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2359glenn | studio - Page 928

post #13906 of 13920
Quote:
Originally Posted by 2359glenn View Post
 


The interesting thing about the EL3N is the impedance of the load/transformer stays the same in triode and pentode.

This makes it easy to work with. It definatly has more gain in pentode it sounds a little diferent I think triode sounds

better in the output stage. Have to give it more listening to but I think the EL3N has enough gain in pentode to make

a one tube per chanel amp.

Less is more the less parts the better it sounds.

 

From what I have read the EL3N triode has curves similar to the 45 and 50 tube (i.e. in good company) and the pentode, well not so much but decent.  Hopefully there will be suitable gain and the minimal parts will more than offset the slightly lesser curves.  The real acid test... let Lucy audition with her Adele CD! :regular_smile :  Will be very interested in the results!

 

BTW, for your output transformers in this type of config. do you run around 7K primary and multiple secondary taps (i.e. 600 ohm, 32 ohm etc.) to support different headphone impedances?

post #13907 of 13920
Quote:
Originally Posted by UntilThen View Post
 

...

Sound as good as your 300B creation? That's just amazing. This is going to sell very well. ;)

 

Where's the love for the 300B sound?

 

I kinda get it - the decent 300B tubes are damn expensive and require a lot supporting infrastructure (driver tubes and hefty transformers). The payoff is in the raw output power (around 8W - enough to drive even the HE6 well, and anything else effortlessly), and the glorious rich mids of some 300Bs (Takatsuki, WE300B and maybe some others).

post #13908 of 13920
Quote:
Originally Posted by TonyNewman View Post
 

 

Where's the love for the 300B sound?

 

I kinda get it - the decent 300B tubes are damn expensive and require a lot supporting infrastructure (driver tubes and hefty transformers). The payoff is in the raw output power (around 8W - enough to drive even the HE6 well, and anything else effortlessly), and the glorious rich mids of some 300Bs (Takatsuki, WE300B and maybe some others).

Still there, I love my Glenn 300B... but 90% of 300B sound for 25% of the price, I'll get one for the office :)

300B still got more potential since more modern tubes are available for tube rolling

post #13909 of 13920
Quote:
Originally Posted by Khragon View Post
 
Quote:
Originally Posted by TonyNewman View Post
 

 

Where's the love for the 300B sound?

 

I kinda get it - the decent 300B tubes are damn expensive and require a lot supporting infrastructure (driver tubes and hefty transformers). The payoff is in the raw output power (around 8W - enough to drive even the HE6 well, and anything else effortlessly), and the glorious rich mids of some 300Bs (Takatsuki, WE300B and maybe some others).

Still there, I love my Glenn 300B... but 90% of 300B sound for 25% of the price, I'll get one for the office :)

300B still got more potential since more modern tubes are available for tube rolling


Not quite 25% more like 50% but the tubes are allot cheaper. It still uses Lundahl transformers.

post #13910 of 13920
Fantastic looking amp Glenn.
post #13911 of 13920
Quote:
Originally Posted by gibosi View Post
 

 

I have been wondering about how the operating points in my OTL are affected by changing rectifiers...

 

 

When you change the rectifier you are indeed changing the overall operating point of the amp, that's why you get a slightly different sound.  You are positioning the output tubes in a different position on their "curves" if that makes sense.  If you move the tube into a part of its operating range where it's less linear you get that romantic sound, and moving it back into a more linear part makes it sound more transparent. 

 

In your case the bias gets set automatically so the amp will adjust itself when voltage goes up or down, the relationship between the voltage and current is visualized by the curve graphs for a tube.  Changing these values changes other things too such as resistance so there are multiple variables in play affecting the behavior of the output stage.

 

For people who don't have auto-biasing amps it's important to have a rough understanding of everything otherwise you'll never get the amp sounding its best.  For a given voltage there is usually one ideal "correct" current value, anything else just reduces linearity and increases distortion.

 

This is my understanding based on years of trying to learn.  If I'm wrong about anything hopefully somebody will correct me.  :)

post #13912 of 13920
Quote:
Originally Posted by 2359glenn View Post
 


The original transformers put out 265 volts or 530 volt center tapped and Whirlwind's Lundahl puts out 250 volts or 500 center tapped.

So it is 15 volts lower to compensate for the better rectifier.

 The OTL is self bias so it will compensate for the higher voltage.

But will still sound different.

All the 5Volt rectifiers even with the same number have different voltage drop. The 42EC4 has such a low voltage drop and can handle

1amp that you cant here a difference between them. Almost like having SS rectifiers.

The 3DG4 has a 25 volt drop at 350ma but it will be less at a lower current draw.

So when people say that such and such rectifier sounds great in there amp it means nothing if you have a different amp.

The current draw will be different so the voltage drop will be different.

 

Quote:
Originally Posted by Xcalibur255 View Post
 

 

When you change the rectifier you are indeed changing the overall operating point of the amp, that's why you get a slightly different sound.  You are positioning the output tubes in a different position on their "curves" if that makes sense.  If you move the tube into a part of its operating range where it's less linear you get that romantic sound, and moving it back into a more linear part makes it sound more transparent. 

 

In your case the bias gets set automatically so the amp will adjust itself when voltage goes up or down, the relationship between the voltage and current is visualized by the curve graphs for a tube.  Changing these values changes other things too such as resistance so there are multiple variables in play affecting the behavior of the output stage.

 

For people who don't have auto-biasing amps it's important to have a rough understanding of everything otherwise you'll never get the amp sounding its best.  For a given voltage there is usually one ideal "correct" current value, anything else just reduces linearity and increases distortion.

 

This is my understanding based on years of trying to learn.  If I'm wrong about anything hopefully somebody will correct me.  :)

 

Thanks guys. I think my understanding, while still pretty blurry, might be just a bit more clear. At the least, I think I understand that if both my and Whirlwind's amp had the same rectifier, say a HEXFRED, they would still sound different due to the fact that the transformers are different. That is, the two different transformers, one putting out 250 volts, and the other, 265 volts, will position the output tubes at different positions on their curve. And thus a different sound.

 

And it is very interesting to learn that rectifier tubes with the same tube number may well have a different voltage drop. So for example, even though the commonly quoted voltage drop for a 5U4G is 44 at 225ma, the actual voltage drop may well be different between 5U4G produced by different manufacturers. This certainly helps to explain why the 5U4G all seem to sound different.

 

Anyway, while the HEXFRED is still in my amp, I haven't had much time for music the last week or so, and therefore, haven't been able to compare it to my favorite 5-volt tubes. Hope to have more time next week.

 

Cheers

post #13913 of 13920
Quote:
Originally Posted by 2359glenn View Post
 
Quote:
Originally Posted by Khragon View Post
 
Quote:
Originally Posted by TonyNewman View Post
 

 

Where's the love for the 300B sound?

 

I kinda get it - the decent 300B tubes are damn expensive and require a lot supporting infrastructure (driver tubes and hefty transformers). The payoff is in the raw output power (around 8W - enough to drive even the HE6 well, and anything else effortlessly), and the glorious rich mids of some 300Bs (Takatsuki, WE300B and maybe some others).

Still there, I love my Glenn 300B... but 90% of 300B sound for 25% of the price, I'll get one for the office :)

300B still got more potential since more modern tubes are available for tube rolling


Not quite 25% more like 50% but the tubes are allot cheaper. It still uses Lundahl transformers.

 

I think this amp is a great option, Glenn....I am not interested in powering speakers with it, but damn....this should be wonderful option for planar headphones as well as the HD800 and still have the tube sound and uses the Lundahl transformers, that is a win, win....I like what I have heard from the EL3N as driver tubes in my OTL amp and they are not running at what the tube is capable of......plus I already have a couple of pair of NOS EL3N hanging out here, waiting for use.

 

I also love the look of the mesh rectifier  :smile: 


Edited by whirlwind - Yesterday at 3:15 am
post #13914 of 13920
Quote:
Originally Posted by whirlwind View Post

I think this amp is a great option, Glenn....I am not interested in powering speakers with it, but damn....this should be wonderful option for planar headphones as well as the HD800 and still have the tube sound and uses the Lundahl transformers, that is a win, win....I like what I have heard from the EL3N as driver tubes in my OTL amp and they are not running at what the tube is capable of......plus I already have a couple of pair of NOS EL3N hanging out here, waiting for use.

I also love the look of the mesh rectifier  smile.gif  

So are you getting one for yourself Joe? 😎
post #13915 of 13920
Quote:
Originally Posted by gibosi View Post
 

 

 

Thanks guys. I think my understanding, while still pretty blurry, might be just a bit more clear. At the least, I think I understand that if both my and Whirlwind's amp had the same rectifier, say a HEXFRED, they would still sound different due to the fact that the transformers are different. That is, the two different transformers, one putting out 250 volts, and the other, 265 volts, will position the output tubes at different positions on their curve. And thus a different sound.

 

And it is very interesting to learn that rectifier tubes with the same tube number may well have a different voltage drop. So for example, even though the commonly quoted voltage drop for a 5U4G is 44 at 225ma, the actual voltage drop may well be different between 5U4G produced by different manufacturers. This certainly helps to explain why the 5U4G all seem to sound different.

 

Anyway, while the HEXFRED is still in my amp, I haven't had much time for music the last week or so, and therefore, haven't been able to compare it to my favorite 5-volt tubes. Hope to have more time next week.

 

Cheers


The variation from one 5U4 to the next should be fairly small.  Enough that it would probably be possible to hear that difference in some cases, but not a big change like switching from a 5U4 to a different tube type.  The thing that people tend to overlook more often is the fact that the specified voltage drop on the data sheet is cited for a *specific load* and this is actually represented as a curve (like most things with tubes).  For example my amp's rectifiers drop about 25 volts according to the data sheet, but that's when 175mA of current is being drawn.  The actual current draw the tube sees in my amp is 112mA maximum and that's handled by two tubes with a total capacity of 350mA.  So these tubes are not being stressed very much.  The actual voltage drop in my amp is probably only about 10-15 volts I'm guessing.  The closer you are to the rectifier's maximum output current draw, the more the voltage sags.  Whether or not the tube is capacitor or choke loaded makes a difference too if things weren't already confusing enough.  :)

 

The OTL is a current hungry amp, so voltage sag is more prominent when going from one rectifier type to another due to the heavy load being put on the tubes.  Amps that are current hungry "respond" to rectifier rolling more noticeably than amps with a more petite appetite because the voltage drop is more prominent.

 

This is why the big prominent Rectifier Tube Rolling Thread that dubstepgirl made being on the front page all the time bugs me so much.  That thread is misleading so many people because they don't understand the impressions they are reading are only valid when using the specific amplifier in question from her testing.  Those guys who all flocked to whatever tube she thought sounded best will go out and buy one for themselves and may very likely get a substantially different result in their own amp.

 

Of course you can't actually post something like this in that thread because I fear fire and pitchforks just as much as the next sane person.


Edited by Xcalibur255 - Yesterday at 11:44 am
post #13916 of 13920
Quote:
Originally Posted by lukeap69 View Post
 
Quote:
Originally Posted by whirlwind View Post

I think this amp is a great option, Glenn....I am not interested in powering speakers with it, but damn....this should be wonderful option for planar headphones as well as the HD800 and still have the tube sound and uses the Lundahl transformers, that is a win, win....I like what I have heard from the EL3N as driver tubes in my OTL amp and they are not running at what the tube is capable of......plus I already have a couple of pair of NOS EL3N hanging out here, waiting for use.

I also love the look of the mesh rectifier  smile.gif  

So are you getting one for yourself Joe? 😎

Well, I am very interested.

 

Glenn said he will be tweaking the amp, so will wait and see how it goes.....I am sure Glenn will get it sorted as to how the amp sounds it's best.

post #13917 of 13920
Quote:
Originally Posted by whirlwind View Post

Well, I am very interested.

Glenn said he will be tweaking the amp, so will wait and see how it goes.....I am sure Glenn will get it sorted as to how the amp sounds it's best.

And perhaps cheaper... 😇
post #13918 of 13920
Quote:
Originally Posted by Xcalibur255 View Post
 


.....The closer you are to the rectifier's maximum output current draw, the more the voltage sags.  Whether or not the tube is capacitor or choke loaded makes a difference too if things weren't already confusing enough.  :)

 

The OTL is a current hungry amp, so voltage sag is more prominent when going from one rectifier type to another due to the heavy load being put on the tubes.  Amps that are current hungry "respond" to rectifier rolling more noticeably than amps with a more petite appetite because the voltage drop is more prominent.

 

 

And assuming I understand this correctly...

 

Running a quad of 6BX7 as output tubes, instead of a pair of 6AS7, lowers the amount of current draw by about 80ma. So the amp draws roughly 140ma running 6BX7 compared to roughly 220ma running 6AS7. As most of the tube rectifiers I use are rated at about 250ma, it seems to me that using a quad of 6BX7 results in a good bit more headroom for these rectifiers and I would guess a somewhat lower voltage drop.

 

However, given that amp sounds so different with the 6BX7 compared to the 6AS7, I think there is no way I can determine how much, if any, of the difference I hear might be due solely to a lower voltage drop....

 

Anyway, this is very useful and interesting stuff. Thanks again. :)

post #13919 of 13920

Right on.  Having more headroom is nice, but the only real benefit is for the longevity of the rectifier itself.  I think there is a small benefit in reduced switching noise too with the tube being under less stress, but we're getting into odds and ends at this point.

 

The major take away point of all of this is basically:  you should hear less significant "swings" in sound quality when switching between different types of rectifiers when you are using your 6BX7 setup because of the less demanding load.  A 5U4G can and probably is dropping more than 50 volts when supplying 6AS7 tubes, with the 3DG4 in place it's probably around 20.  Swap in those 6BX7 and I would guess, very roughly, that the drop is around 30 volts with a 5U4G and in the area of 15 or less with the 3DG4.  So you have a spread of 30 volts difference between the rectifiers in the 6AS7 scenario, and a spread of about 15 with the 6BX7.  Using this logic rolling a 3DG4 in while using your 6BX7 should produce a more mild change than it would if you were using the 6AS7.

 

edit:  I have this feeling I'm remembering the values for the 3DG4 wrong, but the example is still fine for the purposes of illustrating the concept.


Edited by Xcalibur255 - Yesterday at 8:27 pm
post #13920 of 13920
Quote:
Originally Posted by Xcalibur255 View Post
 

Right on.  Having more headroom is nice, but the only real benefit is for the longevity of the rectifier itself.  I think there is a small benefit in reduced switching noise too with the tube being under less stress, but we're getting into odds and ends at this point.

 

The major take away point of all of this is basically:  you should hear less significant "swings" in sound quality when switching between different types of rectifiers when you are using your 6BX7 setup because of the less demanding load.  A 5U4G can and probably is dropping more than 50 volts when supplying 6AS7 tubes, with the 3DG4 in place it's probably around 20.  Swap in those 6BX7 and I would guess, very roughly, that the drop is around 30 volts with a 5U4G and in the area of 15 or less with the 3DG4.  So you have a spread of 30 volts difference between the rectifiers in the 6AS7 scenario, and a spread of about 15 with the 6BX7.  Using this logic rolling a 3DG4 in while using your 6BX7 should produce a more mild change than it would if you were using the 6AS7.

 

edit:  I have this feeling I'm remembering the values for the 3DG4 wrong, but the example is still fine for the purposes of illustrating the concept.


With the HEXFREDS there will be 1 volt drop no mater what the draw. Rated at 6 Amps/6000ma at 1200 volts.

This is headroom like no audio tube rectifier.

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