[Rossliew]

I made the EL3n amp as a alternative to the expensive 45 and PX4 tubes.
The EL3N is only $35 in the US vrs 100s for 45s and PX4s.
I think it sounds close to these best sounding tubes.
Might make a amp EL3N driven by a C3g maybe the most transparent tube made.
And a amp that just uses one C3g or C3m per channel will still be 1.5 watts per channel.
Cant think of any other tubes that sound as good maybe the 2A3 or 6A3 will sound as good
and put out a little more power.
There is also the 46 a odd tube that can be used in place of a 45 with the right adapter.
But the 46 is a little less power 1.1 watts.

The only thing holding me back from building these experimental amps is quality
Lundahl transformers cost $1000 to build a amp. Allot of money to spend on a experiment.

The EL3N driven by a C3G sounds promising and not too costly. I'm all for good sounding tubes that don't cost an arm and a leg

 

[Xcalibur255]

You have the adapter?
I looked this up it says 22ma for class A operation.
https://frank.pocnet.net/sheets/029/4/46.pdf

Yep, you made adapters for this with the amp.

Isn't the grid voltage pretty different from a 45? Or does that "adjust" itself in the circuit? The curves also look wacky at the 45 operating points, but I have never been able to figure out if I'm reading them right or not.

 

[Xcalibur255]

The EL3N driven by a C3G sounds promising and not too costly. I'm all for good sounding tubes that don't cost an arm and a leg

If cost control and a compact chassis are goals I think shooting for a single stage C3g or C3m would be a good idea. We could probably meet or beat the performance of the one Yamamoto Soundcraft makes for a lot less money.

If I don't get laid off next year I would still be tempted to ask Glenn to build me a single stage Emission Labs 30A amp. The culmination of everything I've learned about this hobby over the years suggests to me this might be the top rung on the ladder if the very best transformers and parts were used. The big unknown is what the tube itself sounds like since very few people have built projects with them. I have a hunch it doesn't sound all that different from a 45, just has more gain and output. Those were EML's goals for the design after all.

 

[Xcalibur255]

All the recent talk about the 45 got me thinking that I hadn't listened to the type 76 in over a year. I remember loving the tone of these RCA type 76, and sure enough, matched with a Valvo AZ12 and four Tung-Sol 6BX7, they are every bit as good as I remember, and even better.

I didn't know you could run 76s in your amp. That's pretty cool. I wouldn't have thought you could sub a single triode in place of a twin triode like that.

 

[Xcalibur255]

With regard to a 45 amp, another thing to consider is the availability of this tube. To my knowledge, there are no modern 45s being made. Further, the older and more coveted globe versions are quite scarce and obtaining a matched pair can be expensive. Perhaps Tyrell will comment further...

Finding good ST type (coke bottle) 45s isn't that hard, though the price is creeping up year by year. Finding good globes, ones that are strong and don't have noise issues, is a challenge. The latter point is the big one. You can buy tube after tube and they'll have some kind of hum or buzz because fact of the matter is they're over 80 years old and the physical/mechanical condition of the tube affects it's sonics. This is why I've thought about trying the EML 45 despite the eye watering price. People say they're better than NOS 45 tubes and for that price they should be.

I got lucky (ish) when I got my KenRad globes. The sound is head and shoulders above the newer ST 45s, and when I first got them they were quiet and didn't have any issues with bias drift (important for a manual bias amp like mine). Sadly one of them has developed noise issues over the last year. It's not enough to ruin enjoyment of the music, but the buzzing sound is very much there whenever a track ends.

I think if one were very serious about building a top class 45 amp they should consider the cost of a pair of EML 45s to be part of the budget, or submit themselves to the gambling experience that is buying really old direct heated triodes and hoping they're not junk when you power them up.

edit: sorry for the thread spamming folks.

 

[Rossliew]

Love the conversations here, learning a lot just from reading posts here

 

[gibosi]

I didn't know you could run 76s in your amp. That's pretty cool. I wouldn't have thought you could sub a single triode in place of a twin triode like that.

Like you, I have a Glenn OTL with a single 6SN7 socket. A couple years ago, I asked one of the eBay vendors to build an adapter to allow two 76 to be plugged into a single 6SN7 socket. In terms of bias, it is my understanding that they are relatively comfortable in a 6SN7 socket, and to my ears, this pair of RCA sound better than a grey-glass RCA 6SN7GT.

 

[2359glenn]

Yep, you made adapters for this with the amp.

Isn't the grid voltage pretty different from a 45? Or does that "adjust" itself in the circuit? The curves also look wacky at the 45 operating points, but I have never been able to figure out if I'm reading them right or not.

The grid voltage adjusts with the bias pot in your amp. That is how it changer the current through the tube by adjusting the grid voltage.

 

[2359glenn]

If cost control and a compact chassis are goals I think shooting for a single stage C3g or C3m would be a good idea. We could probably meet or beat the performance of the one Yamamoto Soundcraft makes for a lot less money.

If I don't get laid off next year I would still be tempted to ask Glenn to build me a single stage Emission Labs 30A amp. The culmination of everything I've learned about this hobby over the years suggests to me this might be the top rung on the ladder if the very best transformers and parts were used. The big unknown is what the tube itself sounds like since very few people have built projects with them. I have a hunch it doesn't sound all that different from a 45, just has more gain and output. Those were EML's goals for the design after all.

I do think the EML30A is the best choice for a single tube amp.
Will have to build one of these in the next year. Maybe with a switch like the EL3N amp has with and without a driver stage.
Problem finding a driver good enough without going to a EML20A. A C3g will have to much gain for this and don't think a 6SN7 sounds good enough to use.

 

[2359glenn]

At 599 a pair for the 30A at Tubes USA is not that bad.
Paid more for 1 300B.

 

[Xcalibur255]

Yeah, I see that the 30A isn't the one Jac recommends for output stage use, but it looks like the only one with enough gain to use in a single stage design. There's also the question of how flexible it would be in terms of voltage swing. Could it power a wide range of headphones and impedances? EML claims the distortion on these tubes is almost non-existent so I'm sure it would sound nice.

 

[leftside]

Glenn, how many 300B amps have you made? I honestly don't know how you managed to get a tube amp to sound so clean and airy with such super tight bass.

I see a few people mentioning a hum with this amp. With some rectifiers I can also hear it, but it is very, very quiet and it has to be at night for me to hear it. I certainly can't hear it when music is playing - even quiet music. I also recently purchased a used McIntosh MC205 amp. This is a highly regarded amp, but in my system the transformers generated a humming noise and I could hear buzzing/old modem like sound through the tweeters. The previous owner swore it was quiet in his system. The transformer hum was fixed with a Blue Circle RPD-15.

I took the MC205 into my (very good) tech and he said the amp is superb and has an extremely quiet noise floor, but is susceptible to RF noise. He added RF filters and now all is good.

So, sometimes it can be your environment causing these noises, and not necessarily the equipment, though some equipment can be more susceptible. My older McIntosh MC7270 (from 1982) is dead silent in the same room without any mods.

 

[2359glenn]

I made about 10 of them very simple circuit the less parts the better.
And the C3g driver is a great sounding tube + Lundahl transformers are about the best.
Karagon says that the hum is from the power transformer vibrating the chassis being picked up by the tubes that are slightly microphonic.

 

[2359glenn]

Yeah, I see that the 30A isn't the one Jac recommends for output stage use, but it looks like the only one with enough gain to use in a single stage design. There's also the question of how flexible it would be in terms of voltage swing. Could it power a wide range of headphones and impedances? EML claims the distortion on these tubes is almost non-existent so I'm sure it would sound nice.

The data sheet says that output power is 3 watts more then a 45.
I think it will work good if it don't work can switch to the 20B

 

[leftside]

Only 10. Wow.

Your explanation would explain why I've found some rectifiers worse than others.