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2359glenn | studio - Page 338

post #5056 of 10229
Quote:
Originally Posted by Clayton SF View Post
 

I'm older than you. That's why Glenn set mine at 80 and yours at 70. :)

 

This is the best explanation I ever heard.

 

Is that a gauge for wisdom too?

post #5057 of 10229
Quote:
Originally Posted by 2359glenn View Post
 

Every rectifier will have a different voltage drop changing the  B+ voltage that is why you have to adjust with a rectifier change.

 

I find changing the bias fun actually, it's cool.

 

Quote:
Originally Posted by Clayton SF View Post
 

I'm older than you. That's why Glenn set mine at 80 and yours at 70. :)

 

Well yes that, or the 220V has something to do with it :D

post #5058 of 10229
Quote:
Originally Posted by Ultrainferno View Post
I find changing the bias fun actually, it's cool.

 

I agree! This morning I was adjusting the bias just a tad on both monoblocks and felt like Dr. Frankenstein....

 

IT'S ALIVE!

post #5059 of 10229

I set Ultra's lower to be easier on the rectifier his rectifier is feeding

two 300Bs and two C3g 70+70+20+20= 180 ma for the rectifier plus to have to recharge the caps.

Clayton's mono block 70+20= 90 ma for the rectifier much easier on it.

160ma is about max for a 5U4G a GZ37 can handle much more but might leave it at 70 if you are

using the RK60 rectifier that is similar to a 5U4G.

plus most 300Bs recommend 70ma JJ can handle a little more.

post #5060 of 10229

I'm an RK60 fan. I switch between that and the 5U4GB

post #5061 of 10229
Quote:
Originally Posted by Clayton SF View Post
 
Quote:
Originally Posted by Ultrainferno View Post
I find changing the bias fun actually, it's cool.

 

I agree! This morning I was adjusting the bias just a tad on both monoblocks and felt like Dr. Frankenstein....

 

IT'S ALIVE!

 

I get to adjust my Bias every time I watch the TV News....

post #5062 of 10229
Quote:
Originally Posted by Xcalibur255 View Post

 

Another member of the Glenn Amp mA Meter Club.

Hey, I recognize that cart! :)


Edited by Clayton SF - 9/28/13 at 1:10pm
post #5063 of 10229
Thread Starter 

('Silent One' quietly walks up to the storefront window and looks in..."WOWZA.")

post #5064 of 10229
Glenn/Tyrell, what transformers were put into that beautiful amp?
post #5065 of 10229
The Transformers are Lundahl the best you can get very expensive though
post #5066 of 10229
Quote:
Originally Posted by 2359glenn View Post
 

Tyrell

 

1ma is not going to matter much I don't think the sound will change much with a change of 1ma.

Also you got to realize these are very old tubes and have been sitting for 70 years.

One of those Emperor 45s tested week when you first sent them and I tested them.

I switched to them when one of NUs lit up with gas in the amp.

If you switch the Emperors after you set the bias you will notice a big difference in cathode current.

 

How about a picture of the C3g with the can removed and the filament on.

 

All good points.  I'm learning what needs to be learned about working with old DHTs slowly but surely.  You touched on another question I had, if I put a different pair of tubes in will the bias be way higher or lower?  If the current jumps way up for a short period of time can the tube literally be fried by that if it is too high, and conversely is there such a thing as too low as well?  I am going to get another 46 tube and try your adapters as well, but the nominal current on a 46 is I think 22mA.... so what happens when I put them in the socket will they shoot up the 36 and get fried?  There is so much to know and it's hard to guess without a working knowledge of the circuit.  I need your wisdom!  :D  Is it a good idea to turn the bias down some before swapping tubes, or just put the new ones in and adjust once they are conducting and you can see where they are drawing at?

 

I don't claim to have golden ears, but each change from 32 to 34 to 36 produced a difference in sound I found quite easy to spot.  So far higher seems to sound better.  Once I went to 36 the amp really began to achieve the transparency I was hoping for.  It tightened up the bass very nicely too.  Maybe I'm just crazy, but the tubes seem to sound better after I adjust bias too, whether it be up or down.  The treble seemed a little harsh yesterday, the longer I listened it kept getting more "tizzy" but the second I tweaked the bias pots it went away and sounded great.  Maybe these Emperor tubes are just not very good 45s, I was not very confident about them when I bought them but the Emperor branding was really unique so I bit.  Next week I will probably switch to my Tung Sols.  I want to see how much change in sound I'm going to get by rolling the 45s.

 

I did try to get a photo of the amp running but they won't turn out, it always looks really crappy.  The C3g doesn't glow brightly, there is a mild glow at the top edge of the filament and a dim red glow along the heater/cathode (not sure if I even have that right?), but all in all they are sort of like the 45s they don't put on much of a light show.  The rectifiers produce the most glow by far which isn't saying much because you are just getting 4 glowing dots there too.  I still say the 5998 is the most beautiful tube to see in the dark.  They are like bright orange jewels.  The OTL puts on a much better light show than the 45 does. 

 

My thanks btw, to Stavros and Clayton for their helpful responses.  Glenn too of course.  I want to make sure I'm following good practices with biasing.  The training wheels are off but I'm not riding steady yet. 

post #5067 of 10229
Quote:
Originally Posted by dminches View Post

Glenn/Tyrell, what transformers were put into that beautiful amp?

Lundahl LL1664s if I'm not mistaken.  Glenn thinks I'm crazy spending so much money on high dollar parts, but these are actually very reasonably priced compared to the crazy Tango and Tamura transformers from Japan.  I think Lundahl hits a good sweet spot in terms of price/performance, though that is not really based on anything but my own gut feeling.  They're actually not much higher than One Electron which is considered a budget transformer, but the price of the metal covers has to be taken into account too so overall they are a little expensive.  Lundahls are really ugly looking without the covers so they're pretty necessary.

 

I would like to get some custom O'netics transformers from Bud Purvine for my future 300B monoblocks, but maybe it would be easier to just do Lundahl again.  Glenn seemed to really like the Lundahl main power transformers too.

post #5068 of 10229
Quote:
Originally Posted by Clayton SF View Post
 

 

Another member of the Glenn Amp mA Meter Club.

Hey, I recognize that cart! :)

 

My hat is off to you for introducing me to the joys of owning furniture with wheels on it.  :D

post #5069 of 10229

You can expect different biasing with different tubes of the same type depending how strong they are.

 

But once they settle in you should not need to change the bias.

post #5070 of 10229
Quote:
Originally Posted by Xcalibur255 View Post
 

 

All good points.  I'm learning what needs to be learned about working with old DHTs slowly but surely.  You touched on another question I had, if I put a different pair of tubes in will the bias be way higher or lower?  If the current jumps way up for a short period of time can the tube literally be fried by that if it is too high, and conversely is there such a thing as too low as well?  I am going to get another 46 tube and try your adapters as well, but the nominal current on a 46 is I think 22mA.... so what happens when I put them in the socket will they shoot up the 36 and get fried?  There is so much to know and it's hard to guess without a working knowledge of the circuit.  I need your wisdom!  :D  Is it a good idea to turn the bias down some before swapping tubes, or just put the new ones in and adjust once they are conducting and you can see where they are drawing at?

 

I don't claim to have golden ears, but each change from 32 to 34 to 36 produced a difference in sound I found quite easy to spot.  So far higher seems to sound better.  Once I went to 36 the amp really began to achieve the transparency I was hoping for.  It tightened up the bass very nicely too.  Maybe I'm just crazy, but the tubes seem to sound better after I adjust bias too, whether it be up or down.  The treble seemed a little harsh yesterday, the longer I listened it kept getting more "tizzy" but the second I tweaked the bias pots it went away and sounded great.  Maybe these Emperor tubes are just not very good 45s, I was not very confident about them when I bought them but the Emperor branding was really unique so I bit.  Next week I will probably switch to my Tung Sols.  I want to see how much change in sound I'm going to get by rolling the 45s.

 

I did try to get a photo of the amp running but they won't turn out, it always looks really crappy.  The C3g doesn't glow brightly, there is a mild glow at the top edge of the filament and a dim red glow along the heater/cathode (not sure if I even have that right?), but all in all they are sort of like the 45s they don't put on much of a light show.  The rectifiers produce the most glow by far which isn't saying much because you are just getting 4 glowing dots there too.  I still say the 5998 is the most beautiful tube to see in the dark.  They are like bright orange jewels.  The OTL puts on a much better light show than the 45 does. 

 

My thanks btw, to Stavros and Clayton for their helpful responses.  Glenn too of course.  I want to make sure I'm following good practices with biasing.  The training wheels are off but I'm not riding steady yet. 

When you put in a 46 the cathode current will go way down and you will have to turn it up

I did try the 46 and ran it at 38 ma it actually has a larger plate then the 45 and can handle the 38ma.

You just have to remember to turn down the bias pot before putting the 45 back in.

the 46 is a low cost tube so if you run it hot it don't really matter..

 

DHTs sound best when run hot at there max current.

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