With any of the American tubes like the RCA 6AS7G, you need to give it 3 days and 3 nights of preconditioning to prevent it from arcing in the amp. Also, its a lot happier with 5 ohm cathode resistors to prevent current hogging. The Russian and Chinese tubes seem OK with only 24 hours of preconditioning.
Thks Atmasphere. I need to purchase a bunch of 5 watters and a nice big 110 transformer for the floating supplies.( 1 big step down 220/110 will do nicely to supply 2 full individual bridges)
Your forum name is just a coincidence right or are you are rep of the company?
I'm trying to figure out from the schematic I have how you incorporate the dc offset balance controls.
Your forum name is just a coincidence right or are you are rep of the company?
I'm trying to figure out from the schematic I have how you incorporate the dc offset balance controls.
The V4 driver tube controls the bias on the power tubes, so when you are setting up the DC-Offset for the amp, you are changing parameters on V4.
We used to have a kit years ago but we discontinued it when we found that some people were selling assembled kits as if they were assembled here. On confronting one guy about this (who fancies himself a reviewer and has built an audio review website), he got nasty and began doing his best to defame us. It seemed too much hassle, and that was the end of the kits. We do think about doing it again, the idea being that we would use sheet metal that was unique to the kit, so there would be no mistake.
I remain an advocate of DIY (even though it may not be best for business), I like to tinker myself now and again
Hi all,
Sorry it's not Atmasphere or Trancendent products, but DIY design using 4x6080WA per block, for a "mighty" 20Wrms/8ohms... a pic of one block :
OTL amps are worth the trial, indeed.
A+!
Sorry it's not Atmasphere or Trancendent products, but DIY design using 4x6080WA per block, for a "mighty" 20Wrms/8ohms... a pic of one block :
An externally hosted image should be here but it was not working when we last tested it.
OTL amps are worth the trial, indeed.
A+!
For sure. I'm trying to work on a slightly different driver topology.
The circlotron design has been used by many companies and I'll be using this concept in my amp.
Nice work.
Unfortunately there will always be someone who copies original designs. Just look at the chinese market. The cars for example. Some striking resemblance to the well known manufacturers?
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Hello,
I made some bench trials with a 6080 duet in circlotron configuration, with 2 floating (tube) regulated power supply : unfortunately it didn't compete with the standard SEPP 6080 duet OTL circuit, both in performance and reliability, so that's why I left the circlotron circuit. But may be some of you are luckier !
Another drawback, IMHO and as a result of my several circlotron trials, is that the power supply transformer and the PSU are somewhat critical : it needs to be built with quality requirements close to an output transformer, because all the losses seems to be in parallel with the load. A way to arrange this a bit is to have 2 PSU transformers, but it doesn't do real miracles with standard quality Xfos, and then there is another drawback (for me) : the size and the mass of the unit increases... But it may not be a big problem for much of you all, often akeen to afford titanesque amps !
A+!
I made some bench trials with a 6080 duet in circlotron configuration, with 2 floating (tube) regulated power supply : unfortunately it didn't compete with the standard SEPP 6080 duet OTL circuit, both in performance and reliability, so that's why I left the circlotron circuit. But may be some of you are luckier !
Another drawback, IMHO and as a result of my several circlotron trials, is that the power supply transformer and the PSU are somewhat critical : it needs to be built with quality requirements close to an output transformer, because all the losses seems to be in parallel with the load. A way to arrange this a bit is to have 2 PSU transformers, but it doesn't do real miracles with standard quality Xfos, and then there is another drawback (for me) : the size and the mass of the unit increases... But it may not be a big problem for much of you all, often akeen to afford titanesque amps !
A+!
You might want to take another look at that- if you build a Circlotron properly it is extremely reliable! I've built amps with custom transformers and also surplus parts- the really serious requirement for the transformer is that it be able to handle the current without serious sag as power is increased. Beyond that they have been very non-critical.
I've actually built amps with no filters in the output section power supply at all (they hummed of course but a lot less than I expected); from the sound of your post I am thinking there was some sort of error in your circuit. My guess is it has something to do with the way the regulated supplies were set up.
I've run dead shorts on the output of the amp with the amp at heavy clipping (I do this as a demo at shows), pulled tubes out while the amp was playing music (I do that at shows a lot too), stuff like that and the amp acts as if nothing is going on at all. The circuit, IOW is unconditionally stable- stable with any load and any input condition. I doubt any SEPP would stand up to that...
I've run dead shorts on the output of the amp with the amp at heavy clipping (I do this as a demo at shows), pulled tubes out while the amp was playing music (I do that at shows a lot too), stuff like that and the amp acts as if nothing is going on at all. The circuit, IOW is unconditionally stable- stable with any load and any input condition. I doubt any SEPP would stand up to that...
Cool
Cool
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I'm looking for a new transformer to power the floating supplies.
My idea is to use 1 transformer for each channel but to have 2 individual full wave bridges running from the same secondary.
I believe this is entirely possible and should have no ill effects on the floating supply.
Just trying to figure out the mas amperage I should go for.
What would be the max current each 6080 triode could pull in this design?
Shall we say around 150mA from the data sheet?
So 4 in parallel: 150 * 8 = 1.2 amps
add headroom so may be 2.5-3 amps at 160- volts AC ?
I calculate a 40 volt drop with 1.2 amps draw from 160 volt secondary giving me a nice 120 volts for the B+.
NO thats wrong.You must have TWO SEPARATE secondary per Transformer( for One channel M60 OTL Circlotron Amp),each secondary(110v/1,5-2A)conected to OWN bridge rectifier which resulting in TWO-independent-floating 140VDC supply.(110VACx1,41=141V DC).Thats is Floating Supply requirments for output power stage.But for only four 6080 Circlotron output stage tube(6as7g,6h13c)only 0,75-1A for EACH 110V secondary.
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I don't quite understand why you would need 2 secondaries. They would still be supplied by the same primary.
The form I mentioned they are still 'floating' in terms of DC and have completely separate full wave bridges.
Maybe 'Atma-sphere' used separate trans just for power advantages/performance/control.
Separate secondary is`must`for Balanced Bridge (Circkotron)power stage. Think You stel not understand this topology(concept) complete ..visit this great NET site:Circlotron history page ,there you well find many explanation/theory,Circlotron is so easy....Good Luck
I am not sure what is difficult to understand in the term 'separate'. The power supplies need to be separate, for the same reason primary and secondary need to beseparate - i.e. have no common electrical connection AT ALL. Separate and floating supplies in your context means that you can put any voltage between point A in one supply and point B in the other (A and B being + or - DC output or indeed any voltage inbetween) subject only to the breakdown voltage of the insulation between the separate secondaries or separate transformers.
For 'fun' draw your supply with independent bridges from the same secondary and then see what happens if you do the above - say, put 50V between the negative terminals of the two 'independent' DC supplies (hint: shorts through diodes modulated by the mains frequency). In a circlotron, the output voltage appears connected between the two floating supplies, so guess what would happen if they were not fully independant.
In other words, you have not fully analyzed the situation, usually a great way to make smoke out of electronic components (although it sometimes happens even when you do fully analyze the situation
).
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Your explanation was helpful thanks, but your comment was insulting! Not necessary really.
2 different trannies for each channel.
This will work out expensive. 4 trannies for 2 channels.
thxs bannat. then I could probably use a couple of step down trannies which are common. 220-110 @200-300 watts
2 different trannies for each channel.
This will work out expensive. 4 trannies for 2 channels.
thxs bannat. then I could probably use a couple of step down trannies which are common. 220-110 @200-300 watts
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Yes it is litlle expencive,but dont forget: there is No OPT(output power trans.)on chasis which is more expencive than surplus 220/110v step down trans
.And Tube OTL Circlotron Amps sounds are something unique and exclusive and noncomparable with OPT based PP Amps.All the bestThxs banat.
Yep looking forward to getting this going. Main reason to start this project was due to total lack of OPTs in this country. You can't even buy power toroidals.
Lots of surplus step downs here removed from old USA fridges and stuff as we have 220v and everything is imported. (mostly from china now) but in the old days from the USA with 110volts.
Keep you updated. On the search for power trannies now. And waiting for 5 more 6080s to arrive in the mail from Canada. Hope customs don't grab them.
Yep looking forward to getting this going. Main reason to start this project was due to total lack of OPTs in this country. You can't even buy power toroidals.
Lots of surplus step downs here removed from old USA fridges and stuff as we have 220v and everything is imported. (mostly from china now) but in the old days from the USA with 110volts.
Keep you updated. On the search for power trannies now. And waiting for 5 more 6080s to arrive in the mail from Canada. Hope customs don't grab them.
I'm using two Hammond toroidal transformers for the main HT supplies for my circlotron; one per channel. Each transformer has a pair of 117V windings, which is just fine for getting the two separate HT supplies.
Surely Hammond, or other, toroidal transformers must be available, via internet order, where you are?
Chris
Surely Hammond, or other, toroidal transformers must be available, via internet order, where you are?
Chris
Your explanation was helpful thanks, but your comment was insulting! Not necessary really.
2 different trannies for each channel.
This will work out expensive. 4 trannies for 2 channels.
thxs bannat. then I could probably use a couple of step down trannies which are common. 220-110 @200-300 watts
You actually only need two transformers, each with a pair of high voltage secondaries. Toroids in this application can work quite well, line born noise can be blocked with common mode inductors on the primary and if desired on the secondaries as well. (A few mH of common mode inductance will do the job nicely.)
Amplimo, Plitron, Antek, Talima, and many others make suitable toroids. Antek toroids are just fine for this application and are quite inexpensive, shipping costs to the UK might be an issue. Antek - Your reliable source of transformers, power supplies, and more.
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