Very bright tube amp

AudioFilet
AudioFilet Posts: 235
edited January 2008 in Electronics
My new tube amp sounds very bright to my ears, i thought tubea were supposed to sound all warm & fuzzy. Could there be something wrong with this thing (bad tube?), or need some sort of adjustment?

Sure looks nice though, check the pic (it is Chinese):
2 Channel rig:
LSi9"s (modified xover's) & HSU Sub
Harman Kardon HK 990 Amp
Onkyo C-S5VL SACD
Music Hall MMF 5.1
Furman Elite 15

HT rig:
HK AVR-745 & Polk Monitor Series
MA-1.jpg 109.5K
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  • madmax
    madmax Posts: 12,434
    edited January 2008
    AudioFilet wrote: »
    i thought tubea were supposed to sound all warm & fuzzy.


    That is a misconception a lot of people have. Most are very detailed. I'm not sure why it would sound exceptionally bright though unless there is a component upstream not working well with it.
    madmax
    Vinyl, the final frontier...

    Avantgarde horns, 300b tubes, thats the kinda crap I want... :D
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  • venomclan
    venomclan Posts: 2,467
    edited January 2008
    Have you let it broken in yet?
    Venom
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  • Early B.
    Early B. Posts: 7,900
    edited January 2008
    The first thing you gotta do is to replace all of the stock tubes. Then report back.
    HT/2-channel Rig: Sony 50” LCD TV; Toshiba HD-A2 DVD player; Emotiva LMC-1 pre/pro; Rogue Audio M-120 monoblocks (modded); Placette RVC; Emotiva LPA-1 amp; Bada HD-22 tube CDP (modded); VMPS Tower II SE (fronts); DIY Clearwave Dynamic 4CC (center); Wharfedale Opus Tri-Surrounds (rear); and VMPS 215 sub

    "God grooves with tubes."
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  • RuSsMaN
    RuSsMaN Posts: 17,986
    edited January 2008
    Early B. wrote: »
    The first thing you gotta do is to replace all of the stock tubes. Then report back.

    Why is this becoming a default answer?
    Check your lips at the door woman. Shake your hips like battleships. Yeah, all the white girls trip when I sing at Sunday service.
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  • George Grand
    George Grand Posts: 12,258
    edited January 2008
    Because nobody has solid-state anymore?
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  • RuSsMaN
    RuSsMaN Posts: 17,986
    edited January 2008
    Well, we all know the first thing I do when I get a new sand amp home is get rid of those stock output transistors. Yuk.
    Check your lips at the door woman. Shake your hips like battleships. Yeah, all the white girls trip when I sing at Sunday service.
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  • SolidSqual
    SolidSqual Posts: 5,218
    edited January 2008
    RuSsMaN wrote: »
    Why is this becoming a default answer?

    I agree. Some manufacturers place tubes in their equipment that are very good. Examples: Jolida, Odyssey and Cary - In my own limited experience. Rogue Audio usually requires some tube upgrades (atleast in my system anyway)

    I would look to break in the equipment first and then consider if you are using components that may not mate well together.

    That being said, replacing tubes is likely the cheapest solution if that is truly the problem. But beware, you dn't want to buy an extremely flat tube to make up for a bright component elsewhere.
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  • SolidSqual
    SolidSqual Posts: 5,218
    edited January 2008
    George Grand wrote: »
    Because nobody has solid-state anymore?

    I would guess more people have SS. I have a combination in my system. Best of both worlds in my opinion.
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  • AudioFilet
    AudioFilet Posts: 235
    edited January 2008
    I bought the amp used. the previous owner had it about a year, so I would think it is broken in. The output tubes are KT88, Chinese. The other 4 tubes are 12AT7 & 12AU7, 2 each. Those appear to be the same brand, US, but no brand name.

    What are some good options for changing these out?
    2 Channel rig:
    LSi9"s (modified xover's) & HSU Sub
    Harman Kardon HK 990 Amp
    Onkyo C-S5VL SACD
    Music Hall MMF 5.1
    Furman Elite 15

    HT rig:
    HK AVR-745 & Polk Monitor Series
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  • Early B.
    Early B. Posts: 7,900
    edited January 2008
    The stock tubes on an inexpensive Chinese tube amp are likely to be of poor quality. If the sound of the amp is too bright, then change the tubes. One of the main advantages of buying tube gear is tube rolling. If that doesn't fix the problem, then get another amp.
    HT/2-channel Rig: Sony 50” LCD TV; Toshiba HD-A2 DVD player; Emotiva LMC-1 pre/pro; Rogue Audio M-120 monoblocks (modded); Placette RVC; Emotiva LPA-1 amp; Bada HD-22 tube CDP (modded); VMPS Tower II SE (fronts); DIY Clearwave Dynamic 4CC (center); Wharfedale Opus Tri-Surrounds (rear); and VMPS 215 sub

    "God grooves with tubes."
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  • George Grand
    George Grand Posts: 12,258
    edited January 2008
    Please don't take me seriously. It's much too late in the game for that ****.
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  • SolidSqual
    SolidSqual Posts: 5,218
    edited January 2008
    George Grand wrote: »
    Please don't take me seriously. It's much too late in the game for that ****.

    Duly noted . . . sorry I've had my coffee now.
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  • Ricardo
    Ricardo Posts: 10,636
    edited January 2008
    I don't know....but I wouldn't go changing tubes just like that, with an "unknown" amp. It might get pretty expensive and you might never find "the" tube. Maybe there's something in that amp that will make it sound bright, period.
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  • hearingimpared
    hearingimpared Posts: 21,136
    edited January 2008
    I'm new to tubes but when I've come across harsh, brittle or bright tubes I would replace them with different tubes and find the bad **** went away. Case in point, I burned in my brand new tube CD player for about three weeks. During that time I would take a peak listen. Sometimes it sounded awesome other times I've said to myself, "what have I done." I changed to a different set of tubes and now it sounds awesome and as a bonus, CDs that were unlistenable before are now easy to listen to.

    I would like to add one thing here, the new tubes did not cause the music to have any less detail, music weight, added warmth or less bass punch or extension.
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  • mhardy6647
    mhardy6647 Posts: 34,913
    edited January 2008
    Another possibility, boys, is a "tone control" effect arising from an impedance mismatch between transformer output tap and the speakers. What speakers is the OP using, and what is there nominal impedance? If the chinese amp has multiple taps, you might want to try a different one than the one you're on (e.g., 4 ohm instead of 8; 16 ohm in stead of 8, or vice versa, in either case). Won't do any harm, and it may "cure" the problem.

    I would agree that the Chinese tubes won't be the last word in fidelity, but they're probably OK (unless, of course, they are bad).


    EDIT: FWIW, the KT88s and their kin (the very extended 6L6 family) arent' my faves when it comes to sonics, anyway. YMMV, though.
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  • candyliquor35m
    candyliquor35m Posts: 2,267
    edited January 2008
    Tubes are a good option but you could always google the amp to see if there's any info out in cyberspace about the amp.
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  • Early B.
    Early B. Posts: 7,900
    edited January 2008
    Here's a link for tweaking your amp...

    http://www.lampizator.eu/AMPLIFIERS/CHINA/KT88/Music%20Angel%20KT88%20reworking.html
    HT/2-channel Rig: Sony 50” LCD TV; Toshiba HD-A2 DVD player; Emotiva LMC-1 pre/pro; Rogue Audio M-120 monoblocks (modded); Placette RVC; Emotiva LPA-1 amp; Bada HD-22 tube CDP (modded); VMPS Tower II SE (fronts); DIY Clearwave Dynamic 4CC (center); Wharfedale Opus Tri-Surrounds (rear); and VMPS 215 sub

    "God grooves with tubes."
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  • mhardy6647
    mhardy6647 Posts: 34,913
    edited January 2008
    Early B. wrote: »
    Here's a link for tweaking your amp...

    http://www.lampizator.eu/AMPLIFIERS/CHINA/KT88/Music%20Angel%20KT88%20reworking.html

    heh-heh... here's the best advice of all, I suspect:
    At this stage I would get rid of the entire PCB and start from plain noval sockets mounted to chassis.
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