Why does my Fisher sound kind of lean vs. my Rega Brio-R?

Discussion in 'Audio Hardware' started by action pact, Apr 15, 2019.

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  1. Helom

    Helom Forum member

    Location:
    U.S.
    Spendors can sound great with tube power but I'd start with a minimum of 20 watts/ch and KT88s^.
     
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  2. SandAndGlass

    SandAndGlass Twilight Forum Resident

    The OP's amp is EL34 driven and is rated at 40-Watts per channel.
     
  3. 911s55

    911s55 Forum Resident

    Location:
    Wa state
    He has El84 not 34, more like 15 watts.
     
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  4. timind

    timind phorum rezident

    Bought my Fisher (KX90) amp here and it came with three of the original output tubes. The amp did not sound lean, in fact I'd say the opposite. I ordered a quad of Sovtek EL84M tubes and am very happy with the sound. The new tubes seemed to bring a new level of clarity and definitely cleaned up some sloppy bass. The KX90 runs 7189 tubes.
     
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  5. SandAndGlass

    SandAndGlass Twilight Forum Resident

    Sorry, I meant to comment on that.

    His amp is listed at 40-WPC and I was going to point this out, that it was less than 18-Watts actual, as compared to his SS amp at 50-Watts.

    Back then, the rated power differently, but when I was looking at his power tubes, my mind was "seeing" EL34 instead of EL84.

    I like EL84 power tubes. I have a vintage Scott 222C that has power tubes in the EL84 family, but they can produce more power than a standard EL84. The 222C is rated at 22-Watts RMS.

    Those 15-18 Watts are not enough, coupled with the vintage tube design to power his Splendor's the way a decent 50-Watt SS amp would be able to.

    He would need something at least in the mid 30-Watt range, like a Prima Luna EL34 based Prologue Four at 35-WPC.
     
  6. Whoopycat

    Whoopycat Forum Resident

    Location:
    Des Moines
    The more time and money I spend on this hobby, the more I start to think that there are no good amps, only good amp/speaker pairings. And there's no science or measurement to it other than your ears. I've had amps that I loved with some speakers and hated with others, even when specs suggested otherwise.

    Thine ears hath spoken... instead of rolling tubes, I'd roll with the Brio.

    Do you still have your old speakers, and if so does the Fisher still sound good with them?
     
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  7. action pact

    action pact Music Omnivore Thread Starter

    Actually, the Brio-R's heft and natural tonality excels with jazz. :agree:

    Is that a good thing? :shh:

    I assume you mean vintage Mullards? That sounds pricey, but I'll definitely consider it.

    You betcha...

    The more I think about it, the more I'm thinking it is the output tubes. I remember a couple of years ago, it was sounding rather uninspiring and I went ahead and replaced the GE(?) 12AX7's with the aforementioned RCA long black plates, and got an instant and significant upgrade. I recall it sounding quite lush and rich after installing the RCAs, which is the opposite of what I'm getting now. I got a similar jump forward when I replaced the Sovtek rectifier with the Mullard. So, that leaves the phase inverters and the output tubes...

    I totally get what you're saying about about efficiency, etc., and you're not wrong, but I want to respond specifically to one point:

    You have an amp that is going to sound "soft" and not have the control of a modern day tube amp that is more linear and has larger and better output transformer's.

    Here's the thing... This has always been a pretty 'quick' sounding amp, especially considering its vintage. The bass isn't ever going to be as tight and textured as SS, but it's sounding lean and slightly strident right now, which is the opposite of what one would expect from a '50s tube amp. My understanding is a tube amp with a speaker efficiency mismatch should sound sluggish, right? The amp still has plenty of liveliness and pep, it's just the tonal character is not right.

    Spendors also have a reputation for being very tube-friendly, so there's that too.
     
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  8. action pact

    action pact Music Omnivore Thread Starter

    IIRC Spendor recommends 25 wpc minimum, but I'm not convinced that the problem is with the efficiency. When I acquired the X100, I also still had a Fisher 400 (approx. 28 wpc), and observed at the time that the X-100 not only had a quicker presentation than the 400, but also seemed to be slightly more powerful too. Believe me, that was quite a surprise!

    I could be very happy with this pairing for the long term, but I'm not quite ready to rule out the Fisher yet, you know? I've gotten some amazing reproduction from that amp in the past, so I want to give the old girl another chance. It might end up that I decide that it's not the right match for the Spendors, but sounds to me like something is inherently just not right.

    Yes I do, but the old speakers (Wharfedale Denton 80's) are voiced with a much fuller midband and softer top-end, so they could very well have been masking the issues that the more honest Spendors are revealing.

    Further observations...
    I was listening today to some needledrops that I did a while ago using the Fisher's tubed phono stage - but played through the Rega/Spendor pairing - and they did not sound like when I play records with the Fisher now. The needledrops had that lush midband, round bass, and holographic imaging that I remember, even with a digital file played through solid state.

    At this point, I think my next move will be decided by what I find once the new EL84's arrive.
     
    Last edited: Apr 15, 2019
  9. Helom

    Helom Forum member

    Location:
    U.S.
    I think you're on the right path, though just for fun, you might try swapping polarity at the speaker posts.
     
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  10. bhazen

    bhazen I Am The Walrus

    Location:
    Deepest suburbia
    It is! :)
     
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  11. action pact

    action pact Music Omnivore Thread Starter

    Not a bad idea... I hadn't considered that the absolute polarity could be reversed.
     
  12. SandAndGlass

    SandAndGlass Twilight Forum Resident

    Pretty quick and quick like a modern day tube amp or SS amp are two different things.

    I like the sound of those vintage tube amps and I prefer the lower powered EL84 integrateds over the sound of the larger tube amps. I have a Fisher 500C myself.

    But that "it's sounding lean and slightly strident right now, is a mystery to me also.

    But remember, that it only has so much power and that may well be the major contributing factor to this.

    You do need more power, with a 88 dB sensitive speaker for it to play full and dynamic than 15-18 Watts.

    I think that if you put a more powerful tube amp on it, you would hear a big difference in weight.

    Your amp can still be lively, which would be mostly due to music in the midrange and high frequencies.

    The issues that you are expencing as to tonal character could be accounted for by the lack of support from the lower frequencies, making the tonal character unbalanced.

    Tube friendly and low powered tube friendly will not give you the same dynamics at a given volume level.

    My Fisher 500C has a decent amount of power, sounds good, doesn't really lack in any department soundwise, but I don't have the love for it that I have for the lesser powered EL84 and similar type amps.
     
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  13. sberger

    sberger Dream Baby Dream

    I'm going to go with the folks that are saying it's not enough amp for those speakers. New tubes, biasing, etc, all are a good idea anyway, but I would not use less then 60 watts with speakers of that efficiency. You want to be able to have headroom and not strain the amp. Yes playing quietly you can use the Fisher but realistically it's just not going to be up to the task of allowing those speakers to perform as they were designed. IMO.
     
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  14. action pact

    action pact Music Omnivore Thread Starter

    Great info, and this does makes sense.

    Once the new tubes arrive, I'll be able to confirm whether or not this is the case. It's one of those things where I kind of need to know if there is indeed a fixable problem or if it's just a simple system mismatch. Fortunately a quad of NOS Russian EL84's costs almost nothing, so it's a cheap experiment.


    :)
     
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  15. SandAndGlass

    SandAndGlass Twilight Forum Resident

    That's part of the wonder of the EL84 power tubes.

    And about them lasting 500-hours, that is baloney! These tubes can last thousand's of hours. As specially the NOS ones.

    On top of that, they sound beautiful, and are inexpensive to replace.

    I am currently running my vintage Altec A7's with a 3.9 Watt Decware Mini Torii.

    I have new manufacture 6V6GT tubes by Tung Sol, which cost a whole $45/pr. It is a single ended pentode amp, so it only requires one tube per channel.

    The beautiful thing about having highly sensitive speakers (103 dB), is that you can use so many of these lower powered but fantastic sounding amplifier's, which cost so much less to operate due to the tubes being both low cost and long lasting.

    With a 15-18 Watt EL84 amp, I can practically reproduce the volume and dynamics of a rock concert. And do it without turning the amp all the way up.
     
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  16. gov

    gov Forum Resident

    Location:
    NYC Metro
    What would this do? And whatever it does, is that limited to this amp?
     
  17. Helom

    Helom Forum member

    Location:
    U.S.
    Some Spendors have their midwoofers connected in reverse polarity for phase alignment reasons but that doesn't mean it's necessarily the best arrangement for a particular setup or listening preference.
     
  18. action pact

    action pact Music Omnivore Thread Starter

    Well, you know, I have been tempted to try building one of these...
    Fostex BK-16 Folded Horn Kit - Pair
     
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  19. SandAndGlass

    SandAndGlass Twilight Forum Resident

    I have seen those before and they look interesting. They are different from Altec or Klipsch legacy horn speakers. They are a full range crossover less design.

    I have never heard that type of speaker. They seem like they might be nice for a bedroom or other small room.
     
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  20. Lebowski

    Lebowski Hey, careful man, there's a beverage here!

    Location:
    Greater Boston
    Haha, I had to Google the word to figure out if it had a positive or negative connotation. Could've gone either way. :D
     
  21. timind

    timind phorum rezident

    I just figured he misspelled stinking.
     
  22. Aura

    Aura Forum Resident

    Location:
    Austin, Texas
    As noted above, the amp just doesn't have enough power, nor deliver enough current to the speakers. I have a similar amp topology in the Leben CS300-XS. Great sounding amp at really low volumes with speakers, and it's superb with headphones.

    But the Leben (15w) really needs 95db+ sensitive speakers to sound its best. I ended up buying a fantastic used Luxman SS amp that delivers 125w to my speakers. It just sounds better and better the higher I turn up the volume. The Leben in comparison sounds strident and congested during complicated music passages, or at loud volumes; and it then has a collapsed soundstage - all the hallmarks of a lack of power.

    One other thing to consider: gain staging. Someone mentioned having the volume at 9-10 o'clock and having a loud level with a low power amp. This simply indicates the amp is being either overdriven or driven to its limits within a small range of the volume pot. Some of these vintage or vintage-replica amps have an mV sensitivity on the inputs that becomes overdriven by modern phono amps, cd players and DACs. The other issue is the 12ax7 may not be ideal for driving the EL84 tubes. Try some 5751 tubes or even 12au7 tubes.

    Why not live with both tube and SS, but change how and when you use the Fisher? Use it for late night 65-70db listening or with headphones and save the SS for what it does best, which is drive your speakers!
     
    Last edited: Apr 16, 2019
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  23. action pact

    action pact Music Omnivore Thread Starter

    FOLLOW UP:

    So, the new EL84s finally arrived from Ukraine, and the seller did a careful job of packing them in styrofoam, but the pins were still badly bent up during the trip around the world. I straightened them out and inserted them into the Fisher, powered it on, and immediately one of the tubes started smoking. :(

    I put the old tubes back in and fortunately nothing in the amp was fried.

    I went ahead and checked the bias with a multimeter per the service manual. Proper voltage with the probe on the cathode is 44 volts; the multimeter read around 65 volts! I got the bias properly adjusted, and then had a listen.

    Well, blow me down, the Fisher sounds spectacular now, not at all thin, with plump, energetic bass and extremely spacious, holographic imaging. It has no trouble driving the Spendors in my room.

    That was a nice surprise!
     
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