[TheMiddleSky]

I'm not familiar with the headphone enough to answer the question. @TheMiddleSky spent some time with tele + susvara before I arrived. Perhaps he can weigh in.

The 64 million question is, how will Susvara sound from Telemachus. An expensive way to find out by getting the amp. I could have just flown to your home.

Do me a favor. Try out Susvara with Telemachus and let me know what you think.

Well personally I'm not big fans of Susvara, so perhaps type of sound that I chase may not same as you. Use Chord TT2 and Mola Mola Tambaqui as DAC, feed Telemachus, to Susvara.

Susvara is kind of bright, airy, sweet, and spacious soundstage. All of these attributes are still there. There are some softness in impact/bite of hifiman's house sound that also, still there. With Solid State Rectifier, Mola-Mola is easily my choice as this DAC provide better control, fuller and denser sound through all spectrum, even though not as wide as TT2.

Personally, I would only purchase Telemachus for Susvara, if it comes with Tube Rectifier. Soundstage is slight narrower compared to SS Rectifier, but the additional weight, density, and smoothness to the sound really impressed me (especially how organic is at the Midrange area).

For my own headphones (Meze Elite and ZMF Verite), I think I prefer the SS Rectifier, but for Susvara, it is the opposite.

Telemachus easily beats out some solid state amplifiers such as Formula S/Powerman, Ferrum Oor/Hypsos and Burson GT/Supercharger when drive Susvara. The overall weight, the spacious of soundstage, the clean notes in all spectrum, and the natural organic presentation of Tele is some levels above.

 

[audiargent]

Do you guys end up using output impedance switch in your builds?

I definitely use it for the HE-6SE. Like that I get around 9W into 60 ohms in ultralinear.

 

[UntilThen]

Well personally I'm not big fans of Susvara, so perhaps type of sound that I chase may not same as you. Use Chord TT2 and Mola Mola Tambaqui as DAC, feed Telemachus, tp Susvara.

Susvara is kind of bright, airy, sweet, and spacious soundstage. All of these attributes are still there. There are some softness in impact/bite of hifiman's sound sound that also, still there. With Solid State Rectifier, Mola-Mola is easily my choice as this DAC provide better control, fuller and denser sound through all spectrum, even though not as wide as TT2.

Personally, I would only purchase Telemachus for Susvara, if it comes with Tube Rectifier. Soundstage is slight narrower compared to SS Rectifier, but the additional weight, density, and smoothness to the sound really impressed me (especially how organic is at the Midrange area).

For my own headphones (Meze Elite and ZMF Verite), I think I prefer the SS Rectifier, but for Susvara, it is the opposite.

Telemachus easily beats out some solid state amplifiers such as Formula S/Powerman, Ferrum Oor/Hypsos and Burson GT/Supercharger when drive Susvara. The overall weight, the spacious of soundstage, the clean notes in all spectrum, and the natural organic presentation of Tele is some levels above.

Thanks for the feedback and I can appreciate that everyone has preferences. I like the HiFiMan's sound as evidence from my journey with Arya, He1000se and Susvara. Variety is good though and that's why I had been through most of Audeze's range and some ZMF. As funds permits, there could be another headphone later but I'm pretty contend with living with Susvara now.

It's also my preference to use tube amps with Susvara, particularly Odyssey where the texture fills out. However not everyone thinks so. Many in the Susvara thread still thinks that solid state amps is perfect for Susvara. To everyone their own I guess.

First time I heard about Mola-Mola dac. A quick google shows it's a giant ocean fish. It's a AUD$18,450 price tag from Netherlands.

 

[UntilThen]

I think the best values are the tubes that were left behind in the quest for ever more power. The classic in that regard is the 300b. It was a super obscure, antique tube all the way into the mid 90s until Dennis Had released his Cary 300b amp. Well, I say obscure, it was forgotten about in the US but the Japanese loved it. A large percentage of 300b and practically all the older 300a tubes ended up in Japan before the Americans caught on.

Of course those aren’t inexpensive tubes but I think the concept still holds true with pentodes/tetrodes/whatever. Guitarists and hifi manufacturers were always after more power. As manufacturers brought out things like the KT88, 6550, and 6l6gc the older 6l6, 6l6g, ga, and to a lesser extent the gb were pretty much forgotten about. They are still readily avilible and reasonably priced though starting to rise. The 807 and gbg6 are even less expensive versions of those older tubes.

The other ways to find deals is to use other heater voltages. I love my 12v tubes! I also have an 11n7 that has promise and I might explore the old British 4v tubes in the future.

So yeah, I’m not congratulating myself overly secretly lol. I’m getting amazing sound without having to spend a lot on any particular tube. Though they do add up lol.

I had my time with 6.3v, 12.6v and 25.2v with GOTL for the drivers. 6bx7 and 6336 tubes provides interesting variations on that amp, besides 6as7g, 6080 and 5998.

Not forgetting c3g.

It's interesting to experience these tubes to get an idea of their sonics.

My venture into pentodes started with the Elekit 8200. That's when I started thinking of a custom amp for pentodes as strapped triodes.

 

[Isaacc7]

I had my time with 6.3v, 12.6v and 25.2v with GOTL for the drivers. 6bx7 and 6336 tubes provides interesting variations on that amp, besides 6as7g, 6080 and 5998.

Not forgetting c3g.

It's interesting to experience these tubes to get an idea of their sonics.

My venture into pentodes started with the Elekit 8200. That's when I started thinking of a custom amp for pentodes as strapped triodes.

I’ve been listening to all of the tubes I talk about as single ended pentodes. Pentode operation can be a little trickier to design/build for. You really need regulated screen supplies and have your feedback game on point. Judicious use of local, global, cathode, whatever feedback is necessary and isn’t the easiest thing to design. When done properly pentode operation sounds great. Feedback isn’t a bugaboo, most amplifiers can benefit from at least some. Local feedback (feedback done to the tube without involving the entire output stage) is generally seen as less problematic than global feedback. Strapping pentodes as triodes can be seen as 100% local feedback and ultra linear is some percentage, usually 40%.

My new amp will run the tubes in either triode or ultra linear. Not all tubes can/should be run in ultra linear so it‘s important to do your homework before flipping that switch. It’ll be interesting to see how much or if the characteristics of the tubes changes when run as a triode.

 

[senseitedj]

I’ve been listening to all of the tubes I talk about as single ended pentodes. Pentode operation can be a little trickier to design/build for. You really need regulated screen supplies and have your feedback game on point. Judicious use of local, global, cathode, whatever feedback is necessary and isn’t the easiest thing to design. When done properly pentode operation sounds great. Feedback isn’t a bugaboo, most amplifiers can benefit from at least some. Local feedback (feedback done to the tube without involving the entire output stage) is generally seen as less problematic than global feedback. Strapping pentodes as triodes can be seen as 100% local feedback and ultra linear is some percentage, usually 40%.

My new amp will run the tubes in either triode or ultra linear. Not all tubes can/should be run in ultra linear so it‘s important to do your homework before flipping that switch. It’ll be interesting to see how much or if the characteristics of the tubes changes when run as a triode.

This is a rather noob question, but how do you tell from inspecting the tube's datasheet that its suitable to be run as triode/ultra linear?

 

[gibosi]

This is a rather noob question, but how do you tell from inspecting the tube's datasheet that its suitable to be run as triode/ultra linear?

If you see a mu reading on the datasheet, then triode strapping was likely considered in the design. In the end, strapping it yourself and then listening is probably the best way.

 

[Isaacc7]

This is a rather noob question, but how do you tell from inspecting the tube's datasheet that its suitable to be run as triode/ultra linear?

Technically I guess any pentode/tetrode *could* be run in ultra linear but some just don’t make any sense. When you run a tube in pentode mode the screen grid receives a constant voltage. Ultra linear applies a percentage (usually 40%) of the output voltage on to the screen via the output transformer. You can think of it as a variable/partial triode mode. More modern tubes designed around audio like the el34, 6l6gc, and kt88 have pretty robust screen grids so if you run them at the recommended plate voltages the screens can handle the subsequent voltage. Check out the data sheet fore the 6l6gc:

http://www.tubebooks.org/tubedata/HB-3/Receiving_Tubes_Part_2/6L6-GC.PDF

PP class A1 max ratings are 500v on the plate and a whopping 450v on the screen. Compare that to the 6dq6:

https://frank.pocnet.net/sheets/093/6/6DQ6B.pdf

While the plate can handle an absurd amount of power (it’s hard to know what to use for audio since it was not designed for it) the screen can only handle 150v. If you wanted to try this in ultra linear you’d have to keep the plate voltage down so that 40% wouldn’t be more than 150v. Not much point in using this tube that way if you’re going to gimp the tube like that.

Incidentally, running a tube in triode still requires you to pay attention to the screen grid max voltages. “Strapping” a pentode into a triode usually means connecting the anode and screen grid together so there are now only 3 electrical grids in the tube. Since the voltage is shared between the plate and screen you can usually apply more than you could to just the screen but that varies wildly from tube to tube. For reasons I don’t understand, some screen grids are “greedy” and will soak up more voltage than others. So for example the 6aq5 could be run at 285v in triode (though I’m not sure I trust that) vs. a max of 250v on the screen as a pentode. Apparently you can run a 2e26 at 300v in triode despite the 200v max on the screen with normal operation.

Edit: just cleaned up some typos and hilarious autocorrect issues

 

[Isaacc7]

If you see a mu reading on the datasheet, then triode strapping was likely considered in the design. In the end, strapping it yourself and then listening is probably the best way.

All tubes have a mu (amplification) specification. Best to heed the screen limits. If you have to ask if the tube can be run as a triode and at what voltage and you can’t find info from people that have done it before odds are you shouldn’t be trying it. If you want to try anyway, start at the screen grid voltage and slowly ramp up the voltage. Hopefully you have a clear glass tube so you can see if the screen and/or plate start glowing before it’s too late.

 

[jonathan c]

All tubes have a mu (amplification) specification. Best to heed the screen limits. If you have to ask if the tube can be run as a triode and at what voltage and you can’t find info from people that have done it before odds are you shouldn’t be trying it. If you want to try anyway, start at the screen grid voltage and slowly ramp up the voltage. Hopefully you have a clear glass tube so you can see if the screen and/or plate start glowing before it’s too late.

…from this

to this…

 

[gibosi]

All tubes have a mu (amplification) specification. Best to heed the screen limits. If you have to ask if the tube can be run as a triode and at what voltage and you can’t find info from people that have done it before odds are you shouldn’t be trying it. If you want to try anyway, start at the screen grid voltage and slowly ramp up the voltage. Hopefully you have a clear glass tube so you can see if the screen and/or plate start glowing before it’s too late.

Yes, of course all tubes have a mu specification. But not all datasheets provide this value. For example, the C3g datasheet provides this value and the recommended strapping practice. That tube was designed to perform very well as a triode-strapped pentode. On the other hand, none of the 6AK5 datasheets I have seen provide this value. And yet, the inexpensive Little Dots were designed around the triode-strapped 6AK5. Further, a bunch of us strapped many similar small 7-pin pentodes, as drivers, with no adverse affects.

But obviously, if you are thinking about strapping power pentodes as output tubes, it is best to follow Isaacc7's advice.

 

[UntilThen]

My tubes for Odyssey are :-

KT88, EL34, 6550, KT66, EL12 spez, 807, EL39, KT77, EL156.

They are all safe to run as triode strapped pentodes. I don't need anymore. I have tubes coming out of my ears.

My drivers are either 6SL7 or EL11. On the advice of Tomas, I only switch to UL for EL11. There's also a feedback switch which make UL quieter. I don't use UL mode much because the power in Odyssey from triode mode is sufficient to drive Susvara well. Triode mode is also sweeter sounding to my ears.

Someday I might buy a pair of KT150 or KT170 but I do not feel like chasing tubes anymore.

 

[LoryWiv]

My tubes for Odyssey are :-

KT88, EL34, 6550, KT66, EL12 spez, 807, EL39, KT77, EL156.

They are all safe to run as triode strapped pentodes. I don't need anymore. I have tubes coming out of my ears.

My drivers are either 6SL7 or EL11. On the advice of Tomas, I only switch to UL for EL11. There's also a feedback switch which make UL quieter. I don't use UL mode much because the power in Odyssey from triode mode is sufficient to drive Susvara well. Triode mode is also sweeter sounding to my ears.

Someday I might buy a pair of KT150 or KT170 but I do not feel like chasing tubes anymore.

Curious if you've ever tried 6V6 in driver position, some wonderful 6V6G and GT are out there and still affordable...

 

[UntilThen]

Curious if you've ever tried 6V6 in driver position, some wonderful 6V6G and GT are out there and still affordable...

Nope. I have very specific instructions from Tomas about what tubes I can use and 6v6 is not one of them. Those are power tubes I use in Studio Six. Incidentally I still have a pair of Fivre 6v6 coke bottle shape. Not sure what I'm going to do with those tubes now.

 

[Isaacc7]

Curious if you've ever tried 6V6 in driver position, some wonderful 6V6G and GT are out there and still affordable...

Odyssey requires triodes for input tubes. The 6v6 is a pentode. In theory you could triode strap them and use a pair for each side as long as the power supply could handle it. But that’s a lot of fuss. Especially when it is so much easier to use great sounding twin triodes.

I have seen preamps that use triode strapped 6v6 as their tubes. If you are going to go down that path also look at the 6aq5. They are the same as a6v6 but in a smaller bottle. They are slightly downrated for power but they sound amazing and are even cheaper than the 6v6