Free Shipping on All Orders 1-866-764-1801

Vist our Online Store
+ Reply to Thread
Results 1 to 10 of 10
  1. #1

    Member Sales Rating: (19)

    Join Date
    Sep 2003
    Posts
    8,170

    Default 4 ohm vs. 8 ohm taps

    Can someone explain why there would be a sonic difference between the 4 ohm taps and the 8 ohms taps on my tube monos?

    I unintentionally switched to the 4 ohm taps (I have 8 ohm speakers) and the sound is more pure and more detailed. It's a subtle difference; nevertheless, I wondered what changed in my system, and that's when I realized I switched taps when I hooked my amps back up.

    Thanks.
    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."

  2. #2

    Member Sales Rating: (11)

    Join Date
    Jan 2006
    Location
    Toronto, ON, Canada
    Posts
    1,952

    Default

    I have the same switch in my HK Citation 24 amp, and the speakers do sound different/better in 4-Ohm mode. 8-Ohm mode is a "high voltage" mode, whereas 4-Ohm mode is "high voltage" / "high current" mode.

    I would have to look at the schematics, but my guess is that the amp has more headroom since it expects much worse (i.e. 4-Ohm) load.
    Panasonic PT-AE4000U projector for movies
    EluneVision 92" Cinema Gray fixed screen
    Onkyo TX-SR805 Pre/Pro
    Rotel RMB-1075 Amp
    B&W CDM1-SE fronts
    B&W CDM-CNT center
    B&W CDM1 rears
    Samsung DTB-H260F OTA HDTV tuner
    DUAL NHT SubTwo subwoofers
    Velodyne SMS-1
    Oppo BDP-93 Blu-Ray player
    Belkin PF60 Power Center
    Harmony 890 RF remote
    Panasonic TC-P50G20 TV + PS3 in the living room

  3. #3

    Member Sales Rating: (47)

    Join Date
    May 2005
    Location
    Sufficiently Breathless
    Posts
    11,095

    Default

    Brad,, I've been doing the same thing with the anthem and the 7u's,, but I'm not sure which I prefer 8 vs. 4,,IIRC I think I finally settled on the 4 ohm tap.

    I've been looking around and came up with this,, which for me, was a pretty good read.

    http://www.symphonysound.com/articles/tubefriendly.html
    JC approves....he told me so. (F-1 nut)

  4. #4

    Member Sales Rating: (19)

    Join Date
    Sep 2003
    Posts
    8,170

    Default

    Quote Originally Posted by george daniel View Post
    I've been looking around and came up with this,, which for me, was a pretty good read.

    http://www.symphonysound.com/articles/tubefriendly.html
    Thanks for the link. It's kinda technical, but it reinforces a couple of concepts:

    1. synergy is supremely important

    2. speaker specs are meaningless

    3. due to specs and associated gear, price doesn't mean a damn thing in audio

    4. the only way to determine if speakers are tube friendly is by listening to them

    5. experimentation is important (I've had my amps for several months and hadn't tried the 4 ohm taps:()

    6. tubes rule and solid state sucks!:p
    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."

  5. #5

    Member Sales Rating: (8)

    Join Date
    Mar 2005
    Location
    Fremont, California
    Posts
    922

    Default

    When you use a 8 ohm speaker on the 4 ohm tap, the amp will see double the impedance of primary side of the output transformer. Tubez loves high impedance, and in general, higher impedance has lower distortion. I always put the vintage Polk speakers, which are 6ohm mostly, to the 4 ohm tap. So, what is the catch? The peak rated power is lowered because the voltage the power supply can swing is a constant. When the voltage is eaten up by the increased impedance, the output tubes will be cut-off and stop conducting, i.e. clipping. Unless you hear the amp running out of steam, keep using the 4 ohm tap if it pleases you the most.

    -fredv-

  6. #6

    Member Sales Rating: (21)

    Join Date
    Sep 2002
    Location
    Deep Down the Rabbit Hole
    Posts
    9,610

    Default

    excellent Fred, I have found this to be exactly the case with the Sound Labs which are amp killers, so I hooked the tube BAT's 4 ohm tap to a MF supercharger, then the supercharger to the speaks, I thought it might not matter, well, it does, the 4 ohm tap sounds oh so sweet, but even though its seeing a steady 50K input impedance the tube amp runs out faster than if I use the 8 ohm tap.

    RT1
    REEL TIME THEATRE
    Onkyo-TX-NR5007
    B&K 7270 amplifier
    Polk SWA-500 Subwoofer amplifier
    OppO BDP-83
    Pioneer Elite 50"
    Polk LCi-RTS-105;LCi-RTS-C;LCi-RTSFx;LCi80Fx
    Subs-Twin Polk CSW200
    HTS5000


    RABBIT HOLE RIG
    BAT VK-31SE
    VTL MB-450 Signature monoblock
    Wolcott Presence monoblock
    Musical Fidelity kW SACD
    Rega P25/RB600/Clearaudio Aurum Beta
    Acoustech Phono-Pre
    Sound Lab Millenium ELS
    BillyBags Rack
    MIT S1/3 cables
    Shunyata/PS Audio/Virtual Dynamics Power Cords


    Everthing Matters...Tubes Rule...and It's Over until it's Not Over

  7. #7

    Member Sales Rating: (16)

    Join Date
    Mar 2005
    Location
    In A Van Down By The River
    Posts
    21,186

    Default

    Quote Originally Posted by fredv View Post
    When you use a 8 ohm speaker on the 4 ohm tap, the amp will see double the impedance of primary side of the output transformer. Tubez loves high impedance, and in general, higher impedance has lower distortion. I always put the vintage Polk speakers, which are 6ohm mostly, to the 4 ohm tap. So, what is the catch? The peak rated power is lowered because the voltage the power supply can swing is a constant. When the voltage is eaten up by the increased impedance, the output tubes will be cut-off and stop conducting, i.e. clipping. Unless you hear the amp running out of steam, keep using the 4 ohm tap if it pleases you the most.
    Excellent info.........that's going into my audio knowledge bank.

    H9
    "Appreciation of audio is a completely subjective human experience. Measurements can provide a measure of insight, but are no substitute for human judgment. Why are we looking to reduce a subjective experience to objective criteria anyway? The subtleties of music and audio reproduction are for those who appreciate it. Differentiation by numbers is for those who do not".--Nelson Pass

    Pass Aleph 30; Eastern Electric Mini Max; Adcom GDA600; MIT S3/Z Pc; SDA 1C; Squeezebox; Tubes add soul!

  8. #8

    Member Sales Rating: (2)

    Join Date
    Jun 2004
    Location
    New England
    Posts
    7,981

    Default

    If the load is a perfect 8 ohm impedance, independent of frequency, mismatching to a 4 ohm output tap will give you some response contouring (assuming that the 8 ohm response is flat). Not unlike using interconnects or speaker cables as rather expensive tone controls! :-)

    The fact is that most speakers are very complex, reactive impedance loads for an amplifier, and just may sound better on one tap than another. In general, higher-impedance speakers are preferred (e.g., 16 ohm), as they'll make better use of the OPT secondary.

    A 100% mismatch will have no negative impact on either amp or speaker, so use what you like better.
    all the best,
    mrh

  9. #9

    Member Sales Rating: (19)

    Join Date
    Sep 2003
    Posts
    8,170

    Default

    I've been listening to music for the past three days and there's definitely an improvement on the 4-ohm tap that is more noticeable on some CDs than on others. There's greater clarity, micro-detail, and a slightly wider soundstage. Vocals are a bit more recessed and you can "hear" more of the room. In addition, there's greater contrast between the low passages and the high ones in the same song, thus giving the appearance of increased dynamics. It's interesting.

    Since the sound is different, my next "tweak" may be fooling around with placement again. It always amazes me how moving a speaker less than an inch can make a big difference.
    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."

  10. #10
    Audiophile
    Member Sales Rating: (30)

    Join Date
    Mar 2006
    Location
    Seattle
    Posts
    11,108

    Default

    Quote Originally Posted by george daniel View Post
    I've been looking around and came up with this,, which for me, was a pretty good read.

    http://www.symphonysound.com/articles/tubefriendly.html
    This was a great read and I found it very helpful, yet pretty easy to understand. Thanks for posting it.

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

     

Similar Threads

  1. TAPS - New Release 9/12/06
    By polkatese in forum Music & Movies
    Replies: 5
    Last Post: 09-13-2006, 12:48 PM
  2. Tube amp users! Switch those output taps!
    By organ in forum 2 Channel Audio
    Replies: 10
    Last Post: 02-24-2005, 01:42 PM
  3. *taps*
    By Zero in forum Troubleshooting
    Replies: 0
    Last Post: 08-30-2002, 10:28 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts