[me2621a]

Interesting. Does the amp allow use of a 12 volt tube in a 6 volt spot (switchable?). I use the same noval to octal adapters on my Encore, but at the same voltage spec. 12SL7 slot, 12AT7.

So fun fact, the 12A_7 family for the most part works at both 6 volts and 12 volts, you can see is this data sheet both 6.3 volts and 12.6 volts are supported: https://www.jj-electronic.com/images/stories/product/preamplifying_tubes/pdf/ecc81.pdf

Not all 12 volt tubes support this, for example the 12SL7 will not work in a 6SL7 slot based on my tests (in my tube tester), and I suspect the data sheet supports that as well. In the Mogwai SE/Bigger Ben I have found the 5751, 12AT7 and 12AX7 sound quite good and as their data sheet suggest support 12 and 6 volts.

 

[vonnie123]

So fun fact, the 12A_7 family for the most part works at both 6 volts and 12 volts, you can see is this data sheet both 6.3 volts and 12.6 volts are supported: https://www.jj-electronic.com/images/stories/product/preamplifying_tubes/pdf/ecc81.pdf

Not all 12 volt tubes support this, for example the 12SL7 will not work in a 6SL7 slot based on my tests (in my tube tester), and I suspect the data sheet supports that as well. In the Mogwai SE/Bigger Ben I have found the 5751, 12AT7 and 12AX7 sound quite good and as their data sheet suggest support 12 and 6 volts.

I didn't realize that. Thanks for the explanation. I have several 12A_7 variants, and never checked the data sheets for that particular substitution.

 

[erics75]

ZMF Pendant amp owners, is your 6CA4 rectifier socket wiggly? The power and input sockets are rock solid, but my rectifier socket has a slight wiggle to it. Nothing huge, but it does let the mounted tube wiggle a bit, light a newly loose tooth. Wondering if it's a problem that needs a trip in for fixing, or if that's normal for the rectifier socket. I did try a few different tubes, same behavior with all tubes.

 

[connieflyer]

Hi me2621a, have been following this thread and thought you might be able to help me. I have a Feliks Audio Euforia, and have rolled Genelax KT88 tubes with great results. Am now using the Russian GU 50 tubes, with 12v transformer, and find after burn in of 80 hours to be superior to any other tubes I have rolled over the years. Started out with a Garage 1217 Ember and rolled tubes got me started, many in between but this FA amp has been the best so far. Was wondering if your present amp has the ability to run the GU 50 tubes? They are dirt cheap $10-15 dollars for NOS and take a while to burn in, but once there they are amazing. Will be try a dual adapter for both power slots with one KT88 and one GU 50 in each power adapter. A friend has the TT21's but I have not found any yet, but the KT88's are similar except for the external connection. Thank you for any thoughts, I really like the Amps ans Sound amps and may upgrade in that direction if the GU 50's can be used.

 

[me2621a]

@connieflyer ,
So I will be honest I have not heard of the GU50. I think my bigger question, before I even dig to deeply into this is, does a socket adapter exist for the GU50 -> KT88/6L6G, if not then that would end my exploration as I would not build one.

As far as the question of will it work, I think that is a question for @ampsandsound directly. All of my roles are approved by him, to ensure I do not before blow up the amp haha. I would first though confirm if their is an octal adapter that maps the pins correctly before we continue.

Also just a thought, the Felix Audio gear is nice, I have not personally listened to it, but given that they are OTL amps (let me know if I am wrong), and A&S amps are SET amps (except for the stereo 15, Casablanca, and Zion which are PP), I would say they are different beasts. You may prefer one over the other, but depending on your taste both could probably live side by side and give different sound and flavors.

Also when you say Genelax KT88s are these new production or UK made?

 

[ampsandsound]

ZMF Pendant amp owners, is your 6CA4 rectifier socket wiggly? The power and input sockets are rock solid, but my rectifier socket has a slight wiggle to it. Nothing huge, but it does let the mounted tube wiggle a bit, light a newly loose tooth. Wondering if it's a problem that needs a trip in for fixing, or if that's normal for the rectifier socket. I did try a few different tubes, same behavior with all tubes.

It’s chassis mounted. The socket floats in a captive holder. The wiggle is just the float of the socket. When the tube is seated the connection is correct. The other tubes are soldered to a pcb as such they have a more fixed mounting. Both are as they should be and appropriate. Hope that helps.

 

[connieflyer]

@connieflyer ,
So I will be honest I have not heard of the GU50. I think my bigger question, before I even dig to deeply into this is, does a socket adapter exist for the GU50 -> KT88/6L6G, if not then that would end my exploration as I would not build one.

As far as the question of will it work, I think that is a question for @ampsandsound directly. All of my roles are approved by him, to ensure I do not before blow up the amp haha. I would first though confirm if their is an octal adapter that maps the pins correctly before we continue.

Also just a thought, the Felix Audio gear is nice, I have not personally listened to it, but given that they are OTL amps (let me know if I am wrong), and A&S amps are SET amps (except for the stereo 15, Casablanca, and Zion which are PP), I would say they are different beasts. You may prefer one over the other, but depending on your taste both could probably live side by side and give different sound and flavors.

Also when you say Genelax KT88s are these new production or UK made?

These are the russian-made tubes. Not the Great Britain made tubes. They have been performing very well in our amplifiers. . The gu 50 tube Does need a special adapter? . These are going to be started producing this month. From mrs. X on eBay. The ones I have were made by a friend of mine. In England. I doubt if they knew adapters would have an LED. Has mine have. But I suppose you are correct. , especially if you're not having heard of this tube that I should direct this directly to ampsandsound. . Sorry to take up some of your time on the thread Just thought you may have. Heard of these or use them

 

[me2621a]

These are the russian-made tubes. Not the Great Britain made tubes. They have been performing very well in our amplifiers. . The gu 50 tube Does need a special adapter? . These are going to be started producing this month. From mrs. X on eBay. The ones I have were made by a friend of mine. In England. I doubt if they knew adapters would have an LED. Has mine have. But I suppose you are correct. , especially if you're not having heard of this tube that I should direct this directly to ampsandsound. . Sorry to take up some of your time on the thread Just thought you may have. Heard of these or use them

Hey don't apologize, I am always excited to hear about new tube types, especially if you think they are better then the New Sensor KT88s which for new production tubes are considered pretty good. Can you link me to Mrs. X's eBay profile so I can keep an eye out for the adapters. In general these tubes look pretty interesting so once an adapter exists assuming there are no concerns about electrical incompatibility I am all for trying them.


***Actually, assuming I am reading this website correctly: http://www.jogis-roehrenbude.de/Russian/GU50.htm the GU50 is 12.6 volts on the heater, the Mogwai, Mogwai SE, and Bigger Ben are all 6.3 volts for the heater, which means the tube is incompatible. I do not speak Russian so I am going off the English translation at the bottom.

 

[erics75]

It’s chassis mounted. The socket floats in a captive holder. The wiggle is just the float of the socket. When the tube is seated the connection is correct. The other tubes are soldered to a pcb as such they have a more fixed mounting. Both are as they should be and appropriate. Hope that helps.

That is exactly what I wanted to hear! Thanks for the quick response, I feel better knowing it's normal. Amazing amp, btw. It's my first high end tube amp and I am still amazed how great it sounds. Makes my solid states sound so so dull....

 

[Astral Abyss]

That is exactly what I wanted to hear! Thanks for the quick response, I feel better knowing it's normal. Amazing amp, btw. It's my first high end tube amp and I am still amazed how great it sounds. Makes my solid states sound so so dull....

I was going to say that mine is the same way. I figured it was due to the mounting employed. It took me a bit also to not freak out over it.

 

[55Powers]

@me2621a how are things going with the new amp?

Wondering: did you ever run the Susvaras on the taps of the Mogwai SE?

 

[me2621a]

@me2621a how are things going with the new amp?

Wondering: did you ever run the Susvaras on the taps of the Mogwai SE?

The new amp is fantastic. It has become my reference amp and I listen to it at least a few hour a day.

As for the Susvara and the Mogwai Se, yes I did. It performed excellently. The bigger Ben and Mogwai SE have the exact same power output. The real difference is the output transformers (twice the size and 5 taps). The larger output transformers provided more detail, space, and bass. Power and Drive were the same though between the two, and I fell for the Susvaras on the Mogwai SE.

I do highly suggest you grab a 5AR4 or solid state rectifier though. I use mullard 5AR4s and they sounds great with the Susvara. 5u4gs work but the Susvara likes the additional power.

 

[55Powers]

The new amp is fantastic. It has become my reference amp and I listen to it at least a few hour a day.

As for the Susvara and the Mogwai Se, yes I did. It performed excellently. The bigger Ben and Mogwai SE have the exact same power output. The real difference is the output transformers (twice the size and 5 taps). The larger output transformers provided more detail, space, and bass. Power and Drive were the same though between the two, and I fell for the Susvaras on the Mogwai SE.

I do highly suggest you grab a 5AR4 or solid state rectifier though. I use mullard 5AR4s and they sounds great with the Susvara. 5u4gs work but the Susvara likes the additional power.

Hehe, yeah I am locked and loaded on 5AR4s / GZ34s, running a Mullard as we speak. It makes the amp "grip"a bit better vs a more relaxed 5u4 to me.

I got myself a Susvara as well, still waiting on my banana adapter.
Very happy with the sound the SE offers on jack, but i am anxious to try the taps out.

Do you ever run other output impedances than 8 into the Susvaras though?

 

[me2621a]

Hehe, yeah I am locked and loaded on 5AR4s / GZ34s, running a Mullard as we speak. It makes the amp "grip"a bit better vs a more relaxed 5u4 to me.

I got myself a Susvara as well, still waiting on my banana adapter.
Very happy with the sound the SE offers on jack, but i am anxious to try the taps out.

Do you ever run other output impedances than 8 into the Susvaras though?

On the Mogwai SE, only the 8ohm, on the Bigger Ben I run it on the 16 ohm and 8 ohm tap depending on the tube compliment. Mostly I run it on the 8ohm in general.

 

[55Powers]

On the Mogwai SE, only the 8ohm, on the Bigger Ben I run it on the 16 ohm and 8 ohm tap depending on the tube compliment. Mostly I run it on the 8ohm in general.

Interesting with the 16. I also really like the 8, that being said, I have only 3 jacks.

What's your fav input tube for the Susvara, still on the ECC35?