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2359glenn | studio - Page 739

post #11071 of 14425

Have a nice weekend guys, I'm happy!

 

post #11072 of 14425
Quote:
Originally Posted by whirlwind View Post
 

What is a nice set of 6080 tubes that works well in Glenns OTL.


I would suggest the Chatham 6AS7G copper rod version over just about any 6080 tube.  It depends alot on which headphones you want to drive too of course.

post #11073 of 14425
Quote:
Originally Posted by Xcalibur255 View Post
 


I would suggest the Chatham 6AS7G copper rod version over just about any 6080 tube.  It depends alot on which headphones you want to drive too of course.

+1

 

Of my stash of  6as7 the Chatham/Tung Sol are best. Only the GEC are better.  But never used them since all my cans are low Z so the 6336 are always in my OTL.  

post #11074 of 14425
Quote:
Originally Posted by Xcalibur255 View Post
 
Quote:
Originally Posted by whirlwind View Post
 

What is a nice set of 6080 tubes that works well in Glenns OTL.


I would suggest the Chatham 6AS7G copper rod version over just about any 6080 tube.  It depends alot on which headphones you want to drive too of course.

 

I will be using the Senn HD 800 as my headphone

post #11075 of 14425
Quote:
Originally Posted by Xcalibur255 View Post
 

The transformer Glenn uses is much beefier than what you see in most amps, probably twice as much so.  This is why we can use all the lesser known rectifiers that pull more than 3 amps of heater current and can use the current hungry 6336 tube.  With the 5998 more than doubling the gain of the amp it brings out this hum that is normally inaudible.  A small drawback that is outweighed by the superior performance of the tube IMO.  Unless the phones are very sensitive the hum should be slight, if it's a loud hum then maybe you have bad 5998 tubes which are extremely microphonic due to poor mechanical damping.

 

Following up on your comment about microphonics, checked each of them and managed to find two that are pretty quiet. Much better. But it does seem that I have 5 of these tubes I can't use... :(

post #11076 of 14425

Yeah the 5998 is a very "picked over" tube now.  The prices they sell for are absurd considering how questionable the stock being sold is.  I thought they were absurd when I was paying $150 for my pairs just a couple of years ago and I was able to get tubes that were actually NOS.  Didn't stop one of them from shorting and blowing up my AKG K701s though.......


Edited by Xcalibur255 - 3/13/15 at 4:29pm
post #11077 of 14425

I have read somewhere that the 7236, with an amplification factor of 4.8 and transconductance of 12,500, is more similar to a 5998 than it is to a 6080. If so, does this tube also benefit from being run in the 5998 mode?

post #11078 of 14425

I'm going to defer to Glenn's superior knowledge on this one.

 

The internal resistance is probably different so it will draw different current than a 5998 will under the same conditions.  Speaking strictly in terms of ratings I believe the tube can handle more current but there are a couple of different facets to how that's determined.  I think it's probably fine but my knowledge is limited so take me with a grain of salt.

post #11079 of 14425
Quote:
Originally Posted by Xcalibur255 View Post
 

I'm going to defer to Glenn's superior knowledge on this one.

 

The internal resistance is probably different so it will draw different current than a 5998 will under the same conditions.  Speaking strictly in terms of ratings I believe the tube can handle more current but there are a couple of different facets to how that's determined.  I think it's probably fine but my knowledge is limited so take me with a grain of salt.

 

Quote:
Originally Posted by Xcalibur255 View Post
 

I'm going to defer to Glenn's superior knowledge on this one.

 

The internal resistance is probably different so it will draw different current than a 5998 will under the same conditions.  Speaking strictly in terms of ratings I believe the tube can handle more current but there are a couple of different facets to how that's determined.  I think it's probably fine but my knowledge is limited so take me with a grain of salt.


I don't know without doing some math that I am not going to do right now.

Dinner is cooking

In my first OTL I tried a Sylvania 7236 and did not like them they were run as

a 6AS7 so I sold them. They were pretty tubes so I was able to sell them

for what I paid. Never tried one again.


Edited by 2359glenn - 3/17/15 at 1:47am
post #11080 of 14425
Quote:
Originally Posted by gibosi View Post
 

I have read somewhere that the 7236, with an amplification factor of 4.8 and transconductance of 12,500, is more similar to a 5998 than it is to a 6080. If so, does this tube also benefit from being run in the 5998 mode?


Sorry, this maybe a dumb answer but why don't you run them in both modes & see which sounds better. It is my experience that if a setting is not optimal for a tube it will not sound good or will sound less better.

post #11081 of 14425

Yes, in the end, my ears will decide. Still, I would like to know if the calculations suggest that the 5998 setting is optimal. And further, I want to know if the current draw increases as this will determine if the GZ32 stays in the amp.

post #11082 of 14425
Quote:
Originally Posted by punit View Post
 


Sorry, this maybe a dumb answer but why don't you run them in both modes & see which sounds better. It is my experience that if a setting is not optimal for a tube it will not sound good or will sound less better.


The primary issue isn't whether or not it sounds good, but whether or not the 7236 is okay to operate at the higher current level.  There's a possibility of running the tube over its ratings and dramatically shortening its usable lifespan.  6080 type tubes also tend to........ behave badly in some cases when pushed hard, revealing shorts and other nasties that stay hidden when run more conservatively.  This is the main reason why Woo and others run them conservatively, it cuts down on customers complaining of weird behavior but it also results in inferior sonic performance.

post #11083 of 14425

A couple of the "pin-guides", or whatever they are called, are a bit loose in one of the 6AS7 sockets. It does make it a bit more difficult to pull out tubes, but otherwise, perhaps it is not a serious problem? However, I am wondering if there is a way to tighten these so that they don't pull out like this? 

 

 

post #11084 of 14425

For me I tend to like ceramic sockets better and less likely to have loose pins in my experience. Plastic could get a bit soft when working with warm tubes before complete cool down.


Edited by john57 - 3/18/15 at 3:04pm
post #11085 of 14425

I have been very busy at work lately and have no time listening at home and moved Glenn's amp to my office today.  Now either I'm rocking with Glenn's amp or on crappy headset on WebEx. 

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