Finally, The First OMA Power Amplifier Has Arrived

[jonathan weiss]

We just put up a section on the Products pages for the first OMA power amplifier, the Parallax PL519.  The Parallax has been a bit more than a year in coming, and the amp is now officially in production. Parallax is a very, very special amplifier. It is a single ended amplifier, and you could call it a SET, but the tube it uses is not a triode, at least as it started out its existence. This tube, the PL519, was a European television sweep tube, of extremely heavy duty construction, which has been used in various ways over the years by designers such as Tim DeParavicini, Allen Wright, and others, usually connected for triode operation.

OMA is not using the PL 519 in triode operation. We are using it in a way which to my knowledge has either never been done commercially with any tube amplifier, or perhaps has just not been done at all- it certainly is not publicly discussed- and which we call Screen Mode. The plate of the PL519 is simply disconnected. It is not used at all. The screen of the PL 519, which is mesh, is now used as the plate. What this in effect gives you is a super heavy duty built mesh plate triode, which sounds superior to ANY triode I have yet heard under ten watts. As this amplifier produces a conservative 2.5 watts output, I'll leave the comparisons to that power level. The signature problems inherent with low power SET amps, such as anemic or non existent bass are gone with the Parallax. The detail, sense of ease, power, correctness of timber, is, to be honest, shocking.

All the iron is custom wound for this amp, and the wiring, if you were to open up the bottom plate, closely resembles German Broadcast tube gear of the 1950's-1960's, such as Klangfilm.

The next rollout of the OMA line of power amplifiers is due out in a few months. It is a very large, two chassis GM70 SET, of approximately 100 kilos in weight, and about 17 watts output.

I think that's it for this year in terms of amplifiers, but there is one more project in the works, to fill the hole between the Parallax at 2.5 watts and the new GM70 amplifier at 17 watts.

Jonathan

[Beau]

So that's where you've been hiding.  Congrats, looks like a nice piece.

I'll contact you offline about getting one with MDF panels and instructions to convert to MOSFETS 

Beau

[Joao]

Hi Jonathan

Congrats for the nice Integrated and a welldone job - to Paul as well. BTW, let me give you a hint: for Europe market you'll need a safety cover for the tubes.

Low bass with small power SET? I won't agree with this because those amps are not well designed. You drive me because I'm working on my power amp as well, a 3.5W with AD1 triode.

Regards
Joao

Edit: text correction

[nl]

Congratulations!

[screenmode]

Parallax PL519

I'm very glad with the knowledge that OMA have been taken the Screen Mode PL519 amplifier into production .
I could write a book about how the amp came alive , but most important of course is , the fact that it deserves
a place between other low powered SET amps in today's market .

I would like to encourage everyone to have a listen to this amplifier whenever possible . it sounds like NO other amp I
have came across . But please let your own ears judge !

Best ,
Paul

[kev313]

That is a very interesting approach!  Looks great.  Looking at the description, however, and seeing the pictures, I recall an earlier statement made by someone...

"Take a look at all the pics on the web of Voight pipes and take a look at the Abby. Same thing, different quality of construction. As I have said before, if people want to drop loads of money for nice wood, finish, that's just fine. That was not my point. Sound is what this board is about, not how fine the sandpaper was that made my speakers, etc. And having built a few of these for friends, for kicks, I can tell you that there is going to be no discernible difference between going to Home Depot and buying a few sheets of MDF and making these in an afternoon, and having the world's greatest woodworking making a pair. If you spent the money and dig the finish, enjoy it, but don't start suggesting there is some voodoo about how you aesthetically detail an enclosure that will make it sound better- that's just silly. If it is solid, well built and non resonant, I really don't think that bobinga or fancy joints, tung oil etc are going to make a difference except how your wife feels about the whole thing."

   Kidding, obviously.  The OMA amps look spectacular.  To be honest, I think (OK, I know) I have a more of an issue with WAF than my wife does sometimes.

[jonathan weiss]

You have a remarkably good memory. Perhaps too good.

I think I'd stand behind most of what you quote me on, even if its taken out of context (I believe the original thread was about building Voight pipes, and my position was that its better to build something out of mdf than not build at all. Perhaps I'm mistaken, though.

Obviously, the presence of solid walnut and beautiful, hand done joinery on the OMA amps does not contribute to their sound, but to the pleasure one has in looking at them, and owning something  beautiful. Very few amps are beautiful objects, even if they sound well.

I would say that I'm converted to solid wood for speakers, though. The intervening years since I wrote what you quoted has seen me change my tune on that score.

Jonathan

[kev313]

Yes..totally taken out of context.  The amps are, indeed, beautiful and I would agree that it is an often overlooked aspect of a component (not referring to vault like enclosures and thick faceplates...plenty of those around). 

I have an off-topic question for you:  I was looking at pictures of the 2006 tasting and saw your SL12 enclosures.  Would you happen to have the dimensions for those?  I have three SL12's in a box in the basement looking for a home.

[jonathan weiss]

Hello Kev,

I believe the enclosures you are referring to were about 6 cubic feet, ported.

Jonathan

[Brent Perkins]

Hi Jonathan,

Just wondering how the GM70 SET is coming along? Any updates or photos you'd be keen to share?

Cheers,

Brent

[jonathan weiss]

I'm in Holland right now, and will be visiting the almost finished amps, which are being made here, on Sunday. They ship to the US and the new OMA showroom in NYC end of January. I might take a pic if I can this weekend and post. Otherwise, it won't be long.

Jonathan

[Brent Perkins]

I'm in Holland right now, and will be visiting the almost finished amps, which are being made here, on Sunday. They ship to the US and the new OMA showroom in NYC end of January. I might take a pic if I can this weekend and post. Otherwise, it won't be long.

Jonathan

Hi Jonathan,

Fantastic. Look forward to the pics.

Enjoy Holland and best wishes to you (and the rest of the forum) for the Feastive Season.

Cheers,

Brent

[Brent Perkins]

Also, I'd really appreciate pricing info for the Parallax and the Phono Amplifier. I'm keen to know pricing for the GM70 SET if available too. Just through private messaging would be fine or my personal email.

Cheers,

Brent