Drd 45, 300b

[jeff mai]

Can someone elaborate on problems/ no problems with the CR diode?

Some people will be bothered by the fact that it doesn't glow.

 

[rick57]

How did they let that design slip through?

 

[garbage]

what do you think of your drd 300b?
Have you compared it to others 300bs?

hi rick57

there were too many equipment changes at the show, can't really do a direct comparison with the other 300bs.

the only comments that i solicited regarding the drd is that it is clean sounding and that they sounded "good". i was also out of the tube room during the time when they were playing (was checking out the SS room).

so let me try my best to describe my amps in my setup.
cdp is a sony x3000es top loading player, modded to accept power cables via IEC and using MUR860 fast rectifiers.

preamp is a modded passive pre, with buf634 and opa627 on dual mono supplies. (going to build a preamp using 2x866a MV rectifiers, 6072, 5867, ala audionote m10 design to match the amps)

speakers are audio note az2 tapered quarter wave with rear horn, 93db.

in my setup, the sound has height and depth. bass can be tuned by moving the speakers away from the wall, i currently have them toe-in, with the nearest corner of the speaker 1.5" away from the rear wall. goes much lower than my totem model1, but imaging is not as precise vs the totem.

soundstage is large. the sound is also airy. i've got comments that in my room, the highs are not extended enough. i think this can be tweaked by modifying the crossover of the az2. on emi fujita's camomile extra(which can make ears bleed if the setup is bright sounding), it is sparkling, but not piercing to the ears on extended listening.

all in all, i'm satisified with my first attempt at building tube gear and chassis construction. the only thing that irks me is the 5mv of hum that i can't seem to rid. only if i listen hard for it, can i hear the hum when between tracks on a cd.

a recent pic of my setup

An externally hosted image should be here but it was not working when we last tested it.

OT: will post a url to the post show report when it is out

cheers
garbage

 

[garbage]

OT

sorry for digging up this thread and posting off-topic messages... but since i promised the noising show report, so here it is for anyone who i s interested.

 

[Stixx]

hum

Hi Garbage,

you probably remember my posts a little while ago asking for help with hum in my C3g headphone amp. Even though I tried numerous things it basically stayed the same....
until I got in touch with Mr. Siemens. He's the guy behind the schematic, and he suggested to completely alter my wiring. I tried that...and it not only looks a lot cleaner now....hum has also gone down so much that it's not bothering me anymore....and you know that when listening thru headphones you literally hear the ants cough (or something like that..)!

So maybe you want to check your wiring also and painstakingly try to avoid any AC carrying wires come close to signal wires. It helped for me.

Good luck,
Oliver

 

[garbage]

hi Oliver

sure i remembered. 😉

great to hear that you have squashed hum levels so low that you can actually hear an ant coughing. hahaha

was it just wiring problems?

i think my problem is that the output trans is too close to the main power trans. guess only a rebuild will solve that. will defer that as a future task. i'm gonna build a preamp first.

cheers, and happy diying.

 

[Stixx]

Garbage,

it was only wiring....
Though my chokes are oriented the wrong way they are not causing hum...I tried on longer leads!
And on my Leak TL20 the opt's are VERY close to the power transformer, and obviously that has worked for the last 40 years!!

Happy diying ,
Oliver

 

[garbage]

it was only wiring....
Though my chokes are oriented the wrong way they are not causing hum...I tried on longer leads!
And on my Leak TL20 the opt's are VERY close to the power transformer, and obviously that has worked for the last 40 years!!

serious??!!
then i must look into re-wiring it. but perhaps this time round with copper instead of silver. cost reduction. 😉

 

[Raj1]

hum

Hi,

I recently built a tube output stage that uses opt's. I used 2 different chassis - the B+ tranny having it's own. Unfortunatley there was not enough room in the B+ chassis to house the filament trasformer, so I had to put it in with the opt chassis - it was orintated at 90 degrees from the opt's around 2 inches away. I could hear a low level hum thru the headphones I was using. Eventually I mounted it on the back of the chassis (outside) , leaving the opt's inside. No more hum or hiss.......

It's now completley quiet, even with the volume cranked to max, listening thru sennheiser hd580's........

I guess you need to have the power transformers at an adequate distance from the opt's..........

Thanks
Raja