I am the happy new owner of the system below.  Does anyone have any insight into why I am experiencing a fair amount of hum from the Triode Amp?  I have only had the amp running for ~8 hrs so far, but the hum (with nothing save the speakers connected) has not reduced.  I am using the tubes and power cable suplied shipped from Decware.

Rega P2, rb250
Goldring G1006
NAD PP2
MB Quart QL-C104
Decware Select Zen Triode

Thanks for the tip,  I'll look into my cabling/supply situation tonight.  My thought is that supply noise is a very likely culprit.  I'd love to see the plans for your DIY mains power cable!  Thanks for the help.

I am reaching the end of the break-in period of the amplifier and I am a little concerned that the top end has not filled in like I was hoping it would.  I am admitedly new to vinyl and tubes, but this is becoming a noticable deficincy in my system.  My listening tastes vary from classical to jazz to rock.  Are my speakers too low efficiency?  Do I have the wrong speaker cables ('standard' speaker cable)?  Or is it a matter of tuning my room?  Thanks!

Fair enough.  The MB Quart are just to get me going until I have the money to invest in better speakers.  Maybe I can see about some more efficient speakers in the same price bracket.

[quote author=Rap  link=1161362143/0#5 date=1161698467]Hmm, MB Quart QL-C104 are hardly state of the art, if you mind me saying so I think you should look into new speakers. 86db just isn´t going to make a zen happy. Take a look at the frugal project over on speaker build. [/quote]

For those with larger rooms (or needs) - there's also Scottmoose's expanding family of  BVR/"horns"  

http://www.diyaudio.com/forums/showthread.php?s=&threadid=85156&perpage=10&pagen...


and you might also want to seriously consider upgrading your phono pre- there are several reasonablye cost options in kits or proven DIY circuits that would be as much of an improvement over the NAD as your Decware amp was over previous SS gear.

[quote author=jslusarz  link=1161362143/0#9 date=1161865618]Last night another issue diveloped:  I started to hear popping from one of the speakers on particularly loud sections of music.   [/quote]

My guess is you are clipping the amp.

[quote author=jslusarz  link=1161362143/0#11 date=1161882409]The clippping begins at a volume(control) level near half of full scale.  The signal is generated from the Rega P2, through NAD PP-2 phono preamp and then into the variable inputs on the Zen Select.  How is it possible that I am clippping at an output level around what I would consider normal listening volume.  I will try a digital source tonight to localize the problem to either the amplifier or the phono section. [/quote]

First thing to check out is the cartridge alignment.  As I recall, Rega's past philosphy as regards to VTA was "don't worry, just buy one of our cartridges, and you'll be fine" .  Unfortunately if you're using something else, adjustment can be a bit tricky,  If any of the 3 dimensions are out of alignment, or if the cartridge body is loose, tracking distortions will occur than can be localized to one channel.

As to clipping the amp, it's quite simple - the Goldring is a reasonably high output cartridge (6.5mv), and the NAD's input sensitivity is 3.5mv .  

While you're not likely overloading the phono pre-amp (NAD's specs say that would take 10mv at 20Hz) , it's certainly possible that it's putting out more than enough voltage to drive the Zen to clipping, even with the input level control at  "half".

Couple  that with the MB Quart's moderate sensitivity of  88dB, and depending on the size of room and your definition of "normal" listening levels, clipping of any 2 watt amp is quite possible.    


BTW, we got a bit derailed regarding your original query - have you solved the hum issue yet?  
Have you tested the amp with a shorted input?  Create a shorting plug by soldering a piece of wire from center to ground on a cheap RCA plug. If the noise disappears, it's either the source or the interconnect.  

While you're checking out the cartridge alignment, you might also want to look at the grounding of  cartridge/tonearm wiring.  
If the above test isolates the problem to the table, does the hum get progressively louder as the arm moves towards the center of the disc?  The motor is not particularly well shielded in the Rega table, and a loose connection or poor solder joint anywhere in the arm wiring is another potential problem.    

The Rega arms are huge bang for the buck value, but the quality of wiring and workmanship on early production models was particularly suspect.  A guaranteed huge improvement is something like the Incognito arm wiring upgrade.