Well, time to start playing around with actual tube circuits. To facilitate this I'm putting together a breadboard using 8 pin octal relay sockets. I'll be able to make rapid circuit changes and hope to also have enough room to make more than one output circuit so I can switch between them for instant sound performance comparisons. I've got plenty of ideas I want to try. I'm going to concentrate initially on themes using 6080's. Film at eleven.

Rob

Have you looked at this one?

Are the 6080s for the low gain and so possible low distortion levels. I have a pair but have never seen any in audio circuits.

Thatch,

The 6080 is the ruggedized version of the 6AS7 dual triode and their claim to fame is about the lowest Rp of any of the power triodes with the exception being the 6C33C recently made globally available from the Soviet military which is like 3 6080's in parallel in one big bottle. These triodes make OTL amplifiers practical. The coveted Atmasphere amp uses a large bank of 14, 6AS7's in a output transformerless monoblock. They apparently sound wonderful. I have an interest in exploring OTL with these triodes. I've just made a deal to puchase a lot of 100 6080's at a good price.

Three 6080's or 6AS7's with the two internal triodes all paralleled gives you Rp=46 ohms, and Pd=78 watts.

Rob

SWEET ! You are "The Man" for sure. I can't wait to see what you come up with. I guess more important will be if I can afford it? :eek:
Or at least, what I will have to beg, borrow or steal to get one. :D

Well I finally got a chance to get working on my breadboard this week and have wired up one output stage to operational status with six 6080 tubes in parallel P-P class A. I coaxed 40 watts RMS out of it today with my developmental homemade toroidal output xfmer.

I might end up with a 40 or 50 watt RMS design using 8 power tubes, 16 power tubes for stereo. Since the power supply is so huge It makes sense to build this first pair as monoblocks I think. Now I gotta find a way to get most of this work bench into a single chassis! :)

Rob

A six pack of 6080's alive on my breadboard. Glo-Man-Glo!

Rob

Sure looking good there Rob. Let me know when you want some cash or need someone to audition a pair.:D

Originally posted by Wardsweb
Sure looking good there Rob. Let me know when you want some cash or need someone to audition a pair.:D

Wards,

It is a little early to even say that this is going to be 'the' amp, but don't worry. You have a place at the front of the line. :)

Rob

Rob our friend Ward is much too far away. I live only a hop, skip and a jump away so I'd be more than willing to audition those tube amps and maybe to buy a couple as well.:D :D

Mike

Nice bench you got there Rob. Is the torroid a step on the way to OPTL or do you just to have to power more of the 6080s up. Nice looking Mil Spec potted PS there.
I have a pair I have been coveting for what was going to be a pair of monos using 6V6s with 6BQ5 OPTs but liked your suggestion of the 6Y6s so much I am going to continue to hide them unde my wifes dresser where no tranformer bandit would ever look untill the English guy designs the OPTs.

Originally posted by Thatch_Ear
Nice bench you got there Rob. Is the torroid a step on the way to OPTL or do you just to have to power more of the 6080s up. Nice looking Mil Spec potted PS there.
I have a pair I have been coveting for what was going to be a pair of monos using 6V6s with 6BQ5 OPTs but liked your suggestion of the 6Y6s so much I am going to continue to hide them unde my wifes dresser where no tranformer bandit would ever look untill the English guy designs the OPTs.

Thatch,

In order to find some more bench space I built that bench recently just for the audio work.

That mil spec potted thigy is merely a 20 amp, 6.3 volt filament xfmer. That only does eight 6080's BTW unless I push it past the nameplate rating. I had 12 of those tubes lit filaments only and they were drawing 30 amps. The wiring has to be thick and short.

I'm wanting to experiment with several topologies with the 6080's. This was one of them. OTL will require even more tubes. I have to win an octal socket lotto first.

Glad you are going for the 6Y6. It looks like the distortion is lower than for the 6V6 or any of the others similar. What is the plan SE, P-P, what class?

Rob

Pro Ac,

I have to thank you for passing the word about a certain Sansui 9090 to Kama who passed the word to me and I ended up buying it from the guy in Hamilton. It is an impressive receiver but ya know what?...My P-P, UL 6CA7 Mullards tube amp sounds WAY better, and I'm trying to better that now too.

What speakers do you have that could benefit from a good tube amp?

Rob

Rob right now I'm on the prowl for an efficient pair of speakers to audition a tube amp with. I'm been looking at some Soliloquy Model 5's but I'm not sure their efficient enough. I don't have the nads to try horns as I keep imaging the horns I hear in a dance club or auditorium. My DQ-10's are available and we'll see what I end up with. Thanks for the kind words re: Sansui 9090. I didn't know you bought that.

Mike

How many octals you want? Pay my gas money and I think they are about $.30 ea used,.40 ceramic but I keep those ,sorry.
That potted monster is only for filament or is that all your using it for?
Unless you have a military recycler their you might want to give me some specs and I will give them to Louis. He would love you! He was in on radar before 1940, smart as whip and has 3 warehouses of military gear. My BUD!!!
That is where I get bathtubs and cool stuff like that. Getting hard to find pairs for monos of chokes and transformers.
The plan for the 6Y6 is is a GE JAN 6Y6GT driver, RCA, Ken Rad etc 6Y6G power. 5V4G rectifier.
A pair of those and the 300B is in the bedroom.
Rob, I really have no idea what all this man has. No-one but he does, but he does have some big stuff that if it falls on you , well to bad. He might have some old parabolics or something cool.
BTW I folded and put in an envelope the 211 article and now can't find it. I hope you are not in a hurry.

Mike,

You are only a hop-skip-jump and white nuckle drive on the QEW away so why not drop by some time to my place and hear my big ass horns. Maybe my compact rear horn design will be tweaked by then too. I discovered they crank pretty loud on a 7 watt 300B SET.

Read my first independent revue of these speakers here from BillF: http://www.audiokarma.org/forums//showthread.php?s=&threadid=1653

Rob

Originally posted by Thatch_Ear
How many octals you want? Pay my gas money and I think they are about $.30 ea used,.40 ceramic but I keep those ,sorry.
That potted monster is only for filament or is that all your using it for?
Unless you have a military recycler their you might want to give me some specs and I will give them to Louis. He would love you! He was in on radar before 1940, smart as whip and has 3 warehouses of military gear. My BUD!!!
That is where I get bathtubs and cool stuff like that. Getting hard to find pairs for monos of chokes and transformers.
The plan for the 6Y6 is is a GE JAN 6Y6GT driver, RCA, Ken Rad etc 6Y6G power. 5V4G rectifier.
A pair of those and the 300B is in the bedroom.
Rob, I really have no idea what all this man has. No-one but he does, but he does have some big stuff that if it falls on you , well to bad. He might have some old parabolics or something cool.
BTW I folded and put in an envelope the 211 article and now can't find it. I hope you are not in a hurry.

Thatch,

I only want to buy new ceramics. That guy Louis sounds like a valuable assett. I'll have to mail you a list. You are right, finding pairs of chokes, power xfmers, etc suitable for monoblocks and stereo chassis is hard now. You can buy new from Hammond if you are rich. I can wait for the 211 article, that is on the waiting list anyhow. All that potted thing is is a 6.3 volt 20 amp, one winding filament xfmer, 115 volt primary. I have 3 identical. Can you believe the first one I put in was faulty?! It was only delivering 5 volts and after a while smoke started to come off one of the output terminals. Glad I have a pair of spares. I'll need one each for the monoblocks unless I find another xfmer. I have an idea that will be more compact though.

Rob

Rob I would love too! PM me your address and number and maybe we can set a date.

Mike