Wanting To Learn About Tube Amps

[mhardy6647]

Discrete and no op amps are two (very) different parameters.
Just sayin'.
... and, again, vacuum tube op amps are pretty straightforward to implement.
Analog computers could be (more or less) full of them in the days when transistors were not the norm.

source: https://www.allaboutcircuits.com/textbook/semiconductors/chpt-8/operational-amplifier-models/

 

[CuteStudio]

There's lots of good resources on the web to learn about tubes:
E.g: https://tubecad.com/

Tubes are more linear, but higher voltage. Because of their linearity, I guess, in general fewer are required, and less GNFB can be used - which again means fewer are needed.
Also tubes have to amplify more, a 1V input may be 450V at the output tube's anode, and a 450V B+ rail can result in 900V swing due to the inductance of the OPT primary (OPT = OutPut Transformer).

But in general, they are similar to design as transistors - IMO - but they are all NPN - no PNP in tubes
My favourite tube amlpifier I designed myself, using the parts of a Sweet Peach cheap chinese single-ended amplifier, using cheap (but very good) russian GU50 tubes.

My design is fairly unique in that the OPT is not within the GNFB loop. Thorsten Loech write about this, so I tried it, and decided it was indeed, far better. This allows tight feedback between driver triode and output pentode - and results in a huge, expansive sound (currently shaking the sofa with Laura Marling's 'Wild One'). It's about 20Wpc into regular 86dB/Watt speakers (Kef B139/B11-/T27(ish) and it sounds good with avery genre.

Single ended = fewer tubes too. I have one input tube, dual triode ECC88, into 6N2P (two tubes in SRPP) and two power tubes.
PushPull needs a phase splitter, two drivers and then four power tubes - lots more tubes.

I can recommend you get a copy of LTSpice and some tube models from Diyaudio, and play with some circuits.

Currently I'm using LTSpice to play with a push-pull idea (as I have the hardware - another China amp) on the same principles as my single ended: no feedback around the transformer - a pet goal of mine since I heard it - In this case 3 small tubes 2 power tubes per channel: I may need a separate heater transformer

It's possible I also like tubes because they are easier to DIY, assuming one doesn't die of electrocution. point to point wiring requires no PCB
Incidentally when taking apart an old Pioneer transistor amp I found 100V across the big caps - so it's not just tube gear to be careful with, always measure, and add bleed resistors if not fitted ! I actually add LEDs in mine, so there's a light on if there's > 12V around.

 

[Spkrdctr]

I, also - and FWIW* - don't like wearing headphones at all.
Besides which: Listening to loud sound using something up against - or in - one's ears sounds like a recipe for hearing loss sooner rather than later, since the damage is cumulative (edit: and irreversible).

_______________
* which ain't much, especially in the context of the thread's topic.

I have headphones too and they are my last "go to" for listening to anything. I use them when I must, meaning the wife says "Do you want to use your headphones"? That is code for put your headphones on- NOW. LOL

 

[raindance]

Take a look at Glassware Audio / tubecad. There's a lot of educational stuff on the forum there and you can buy circuit boards to build stuff.

 

[MattHooper]

This is the gear. I bought it used. So the Output tubes are not OEM. But, the Rectifier and Diver tubes are. So know I need to learn about tubes to find out what kind of Equivalent tubes do to sound. Purchased from TMR Audio.

That’s a nice looking little tube amp! How’s it going?

I’m a big fan of tube amps, and I’ve been using mostly tube amps since the 90s in my set ups (also the occasional solid state amp, but I always go running back to tubes).

When people ask why the interest in tube amps, obviously it’s going to depend on the individual. Some people like building them (not me). Some people just think they’re cool and don’t really look for a “tube amp” sound.

Most people on this site are looking for strictly neutral gear, where they don’t want to think about “the sound of the gear.”

But there are plenty of audiophiles, like me, who do you like to play with “ the sound of the gear.”

So for me with that respect, I find solitude amplification to be pretty boring. Audible neutrality was a solved issue a long time ago, so they’re all going to sound the same when used properly and there’s nothing really new to encounter.

When I was in introduced to tube amplifiers back in the 90s it was like “ a new frontier has opened up for exploration.” And given the huge variety of design in terms of tube amplifiers (and how they interact with all sorts of different designs), there’s a possibility of an almost never ending landscape to explore in terms of different sounds.

So that’s how I have had fun through the years. My workhorse tube amplifiers are Conrad Johnson premier 12 tube monoblocks, which at 140 W of push pull power, they’ve been able to drive every loudspeaker I’ve owned for the past 25 years.

I’m actually late to tube rolling myself having only really started several years ago, but I’ve been loving that too. So much fun. But as others have stated also expensive! But I’ve got all the tubes I need to roll and I don’t need to purchase anymore.

If a newbie audiophile came to me, asking for advice, I would not direct them to tube amplifiers, especially given the expense in the performance to price ratio versus solid state.

However, if that person was “tube curious” there’s nothing wrong with that if they want to go down that route and educate themselves.

Some people just find tube amplifiers more fun or compelling, so let 1000 flowers bloom IMO.