|
Post by Abandoned on Jul 4, 2013 19:28:50 GMT -7
My M12 stopped putting out sound/signal completely.
PLEASE help ASAP. Is it most likely the EF86? It's not the 12ax7 as I already tried to replace it. The power tubes are still lit up and the amp stays on still. But no signal.
|
|
|
Post by doctorice on Jul 4, 2013 19:44:16 GMT -7
|
|
|
Post by Abandoned on Jul 4, 2013 20:05:15 GMT -7
The 12ax7 is REALLY warm to the touch (almost hot to the touxh, ouch if you hold it tight... the EF86 is barely warm at all... I actually can't tell if it is even warming up. Is that normal? Can someone please test this for me? Power tubes still light up. If a rectifier tube goes out will all signal cut out from the amp?
|
|
|
Post by Jefferson on Jul 4, 2013 20:41:41 GMT -7
Tubes are funny things. Do a tube swap on each tube separately until you isolate the culprit. I would recommend a Dario mini watt EF86 if you replace. Also, I have had great luck with burned in EL84's from lord valve at NBS electronics in Denver. Both those tubes are notoriously touchy and give up too easily...
|
|
|
Post by Abandoned on Jul 5, 2013 4:24:13 GMT -7
If the power tubes were gone it wouldn't stay powered up, and I already tried replacing the 12ax7. EF86 is the last one besides the rectifier tube. I just don't have an ef86 tube or rectifier tube on me.
|
|
|
Post by BritInvasion on Jul 5, 2013 6:16:30 GMT -7
From what you're describing , my money's on the EF86 being dead. First in line pre-amp tube , if it's dead no signal is being passed.
|
|
|
Post by Abandoned on Jul 5, 2013 9:55:34 GMT -7
It was rectifier tube... and possibly power tubes. Fixed. Thanks all!
|
|
|
Post by DRZ on Jul 5, 2013 10:27:54 GMT -7
Cool, glad you got it fixed.
Z
|
|
|
Post by Abandoned on Jul 5, 2013 22:42:42 GMT -7
Cool, glad you got it fixed. Z Yeah me too. Thanks Dr. Z. We replaced both the rectifier and the power tubes. But just the rectifier tube was bad but he found burn marks on the glass of the power tubes so he wanted to replace them just in case they were what caused the rectifier to go bad. Funny thing is I like the sound of my old tubes better than the new ones we just replaced them with... Just before they went out that is. Why would I like the older ones better? The new ones sound dryer, harsher and a bit more sterile than my old ones. But the bad ones were replaced with the exact same brand name and model tubes that were used before and from the tube info on your website.
|
|
|
Post by DRZ on Jul 6, 2013 5:24:11 GMT -7
Not completely sure from your short description but I'll try. The M 12 is self biasing , I designed around MEDIUM currant output EL-84's, or what some tube sellers call Medium Range. If you install a HIGH gain set of EL-84's the amp can get a bit harsh, and tight sounding.
Always ask for Medium range matched sets of EL-84's for Z-Amps.
DR.Z
|
|
|
Post by Abandoned on Jul 6, 2013 5:38:31 GMT -7
Not completely sure from your short description but I'll try. The M 12 is self biasing , I designed around MEDIUM currant output EL-84's, or what some tube sellers call Medium Range. If you install a HIGH gain set of EL-84's the amp can get a bit harsh, and tight sounding. Always ask for Medium range matched sets of EL-84's for Z-Amps. DR.Z Ok gotcha. Ok I'll check to see which kinda he put in.
|
|
|
Post by Abandoned on Jul 6, 2013 6:53:07 GMT -7
So I was playing more through it this morning and it is EASILY and way noticeable that the tone is not near as smooth or warm. It way brighter, or at least the high end is much more strident. And the tone is much DRYER, as in less smooth and less polite. I'm trying to get ahold of the shop that fixed itmtomfind that info out. But yeah... this is very strange. I mean I can't really fully recall how the amp sounded when I first got it but to my recollection this still sounds way different.
|
|
|
Post by Jefferson on Jul 6, 2013 7:45:03 GMT -7
Tubes can make a huge difference in the tones your amp produces. All tubes, even from the same manufacturer are sadly not created equal. You may need to take control of this element of your amps care and feeding by building a relationship with someone in the tube business who understands the tube inequality concept and can work with you to ensure that you are getting the best possible tubes for your needs.
Lots of folks here have worked with Mike at KCA NOS tubes. I personally work with Fat Willie aka lord valve at NBS electronics in Denver. He can be a pain in the rear to talk to, but he knows his stuff and does his own tube testing and burn ins prior to shipping.
Point is, the days of just picking a tube off a shelf and expecting the next one to sound\work like the last one are over!
|
|
|
Post by Abandoned on Jul 6, 2013 7:59:03 GMT -7
There are a few code numbers on the box of my new power tubes. Can I figure out if they are high gain by those?
Like this:
IP: 23 Gm: 7,900
|
|
|
Post by Abandoned on Jul 10, 2013 6:19:03 GMT -7
So my power tubes are not high range power tubes. So that's not the problem.
Anyone have insight into why my M12 is now much brighter and harder sounding than before? Again, power tunes and rectifier tube have been replaced with brand new ones and they are the same exact brand name and model and type currently has on his website.
A little more background... my amp stopped working several days ago, it stopped putting out any signal. Amp stayed on, power tunes hot and lot up (normal, good) and everything. Found out it was a bad rectifier tube. Repair guy only replaced rectifier tube and power tubes. Now the amp sound much brighter and harder. I can't figure out why,
|
|
|
Post by Abandoned on Jul 10, 2013 6:34:34 GMT -7
Maybe my old power tubes were just pretty dead and sounded duller? And I like that sound i guess. They were in there for a solid 8-9 months with constant use. Like 25hrs/wk.
|
|
|
Post by Abandoned on Jul 12, 2013 5:03:44 GMT -7
Well I did a ton of tube swapping yesterday afternoon with no good results. The tone still sound brighter and stiffer. So the only answer I can conclude by myself is that my old power tubes were really warm out and old and near the end of their life.
|
|
|
Post by DRZ on Jul 12, 2013 5:52:02 GMT -7
Josh I have over 45 years of experience fixing electronic devices, I have learned always look to the last thing changed before the failure happened, 90% of the time that is the problem.
So you are swapping output tube sets and feel the worn out set is what you like, well when the amp was new and the tubes were new was it stiff and bright?
Remember you changed rectifiers as well, was it replaced with a JJ 5Y3? A rectifier can cause a change in tone contrary to what some techs say.
Failures are easy to fix, I believe Don told you in your first E-mail that it was the rectifier, but SUBJECTIVE problems on working units are difficult at best to fix, sometimes it's more than the amp that needs fixing.
DR.Z
|
|
|
Post by Maddog on Jul 12, 2013 6:20:51 GMT -7
..........Remember you changed rectifiers as well, was it replaced with a JJ 5Y3? A rectifier can cause a change in tone contrary to what some techs say........... DR.Z +1,000,000
|
|
|
Post by Abandoned on Jul 12, 2013 12:58:22 GMT -7
Well I had an amazing talk with Dr. Z amps this afternoon. Phenomenal customer service, help and info. He explained everything to me and I'm golden now.
I am a huge Dr. Z fan for the amazing tone I get from all his amps, not just my M12. But his customer service will keep me for life.
|
|
|
Post by "Z" Steve on Jul 12, 2013 13:15:27 GMT -7
You are NOT Abandoned! (at least not here). Doc is great and so is his crew - CS second to none. Glad you got it corrected and had your questioned answered - spread the word!
|
|