advances in tube amp design?

[rick57]

Great! Thanks for all the info, these are the kind of things I thought must be out there.

It’ll take quite a while to digest, and longer to evaluate.

Advanced tube amp shortcut (I’m more of a speaker guy), expecting little likelihood:
are any of the good new approaches at present available in a kit??

Thanks

[jeff mai]

Originally posted by rick57
these are the kind of things I thought must be out there.

What things are you talking about? There was one list of ideas that are clearly more complex than the old designs, but that's no indicator of progress which is what you are seeking.

[leadbelly]

Originally posted by rick57
Advanced tube amp shortcut (I’m more of a speaker guy), expecting little likelihood:
are any of the good new approaches at present available in a kit??

There's a LOT of kits out there. Maybe you should state what your expectations are, i.e. why you are looking to buy a "new approach" amp? Do you just like the idea of having a cutting edge gadget if for no other reason (nothing wrong with that IMO by the way)? Do you expect cost to be lower with some sprinkling of silicon in the design? Do you expect that it must necessarily sound better with new designs? Do you expect it to last longer because shorter life components have been substituted out?

[Kent Smith]

Sorry if I sounded overly negative, but I had to get it out of my system.... There is some good stuff out there.... but a lot of snake oil too. You guys are right, capacitors in the old stuff have to be replaced. Components are better now.

Andy; I LOVE those new Svetlana 6N1P's. VERY lively sounding. I liked them so much, I just built a PP amp with those in the output stage! No more than a couple watts, but sounds good. Those old 6S4A's are very nice for cheap power too (I have some).

[Kent Smith]

PS: one more comment; it IS encouraging to me that good old fashioned do-it-yourself is still around! For some reason, I thought it died with Heathkit. Until I started looking around the net, I thought nobody did this stuff anymore. Thank God for you people. There are still people who are willing to look past the commercial compromises and find out what really works. Never let that flame die!

[DigitalJunkie]

I don't think there's a whole lot new in the tube world...
There may have been a few "refinements" over the years,as we learned more about transformers,components,etc..
I think now theres a lot of 'relearning' going on..I think alot of the tube information kinda died off,now people are digging it up,and relearning it all over again..

Components have certainly become better,and there are things available now that weren't around back then...Now you can use SS devices as slaves to the tubes,and come up with CCS's,simple B+ delay circuits,and other things like that..Not to mention reliable SS rectifiers.

There's been a few new ideas tossed around,battery biasing with Ni-cd cells or other similar things with zener diodes,etc.

Also some companies are making "new" tube types,Like the Sovtek 12AX7LPS,with low-hum spiral filaments,like a 7025...
Not really new a tube,but atleast a new variant..(and I kinda like them)

But the basics remain the same.. Circuits are still pretty much the same,Some of the parts have become better (caps),or there might be minor tweaks (B+ delays,bias monitoring,etc) but it's pretty much all the same.. Whatever works

[amperex]

The new tube amp kits are better than most vintage amps.

Modern higher-end coupling capacitors are superior to every vintage capicator I ever auditioned if one likes clean & transparent sonics.

The internet is a boost to the DIY tube audio crowd.

I believe it is a great time for tube audio, however best squirrel away older tubes for supporting your favorite tube amp. Older quality tubes will be used for trading for other tubes in the future.

[jeff mai]

Originally posted by amperex
The new tube amp kits are better than most vintage amps.

Typically, the circuits used in new kits are older than the circuits used in vintage amps you've compared them to.

[rick57]

Thank you for all your replies, some of which took a while to write (it will take me a while to read all the links).

The thing that strikes me the most is the depth, intelligence and plain good nature of the posters here. Someone once said to me that most people in the wine trade (small wineries, of which there are quite a number here in Australia) are “good people”; it seems the same with tube people.

This gives me a little extra incentive to jump camp from the SS world.

It may have appeared that I was keen to do a “new approach”. (Partly what triggered my thinking was seeing Dynaco clone kits for sale). I don’t mind an old approach if eg there are no new designs have been done that take advantage of the better quality components etc to refine the design, maybe from motor run polypropylenes, triode output stages.

Whatever gives the most dynamics and the cleanest mids and treble. Budget is probably max $US 1200 for a two channel 20 w power amp, preferably less say $1000.

It seems many of the components have improved, except notably the tubes.

** I just remembered an experience from a while back, that at the back of my mind triggered the original post:
I compared three amps through very good Osborn made Focal speakers.
- well regarded Bryston 4B - 3rd on sound quality
- Audio Research of a quarter the power - 2nd, and
- Lowest powered but unusual Audio Aero’s Capitole - 1st .

The difference between AA – AR, seemed more than the difference AR – Bryston.

From www.audioaero.com/
“50 W Class A special push-pull configuration leans on the very musical E34L triode wired, supported all the time by the powerful KT88 pentode.”

I recall (a little dimly now) that the Audio Aero had an unusual topology, that they claimed someone had tried to do in the 1950s, and failed. Maybe wrong, but I think it was this amp that operates SET up to a certain watts, then switches automatically into pentode mode.

Anyone heard the AA Capitole (different topology to the less expensive AAs)?

andy what is CCS?

Jeff
> Typically, the circuits used in new kits are older than the circuits used in vintage amps you've compared them to.
Why would that be?

Cheers

[jeff mai]

Originally posted by rick57
Jeff
> Typically, the circuits used in new kits are older than the circuits used in vintage amps you've compared them to.
Why would that be?

Because most of the available and popular kits are grounded cathode SET amps. This is the configuration of the first amplifier ever made. Most vintage amps are of the PP Ultralinear topology - a much later development.