Ok, what's the deal?...BDT is scratchin' his head

TroyD
TroyD Posts: 13,077
edited December 2009 in 2 Channel Audio
Ok, I borrowed David's Classe CA-150 amp...(I LOVE Classe, btw) and it's connected to the Quad rig. Everything is great, right?

Ok, if I'm listening to an LP....about 10-15 mins in...the protection circuit shuts the amp down. Listening to a CD, no worries. (at least I haven't had it happen yet)

Now: here is a rundown of the gear:
VPI Scoutmaster turntable
Dodd tube phono stage
Melos SHA preamp
Classe CA-150 amp
Quad 988's

Mind you, we aren't talking about earsplitting volumes (if that were the case, the Quad's protection circuits would have kicked in....I haven't had any wierd tube issues either.

I'm sort of at a loss here to be honest. Any ideas??

BDT
I plan for the future. - F1Nut
Post edited by TroyD on
· Share on FacebookShare on Twitter

Comments

  • dkg999
    dkg999 Posts: 5,647
    edited December 2009
    Is the gain of your phono pre low enough that you're having to really crank the output of your preamp, so the voltage output of the preamp is pretty high and forcing the Classe into clipping?
    DKG999
    HT System: LSi9, LSiCx2, LSiFX, LSi7, SVS 20-39 PC+, B&K 507.s2 AVR, B&K Ref 125.2, Tripplite LCR-2400, Cambridge 650BD, Signal Cable PC/SC, BJC IC, Samsung 55" LED

    Music System: Magnepan 1.6QR, SVS SB12+, ARC pre, Parasound HCA1500 vertically bi-amped, Jolida CDP, Pro-Ject RM5.1SE TT, Pro-Ject TubeBox SE phono pre, SBT, PS Audio DLIII DAC
    · Share on FacebookShare on Twitter
  • TroyD
    TroyD Posts: 13,077
    edited December 2009
    Nope, it's a high output MC cart, so gain isn't the issue......(or it hasn't been in the past)
    I plan for the future. - F1Nut
    · Share on FacebookShare on Twitter
  • treitz3
    treitz3 Posts: 19,033
    edited December 2009
    Operator error? :D

    I dunno Troy. This one's got me scratching my head as well. Compromised IC?
    ~ In search of accurate reproduction of music. Real sound is my reference and while perfection may not be attainable? If I chase it, I might just catch excellence. ~
    · Share on FacebookShare on Twitter
  • TroyD
    TroyD Posts: 13,077
    edited December 2009
    Tom, that's usually the case at Casa de Big Dumb....however, I usually correct/adjust pretty well!

    Lemme swap the IC's and see....

    Is it possible that the tube in the phono stage is jacked? That was my first thought but it sounds fine. No audible artifacts at all....

    BDT
    I plan for the future. - F1Nut
    · Share on FacebookShare on Twitter
  • treitz3
    treitz3 Posts: 19,033
    edited December 2009
    It's possible. Anything is possible. Let me ask you this.....is the TT stable enough not to have SS rumble? I may be off here but the TT may be sending subsonic frequencies itself that something in the rig doesn't like.

    If the CDP works fine in the rig, it's gotta be something downstream from the TT and upstream from the amp.
    ~ In search of accurate reproduction of music. Real sound is my reference and while perfection may not be attainable? If I chase it, I might just catch excellence. ~
    · Share on FacebookShare on Twitter
  • hearingimpared
    hearingimpared Posts: 21,137
    edited December 2009
    I think the ICs from the phono pre or the phono pre itself might be the culprit.
    · Share on FacebookShare on Twitter
  • megasat16
    megasat16 Posts: 3,521
    edited December 2009
    If you have subsonic filters in your Pre, turn it On. My guess is that the TT is somehow rambling the ultra low frequencies and the amp doesn't seem to like it with the demanding speakers such as Quad. Even though you can't likely hear these low frequencies, the amps and the speakers still reproduce them to a certain level.
    Trying out Different Audio Cables is a Religious Affair. You don't discuss it with anyone. :redface::biggrin:
    · Share on FacebookShare on Twitter
  • disneyjoe7
    disneyjoe7 Posts: 11,435
    edited December 2009
    +1 I agree with megasat16 :)

    Speakers
    Carver Amazing Fronts
    CS400i Center
    RT800i's Rears
    Sub Paradigm Servo 15

    Electronics
    Conrad Johnson PV-5 pre-amp
    Parasound Halo A23
    Pioneer 84TXSi AVR
    Pioneer 79Avi DVD
    Sony CX400 CD changer
    Panasonic 42-PX60U Plasma
    WMC Win7 32bit HD DVR


    · Share on FacebookShare on Twitter
  • TroyD
    TroyD Posts: 13,077
    edited December 2009
    Hadn't thought about the rumble.....possible.

    I've swapped the IC's from the table to the phono pre.....I had tossed a set of DH Labs Silver Sonics on there awhile ago....I've got another pair of MIT's....

    BDT
    I plan for the future. - F1Nut
    · Share on FacebookShare on Twitter
  • RuSsMaN
    RuSsMaN Posts: 17,987
    edited December 2009
    Troy, I think they are all paralleled anyway, but change the input on the Melos, hook the TT up to a different one than it is on.
    Check your lips at the door woman. Shake your hips like battleships. Yeah, all the white girls trip when I sing at Sunday service.
    · Share on FacebookShare on Twitter
  • TroyD
    TroyD Posts: 13,077
    edited December 2009
    Ok, I swapped the IC's.....made it through an entire side and hasn't shut down yet.

    Hmmmmm....

    BDT
    I plan for the future. - F1Nut
    · Share on FacebookShare on Twitter
  • TroyD
    TroyD Posts: 13,077
    edited December 2009
    F*ck me, but I think it may be as simple as swapping the IC's.

    I thought all wire was the same?? ;)

    BDT
    I plan for the future. - F1Nut
    · Share on FacebookShare on Twitter
  • megasat16
    megasat16 Posts: 3,521
    edited December 2009
    TroyD wrote: »
    F*ck me, but I think it may be as simple as swapping the IC's.

    I thought all wire was the same?? ;)

    BDT

    :D MIT came to your rescue? Magic Boxes? May be they have filters on these magic boxes to block untamed frequencies ! :eek:

    Are you using the same vinyl that was causing problems before?
    Trying out Different Audio Cables is a Religious Affair. You don't discuss it with anyone. :redface::biggrin:
    · Share on FacebookShare on Twitter
  • dorokusai
    dorokusai Posts: 25,577
    edited December 2009
    Did you remove the MIT and go with another cable? I've had problems with capacitance when using MIT cables with some gear, specifically tube gear.
    CTC BBQ Amplifier, Sonic Frontiers Line3 Pre-Amplifier and Wadia 581 SACD player. Speakers? Always changing but for now, Mission Argonauts I picked up for $50 bucks, mint.
    · Share on FacebookShare on Twitter
  • hearingimpared
    hearingimpared Posts: 21,137
    edited December 2009
    I had all kinds of trouble with ICs going from my step-up xformer to my phono pre. I was having hum problems in varying degrees depending on which IC I used. The funny thing was I swapped a 1980s high end IC and the hum went away but I didn't like the sound. So I decided to use my Spectral as the phono pre and set to the gain to 56 db and took the step-up xformer out of the equation.

    Long story short the ICs made big changes in hum. I even had hum using an MIT S3. Joe Abrams told me to twist the ICs together making eights twists. That decreased the hum but didn't eliminate it.
    · Share on FacebookShare on Twitter
  • reeltrouble1
    reeltrouble1 Posts: 9,312
    edited December 2009
    dorokusai wrote: »
    Did you remove the MIT and go with another cable? I've had problems with capacitance when using MIT cables with some gear, specifically tube gear.


    true dat no doubt, although it is rare, we had it happen at Georgia PF.

    BDT clearly states he put the MIT back in and so far it seems resolved.

    maybe the other ones have some kind of warranty. Although they may find nothing wrong with them, if you have time and inclination you can try the Silvers in another rig and see what happens.

    Anyway glad your running again.

    RT1
    · Share on FacebookShare on Twitter
  • TroyD
    TroyD Posts: 13,077
    edited December 2009
    Not sure why (other than it was the pair I grabbed) how the DH Labs ended up in the mi x....Hopefully that particular gremlin is banished.

    More to follow...

    BDT
    I plan for the future. - F1Nut
    · Share on FacebookShare on Twitter
  • TroyD
    TroyD Posts: 13,077
    edited December 2009
    Ok, well, ****...now it did it with the turntable AND the cd player.

    Either the amp has an issue or it doesn't like the Quads. Hmmmm. Time to plug the Heathkits back in....I'll have to bring them back this w/e.


    F**K me.

    BDT
    I plan for the future. - F1Nut
    · Share on FacebookShare on Twitter
  • treitz3
    treitz3 Posts: 19,033
    edited December 2009
    Check the Quads.
    ~ In search of accurate reproduction of music. Real sound is my reference and while perfection may not be attainable? If I chase it, I might just catch excellence. ~
    · Share on FacebookShare on Twitter
  • disneyjoe7
    disneyjoe7 Posts: 11,435
    edited December 2009
    Sell the Quads ;)

    Speakers
    Carver Amazing Fronts
    CS400i Center
    RT800i's Rears
    Sub Paradigm Servo 15

    Electronics
    Conrad Johnson PV-5 pre-amp
    Parasound Halo A23
    Pioneer 84TXSi AVR
    Pioneer 79Avi DVD
    Sony CX400 CD changer
    Panasonic 42-PX60U Plasma
    WMC Win7 32bit HD DVR


    · Share on FacebookShare on Twitter
  • TroyD
    TroyD Posts: 13,077
    edited December 2009
    Wanna buy 'em?

    BDT
    I plan for the future. - F1Nut
    · Share on FacebookShare on Twitter
  • DAGLJAM6
    DAGLJAM6 Posts: 635
    edited December 2009
    As Ted pointed out ,the Classe had a problem with the Isonic that we set up (tried ) in the garage rig. We ran a seperate CD player on one set of inputs on the pre and the Isonic on another input (same pre) switched between the two and the Classe went into protection with the Isonic every time.
    Not that that helps but it does happen......
    · Share on FacebookShare on Twitter
  • billbillw
    billbillw Posts: 6,767
    edited December 2009
    Troy, I'd grab a multimeter and check to see if you have any DC coming out of your preamp and/or the phono stage.
    For rig details, see my profile. Nothing here anymore...
    · Share on FacebookShare on Twitter
  • TroyD
    TroyD Posts: 13,077
    edited December 2009
    Well, I MAY have the issue in hand...

    Swapped out the tubes in the Melos....been spinning vinyl and playing CD's...so far hasn't tripped yet.

    BDT
    I plan for the future. - F1Nut
    · Share on FacebookShare on Twitter
  • TroyD
    TroyD Posts: 13,077
    edited December 2009
    Well into day 2 and no issues.....f*cking tubes.

    BDT
    I plan for the future. - F1Nut
    · Share on FacebookShare on Twitter
  • treitz3
    treitz3 Posts: 19,033
    edited December 2009
    Hey, at least you found the issue. Now you get to enjoy the tunes. What more could you ask for?
    ~ In search of accurate reproduction of music. Real sound is my reference and while perfection may not be attainable? If I chase it, I might just catch excellence. ~
    · Share on FacebookShare on Twitter
  • TroyD
    TroyD Posts: 13,077
    edited December 2009
    What more could I ask for??

    Where do I start?? :)

    I also think that this may have been at the heart of the disappointing performance of the Quad rig at PF...

    BDT
    I plan for the future. - F1Nut
    · Share on FacebookShare on Twitter
  • treitz3
    treitz3 Posts: 19,033
    edited December 2009
    No worries. PF was a grand dig that nobody can deny. It happens, lesson learned.

    You could ask for TLW to make the the shrimp and grits again for everybody if it will make you feel better. :D

    or maybe slide me the recipe? Hint, hint.....
    ~ In search of accurate reproduction of music. Real sound is my reference and while perfection may not be attainable? If I chase it, I might just catch excellence. ~
    · Share on FacebookShare on Twitter
  • treitz3
    treitz3 Posts: 19,033
    edited December 2009
    BTW, TLW is all that and more. Seriously, what more could you ask for?
    ~ In search of accurate reproduction of music. Real sound is my reference and while perfection may not be attainable? If I chase it, I might just catch excellence. ~
    · Share on FacebookShare on Twitter