Hey Djn,
Ari can explain much better than I do, but the input transformer inverts the phase of the input signal. According to Ari in most recordings the (left-right) bass signals are in phase. The invertion by means of the input transformer, makes sure that the bass signals do not extinguish each other in the core of the OPT. The invertion could also be done with an Opamp, this mod was suggested to Ari by Giovanni Mariani who is chief R&D at Graaff amplifiers. Ari at first did not believe that it would work. But an unchanged signal with the bass signals in phase showed a -3dB point at 40 Hz, but with phase inversion it went down to 5 Hz.
Ari is the expert so should you have any questions, best mail him about this subject, like I wrote before he is a really likeable guy and given the time he will answer. Hope my explanation made some sense.
Ari can explain much better than I do, but the input transformer inverts the phase of the input signal. According to Ari in most recordings the (left-right) bass signals are in phase. The invertion by means of the input transformer, makes sure that the bass signals do not extinguish each other in the core of the OPT. The invertion could also be done with an Opamp, this mod was suggested to Ari by Giovanni Mariani who is chief R&D at Graaff amplifiers. Ari at first did not believe that it would work. But an unchanged signal with the bass signals in phase showed a -3dB point at 40 Hz, but with phase inversion it went down to 5 Hz.
Ari is the expert so should you have any questions, best mail him about this subject, like I wrote before he is a really likeable guy and given the time he will answer. Hope my explanation made some sense.
Here is my old John Hogan 300B amp with line stage on top. I made the chassis. I sold the amp last year and kept the chassis which I will now use for my 6C33C. I am planning on having the two power supplies on the bottom chassis and the signal path on the top chassis with ambilical chord between them. I am going with Ari's Simplex and becasue the top chassis is almost too small, I will use his SCC 2 on 1 OT.
In honnor of John Hogan (we lost John last year) I will spay paint the chassis cringel black and lable all the tubes and such with a gold paint pen.
What issues do you see with this layout? Cheers.
P.S., I might add that in Ari's schem he uses diod recs, but for mine I will use 2 6D22S half wave rec tubes for the 6SN7 B+ and 1 AZ1 rec tube for the 6C33C B+
In honnor of John Hogan (we lost John last year) I will spay paint the chassis cringel black and lable all the tubes and such with a gold paint pen.
What issues do you see with this layout? Cheers.
P.S., I might add that in Ari's schem he uses diod recs, but for mine I will use 2 6D22S half wave rec tubes for the 6SN7 B+ and 1 AZ1 rec tube for the 6C33C B+
Attachments
DJN,
I doubt that your AZ1 is powerful enough, in the Duplex the B+ for 4 pcs 6C33C is 1.2 Amps.
Other than that I see no problem in using a separate PSU, Ari did it and I have seen a lot of German builders do the same.
I am not a tube expert, I am more of a builder than designer, but I would look into the spec of the AZ1 you plan to use.
BTW I received my SC-SCC OPT yesterday, a sizeable hunk of metal, I can't wait to start building. But my wife made a slight complaint that she would rather see that I first tackle an assorted number of chores in and around the house. And rightfully so I am ashamed to admit
I doubt that your AZ1 is powerful enough, in the Duplex the B+ for 4 pcs 6C33C is 1.2 Amps.
Other than that I see no problem in using a separate PSU, Ari did it and I have seen a lot of German builders do the same.I am not a tube expert, I am more of a builder than designer, but I would look into the spec of the AZ1 you plan to use.
BTW I received my SC-SCC OPT yesterday, a sizeable hunk of metal, I can't wait to start building. But my wife made a slight complaint that she would rather see that I first tackle an assorted number of chores in and around the house. And rightfully so I am ashamed to admit
Good point about the AZ1. It is most often used in pre amps. I do have 2 of them and 2 of their special sockets. I wonder if I could parelle or series them for increased amp handling capabilities. I am a builder as well. Most of this stuff goes over my head. I got the dimentions of the SCC from Ari the other day and it will work, but yes, it is big. Cheers.
Banned
Joined 2002
Banned
Joined 2002
This could be an interesting option. What do you think? I could put all 4 6c33c tubes on top and the PS on the bottom. Cheers.
Andrea Ciuffoli - Home Page
Andrea Ciuffoli - Home Page
Thank you all for your attention and particularly Midlife, DJN, K.A.B. , Bas Horneman, the ones I forgot and, last but not least, Charles Wasserf.
You can find more information on the Split Core Stereo Common Circuit output transformers (SC-SCC also designed as "Double ended") in the site ETF2008 - European Triode Festival 2008 under "Lectures - Ari Polisois" .
I am at your disposal for further details.
By the way, I am using now inverted signals entries in all my SE amps for better signal freedom.
Cheers,
Ari Polisois ( G.Cesar).
You can find more information on the Split Core Stereo Common Circuit output transformers (SC-SCC also designed as "Double ended") in the site ETF2008 - European Triode Festival 2008 under "Lectures - Ari Polisois" .
I am at your disposal for further details.
By the way, I am using now inverted signals entries in all my SE amps for better signal freedom.
Cheers,
Ari Polisois ( G.Cesar).
Yeah, i just need the $$$, even if i had some spare parts to get them up and running id be happy, kinda like how dave says it, scrounge for parts to make it work then upgrade stuff later. The hard part is, no one wants to part with transformers for cheap or free
Hey Jleaman, one option is to find old used OPTs from an organ or counsol pull and use them until you can upgrade to the SC-sCC.
Hi Ari, I am still collecting parts for my Duplex. The problem I am having is: it's sailing season. I won't spend much time in the house until I put the boat away for the year. This is the time when I collect parts though. Cheers.
Hi Ari,
Where DJN is sailing, I have to finish the chores on my house before, I know it seems forever away, the fall kicks in. I have not even finished my Harley I planned on riding this summer. I 'd better hurry before this turns into summer 2011. Bought great speakers though, I am dying to hear how they sound on Duplex, which I plan on building during the winter.
It should provide for some nice additional heating
Take care,
Rob, AKA "Midlife"
Hi Midlife,It should provide for some nice additional heating
do you mean for your soul or body, maybe both?
Hi ma_coule I think both, I hope my new (second hand) speakers will sound fantastic on my new 6C33C Duplex amp, they already sound great on my Yarland SE EL 34 amp, which I imported from China a few years ago.Hi Midlife,
do you mean for your soul or body, maybe both?
But 4 tubes 6C33C will give off a serious amount of heat, so apart from great music that wil warm the soul, in wintertime they will heat the house too, well a little anyway
Getting started
I've had a pair of 6C33C's for a while now and haven't gotten around to doing anything with them. Today I ordered a pair of Eastern Audio 600ohm o/p trannys and I think it's time to start getting serious with this project. I've been interested in the Simplex circuit but in sourcing the power transformer requirements for mono-blocks, I'm a little leary. I may go for the Borbely or one of the other designs. I'm planning on keeping my entire power supply tube rectified, which drive the cost and size of transformers up considerably. I used to use solid state supplies but I just can't go back after using tubes.
I've had a pair of 6C33C's for a while now and haven't gotten around to doing anything with them. Today I ordered a pair of Eastern Audio 600ohm o/p trannys and I think it's time to start getting serious with this project. I've been interested in the Simplex circuit but in sourcing the power transformer requirements for mono-blocks, I'm a little leary. I may go for the Borbely or one of the other designs. I'm planning on keeping my entire power supply tube rectified, which drive the cost and size of transformers up considerably. I used to use solid state supplies but I just can't go back after using tubes.
Borbely 6C33C SE question
So I settled on the Borbely design but I've run into a little confusion regarding the B+ for the 6C33C. Drawing a loadline from 210V and a 600Ohm transformer, the max current appears to me about 350 mA. So my first question is why do we need 500mA of B+ current for a single 6C33C. The second question is regarding the -70 Bias. Looking at the curve with a 600ohm transformer and 210VDC and a bias voltage of -70 on the grid, it sets the operating point at about 170VDC @ 70 mA. This doesnt seem to place the operating point in a very linear part of the curve. I know this is a good design, so I must be missing something, if anyone could help It would be appreciated.
Thanks
So I settled on the Borbely design but I've run into a little confusion regarding the B+ for the 6C33C. Drawing a loadline from 210V and a 600Ohm transformer, the max current appears to me about 350 mA. So my first question is why do we need 500mA of B+ current for a single 6C33C. The second question is regarding the -70 Bias. Looking at the curve with a 600ohm transformer and 210VDC and a bias voltage of -70 on the grid, it sets the operating point at about 170VDC @ 70 mA. This doesnt seem to place the operating point in a very linear part of the curve. I know this is a good design, so I must be missing something, if anyone could help It would be appreciated.
Thanks
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.