[Rico613]

I've received a few duds from Brent, what are the drivers?  stock 6C45pi ?  

 

[bmichels]

    
 
If someone is interested, I took some pictures inside the 445 power supply. 

 

[gsr108]

stock

  I've received a few duds from Brent, what are the drivers?  stock 6C45pi ?  

Yes the stock 6C45pi.  I have some 5842's and WE417a but am waiting on a adapter before I try them out.  And I did not try the 5842's or WE417a's in the 4-45. 

 

[Radio_head]

I've received duds from Jesse as well.  Be careful to re-test and call him out if he's cheating you.

 

[Rico613]

  I've received duds from Jesse as well.  Be careful to re-test and call him out if he's cheating you.

I've noticed that, when buying pairs of NOS tubes, some of these 'reputable' tube dealers will often pair one strong NOS tube with one that is much weaker has gas leaks or even shorts.  Brent will make good on his guarantee but once I had to send EZ-90 tubes back twice to get a decent pair.  I think it maybe easier to just buy some new EML tubes and pay the man!

 

[bmichels]

 

---

Back with my HUUMMMMM problem. Looks like I have a problem with the power supply of  my 445 

Indeed, I made a mistake believing that I was hearing the humm through the Headphone, because
in fact it is coming.... from the power supply, and everybody can hear it in the room.. and my
headphone do not isolate well  
 
This explain why it was totally independent from the  position of the volume pot or of the input selector. 

So… Is the 445's power supply supposed to be totally silent or it is possible to hear it in the room
when the music do not play ? it is quite annoying to hear it between each music file.
 
Cuthus answered to my problem : " The transformer can buzz. The most common cause is a mismatch
with the rectifier tubes. Either one tube is bad, or the cap on top is not making a good connection.
The other cause can be some DC offset, or high line voltage on your power outlet.
The transformer is bolted to the chassis, sometimes loosening the screw will reduce mechanical coupling". 
 
What is " DC offset " ?  Are your Eddie curent's totally silent ?  what do you think I should try first ?

 

[Rico613]

My 445 is totally silent.   (except for a little microphonic type noise from Mars when I first turn it on)
 
Checking to see if the transformer is firmly attached should be easy enough.  Is is it firm or does it move around a little?  Can you tighten the screws?
 
You can check your line voltage with a meter.  
 
You can check the cap on top of the rectifier tubes - they can easily fall off.  You might want to clean up those contacts with Deoxit.  
 
Since Craig said the most common problem is mismatched tubes you'd want to get them tested.  Maybe since it's under warranty Craig will do it or simply get replacements from Craig (you would probably want backups anyway).  I don't know if it is easy to find those tubes at a tube dealer but you could try that.  I'd only go with new ones, not NOS.  If this has been going on since day one, I would be sure to let Craig know about it and get his support in fixing it.
 
I don't have a clue what DC offset is all about.
 
Keep us posted.

 

[bmichels]

  My 445 is totally silent.   (except for a little microphonic type noise from Mars when I first turn it on)
 
Checking to see if the transformer is firmly attached should be easy enough.  Is is it firm or does it move around a little?  Can you tighten the screws?
 
You can check your line voltage with a meter.  
 
You can check the cap on top of the rectifier tubes - they can easily fall off.  You might want to clean up those contacts with Deoxit.  
 
Since Craig said the most common problem is mismatched tubes you'd want to get them tested.  Maybe since it's under warranty Craig will do it or simply get replacements from Craig (you would probably want backups anyway).  I don't know if it is easy to find those tubes at a tube dealer but you could try that.  I'd only go with new ones, not NOS.  If this has been going on since day one, I would be sure to let Craig know about it and get his support in fixing it.
 
I don't have a clue what DC offset is all about.
 
Keep us posted.

 
Thanks, I will try those mentioned things and come back to Craig.
 
but
 
- what does he mean by "mismatch with the rectifier tubes" ? does he means that the 2 tubes can be good but NOT "matched" together,  or does he means that one tube can be defective ?    How can I test them ????   Are those tube expensive ?  
 
- what do you mean by "ou can check your line voltage with a meter" ?  do you speak about the voltage coming from my wall outlet or the voltage inside the EC's power supply ? 
 
thanks 

 

[Rico613]

He means the voltage coming from the wall.  Maybe you could maybe ask the power company if there are variations in the voltages.
 
to test the tubes You'd have to find someone with a tester.  Ask around your local Hi Fi shops or Electronics stores if they know someone.  Maybe there is someone who repairs old radios?   I have a good tester, but I'd have to load the data for those tubes and I haven't gotten around to that yet.  
 
Mis-match tubes can mean anything.  One good one bad, one weak one strong, etc.  You can look up those tubes online and find a price.  I haven't tried yet so I don't know.  I don't think they are super expensive.  
 
Be sure to check the caps on those rectifier tubes they could easily fall off.  

 

[bmichels]

my HUUMMMMM problem cont...
 
 
I did some more testing today by (1) bringing my 445 to another house (2) tightening/un-tightening the transfos (3) checking the rectifer's cap on top connection.
 
1 - the hummm in the headphone is gone 

 .....in the other house

.  But it is still there at my home (and it disapear when I put my hand on the 445, my body creating some sort of "human mass" I guess ? ) !
--> so there must be some bad electrostatic noise or bad mass in my house's AC circuit.  I hope it cannot damage the 445 !  I will have to call an electrician to check my house's circuit or...buy a power conditioner ??.
 
 
2 - In the other house, the hummm coming out from the 445's power supply box is still there.

  And the noise increase when the top coven is on ! the top cover must amplify micro vibrations. 
--> I will have to buy 2 new rectifer tubes ?

 

[Rico613]

  my HUUMMMMM problem cont...
 
 
I did some more testing today by (1) bringing my 445 to another house (2) tightening/un-tightening the transfos (3) checking the rectifer's cap on top connection.
 
1 - the hummm in the headphone is gone 

 .....in the other house

.  But it is still there at my home (and it disapear when I put my hand on the 445, my body creating some sort of "human mass" I guess ? ) !
--> so there must be some bad electrostatic noise or bad mass in my house's AC circuit.  I hope it cannot damage the 445 !  I will have to call an electrician to check my house's circuit or...buy a stabilized HiFi power supply.
 
 
2 - In the other house, the hummm coming out from the 445's power supply box is still there.

  And the noise increase when the top coven is on ! the top cover must amplify micro vibrations ?? 
--> I will have to buy 2 new rectifer tubes ?

to make the hum disappear, do you put your hand on the 445 amplifier, or the power supply?
 
Craig said the most likely problem was the rectifier tubes so you could try replacing them with new ones.  If that doesn't work, I'd run it past Craig again and see what he suggests.  Have you thought of shipping back the power supply to Craig and let him deal with it?  It is under warranty.  Maybe Craig could ship you another power supply to test in your environment.  I would get a meter on your main power source to be sure it is within specifications or call an electrician to check it.  There are a lot of power conditioners out there some are good some are a waste.  I have had good results with the latest Shynyata power cords and power distributors.  I suppose the power cord may be the problem.  I'd try using a heavy guage power cord from the hardware store and see if there is any change.  The Shyunyata Zitron Alpha power cord would be perfect, but it's nasty expensive. 

 

[bmichels]

to make the hum disappear, do you put your hand on the 445 amplifier, or the power supply?

Craig said the most likely problem was the rectifier tubes so you could try replacing them with new ones.  If that doesn't work, I'd run it past Craig again and see what he suggests.  Have you thought of shipping back the power supply to Craig and let him deal with it?  It is under warranty.  Maybe Craig could ship you another power supply to test in your environment.  I would get a meter on your main power source to be sure it is within specifications or call an electrician to check it.  There are a lot of power conditioners out there some are good some are a waste.  I have had good results with the latest Shynyata power cords and power distributors.  I suppose the power cord may be the problem.  I'd try using a heavy guage power cord from the hardware store and see if there is any change.  The Shyunyata Zitron Alpha power cord would be perfect, but it's nasty expensive. 

t o make the hum disappear I you put my hand on the 445 amplifier ( but Remember, the problem do not exist in the other house. So, THIS Hummm is not the 445 fault)

 

[Rico613]

But you still get hum from the power supply in both houses?

 

[bmichels]

But you still get hum from the power supply in both houses?

Yes, the noise generated by the power supply exist in booth houses. And It is not in the headphone, It can be heard by everybody in the room.

 

[Rico613]

Things to check on the power main:  Ground, voltage, heavy duty power cord  
 
Things to check in the power supply:  fuse, tubes, tube caps, loose wiring, contact cleaner
 
Did you try Dexoit on the tube caps?  I used it on all electrical connectors, tube pins, etc.     
 
http://store.caig.com/s.nl/sc.2/category.188/.f
 
I use a cotton swab (Q-Tip) to apply the 5% solution that cleans and protects the contact.