Discussion in 'Audio Hardware' started by GoldprintAudio, May 20, 2016.
I don't see a photo. Just a question mark.
Hey guys, curious what you all are running for speaker cables from your 508's. After some time with the amp I'm finding a bit of a fatiguing shrillness in the upper mids that I didn't ever have with the Rogue CMii/Harbeth C7 combo. Overall there's a lot more presence with the 508 vs the CMii, which I like, but in that upper mid range it's just way too much. I'm wondering if part of it is the relatively simple/inexpensive cables I've tried. I started with some QED 79 Strand, then I tried some Duelund DCA16GA. Of the two the QED was a bit better. I didn't even plan on fatigue being an issue with the Harbeths or the 508. Any suggestions, cables or otherwise?
What NFB setting are you using
What is your source?
Are you using original tubes?
How are your Harbeths angled towards your listening seat?
I'm using the 508 with an AMR DP777SE dac and a pair of Klipsch Cornwall III speakers. I love the emphasis in the midrange, as it puts the vocals a bit forward in the sound image, but I've yet to register any listening fatigue.
NFB: 3 (I’ve tried 4 and it’s still too bright but I lose some bass weight that I enjoy).
SOURCES: Linn LP12 w/ Ekos/Hana SL and Border Patrol DAC
TUBES: Original 805s and 300bs. Added some Black Treasure CV181-z and the Tung Sol 6SU7GTY (150+ hours on the new ones)
PLACEMENT: Slight toe in, but I’ve played with less with no improvement.
Honestly the only difference is the 508 vs the Rogue Cronus Magnum II. In theory i would have thought the 508 would be the less fatiguing and bright amp, but I never had any of either with the CMII.
is the LM underpowering the Harbeths? I'd be shocked if a speaker cable change "fixed" it.
I've never been a huge fan of the stock 805's on the amp. I had a fuller, sweeter yet still detailed, sound when I changed them. The stock power tubes really don't let it show off what it's capable of doing.
I also purchased Chord Odyssey II speaker cables which also smoothed out the sound a bit as well, but they replaced very budget monster cable that was basically 16awg lamp cord.
I'm about to change out speakers and am replacing the chord cables with Auditorium 23's. I'll have the cables before the new speakers arrive and can do a very direct sound comparison between speaker cables and let you know if there is any sound improvement with those or not.
I'm really only changing brands because I need a few extra feet of cable to reach the new speaker placement and figure I may as well match the speaker cable brand to the interconnect brand that I currently use.
This is helpful. A smoother sound is definitely what I’m looking for. I was used to being able to turn the music up but as soon as I got the 508 anything more than a couple hours in the mid 80’s (dB) and my ears are getting tired. Tubes were definitely the other place I was thinking I could tweak.
Do keep me posted on the A23 cables. I’m wondering if these QED and Duelund might just be glorified lamp cord
My experience is with the 518 (and Harbeth C7es3), but I'm pretty sure you can address that type of issue with tube rolling. Probably one type of tube in your combo is causing that little bit of shrillness. If you can figure out which one(s) it is and make a change I think you can get whatever sound you want. The Harbeths will let you hear every tube change you make, that is for sure. While you will also hear changes to power cables and interconnects, I don't think your problem will be solved by them. Although you may like different cables for different reasons.
Can you tell me more about the Black Treasure tubes you are using? They are used as preamp tubes in your amp, right? That is the first spot I would look to solve the upper midrange glare, just based on what I have learned by rolling tubes through my 518 (which uses 12AX7's instead of 6SN7's for preamp duty). If you can try some old stock Mullard or Brimar in that spot, it will smooth things out a lot. But any NOS tubes in that spot will likely be an improvement.
Yeah. I tried putting the originals back in there and it didn’t make a huge difference and I’ve been researching tubes for both The 6SN7 and 6SL7 positions. Maybe others can chime in on the 6sn7’s. Should I be experiencing a decent change in tone there by rolling tubes being as it’s a pair of driver tubes, not preamp tubes? I’m having a hard time noticing differences between stock and the CV181s cause I’m pretty distracted by the glare, but there’s a good chance the CVs are just a better version of what’s there, so tonaly they’re similar.
Yeah, they are both Chinese, right? Both Shuguang. Although the Black Treasures probably will last longer, their sound is going to be cut from the same cloth. So moving away from the Chinese (or Russian) tubes there would be the direction I would take.
I thought the 300B's were the driver tubes in your model, the 805's for output, and the single 6SL7 a rectifier. Do I have this right?
Yeah. There definitely seems to be some confusion about what all the tubes in this circuit do. But based on what I’ve read and seen confirmed by James at Line Magnetic and others, the 805s are power tubs, both the 6SN7s and 300Bs are drivers and the single 6SL7 is the sole preamp tube. Anyone with a different understanding?
Even if that’s the case I’m not sure if that means to not spend much energy/money on the drivers or if it’s still worth tweaking those. I’m sure they make a difference, maybe just less so?
I think your Tung Sol is probably a pretty good sounding tube. I doubt that is the source of shrillness.
I agree it makes more sense that the 6SL7 is used as a preamp tube. And 6SN7's, as I understand it, are commonly used to drive 300B's. But if all this is true, what is used for rectification? This model isn't solid state rectified, is it? I didn't think Line Magnetic used solid state rectification in their amps.
Yeah. JeffC posted recently about an exchange with James at Line Magnetic where James said "the 6SN7 in LM-508IA is the driver tube. It is still in the circuit even if you are choosing to Pre-IN."
Pretty sure it is solid state rectified.
Are the Dynaudio X34s listed under your "Information" the new speakers you're awaiting or the ones you'll be replacing? I love my Auditorium 23 speaker cables. I've had great success with them on my Leben CS 300Xs (used with Dynaudio Focus 160s and vintage Tannoys) as well as on the 508IA. I'd like to try the Auditorium 23 interconnect as well.
No, the X34's are what I'm replacing. They are only a year old, so I'll probably move them to my weekend home or sell them. I'm replacing them with Trenner and Friedl Pharoahs. I really wanted a wide baffle, fairly sensitive speaker.
Everyone who uses A23 speaker cables swears by them so I figured I should just take them plunge on them as well.
I love their interconnects and SUT. I cant go wrong with them the way I see it.
Congrats on the new speakers! I'd love to hear those Pharaohs. Is it safe to assume you bought them from In Living Stereo?
Thanks! I'll let you know when they come in and you can come by for a listen if you'd like. Time to return the favor (though I STILL haven't managed to change my phono stage!) Talk about being indecisive.
And yes, In Living Stereo is where I got them.
Cool. Maybe I can bring my Phonomaster over so you can hear it in your system.
That's a great idea. Our amplifiers are very similar so with your phono stage in the picture, it would give a pretty good idea of what your system would sound like with the Pharoahs.
Your turntable is a bit higher end than mine, but overall the sound should be similar. I'd love to hear the phonomaster in the chain. Maybe It'll finally push me to pull the trigger on a new phono stage.
@Seafinch Have you played with switching around the speaker connections to a different impedance. Should be a quick experiment.
Unrelated/related note—on my rogue Cronus mag 2, I’ve heard people say the 12ax7 or 12au7 (non pre) changes make little difference.
With the same speakers @Seafinch has I found definitive, noticeable and tangible differences rolling them. I’ve finally found *my* magic and my wallet and time wish none of this was the case but it certainly was.
Seafinch, I’d suggest giving Andy at vintage tube services a call. He’s more expensive than the others but will help you diagnose/decide and he will also let you try something. I found this a hugely valuable service I was willing to pay more for.
Tried this. Didn’t fix the issue and didn’t sound as good overall. Thanks for the suggestion though.
Yes. I’ve got a couple different sets of speaker cable coming to try and then I spent some time on the phone with Brent Jessee talking about tubes and I purchased a few things from him to try. I’ll keep you guys posted. Thanks again for the suggestions.
You have both the 508 and the Leben? Which do you like better overall?
Separate names with a comma.