Sc-opt
@Anders,
Like you I am drawn to the design of Ari Polisois, his ideas appeal to me, it's like I just have to build me this amp. Sometimes I doubt if it is a good amp and am inclined to build a more conventional amp.
The only thing that puzzles me about Ari's SC-OPT's, with the special tertiairy winding they are designed for more "headroom". But when I read the spec's on Ari's site -3dB frequency range is 40 Hz to 35 kHz. The bass does not seem to extend very deep, whereas a commercial design like the Almarro 318B claims a frequency range from 10 Hz to 30 kHz.
Since you have listened to many amps, I would like to ask you if the Simplex is lacking bass in the real world or only on paper?
The Duplex is much better in that respect with a bass extending to a claimed 5 Hz, but I do not trust the "negligble crosstalk" between the two channels, not audible from 3 metres lsitening distance but measurable at -20 dB.
So I was wondering what your opinion is if you compare the Simplex to other designs. To help me make a choice and start me building.
I am also wondering in general, what the other builders experience regarding the heat this great looking tube produces.
I read on "Jogi's" site that Klaus who built a lot of amps with these tubes, had a way of mounting them, so that they ran about 70 degrees Celcius cooler. He called this the chimney effect, he mounted the tube sockets on a subchassis fixed to the housing. The tubes protruded through the housing through a hole bigger than the diametre of the tubes, so that air could pass from the bottom of the amp past the tubes and out of the housing, in fact like a chimney. You can see it on some pictures on the website.
@Anders,
Like you I am drawn to the design of Ari Polisois, his ideas appeal to me, it's like I just have to build me this amp. Sometimes I doubt if it is a good amp and am inclined to build a more conventional amp.
The only thing that puzzles me about Ari's SC-OPT's, with the special tertiairy winding they are designed for more "headroom". But when I read the spec's on Ari's site -3dB frequency range is 40 Hz to 35 kHz. The bass does not seem to extend very deep, whereas a commercial design like the Almarro 318B claims a frequency range from 10 Hz to 30 kHz.
Since you have listened to many amps, I would like to ask you if the Simplex is lacking bass in the real world or only on paper?
The Duplex is much better in that respect with a bass extending to a claimed 5 Hz, but I do not trust the "negligble crosstalk" between the two channels, not audible from 3 metres lsitening distance but measurable at -20 dB.
So I was wondering what your opinion is if you compare the Simplex to other designs. To help me make a choice and start me building.
I am also wondering in general, what the other builders experience regarding the heat this great looking tube produces.
I read on "Jogi's" site that Klaus who built a lot of amps with these tubes, had a way of mounting them, so that they ran about 70 degrees Celcius cooler. He called this the chimney effect, he mounted the tube sockets on a subchassis fixed to the housing. The tubes protruded through the housing through a hole bigger than the diametre of the tubes, so that air could pass from the bottom of the amp past the tubes and out of the housing, in fact like a chimney. You can see it on some pictures on the website.
Banned
Joined 2002
Ditto,
I did find this from a member on another forum tho
No opt's needed!
Information • DIY Audio Projects Forum
Hi Lawbadman,
They can be ordered in Europe from a host of suppliers like Tribute, Lundahl, AE-europe, Hammond has them I think, a number of German suppliers.
You can even order them custom wound, with EI or C core, there is also a supplier on ebay, if you search for "6c33c output transformer" you find them, dirt cheap at $60.00 a piece, since I have never seen these in real life, I cannot judge the quality.
But the saying goes, you get what you pay for, on the other hand, I also listen to a ready built Chinese EL 34 SE amp which I bought for $150,00, maybe it has crappy OPT's, but it sounds great.
Better not open these things up for fear of what you find, what you don't know doesn't hurt you
They can be ordered in Europe from a host of suppliers like Tribute, Lundahl, AE-europe, Hammond has them I think, a number of German suppliers.
You can even order them custom wound, with EI or C core, there is also a supplier on ebay, if you search for "6c33c output transformer" you find them, dirt cheap at $60.00 a piece, since I have never seen these in real life, I cannot judge the quality.
But the saying goes, you get what you pay for, on the other hand, I also listen to a ready built Chinese EL 34 SE amp which I bought for $150,00, maybe it has crappy OPT's, but it sounds great.
Better not open these things up for fear of what you find, what you don't know doesn't hurt you
Banned
Joined 2002
Ari Polisois D.C.M.B.
Hello, Midlife,
It's great there are more people how are interested in Ari Polisois design, I found by chance a website in which he told how the design worked this was when I was pretty new to tubes/valves it seemed promising. I soon forgot it but after visiting a friend who owns a bunch of BAT VK150 and then I fell in love with the sound of the 6C33 tube on my way home I remembered Ari's page. I have now lived with this amp for almost two years now, wow how time flies.
I will try to answer as best I can to your questions.
Yes, the way you have doubt, I also have my doubts to about it but this is a good amp and it has been many times while I collect components I changed my mind and was going to build a more conventional SE amplifier. But I just went on trusting my gut feeling and today it feels right.
I can understand you are wondering about Ari's description of the frequency spectrum but I do not miss anything in the bass. If you want a deeper bass you should probably look at Ari's SC-SCC, according to Ari it will be a notch or two better in the bass and soundstage. If I build an DCMB again it will be with the SC-SCC OPT.
I dont understand the question about the duplex can it be that you mean SC-SCC OPT?
You want me to convince you to build an amplifier of Ari's design. What are your gut feeling? Do you dare to take a risk to try something new, if you answer yes to the questions, go for it!
Maybe I should tell you how it differs to other amplifiers. Now it's very subjective what we are listening for, but once I had played for a while on the amplifier I tried my EL84 SE amplifier I realized very quickly there where lots of details missing. DCMB amplifier takes up the details in the music in a way that I have not heard before without being intrusive, it's flow. Imagine the best tube amp you have heard and add a dimension that's DCMB.
Others who have heard my DCMB amp is impressed by how it sounds, most comments I get is how well it takes up the smallest details and how hard it is not tapping theres feet. I listen to very different music styles, and yet I have not been disappointed.
These tubes can get very hot and you must ensure that there is very good ventilation, I thought that I had good ventilation in my top plate, but it was not so. I keep on to improving ventilation with a brand new box where I can install a fan if I want to. I'm waiting for my new top plate to be water-cut so I can re-assemble my amp again.
If you built with the SC-OPT be aware they weight 6.6kg each and SC-SCC weights much less with two main transformers the weight adds on quickly.
Get in touch with Ari, he is really nice and helpful he will help you with more technical issues.
Anders
Hello, Midlife,
It's great there are more people how are interested in Ari Polisois design, I found by chance a website in which he told how the design worked this was when I was pretty new to tubes/valves it seemed promising. I soon forgot it but after visiting a friend who owns a bunch of BAT VK150 and then I fell in love with the sound of the 6C33 tube on my way home I remembered Ari's page. I have now lived with this amp for almost two years now, wow how time flies.
I will try to answer as best I can to your questions.
Yes, the way you have doubt, I also have my doubts to about it but this is a good amp and it has been many times while I collect components I changed my mind and was going to build a more conventional SE amplifier. But I just went on trusting my gut feeling and today it feels right.
I can understand you are wondering about Ari's description of the frequency spectrum but I do not miss anything in the bass. If you want a deeper bass you should probably look at Ari's SC-SCC, according to Ari it will be a notch or two better in the bass and soundstage. If I build an DCMB again it will be with the SC-SCC OPT.
I dont understand the question about the duplex can it be that you mean SC-SCC OPT?
You want me to convince you to build an amplifier of Ari's design. What are your gut feeling? Do you dare to take a risk to try something new, if you answer yes to the questions, go for it!
Maybe I should tell you how it differs to other amplifiers. Now it's very subjective what we are listening for, but once I had played for a while on the amplifier I tried my EL84 SE amplifier I realized very quickly there where lots of details missing. DCMB amplifier takes up the details in the music in a way that I have not heard before without being intrusive, it's flow. Imagine the best tube amp you have heard and add a dimension that's DCMB.
Others who have heard my DCMB amp is impressed by how it sounds, most comments I get is how well it takes up the smallest details and how hard it is not tapping theres feet. I listen to very different music styles, and yet I have not been disappointed.
These tubes can get very hot and you must ensure that there is very good ventilation, I thought that I had good ventilation in my top plate, but it was not so. I keep on to improving ventilation with a brand new box where I can install a fan if I want to. I'm waiting for my new top plate to be water-cut so I can re-assemble my amp again.
If you built with the SC-OPT be aware they weight 6.6kg each and SC-SCC weights much less with two main transformers the weight adds on quickly.
Get in touch with Ari, he is really nice and helpful he will help you with more technical issues.
Anders
Last edited:
Banned
Joined 2002
Banned
Joined 2002
These are still available,
600OHM SE AUDIO OUTPUT TRANSFORMER FOR 6C33C,6AS7 - eBay (item 330431899698 end time May-19-10 08:31:47 PDT)
600OHM SE AUDIO OUTPUT TRANSFORMER FOR 6C33C,6AS7.
But to find a main's transformer x 2 and schematic this would work with.
All this work together ?
Sorry for doubble posting, starting to gather parts
600OHM SE AUDIO OUTPUT TRANSFORMER FOR 6C33C,6AS7 - eBay (item 330431899698 end time May-19-10 08:31:47 PDT)
600OHM SE AUDIO OUTPUT TRANSFORMER FOR 6C33C,6AS7.
But to find a main's transformer x 2 and schematic this would work with.
An externally hosted image should be here but it was not working when we last tested it.
All this work together ?
Sorry for doubble posting, starting to gather parts
@lawbadman
Here comes the link to Ari's site Polisois audio amplifiers and transformers: designing and building audio amplifiers and output transformers
And fore the schematic http://www.polisois-audio.com/documenti/Simplex and Simplex Redux .pdf
But the schematic are updated to this http://www.polisois-audio.com/documenti/Duplex double ended_6C33C-B_RRR.pdf minus two tubes in my amplifier.
Anders
Here comes the link to Ari's site Polisois audio amplifiers and transformers: designing and building audio amplifiers and output transformers
And fore the schematic http://www.polisois-audio.com/documenti/Simplex and Simplex Redux .pdf
But the schematic are updated to this http://www.polisois-audio.com/documenti/Duplex double ended_6C33C-B_RRR.pdf minus two tubes in my amplifier.
Anders
Banned
Joined 2002
Anders,
Thank you very much for your elaborate reply, I think this was the little push I needed to convince me that I might be on the right track. You say it like it is, my gut feeling with this amplifier is that it might be something really special. But since it uses some novel approaches, it is regarded as "strange", that is why you are inclined to build something more conventional, proven if you will. By Duplex I mean the amplifier which uses the SC-SCC OPT, Ari himself called it the Duplex. I might go for that since it seems to have a bass normally associated with solid state amps.
About the temperature I can only guess that most builders are not familiar with the amplifiers made by Klaus Barton from Germany, he mounts the tube sockets on a subframe which is mounted underneath the chassis, this way he creates a natural flow like in the chimney of a fireplace. His measurements showed that this decreased temperature by as much as 70 degrees. When he covered the chimney opening and let the cooling rely on holes drilled in the chassis, as used by most, the temperature quickly rose.
I will keep you posted about future developments.
Thank you very much for your elaborate reply, I think this was the little push I needed to convince me that I might be on the right track. You say it like it is, my gut feeling with this amplifier is that it might be something really special. But since it uses some novel approaches, it is regarded as "strange", that is why you are inclined to build something more conventional, proven if you will. By Duplex I mean the amplifier which uses the SC-SCC OPT, Ari himself called it the Duplex. I might go for that since it seems to have a bass normally associated with solid state amps.
About the temperature I can only guess that most builders are not familiar with the amplifiers made by Klaus Barton from Germany, he mounts the tube sockets on a subframe which is mounted underneath the chassis, this way he creates a natural flow like in the chimney of a fireplace. His measurements showed that this decreased temperature by as much as 70 degrees. When he covered the chimney opening and let the cooling rely on holes drilled in the chassis, as used by most, the temperature quickly rose.
I will keep you posted about future developments.
Midlife,
You will not be disappointed when you are finished.
Ari has a nice way to name his amplifiers Simplex is a tube per channel, duplex two (duo) tubes then we have King who has everything and the new one Big, Fury, Spartan how I do not know anything about.
It is a unique way to solve the problems that exist in SE amplifiers. I have read in many forums some negative opinions about the design but it is the people who may not understand how it works. It tends to be negative opinions about new solutions to get acceptance and old designs feel more secure because then they know what they get.
I have read what Klaus Barton writes about the tube is an interesting solution and is easy to apply but I had already built my amp I have chosen another method of massive slots and immersed tube bit to get proper ventilation. The tube can reach a temperature of 280 C if you can get it a bit cooler you can get longer lifespan. Another thing to keep in mind have some space between the tubes around 6-10 cm, so they do not warm up each other. I held my hand once over one of the tubes and I could feel the air flow, but I have not measured how hot they get but I will do it when the amplifier assembled next time.
Do you have a link to Kalus Barton it seems that it has disappeared.
I have pictures of a Duplex with the SC-SCC that Ari has built, I hope that Ari does not get angry because I show them. The amplifier in the pictures is no beauty in design but it shows how it looks. Maybe you even get more determined to build an Duplex SC-SCC.
Anders
These are still available,
600OHM SE AUDIO OUTPUT TRANSFORMER FOR 6C33C,6AS7 - eBay (item 330431899698 end time May-19-10 08:31:47 PDT)
600OHM SE AUDIO OUTPUT TRANSFORMER FOR 6C33C,6AS7.
But to find a main's transformer x 2 and schematic this would work with.
An externally hosted image should be here but it was not working when we last tested it.
All this work together ?
Sorry for doubble posting, starting to gather parts
The operating voltage and current shown in that schematic don't look right for a 600ohm transformer.
Last edited:
@jleaman,
Jeb-D noticed correctly about the voltage, the 6C33C doesn't like voltages that high.
A guy that has written a lot about this tube is "Romy the Cat" he has some very outspoken ideas, but he has a lot of experience using this tube. Read about his Melquiades amplifier on his site and the 6C33C survival guide in which he writes "Generally look for 180-210 Volt on the 6C33C's plate and 180-230 mA of plate current. And I have read similar voltages on other sites.
In the link to his forum, you can read about the survival guide
GoodSoundClub Romy the Cat's Audio Site
Jeb-D noticed correctly about the voltage, the 6C33C doesn't like voltages that high.
A guy that has written a lot about this tube is "Romy the Cat" he has some very outspoken ideas, but he has a lot of experience using this tube. Read about his Melquiades amplifier on his site and the 6C33C survival guide in which he writes "Generally look for 180-210 Volt on the 6C33C's plate and 180-230 mA of plate current. And I have read similar voltages on other sites.
In the link to his forum, you can read about the survival guide
GoodSoundClub Romy the Cat's Audio Site
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