[kds5000]

Quote:

Originally Posted by indydieselnut /img/forum/go_quote.gif When I first turn mine on (s/n 3), there is an audible hum. As the amp warms up (first 180 seconds) the hum subsides into near inaudibility. With no music playing, if I turn the volume up around 2-3 o'clock I can get a very subtle hum again. This is not "hiss" but a hum, just as you described it. I don't experience the vibration but I took the stock feet off and have the amp on a trio of Mapleshade Surefeet on a block of walnut supported by the Mapleshade rubber/cork footers. I had all that stuff sitting around so I thought I'd try it. Seems to be working well. Cheers!

Thanks for replying indydieselnut. It sure puts my mind at ease knowing now that mine isn't the only one with this hum

The vibration I feel is very slight when the amp's properly warmed up. There's no noise coming from the transformer so it's no issue. Will try some TAOC wooden footers soon too as it'll give the amp some ground clearance to aid cooling if nothing else...

And man, does this amp run hot!

 

[Afrikane]

About 400mW into 120ohms, just inside the K1000 comfort zone.

 

[mrarroyo]

kds5000 if you have access to a "cheater plug" try it and rotate it to see if it eliminates the hum. If by rotating it the hum goes away you most likely have a ground loop.

http://en.wikipedia.org/wiki/Ground_loop_(electricity)
Ground loop problems and how to get rid of them

 

[kds5000]

Ah! Will certain look for one and try it.

Many thanks Miguel!

 

[mazinguerbeta]

Hello, although I have not received my HD250 yet, I'm already thinking about buying a new headphones to use the full potential of my new amp, I was thinking about the ps1000 with black dragon cable, what do you think about this combination?,thanks

 

[indydieselnut]

Quote:

Originally Posted by mazinguerbeta /img/forum/go_quote.gif Hello, although I have not received my HD250 yet, I'm already thinking about buying a new headphones to use the full potential of my new amp, I was thinking about the ps1000 with black dragon cable, what do you think about this combination?,thanks

I haven't heard the PS1000 yet, but I've tried GS1000i, RS1i, and 325is with my HD250 and they all sound great! Best of luck making your decision.

 

[kds5000]

The HD250SE made me keep my GS1000 when I was trying to sell it previously. I've always felt that the PS1000 had a similar sound signature to the GS1000, so the combination should be very good. BTW, it drives all the cans in my sig beautifully, including the K1000 which I borrowed for a week.

 

[DustyRoads]

Do you like the sound of the HD800's with the MAD 250?

 

[Budley007]

Well, been listening to mine, (#6), for a couple of weeks now. Still only got about 40 hours on it, but the SQ hasn't changed much, if at all since I got it. This amp is dead quiet, with no hum and haven't yet heard any tube microphonics with handling or the occasional bump.

I have some telefunken EL84s along with some Rayovac 12AX7s and Sylvania 5751s waiting in the wings, but haven't rolled them in yet. The original tubes sound pretty good. The amp in general has really impressed me and I think I've finally found the sound I'm looking for with my Grados.

I was worried that a tube amp, (my first), would be "syrupy" and too warm for my taste, but this sucker is tight with just a little dab of butter. Just enough warmth to take the edginess outta my digital sources without muddying up the detail. I'm through amp hunting for awhile. (I just might mean it this time.) Dr. Peppard has put together a wonderful design and has made me a very happy man. Thanks Lloyd!

 

[mazinguerbeta]

Hello, I have a problem, my rs1 make a disagreeable noise connected to hd250, the right side almost imperceptible or non-existent but in left side it is very strong, connected to corda opera don´t exist the noise. Thanks

 

[indydieselnut]

Quote:

Originally Posted by mazinguerbeta /img/forum/go_quote.gif Hello, I have a problem, my rs1 make a disagreeable noise connected to hd250, the right side almost imperceptible or non-existent but in left side it is very strong, connected to corda opera don´t exist the noise. Thanks

Contact Lloyd, he'll be the most qualified to trouble-shoot with you.

 

[mrarroyo]

mazinguerbeta, turn the amp off and after 3 minutes or so gently remove the tubes and swap their locations. Make sure they are all properly seated and turn the amp back on, if the noise changed channels then it is a bad tube. Another thing I have found is that for the first 20 to 100 hours of operation some tube amps have "noises" which then go away not to return. Why? I have no idea but if you have a pair of cheap headphones leave them plug while you burn-in the amp for about 20-100 hours and see if the noise goes away. If not talk to Dr. Lloyd.

 

[MacedonianHero]

Great advice...I started to type basically the same response and then read yours...

 

[mazinguerbeta]

thanks mrarroyo, I have changed the tube location but the problem continues, I have used a iems and have verified the same problem, noise happens in the left side.Only don´t listen with 702

 

[mrarroyo]

How about a driver tube? Do you have a second one to swap in? How many hours of burn-in does the amp have? Have you made sure the source sound is clean by trying another amp?

Otherwise time to call Dr. Lloyd.