of my home theater set up. I just bought an external 7 channel Monoprice Monolith amp to use with my Marantz SR6011. It looks like the Monolith is Common Ground (checked with VOM). Hooked up all bed layer speakers to the external Monolith amp (going from 7.2 to 7.2.4). I get a loud nasty sound from the speakers when the SDA SRS interconnect cable is connected (blade/blade). Works fine when I disconnect it. Since the amp appears to be Common Ground I'm not sure what else to trouble shoot here. The speakers have worked fine over the years with multiple Yamaha and Marantz amps, but I think they will do much better with the 200w/channel Monolith and it allows me to go with a Pre/Pro setup in the future. Any advice appreciated. Thanks!
Answers
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What setting on the VOM did you use? What reading did you get? What are bed layer speakers?Political Correctness'.........defined
"A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."
President of Club Polk -
200 ohm setting on one meter and got 2.6 ohms. Have another meter that showed 1.6 ohms (I think I trust that one more). Center channel is a Polk CS1000p and the 4 surrounds are FX 1000's. 2 Subs are SVS PC-2000's. The four Atmos speakers that started this change are the Polk Reserve R900's. Thanks.
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I've never heard the term bed layer speakers.
It appears the Monolith is common ground. How you are driving the 11 pair of speakers? What is driving the R900's?Political Correctness'.........defined
"A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."
President of Club Polk -
I think I got this one....not SDA but a Legend setup
I have a ..
Marantz AV7706
Sunfire TGA-7201 7-chnl amp
Outlaw 5000X 5 chnl amp
When I fired up my new Atmos HT setup, I too got a nasty hum
Ran a common ground wire from the Outlaw gnd lug to the Marantz chassis stopped it immediately
Had to find out which was my issues
The monolith has the same type ground terminal
2-channel: Modwright KWI-200 Integrated, Dynaudio C1-II Signatures
Desktop rig: LSi7, Polk 110sub, Dayens Ampino amp, W4S DAC/pre, Sonos, JRiver
Gear on standby: Melody 101 tube pre, Unison Research Simply Italy Integrated
Gone to new homes: (Matt Polk's)Threshold Stasis SA12e monoblocks, Pass XA30.5 amp, Usher MD2 speakers, Dynaudio C4 platinum speakers, Modwright LS100 (voltz), Simaudio 780D DAC
erat interfectorem cesar et **** dictatorem dicere a -
I only heard the term 'bed layer' recently when exploring how to set up Dolby Atmos speakers (I'm assuming it's to differentiate your main + surround 'lower' speakers from the Atmos height channels). The 7 bed layer speakers (Mains+Center+4 Surrounds) are all driven by the Monolith amp (through the pre-outs on the Marantz). External amp settings are switched to RCA inputs (not XLR). The four Atmos speakers are driven by the Marantz and the two subs have their own amps built-in. The 'Amp Assign' on the Marantz is set to 11.1 surround with Fronts set to 'pre-out' (which should be the correct setting). Since it works fine without the SDA interconnect cable I would think it should work with it as well?
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Ok, you need to do what txcoastal1 did and create a common ground between the AVR and amp. That is the direction I was going, but wanted to get as much info from you as possible first.
Report back.Political Correctness'.........defined
"A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."
President of Club Polk -
If youhaven't done so, your crossovers are due to be refurbished and they make better tweeters for them as well. You might want to get the tweets as soon as possible because there is no telling how much longer they will be available.
The Gear... Carver "Statement" Mono-blocks, Mcintosh C2300 Arcam AVR20, Oppo UDP-203 4K Blu-ray player, Sony XBR70x850B 4k, Polk Audio Legend L800 with height modules, L400 Center Channel Polk audio AB800 "in-wall" surrounds. Marantz MM7025 stereo amp. Simaudio Moon 680d DSD
“When once a Republic is corrupted, there is no possibility of remedying any of the growing evils but by removing the corruption and restoring its lost principles; every other correction is either useless or a new evil.”— Thomas Jefferson -
I thought that would work, but sadly no. It's not really a hum, it's more of a slightly deafening pulse (like a fast heartbeat). Thanks for the heads up about the tweeters and crossover. I've been down a few rabbit holes in the course of trying to figure this out and just learned about that. Definitetly interested!
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Well, damn!
I feel safe in saying that the issue is common ground related, but I'm out of ideas/suggestions right now.
I noticed your amp is capable of drawing 1800 watts/15 amps and therefore has a 20 amp IEC. Is the amp on a dedicated 20 amp line? If so, is the AVR on the same line or a separate one?
Political Correctness'.........defined
"A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."
President of Club Polk -
Ah, a shot in the dark. Try running a wire from the ground lug on the amp to the screw holding the outlet cover in place.Political Correctness'.........defined
"A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."
President of Club Polk -
Have another question...are you using XLR/balanced or single ended rca connection from AVR to amp?
Marantz 7706 prepro XLR/balanced is Euro config reversing pins2-channel: Modwright KWI-200 Integrated, Dynaudio C1-II Signatures
Desktop rig: LSi7, Polk 110sub, Dayens Ampino amp, W4S DAC/pre, Sonos, JRiver
Gear on standby: Melody 101 tube pre, Unison Research Simply Italy Integrated
Gone to new homes: (Matt Polk's)Threshold Stasis SA12e monoblocks, Pass XA30.5 amp, Usher MD2 speakers, Dynaudio C4 platinum speakers, Modwright LS100 (voltz), Simaudio 780D DAC
erat interfectorem cesar et **** dictatorem dicere a -
The Theater equipment (except the projector) is on a single 20amp circuit. I plugged them both into the same outlet earlier and still had the issue. I'll try the wire from the chassis trick as soon as I can. Thanks!
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txcoastal1 wrote: »Have another question...are you using XLR/balanced or single ended rca connection from AVR to amp?
Marantz 7706 prepro XLR/balanced is Euro config reversing pins
He stated earlier, "External amp settings are switched to RCA inputs (not XLR)."Political Correctness'.........defined
"A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."
President of Club Polk -
Another suggestion, contact Monolith and explain the issue. Also ask about the grounding architecture of the amp.Political Correctness'.........defined
"A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."
President of Club Polk -
The Monoprice 7 channel amp uses two toroidal transformers inside. Could be a common ground issue because of that design if the SDA speakers are not running from the output modules linked with just one of the toroidals.
My solution would be to run the SDA speakers from a separate known common ground two channel amp (or the receiver temporarily) and use the Monoprice amp for the other channels.
Monoprice tech support may also be able to help. -
The Monoprice 7 channel amp uses two toroidal transformers inside. Could be a common ground issue because of that design if the SDA speakers are not running from the output modules linked with just one of the toroidals.
That certainly sheds new light on the issue and why I suggested asking about the grounding architecture.Political Correctness'.........defined
"A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."
President of Club Polk -
Yeah more of a dual mono vs a common ground
If you can speak with support see what channels or other components are on each transformer
Ask if negatives can be strapped together
Also wonder if the inputs are config'd in a 1-3-5-7 w/common and a 2-4-6 w/common config2-channel: Modwright KWI-200 Integrated, Dynaudio C1-II Signatures
Desktop rig: LSi7, Polk 110sub, Dayens Ampino amp, W4S DAC/pre, Sonos, JRiver
Gear on standby: Melody 101 tube pre, Unison Research Simply Italy Integrated
Gone to new homes: (Matt Polk's)Threshold Stasis SA12e monoblocks, Pass XA30.5 amp, Usher MD2 speakers, Dynaudio C4 platinum speakers, Modwright LS100 (voltz), Simaudio 780D DAC
erat interfectorem cesar et **** dictatorem dicere a -
Sent a common ground question to Monoprice Tech Support. I did check for continuity on all 7 channels with each other and it appears they are all grounded to each other as well as to the ground prong on the power cable. I switched the SDAs back to the Marantz to make sure they still worked ok on that receiver and they do. It does seem like a common ground issue, but it also looks like it's a common ground amp. Hmmm.
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Could this be a differential output issue?The Gear... Carver "Statement" Mono-blocks, Mcintosh C2300 Arcam AVR20, Oppo UDP-203 4K Blu-ray player, Sony XBR70x850B 4k, Polk Audio Legend L800 with height modules, L400 Center Channel Polk audio AB800 "in-wall" surrounds. Marantz MM7025 stereo amp. Simaudio Moon 680d DSD
“When once a Republic is corrupted, there is no possibility of remedying any of the growing evils but by removing the corruption and restoring its lost principles; every other correction is either useless or a new evil.”— Thomas Jefferson -
What would a differential output issue look like. (The amp is 200 watt/channel. all channels are independent, so whatever is happening on one channel doesn't effect the others).
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It might be helpful to check the continuity between any of the speaker negative terminals and the chassis ground lug and the continuity between any of the speaker negative terminals and a ground connection on any of the RCA sockets.
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Another test I did was to disconnect the power from the Marantz and the Subs and only turn on the Monolith external amp (with speakers hooked up). Still got the Loud Pulsing sound.
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What might be happening is that when you are making the continuity measurement between the negative speaker terminals that amp is off, correct? It is possible whatever protection circuit the amp uses is in a standby mode thus giving you the continuity connection. When the amp is actually in use the protection circuit is disengaged and if the amplifier has a balanced output design when in use the SDA connection is a short.
Try removing speaker connections and switching the amplifier on and make the same continuity measurements. -
2-channel: Modwright KWI-200 Integrated, Dynaudio C1-II Signatures
Desktop rig: LSi7, Polk 110sub, Dayens Ampino amp, W4S DAC/pre, Sonos, JRiver
Gear on standby: Melody 101 tube pre, Unison Research Simply Italy Integrated
Gone to new homes: (Matt Polk's)Threshold Stasis SA12e monoblocks, Pass XA30.5 amp, Usher MD2 speakers, Dynaudio C4 platinum speakers, Modwright LS100 (voltz), Simaudio 780D DAC
erat interfectorem cesar et **** dictatorem dicere a -
Typically most multi channel amps are not common ground. Frequently they have separate boards for each channel, making that near impossible. As you stated above, you got more than 1 ohm, maybe closer to 3, when measuring the resistance between negative terminals. That is a clear sign the amp is not common ground. If you cannot strap the negative terminals ( ask manufacturer), it will not work without a dreadnought.
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Typically most multi channel amps are not common ground. Frequently they have separate boards for each channel, making that near impossible. As you stated above, you got more than 1 ohm, maybe closer to 3, when measuring the resistance between negative terminals. That is a clear sign the amp is not common ground. If you cannot strap the negative terminals ( ask manufacturer), it will not work without a dreadnought.
Interesting. I never heard of that before. Does that mean the power supply has a ground, and each amp has its own ground? That would seem to be ground loop heaven.
Lumin X1 file player, Westminster Labs interconnect cable
Sony XA-5400ES SACD; Pass XP-22 pre; X600.5 amps
Magico S5 MKII Mcast Rose speakers; SPOD spikes
Shunyata Triton v3/Typhon QR on source, Denali 2000 (2) on amps
Shunyata Sigma XLR analog ICs, Sigma speaker cables
Shunyata Sigma HC (2), Sigma Analog, Sigma Digital, Z Anaconda (3) power cables
Mapleshade Samson V.3 four shelf solid maple rack, Micropoint brass footers
Three 20 amp circuits. -
Cannot use a dreadnought on blade/ blade speakers.
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Typically most multi channel amps are not common ground. Frequently they have separate boards for each channel, making that near impossible. As you stated above, you got more than 1 ohm, maybe closer to 3, when measuring the resistance between negative terminals. That is a clear sign the amp is not common ground. If you cannot strap the negative terminals ( ask manufacturer), it will not work without a dreadnought.
Well DOH on me. You're right, it is not a common ground amp.Political Correctness'.........defined
"A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."
President of Club Polk -
OK, I submitted a technical support request to Monoprice. First, they said that it is a Common Ground amp (could be the case that they are interpreting that to mean that it has a 'ground prong' on the power cord, but hopefully they understood the question).
Their first ask was to replace the RCA cables going from the Marantz Pre Out to the Monolith amp. I replaced the 2 pre out RCA cables that supply the signal to the Monolith channels that the SDAs are on with an old pair of Monster Cables and that fixed the problem (maybe more shielding?).
Here's why I thought that wouldn't work. Most of the RCA cables were new (Product # 2864 from Monoprice...They have RCA Cables called Monolith cables (which I assume are better), but they were out of stock when I ordered). Also, when the SDA interconnect cable was connected, and I disconnected the left SDA speaker wires from the amp it worked without the loud pulsing sound. When I disconnected the Right SDA speaker wires from the amp It worked fine and when I disconnected the Interconnect cable and had all speakers connected it also worked fine. Only when the SDA Interconnect cable was hooked back up did the Loud Pulse resume. When I switched the two RCA pre out cables going to the Monolith Amp with the Monster cables the pulsing went away, and everything seems to be working as it should.
Regarding the Common Ground question. My understanding is that a Non Common Ground amp will give you an 'Infinitiy' or 'Open' circuit reading on an Ohm Meter (0.L etc) when checking black-to-black speaker outputs on the back of the amp. Getting a very low resistance reading would indicate contact (not an open circuit). I checked some black-to-black speaker terminals on my Marantz AVR and got anywhere from .4 to .8 Ohms (not zero). I took a reading on a black to red speaker terminal and got an open circuit reading (0.L). I believe that would indicate that the Monolith is in fact a Common Ground amp. -
Here's how I incorporated the SDAs into my Home Theater if anyone is interested.
Here is a local article about the theater and soundproofing etc.
https://www.cityscenecolumbus.com/silence-is-golden/
Here's a couple pics.
