should brand new Ref 8B's XLR sound distorted???

tdangelo · « **on:** 6 Sep 2005, 05:45 pm »

just got these and they sound terrible in my system. I realize they need 40+ hrs for breakin but MAN - they sound terribly distorted. Maybe I have a bad pair? The distortion seems midrange based - I tried various music - moved the cables around - tried different input cables and power cords - same thing. The amps are each on their own 20 amp dedicated circuit - preamp and SB on another 20 amp circuit. My system:

Slimdevices Squeezebox 2
Tact 2.0S preamp/DAC w/Aberdeen PS
Ref 8b's.
VMPS RM40's W/TRT's

Any ideas? Am I just hearing what everyone else says is edginess?

Thanks!

KJ · « **Reply #1 on:** 6 Sep 2005, 06:16 pm »

How many hours do you have on the Ref 8bs so far? Nuforce states you need 75 hours of burn-in time, but the Ref 9s I used did not show any signs of distortion (after only ~12 hours of burn-in).

I think the 8bs will be lacking in power to fully drive your RM40s (IMO).

-KJ

tdangelo · « **Reply #2 on:** 6 Sep 2005, 06:34 pm »

They only have about 2 hrs on them. I wouldn't expect them to sound distorted though just because they aren't broken in - should they?

Casey called me and is sending a new pair - thinks the MOSFETS may be bad. On certain music the problem is readily apperent - Jay Hoggards 'Days like These' CD the song 'We got By' has lots of xylophon - the distortion is real distinct on this. I put my old Aragons back on and no problem at all. Hopefully the new amps wont have the same problem. Great customer service from Nuforce though!!! My room is only 12x14 and the 8B's seemed to work ok loudness wise - just darn distorted even at very low levels.

Thanks

Tony

KJ · « **Reply #3 on:** 6 Sep 2005, 06:47 pm »

Tony,

I agree you shouldn't be hearing distortion right out of the box. If it is an issue with the MOSFETS, I wonder if the same problem exists with the pair that went to the NTAJ. Glad to hear about the great customer service. Keep us informed.

-KJ

tvyankee · « **Reply #4 on:** 6 Sep 2005, 07:01 pm »

hello,

sorry to hear about your problem.have you tried to isolate the problem.

try disconnecting your rca's from your amps inputs(turn them off before reconnnecting) and see if the amps are quite by themselves,if they are then its something infront of them make them sound like that.

then when you start hooking them up do it one at a time so you can hear when the noise comes back.

you may have a bad cable somewhere that the nuforce is a little more sensitive about then the other amps you were using before.

tdangelo · « **Reply #5 on:** 6 Sep 2005, 07:06 pm »

Hi, the amps are quiet when no music is playing - connected via XLR or not - only distorted when playing. I did try 2 different pairs of XLR cables - same thing.

thanks for the suggestion

Tony

rustydoglim · « **Reply #6 on:** 6 Sep 2005, 08:32 pm »

We're shipping a new pair to tdangelo for him to compare with his current pair to find out what's going on. It is puzzling.

Oh well, we'll find out this weekend.

tvyankee · « **Reply #7 on:** 6 Sep 2005, 10:32 pm »

hey,

have you tried rca's?the singal ended output of your pre should be less then the balanced output.

mybe the balanced output is to hot for the input on the amp.if you have the volume set real low and it still sounds distorted then i would say that the balanced output is set to high for the input.

good luck.

Charles Calkins · « **Reply #8 on:** 6 Sep 2005, 10:46 pm »

Did you try one amp at a time? Seems odd that both amps would have a problem.

Cheers
Charlie

tdangelo · « **Reply #9 on:** 6 Sep 2005, 11:24 pm »

I did - the left one has a definite problem - much less with the right one but still noticable. If I move the left amp to the right speaker it follows. If I swap the XLR's for left - right it stays with the bad amp.

tdangelo · « **Reply #10 on:** 6 Sep 2005, 11:24 pm »

I did - the left one has a definite problem - much less with the right one but still noticable. If I move the left amp to the right speaker it follows. If I swap the XLR's for left - right it stays with the bad amp.

rustydoglim · « **Reply #11 on:** 6 Sep 2005, 11:47 pm »

We just realized that Tony's amps have the default Cardas binding post replaced with the Cardas banana binding post. We have only done that a few times. The case was not designed specifically for the Cardas banana binding post and we have to carefully cut out some plastic to make it fit and now we suspect that the speaker post got shifted and is now touching the case. By shorting a single speaker terminal to ground, the MOSET might have been damaged. And that will explain the distortion.

So we decided to put in the Eichmann Cablepod for free (only this time) and I think Tony will be happy.
And we're not going to offer the Cardas banana binding post as a free option as it is hard to fit into the case. Eichmann Cablepod will be the only alternative binding post that we offer and it cost $25 per unit for the replacement. Still a good deal.

tdangelo · « **Reply #12 on:** 7 Sep 2005, 04:07 am »

Thanks Jason - I looked at the back of the amps and noticed that both the binding posts are shifted down to the left a little - so I'm thinking thats what happened. The amp thats really bad makes a terrible sound on turn off - kinda like a siren driving by, hehe.. Thanks again for the great customer service and also to the dealer - Lou Fink at Underground Audio. He called me twice today to check on my progress - excellent service

I'll post the results after I get the amps.

Tony D.

tdangelo · « **Reply #13 on:** 8 Sep 2005, 11:08 pm »

UPDATE: Well I got the amps today and one of the first amps definitely had a problem. These new amps sound much better but I still have the distortion

I tried several things - I eliminated my Squeezebox and hooked a DVD player to the Tact RCS 2.0S using the digital out - same distortion - tried a different dig. cable - same thing. I tried 3 different sets of power cables on the amps - put the Tact and SB on normal house circuits (not on the 3 dedicated circuits I normally use) with the amps on their own dedicated - put the amps 4 feet away from the Tact and SB - used different XLR cables - put everything on the floor with all the components as far apart from each other as the cables allowed - NO matter what I did the distortion was there - levels dont matter although if its loud its obviously more apparent. My dealer (Lou Fink of Underground Audio in Margate, FL) was on the phone with me trying to suggest things. Nothing worked

Lou is sending me some RCA-XLR converters so I can bypass the Tact and use the analog output of the SB into the amps via RCA cables(my Tact has no Analog inputs) - maybe its the Tact?? I have an upgraded Aberdeen PS for the Tact - I tried the stock PS - same thing. Anyway I'm frustrated I guess but Nuforce is trying to figure it out

I'll update when something changes.

Tony D.

tdangelo · « **Reply #14 on:** 10 Sep 2005, 04:56 pm »

update:

well it's NOT the Tact

I used the SB2 direct to the Ref 8b using RCA cables (analog out) with Cardas XLR-RCA adapters on the amps. With the following it works fine:

MAS Silver interconnects RCA 6' lengths = NO PROBLEM
http://www.audiopartsinc.com/INTERCONNECTCABLES.HTM

Goertz ??? RCA - (about 1/4 wide unshielded flat copper) = NO PROBLEM

Monster Cable M1000 RCA 1' length - PROBLEM!!! Same distortion as when using the Tact

Thing is though - with the Tact it happens with all my cables including MAS Signature XLR's - 3' and 4' lengths and all the above cables.

I just tried another experiment as I was writing this:

used male RCA-male RCA on the SB analog output - connected the Cardas RCA-XLR adapters to that and used my XLR cables - with the 4' cables very bad distortion - even with no music playing - with the 3' cables same distortion as with the Tact.

Soooo - using the Tact and the SB or DVD/CD player I get the problem with all cables. SO, it all seems to point to some kind of problem with the Ref8B somehow?? They seem to be really sensitive to cable impedence/capacitance/resistance??

Any help? I sold my Aragon Palladiums before I got the Ref8B's - I had no problem the the Aragons.

Thanks

Tony

John Casler · « **Reply #15 on:** 10 Sep 2005, 05:20 pm »

Quote from: tdangelo

UPDATE: Well I got the amps today and one of the first amps definitely had a problem. These new amps sound much better but I still have the distortion I tried several things - I eliminated my Squeezebox and hooked a DVD player to the Tact RCS 2.0S using the digital out - same distortion - tried a different dig. cable - same thing. I tried 3 different sets of power cables on the amps - put the Tact and SB on normal house circuits (not on the 3 dedicated circuits I normally use) with the amps on th ...

Hi Tony,

I know this is a "long shot", but take a couple minutes and try this:

1) Use the DVD player as a "source"

2) Use a standard (good quality) "audio" interconnect in place of the "digital" cable from the DVD player to the TACT.

My money says it will solve the problem.

(Fingers crossed)

tdangelo · « **Reply #16 on:** 10 Sep 2005, 05:31 pm »

Hi John - thanks for helping

I tried it using 2 different analog cables and I have the same problem

Thanks

tdangelo · « **Reply #17 on:** 10 Sep 2005, 05:34 pm »

I think I'm gonna get a cheap toslink cable and see what that does

rustydoglim · « **Reply #18 on:** 10 Sep 2005, 06:48 pm »

This seems to point to some grounding incompatibility with Tact 2.0 and Ref 8b. It is possible that Tact 2.2 and Tact 2.0 has different grounding scheme and that explains why it works fine with Shane's system and not Tony's system. The Monster Cable M1000 could have similar issue with its RCA ground design. We advice people to use Ref 8b only in a true balanced system. Anyway, we asked Tony to send the Tact 2.0 and his cables to us for diagnostic. We pay for shipping as usual

May be the quickest way to resolve this is to swtich to Ref 8 instead of Ref 8b. But we'll get to the bottom of this.

hometheaterdoc · « **Reply #19 on:** 11 Sep 2005, 07:29 am »

Quote from: nuforce-jason

This seems to point to some grounding incompatibility with Tact 2.0 and Ref 8b. It is possible that Tact 2.2 and Tact 2.0 has different grounding scheme and that explains why it works fine with Shane's system and not Tony's system. The Monster Cable M1000 could have similar issue with its RCA ground design. We advice people to use Ref 8b only in a true balanced system. Anyway, we asked Tony to send the Tact 2.0 and his cables to us for diagnostic. We pay for shipping as usual
May be the quickest way ...

I'm experiencing none of the issues described above. I have used the Ref 8's and Ref 8Bs with a Tact 2.2X, and a TCS MKII. I have run the 8's and 8Bs off the same set of channel outputs (the Tact has a digital output, a set of RCA outputs, and a set of XLR balanced ouptuts which are all always active. So I have run up to three sets of amps off those outputs, using all the available connections). I've run just the ref8s and just the ref8Bs.

Speakers have been the Von Schweikert VR-4SRs, VR-4jrs, and the Usher Dancer II CP-8571s with the beryllium tweeters....

I haven't had a single issue with the Nuforces and the Tact. I can't see it as being a grounding issue. I have used a bunch of different ICs with no problems. I have used balanced power conditionning and straight into the wall... zippo issues... The Nuforces, when combined with the Tact are one of the biggest surprises I've encountered in audio. The combo is world beating for the money....