Annoying High frequency noise...

[tbrannon]

Very glad you've got the one working quietly and a plan of attack on the other.  
 
Did you come up with a schematic for these to take to the repair guy?  Seems odd that you'd get two bad power supplies.  They seem to be pretty robust units.  
 
Does this mean you'll be sporting the Series II on stage for the pre-Olympics gig at the Symphony Hall?  If so- some pictures and hopefully a decent video or sound board recording should be in the plans!
 
(Message edited by tbrannon on July 02, 2012)

[jazzyvee]

Yeah I got a schematic drawing emailed to me by Keith which I took with me.  Yeah it does seem odd to get two with problems but these things do happen. It would be good exchange for one of the smaller units.
As for the pre-olympic gig that's my plan to take the Series II to that gig. at the moment I don't have any information on what time we are playing and for how long.
 
 
I'm just popping over to the gig section to post a picture of the event flyer.
Jazzyvee

[terryc]

jazzyvee..interesting repair, I would have thought as a matter of course that all Alembic PS's have voltage regulation, even the most cheapest PSU from Maplins have this.
Anyway glad you got sorted and looking forward to the pics

[jazzyvee]

Now I don't even know what to think.  
I got the DS-5 back on Monday and took it home. Plugged into Mesa boogie Walkabout amp... and got loads of hum still.  
 
Rigged up my Alembic Rig with F1-x and QSC and no noise. Set up the rig in stereo and still no noise. However the bass pickup is still louder when the DS-5 is switched to stereo compared to when both pickups are selected in mono mode. I will wait till my other DS-5 comes back from having the transformer changed and see if it behaves in the same way.  
 
 
Jazzyvee  
ps: you may remember a while back I had problems with a regular clicking noise from my Roland JC120 when using my Dragon Series guitar.  
I've found that the problem is due to one of these lovely things.  
http://www.pcworld.co.uk/gbuk/devolo-1383-dlan-highspeed-ii-85mbps-powerline-starter-kit-00939029-pdt.html?intcmpid=display~RR~Computing~00939029  
 
When it's on the signals are getting into the amp vial the power socket.  
Turned off... silence.  
Time to get a filter cable or mains conditioning unit for my gear.  
 
Jazzyvee

[jazzyvee]

Now that seems sorted I'm definitely taking my new Series II to the gig.  
 
I did take the bass to rehearsal last night and to be honest it sounded less than ordinary.  
It was at a rehearsal room and plugged into a Hartke HA2500 and a peavey 4x10 cab. I usually have my Mesa boogie amp just flat and use the bass to give me the tone I want but this one wasn't giving me anything back, the bottom end was wooly and the treble side was not giving me any punch or the crispness i was expecting.  
 
 
I know it sounds great through my rig and when I played it through some rigs at the California meet. I hope for this symphony hall gig tonight they have a decent bass rig for me or I may have to take a leaf out of Jimmy Johnson's book and just go into a DI and use the on-stage monitor.  
 
Hopefully someone will be taking photo's and I can get some to post  up here.  
Jazzyvee

[jzstephan]

http://www.soundstage.com/noisy15.htm

[Stefano]

Yeah I got a schematic drawing emailed to me by Keith which I took with me.  Yeah it does seem odd to get two with problems but these things do happen. It would be good exchange for one of the smaller units.
As for the pre-olympic gig that's my plan to take the Series II to that gig. at the moment I don't have any information on what time we are playing and for how long.
 
 
I'm just popping over to the gig section to post a picture of the event flyer.
Jazzyvee

Hi Jazzyvee,

old post, but current problem: I have a hum/noise coming from my DS-5 and would like to know if you can email me the schematics so I can take it to repair or check it.

Thanks a lot in advance!
Stefano

[rv_bass]

Stefano, this link to an old thread has a DS-5 schematic…

http://alembic.com/club/messages/395/60881.html?1246843699

[Stefano]

Thanks a lot RV!

[BeenDown139]

chiming in a little late - got unmotivated at work and stumbled across this thread.  this may or may not help. YMMV :

years ago i had a rack that consisted of a DS-5, F2-B, power conditioner and a mesa boogie tube amp.  Once everything was mounted and secured in the rack and hooked together, it hummed.  not very much, but noticeable and irritating, especially on a rig like that with a series II plugged into it.  remove everything from the rack, hum stops.  It should be mentioned that everything had a 3-prong power plug that hooked into a good quality grounded outlet strip.

Long story short, it turned out to be a ground loop caused/exacerbated by the 1/4" shielded patch cables combined with the fact that everything was grounded through their respective power cords and by the chassis mounted together in a conductive metal frame in the rack.  The solution was a trick i learned from my days in the amp shop.  Disconnect and insulate the sleeve from the 1/4" jack from the ground braid on one end only of the patch cable.  do this for all of the patch cables that connect from one device to another.  try to keep all of the grounded ends on the same device.

the sparkies (of which i'm a card-carrying member) call this hack a ground buster.  The electricians (of which i'm also a card-carrying member) who are familiar with the NEC will recognize this phenomena as objectionable ground current.  You almost always want a single point of grounding (or earthing as they call it across the pond) or strange stuff will happen.

HTH - back to the salt mines...