[whirlwind]

Tonight its Snowy White,Joe Bonamassa,Pink Floyd and The Guess Who.
Who says OTLs and easy to drive headphones dont mix?!
Focal Stellia in the house. Big bass,excellent staging for a closed back,with excellent imaging. Very dynamic.Good stuff.

Great cans, great music, great amp = great time!

 

[mordy]

A scary experience but all is well that ends well.
You do get very attached to your equipment and tubes......

 

[2359glenn]

Had a little scare yesterday.

We moved to Dallas for a job and have been looking for a house while living in an apartment complex close to work. Apartment building alarm goes off meaning that there could be a possible fire somewhere. The wife and I grab our dogs, wallet/purse, and car keys. Smelled smoke on the way out.

First thing I thought when we were all outside safe, "Damn...the GOTL and tubes are going to be hard to replace if goes up with the building".

Luckily whatever was burned (they were cooking) had been put out by the tenant in that unit.

I would have built you another OTL at cost if that happened.

 

[Phantaminum]

I would have built you another OTL at cost if that happened.

That’s a comfort Glenn, thanks.

I’m glad it all ended well. And after this we’re in the process of making an emergency bag just for situations like this.

Also, imagine having to send a list to a claims adjuster: 1 x Glenn OTL amp, 4 x ECC35, etc..then receiving a check back for a Little Dot Amp and the pricing of Chinese audio tubes.

 

[2359glenn]

That’s a comfort Glenn, thanks.

I’m glad it all ended well. And after this we’re in the process of making an emergency bag just for situations like this.

Also, imagine having to send a list to a claims adjuster: 1 x Glenn OTL amp, 4 x ECC35, etc..then receiving a check back for a Little Dot Amp and the pricing of Chinese audio tubes.

I know.
The problem lveing in a apartment complex is who knows what morons are in the other units.

 

[leftside]

Tonight its Snowy White,Joe Bonamassa,Pink Floyd and The Guess Who.
Who says OTLs and easy to drive headphones dont mix?!
Focal Stellia in the house. Big bass,excellent staging for a closed back,with excellent imaging. Very dynamic.Good stuff.

Enjoy. I've really been enjoying the Stellia the last few months. I almost lost them to my wife, but managed to get them back once I purchased a nice set of headphones for her. The Stellia have been getting a lot of use this summer with the iBasso DX220. And apparently the DX220 will have a tube amp/module next month...

In theory OTL amps shouldn't be a good match for the Stellia! Their impedances are too similar. But, then I found this post by Glenn:
https://www.head-fi.org/threads/2359glenn-studio.600110/page-1052#post-13749687

 

[L0rdGwyn]

Glenn, other than having the 6/12/25 volt switch, why is it the GOTL is so flexible with different input tubes? Is it the input biasing scheme, or related to having an SRPP output stage?

I know this is not the case for many other amps. For example, using the 6SN7 vs 6N7. I asked Bottlehead if I could sub a 6N7 rather than a 6SN7 in my cathode-follower, they told me it would put a +10V bias on the grid, causing it to draw current and eventually destroy the tube, so we're not doing that.

 

[mordy]

Chanced upon another excellent driver, the National Union 6SL7WGT brown Micanol base from 1953.

There is a single offering on eBay from a Greek seller - I like his description:
"Rare decade 1950 NATIONAL UNION 6SL7WGT Test tube Super strong balanced platinum. rare tubes with oval mica. Platinum Agreed high quality demo tape AVO MK IV Mark An excellent tube, the NATIONAL UNION USA is one of the best available guitars and acoustic tubes. It is also a very complete and unique pipe construction. This tube has a great sound to your amp and guitar sounds very good, perfectly balanced "colorful" harmonious and beautiful clear sound overdrive when pressed. The top of the HI FI AUDIO sound. The best perfect sound."
I guess that the "unique pipe construction" refers to the "umbrella spokes"....
I think that some British tubes use the same type of umbrella spokes.
Come to think of it, all the National Union tubes I have sound great - I hereby nominate National Union as the American GEC!

 

[Phantaminum]

Chanced upon another excellent driver, the National Union 6SL7WGT brown Micanol base from 1953.

There is a single offering on eBay from a Greek seller - I like his description:
"Rare decade 1950 NATIONAL UNION 6SL7WGT Test tube Super strong balanced platinum. rare tubes with oval mica. Platinum Agreed high quality demo tape AVO MK IV Mark An excellent tube, the NATIONAL UNION USA is one of the best available guitars and acoustic tubes. It is also a very complete and unique pipe construction. This tube has a great sound to your amp and guitar sounds very good, perfectly balanced "colorful" harmonious and beautiful clear sound overdrive when pressed. The top of the HI FI AUDIO sound. The best perfect sound."
I guess that the "unique pipe construction" refers to the "umbrella spokes"....
I think that some British tubes use the same type of umbrella spokes.
Come to think of it, all the National Union tubes I have sound great - I hereby nominate National Union as the American GEC!

They’re beautiful sounding tubes and are among my top favorites. Never seen one with the brown base. Interesting on the umbrella spokes, sounds like an Osram/Marconi type build.

 

[2359glenn]

Glenn, other than having the 6/12/25 volt switch, why is it the GOTL is so flexible with different input tubes? Is it the input biasing scheme, or related to having an SRPP output stage?

I know this is not the case for many other amps. For example, using the 6SN7 vs 6N7. I asked Bottlehead if I could sub a 6N7 rather than a 6SN7 in my cathode-follower, they told me it would put a +10V bias on the grid, causing it to draw current and eventually destroy the tube, so we're not doing that.

I think you mean 6AS7 cathode follower? If you use a 6N7 that the two cathodes are hooked together into a single cathode it would short the two channels together.
In my OTL the 6SN7 is a voltage amplifier and the signal is taken off the plates. The 6N7 is not a proper tube with a single cathode.
The adapter used should hook the 6N7 cathode to both 6SN7 cathodes to bias correctly. I don't know never checked one of these adapters or tried a 6N7.
With the single cathode there is possible cross talk between channels but the cathode resistor bypass capacitor should take care of cross talk.
Most people like the sound of the 6N7 even though I have never tried it. It will not heart anything in the 6SN7 socket but don't try it in a 6AS7 socket that will be all bad.

 

[L0rdGwyn]

I think you mean 6AS7 cathode follower? If you use a 6N7 that the two cathodes are hooked together into a single cathode it would short the two channels together.
In my OTL the 6SN7 is a voltage amplifier and the signal is taken off the plates. The 6N7 is not a proper tube with a single cathode.
The adapter used should hook the 6N7 cathode to both 6SN7 cathodes to bias correctly. I don't know never checked one of these adapters or tried a 6N7.
With the single cathode there is possible cross talk between channels but the cathode resistor bypass capacitor should take care of cross talk.
Most people like the sound of the 6N7 even though I have never tried it. It will not heart anything in the 6SN7 socket but don't try it in a 6AS7 socket that will be all bad.

Oh no, not using the 6N7 as the cathode follower, my amp is a 6SN7 input and 6AS7 cathode follower. I cannot use the 6N7 in place of the 6SN7 though according to the designer, but really happy the GOTL can, it just seems so flexible with input tubes. I'll have a few to try when it arrives, everyone hear raves about them. Deyan is fashioning the adapter for me, so I trust him to get it right.

 

[gibosi]

I finally managed to pick up a Telefunken RGN4004 rectifier for a price I was willing to pay. These tend to be pretty expensive. Globe mesh plates manufactured in the late 1930's typically go for more than $500. The somewhat later globes with sheet metal plates manufactured during WWII still command prices in the hundreds of dollars. After the war, Telefunken switched to the ST bottle and while still expensive, every once in a while one shows up for less than $200. And taking advantage of a promotional offer on eBay I managed to get this one for a very good price. It was manufactured in August, 1949 (ym)



The RGN4004 requires an adapter as it is a 4-volt tube. Further, the heater draws 4 amps. Other than the Glenn, I don't know of any other headphone amp that can provide 4 amps to a rectifier. As a result it can provide 300ma of current, a pretty poweful rectifier.

Telefunken rectifiers are among the brightest rectifiers I have ever heard, and to my ears, they match up well with darker drivers, such as the Lorenz C3g. However, up to now, I have been limited to running only four 6BL7 as the two Telefunken rectifiers I have, the AZ12 and WE56, can provide at most 200ma. So I have been waiting very patiently for this rectifier to show up at a good price. And finally, I can run 5998 and the Lorenz.

 

[rosgr63]

Very nice Ken.

 

[Monsterzero]

@leftside

The audiophile gods smiled upon me today. Look what Fred from Lampizator just dropped off at my house!!!

I begged him not to bring me one of their mega buck DACs....He didnt listen. I guess thats why he has his job.
Im terrified to actually listen to this beast,cuz then I will have to buy one...no clue how I will pull that off.

 

[2359glenn]

I finally managed to pick up a Telefunken RGN4004 rectifier for a price I was willing to pay. These tend to be pretty expensive. Globe mesh plates manufactured in the late 1930's typically go for more than $500. The somewhat later globes with sheet metal plates manufactured during WWII still command prices in the hundreds of dollars. After the war, Telefunken switched to the ST bottle and while still expensive, every once in a while one shows up for less than $200. And taking advantage of a promotional offer on eBay I managed to get this one for a very good price. It was manufactured in August, 1949 (ym)



The RGN4004 requires an adapter as it is a 4-volt tube. Further, the heater draws 4 amps. Other than the Glenn, I don't know of any other headphone amp that can provide 4 amps to a rectifier. As a result it can provide 300ma of current, a pretty poweful rectifier.

Telefunken rectifiers are among the brightest rectifiers I have ever heard, and to my ears, they match up well with darker drivers, such as the Lorenz C3g. However, up to now, I have been limited to running only four 6BL7 as the two Telefunken rectifiers I have, the AZ12 and WE56, can provide at most 200ma. So I have been waiting very patiently for this rectifier to show up at a good price. And finally, I can run 5998 and the Lorenz.

I suppose you are using it with the adapter to a 3DG4? That tube will burn up most adapters with the built in resistor.
So how does it sound??