Does Increased Wattage Change Tweeter Sound?

Hello,

A couple years ago I acquired a pair of SRS 2s, not knowing anything about the SDA rabbit hole or speakers in genral, I purchased a cheap 2 channel Yamaha Inegrated receiver from best buy. Undoubtedly the SDAs were the best stereo system I had ever heard, and I started reading and looking into what would make the speakers even better. I decided to move to separates and buy better equipment as a start. Fast forward to now, I managed to get ahold of the last part that I needed, and could assemble the system. I hooked everything up, and though I didn't have the speakers positioned correctly, I noticed that most of the warmth was gone, replaced by a harsher metalic tone. It was such a stark change that I doubt I would have recognized the Polks in a blind listening test. The clarity however was incredible, and I noticed things in recordings I had never heard! I expected a change in the sound but didn't anticipate this.
If its any help, my equipment is as follows:
Preamp: Marantz AV 7705
RCA interconnects: Tributaries 8a
Amp: Belles 350a Reference
Speaker cables: Blue Jeans Cable 10 white cable (10 awg)
Speakers: SDA SRS 2 1968 blade-blade, sl2000 tweeters
To my knowledge, none of the components are known to exhibit these characteristics aside from the sl2000s. They didn't sound like this before, but I am guessing that was because the Yammy could only deliver 110 watts per channel. I am still fairly new to audio, but would under-powering the tweeters be responsible for their initial laidback appearance? Please let me know what you think, if the tweeters are to blame, I may upgrade to rd-0194s, but it may be another component that I'm overlooking.

Thanks.
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Comments

  • pitdogg2
    pitdogg2 Posts: 25,436
    edited May 2022
    I know it's a mistake, no SDA 2 in 1968 😂😂. Replace those sl2000 with RD-0194 asap.
    So what kind of decibels are you running them at?
    Did you run any of the room correction from the Marantz pre?
    FWIW it is not all about watts you need good current delivery as well. The Belles should have it in spades.
  • BinKY188_5
    BinKY188_5 Posts: 133
    edited May 2022
    I believe the Belles 350a is a dual mono amp that will not work with blade/blade SDA SRS 2.
    Post edited by BinKY188_5 on
  • pitdogg2
    pitdogg2 Posts: 25,436
    edited May 2022
    BinKY188_5 wrote: »
    I believe the Belles 350a is a dual mono amp that will not work with blade/blade SDA SRS 2.

    Good point. That might explain the sound. Usually you get a loud screech that makes you shut it down
  • Clipdat
    Clipdat Posts: 12,934
    It's times like these that I really miss @cfrizz popping in and incorrectly informing OP that he needs at least 200 watts per channel.
  • pitdogg2
    pitdogg2 Posts: 25,436
    Found this which seems to confirm it is a dual mono design.
    The 350A V2 is a solid-state dual mono design with a single common 2000 VA toroidal transformer.
  • PILAC
    PILAC Posts: 23
    First, thanks for all of the comments, I appreciate it!
    Second, to answer Pitdogg's questions:
    I never got around to turning them up too loud, comparing on another system with a db. meter I would say about 60 decibels max.
    I had not enabled any room correction for the Marantz, just set it up for 2ch playback.
    The above considered, I do have a couple questions:

    Correct me if I'm wrong, but from my limited research it appears that a dual mono amp is essentially two amps in a single box, handling each channel separately. Typically, this would mean separating everything related to the amps, but it appears that the Belles may still be a common ground amplifier. I was under the impression that SDAs, at least those of the blade-blade interconnect type, which were not candidates for dreadnaught, needed a common ground amplifier. If the Belles was a "dual" Monoblock I am guessing the SDAs should no longer be functioning, as common ground would not be present. I did a test with a multi meter and got a reading touching both black terminals. I also found a photo taken by audioluvr, which shows 4 black wires connecting on a single point/pin. (Note: it's a little tricky to see, but I am referring to the black wires with yellow bands on the end, as they are also connected to the main boards and what appears to be the rear terminals.) This would make me think that the Belles is a common ground amp. If so, is there another specific requirement for SDAs that I am unaware of, and why is it so damaging to use?

    Also, it's entirely possible that I'm mixed up on some of this, if so please don't hesitate to correct me.
  • F1nut
    F1nut Posts: 50,537
    edited May 2022
    With the amp unplugged what ohm reading do you get between the two negative binding posts?

    Also, you didn't list what source you are using.
    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

  • mhardy6647
    mhardy6647 Posts: 33,786
    60 dB is quiet.
    just sayin'.

    pyloolukef24.png
    source: https://www.osha.gov/noise
  • F1nut
    F1nut Posts: 50,537
    A phart is louder....just saying.
    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

  • PILAC
    PILAC Posts: 23
    F1nut,
    Just touching the leads together with the multi meter set to 200 ohms I get somewhere between 0.5 and 0.6 ohms. In the terminals (amp unplugged) it reads steady 0.5 ohms.
    Source for the multi meter test:

    https://forum.polkaudio.com/discussion/30731/test-for-common-ground-amp#:~:text=In the old days the meter reading was,and correctly. You have a common ground amp.

    The 2 sites I used to get a rough idea of what a dual mono amp is:

    https://www.williamssoundstudio.com/mixing/dual-mono-and-stereo-explained.php

    https://www.sweetwater.com/insync/what-is-dual-mono-versus-stereo/

    SDA info:
    I've read quite a few threads on the forum.

    It might be overkill as far as sources go, but better safe than sorry.


    mhardy664,
    I agree, it seems like it should have been louder than that, but the decibel meter on my phone gave the same reading. That being said, it's entirely possible that the decibel app could be off by a fair amount. It wouldn't surprise me.

  • PILAC
    PILAC Posts: 23
    edited May 2022
    F1nut: :D
    Thinking back, my guess would be closer to 70 db. Still quieter than I normally listen.
  • mhardy6647
    mhardy6647 Posts: 33,786
    are the
    PILAC wrote: »
    F1nut,
    Just touching the leads together with the multi meter set to 200 ohms I get somewhere between 0.5 and 0.6 ohms. In the terminals (amp unplugged) it reads steady 0.5 ohms.
    Source for the multi meter test:
    ...
    I'm not @F1nut but I am under consideration to play him in the miniseries streaming soon on Amazon Prime Video... B)

    Are the batteries in the DMM you're using good (fresh)? The shorted test leads ought to read 0 ohms.

    Did you try measuring some component known to be "good" with a known, low DC resistance (e.g., a 10 ohm resistor)?

  • pitdogg2
    pitdogg2 Posts: 25,436
    You are correct you can have a dual mono architecture and still be common ground.
  • F1nut
    F1nut Posts: 50,537
    edited May 2022
    By source, I meant your music source such as vinyl, CD, streaming, etc.
    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

  • F1nut
    F1nut Posts: 50,537
    pitdogg2 wrote: »
    You are correct you can have a dual mono architecture and still be common ground.

    Yep, he seems to have 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

  • F1nut
    F1nut Posts: 50,537
    mhardy6647 wrote: »
    I'm not @F1nut but I am under consideration to play him in the miniseries streaming soon on Amazon Prime Video... B)

    Right now the first episode will feature my Bozo list with in depth explanations for each. Should you get the part I'll go over the details with you.

    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

  • pitdogg2
    pitdogg2 Posts: 25,436
    I had not enabled any room correction for the Marantz, just set it up for 2ch playback.
    You may need to get into menu and find out exactly how the parameters are set up. If this was bought second hand the settings could be wonkie for your use. Just a thought unless you've been deep into it and have it all set to flat.
  • mhardy6647
    mhardy6647 Posts: 33,786
    F1nut wrote: »
    mhardy6647 wrote: »
    I'm not @F1nut but I am under consideration to play him in the miniseries streaming soon on Amazon Prime Video... B)

    Right now the first episode will feature my Bozo list with in depth explanations for each. Should you get the part I'll go over the details with you.

    ... unless I am already on the list, in which case it'll be logistically difficult :#
  • F1nut
    F1nut Posts: 50,537
    mhardy6647 wrote: »
    F1nut wrote: »
    mhardy6647 wrote: »
    I'm not @F1nut but I am under consideration to play him in the miniseries streaming soon on Amazon Prime Video... B)

    Right now the first episode will feature my Bozo list with in depth explanations for each. Should you get the part I'll go over the details with you.

    ... unless I am already on the list, in which case it'll be logistically difficult :#

    Well, obviously that's not the case.
    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

  • PILAC
    PILAC Posts: 23
    F1nut wrote: »
    By source, I meant your music source such as vinyl, CD, streaming, etc.

    Thanks for the clarification, I am enjoying the ongoing conversation. ;)
    I was streaming from my phone as that's how I had been transmitting audio before.
  • PILAC
    PILAC Posts: 23
    pitdogg2 wrote: »
    I had not enabled any room correction for the Marantz, just set it up for 2ch playback.
    You may need to get into menu and find out exactly how the parameters are set up. If this was bought second hand the settings could be wonkie for your use. Just a thought unless you've been deep into it and have it all set to flat.

    I appreciate the thought, I did buy it used, and haven't dug into the settings too far yet. Thats something I will need to put on the list. I didn't notice anything that had been changed from the defaults though, so I suspect it may have been reset.
  • Emlyn
    Emlyn Posts: 4,487
    Marantz processors have a direct and pure direct mode that will avoid digital signal processing. Easy way to force it into a two channel only mode.

    My guess is your system is just higher resolution now and you are hearing the effects of everything in the signal chain revealing the source material with far more clarity. None of the elements are inherently harsh sounding individually except for the SL2000 tweeters and possibly using the phone as a source. I find the BJC speaker cables to be very neutral even when using them with Magnepan speakers. And Marantz products are usually not considered bright sounding.

    My theory is still that those SL2000 tweeters produced acceptable sound in the mid 1980s on the gear that most people were driving them with at home but that hasn’t been the case for the last 20 plus years.
  • PILAC
    PILAC Posts: 23
    edited May 2022
    BinKY188_5 wrote: »
    I believe the Belles 350a is a dual mono amp that will not work with blade/blade SDA SRS 2.

    So now the million-dollar question, is it safe to assume that the Belles is alright to run with the SDAs and the tweeters just need to be replaced?
    Also, thanks again for all the advice and helpful comments, I really appreciate it!
  • F1nut
    F1nut Posts: 50,537
    It appears your amp is ok to use. As mentioned, the increased resolution is exposing the short comings of the tweeters and your phone. As it all starts with the source, your phone, look into upgrading that.
    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

  • PILAC
    PILAC Posts: 23
    Sounds good, thanks again for all the advice and insight!
  • audioluvr
    audioluvr Posts: 5,582
    PILAC wrote: »
    BinKY188_5 wrote: »
    I believe the Belles 350a is a dual mono amp that will not work with blade/blade SDA SRS 2.

    So now the million-dollar question, is it safe to assume that the Belles is alright to run with the SDAs and the tweeters just need to be replaced?
    Also, thanks again for all the advice and helpful comments, I really appreciate it!

    Just keep and eye on it. If it runs unusually hot at moderate listening levels you may have an issue. My 350A Reference runs quite warm on a 4 ohm load but you should still be able to touch the heat sinks without leaving a mark... As for the difference between it and a Yammy. Well IMHO Yammy's seem dull and lifeless compared to the Belles. It's a very revealing amp and you'd be very happy with the RDO upgrade.
    Gustard X26 Pro DAC
    Belles 21A Pre modded with Mundorf Supreme caps
    B&K M200 Sonata monoblocks refreshed and upgraded
    Polk SDA 1C's modded / 1000Va Dreadnaught
    Wireworld Silver Eclipse IC's and speaker cables
    Harman Kardon T65C w/Grado Gold. (Don't laugh. It sounds great!)


    There is about a 5% genetic difference between apes and men …but that difference is the difference between throwing your own poo when you are annoyed …and Einstein, Shakespeare and Miss January. by Dr. Sardonicus
  • gp4jesus
    gp4jesus Posts: 1,987
    Sorry to derail the threat.

    Dual mono w/a shared transformer?

    For years I had believed dual mono meant separate transformers, etc, sharing only the power cord, chassis, but nothing else.

    From “looking under the hood” I’ve observed Parasounds*, Rotels & Hafler XL-280s have dedicated secondary windings, bridge rectifiers, & capacitor banks. Why aren’t they considered dual or multi* mono?
    *even the P’sound 855 - 5 X 85 -> 8 ohms w/dedicated secondary windings, etc

    Again, a big “I’m sorry” to PILAC.
    Samsung 60" UN60ES6100 LED Outlaw Audio 976 Pre/Pro Samsung BDP, Amazon Firestick, Phillips CD Changer Canare 14 ga - LCR tweeters inside*; Ctr Ch outside BJC 10 ga - LCR mids, inside* & out 8 ga Powerline: LR woofers, inside* & out *soldered LR: Tri-amped RTi A7 w/Rotels. Woofers - 980BX; Tweets & “Plugged*” Mids - 981, connected w/MP Premiere ICs Ctr Ch: Rotel RB981 -> Bi-amped CSi A6 Surrounds: Premiere ICs ->Rotel 981 -> AR 12 ga -> RTi A3. 5 Subs: Sunfire True SW Signature -> LFE & Ctr Ch; 4 Audio Pro Evidence @ the “Corners”. Power Conditioning & Distribution: 4 dedicated 20A feeds; APC H15; 5 Furman Miniport 20s *Xschop's handy work
  • Emlyn
    Emlyn Posts: 4,487
    edited May 2022
    The 350a doesn’t meet the definition of a dual mono amplifier design because it only uses a single shared transformer in one box. That is a stereo amp. If it had two smaller separate transformers it could have been a dual mono design but it doesn’t and it would have performed worse.
  • Schurkey
    Schurkey Posts: 2,101
    Emlyn wrote: »
    The 350a doesn’t meet the definition of a dual mono amplifier design because it only uses a single shared transformer in one box. That is a stereo amp. If it had two smaller separate transformers it could have been a dual mono design but it doesn’t and it would have performed worse.
    A single, double-wound transformer is essentially the same as two separate transformers on a single iron core.




    Every "Dual Mono" amplifier I've personally dealt with (not all that many) has had some version of common-ground. The insulated side is separate, the ground side is shared.

    As has been said...get that preamp adjusted so it's not **** with the sound.

    The SDA SRS 2 Blade/blade is a fine speaker system...after you gut the ancient electrolytic caps, pull the Dacron back up where it belongs, and perform the other half-dozen or so "usual improvements".
  • gp4jesus
    gp4jesus Posts: 1,987
    edited May 2022
    “A single, double-wound transformer is essentially the same as two separate transformers on a single iron core.”

    So you claim the Belles 350 transformer shares only a single core and a power cord. Each channel’s “power supply” has its own set of primary windings in addition to each having secondary windings.

    I’d be inclined to agree it’s a dual mono amp sharing a single chassis etc. Some have their own definition. They’re entitled to that.

    I use two 2 channel amps to tri-amp each tower. One amp powers the tweeter and the mid. The other powers the twin woofers. In spite of the separate secondary windings, bridge rectifiers, and cap banks some would claim bi-amp because of just two chassis.

    I hope you get to enjoy the fruits of your labor w/no glitches or roadblocks soon.

    Tony
    Samsung 60" UN60ES6100 LED Outlaw Audio 976 Pre/Pro Samsung BDP, Amazon Firestick, Phillips CD Changer Canare 14 ga - LCR tweeters inside*; Ctr Ch outside BJC 10 ga - LCR mids, inside* & out 8 ga Powerline: LR woofers, inside* & out *soldered LR: Tri-amped RTi A7 w/Rotels. Woofers - 980BX; Tweets & “Plugged*” Mids - 981, connected w/MP Premiere ICs Ctr Ch: Rotel RB981 -> Bi-amped CSi A6 Surrounds: Premiere ICs ->Rotel 981 -> AR 12 ga -> RTi A3. 5 Subs: Sunfire True SW Signature -> LFE & Ctr Ch; 4 Audio Pro Evidence @ the “Corners”. Power Conditioning & Distribution: 4 dedicated 20A feeds; APC H15; 5 Furman Miniport 20s *Xschop's handy work