[jtwrace]

Other then the Transcendent Audio OTL amp are there any other DIY OTL amps? 

The Transcendents look interesting but the cost seems really high.  I mean, I could purchase a used Atma-Sphere for what they cost. 

[Wayne1]

I noticed a thread on diyAudio.com where Ralph from Atma-Sphere gives his schematics for the M-60 MKII.3.

DIY M-60 MKII.3 OTL

A BOM and revised DIY schematics are also in the thread.

The ballpark parts cost for a single mono-block would be in the $1500.00 area.

It would be less expensive to buy used but by going the DIY route you can customize the amp just for your purposes.

[FullRangeMan]

A hot insider at Atma-Sphere said they may release again the Novacron 6C33 OTL KIT, maybe this 2010 year. It is a small number of kits tough.
Gustavo

[jtwrace]

A hot insider at Atma-Sphere said they may release again the Novacron 6C33 OTL KIT, maybe this 2010 year. It is a small number of kits tough.
Gustavo

What do you think the rough cost would be?  If you had to guess...

[FullRangeMan]

What do you think the rough cost would be?  If you had to guess...

I do not know this info, but I would like to know it too.  A friend of mine told me about this NovaCron Kit info afew months ago.
So I just phoned him now, he was changing email with Mr.Ralph Karsten himself, about the NovaCron Kit, the kit was not avaliable
at the time(late 2009), maybe now the situation changed.
You could emailed to Mr.Karsten, I read the various reply from Mr.Karstern to my friend and I was surprised to see Mr.Karsten is a gentleman
and huge patience to explain 6C33 tube details to a layman as my pal.
Cheers,   Gustavo

[Wayne1]

Very interesting about the 6C33 kit. In the thread about the DIY build, Ralph goes into great detail about the "problems" using a 6C33 in OTL. Specifically the huge amount of heat generated by the tube. So much that he says the tube sockets need to be replaced at least every 350 hours because of pin failure. He also talks of the wire insulation melting off near the filament pins.

[FullRangeMan]

What do you think the rough cost would be?  If you had to guess...

Responding your question:   IF I had to guess the price, as the Novacron OTL is a monoblok 60W 8ohms four 6C33 tubes per channel I could say a adequate price could be around 2.5K dollars for a complete kit(two amps set).
Gustavo

[jtwrace]

Bad News from Ralph:

We have thought about the Novacron again but the project, with everything we have learned in the 15 years since it went out of production, is daunting. To start with it violates a basic ethic we have: don't build equipment for tubes that are not being made. The factory that made the 6C33 got torn down about 7-8 years ago.

[FullRangeMan]

Very interesting about the 6C33 kit. In the thread about the DIY build, Ralph goes into great detail about the "problems" using a 6C33 in OTL. Specifically the huge amount of heat generated by the tube. So much that he says the tube sockets need to be replaced at least every 350 hours because of pin failure. He also talks of the wire insulation melting off near the filament pins.

Yes, the 6C33 is a hot tube, as a double triode it have four heater pins, it is too much pins and all the 7 pins are all close to each other creating electrical interactions when that white cheap ceramic socket is used.
A Yamamoto or Parts Connexion teflon socket is recommended.
Gustavo

[FullRangeMan]

Bad News from Ralph:

We have thought about the Novacron again but the project, with everything we have learned in the 15 years since it went out of production, is daunting. To start with it violates a basic ethic we have: don't build equipment for tubes that are not being made. The factory that made the 6C33 got torn down about 7-8 years ago.

This is not problem per se.   There is millions of this tube stocked in Siberia, the Russian army use alot of 6C33 tubes.
IF I had a 6C33 amp, I would buy about twenty spare 6C33 tubes or more to stock it for my amp.

[zybar]

This is not problem per se.   There is millions of this tube stocked in Siberia, the Russian army use alot of 6C33 tubes.
IF I had a 6C33 amp, I would buy about twenty spare 6C33 tubes or more to stock it for my amp.

6C33 also have a fairly high failure rate from what I remember reading.

That being said, it is a great sounding tube.  My Audio Mirror amps use a pair per each mono block.  If I didn't have my Atma-Sphere amps, I would be using the Audio Mirror amps.

George

[atmasphere]

Very interesting about the 6C33 kit. In the thread about the DIY build, Ralph goes into great detail about the "problems" using a 6C33 in OTL. Specifically the huge amount of heat generated by the tube. So much that he says the tube sockets need to be replaced at least every 350 hours because of pin failure. He also talks of the wire insulation melting off near the filament pins.

750 hours is what the Russian spec sheets call for. In practice, seems you get about 5000-7000 hours out of the socket before you really start thinking about replacing them.

The problem is that the filament connections are under-rated on the socket and will overheat, even if there is no B+ on the tube. You can improve things by using forced-air...

[FullRangeMan]

750 hours is what the Russian spec sheets call for. In practice, seems you get about 5000-7000 hours out of the socket before you really start thinking about replacing them.

The problem is that the filament connections are under-rated on the socket and will overheat, even if there is no B+ on the tube. You can improve things by using forced-air...

Once I read in the JACMusic or Yamamoto Site the 6C33 need a heavy gauge wire in the Anode pin to heat dissipation.
Gustavo

[FullRangeMan]

6C33 also have a fairly high failure rate from what I remember reading.

That being said, it is a great sounding tube.  My Audio Mirror amps use a pair per each mono block.  If I didn't have my Atma-Sphere amps, I would be using the Audio Mirror amps.

George

I see the AudioMirror Site, they are great looking amps.  I could not complaint IF I had one of these babies.
Do you think they are well made underside??
Gustavo

[JoshK]

I've seen mention of folks wrapping the filament wire around the filament pin to help dissipate the heat.  Don't know from experience if that would work.

[jtwrace]

My Audio Mirror amps use a pair per each mono block.  If I didn't have my Atma-Sphere amps, I would be using the Audio Mirror amps.

George

Knowing how much you love your Atma's, that's saying a lot.  That good huh?