Seeking a little knowledge and whole lot of opinions! Lol
I would eventually like to add pentode mode to my SSE, of course not until it is up and running first. I do not believe my transformer has a ul tap.
So I'm looking for a bit of help.
I know nothing about designing power supply circuits, so bare with me.
My power transformer has 360-0-360 220ma, 6.3v 7A, 5v 4A, and an unused 60v 800ma secondary. Is it possible to use that 60v line with a voltage doubler or tripler to create a separate B+ for pentode mode screen Grids? Would it be possible to make it somehow an adjustable B+ by using an attenuator as well; or some other method I am not mentioning?
(Any knowledge you pass on will make me a more dangerous person towards myself!!!! LOL ) but seriously thanks in advance!
Sent from my SM-T810 using Tapatalk
I would eventually like to add pentode mode to my SSE, of course not until it is up and running first. I do not believe my transformer has a ul tap.
So I'm looking for a bit of help.
I know nothing about designing power supply circuits, so bare with me.
My power transformer has 360-0-360 220ma, 6.3v 7A, 5v 4A, and an unused 60v 800ma secondary. Is it possible to use that 60v line with a voltage doubler or tripler to create a separate B+ for pentode mode screen Grids? Would it be possible to make it somehow an adjustable B+ by using an attenuator as well; or some other method I am not mentioning?
(Any knowledge you pass on will make me a more dangerous person towards myself!!!! LOL ) but seriously thanks in advance!
Sent from my SM-T810 using Tapatalk
The terminal blocks on the back of the SSE board, where the output transformers ("OPT") connect, have three interfaces to the board: B+, Screen Grid, and Plate (Anode).
The B+ goes to the primary of the output transformer, the Plate connects to the plate lead of the OPT. The screen grid can be connected in three ways: 1) it can go to a separate lead on the OPT (UltraLinear or "UL"), 2) it can be jumpered to the plate to make a triode connection, or 3) it can be jumpered to the B+ to make a pentode connection, thus your SSE board is already adapted for pentode mode; it does not need to be added. Most people use connection 1 or 2.
For the common tubes the board was designed for, such as 6550, 6L6GC, EL34, KT88, etc., screen voltage is a non isssue - the screens can handle whatever B+ ( within reason ) that you are supplying the board. You may find that you like this pentode sound - or not. I personally think that - with the tubes I've used as pentodes - the onboard cathode feedback is inadequate and more feedback must be added. This is an entirely different subject, sometimes lightning rod polarizing. The Edcor OPT's I am familiar with do have UL taps.
You sound like you want to experiment, and the SSE board is terrific for that - it's like a tube amp lab on a printed circuit board ("PCB"). Everything I kow about tube amps - which is honestly very little - has come from abusing my SSE board(s). But you must be aware that experimenting can come with a price - some experiments can go really wrong and cause significant damage. I have first hand experience with this. If you get careless around the voltages commonly used in tube amplifiers, it can be lethal. High voltages are a bit like aviation - really bad things can happen really fast, and when they do, they can be very unforgiving.
This is why the best advice is to always build your board in a stock configuration as specified, and leave it alone.
But once you get it working properly, and if for some reason that is not entirely satisfactory to your particular situation, then carefully consider what changes you want to make ( experiment ) with. There is a wealth of information on this sub forum with ways people have adapted their SSE and TSE boards to their unique needs.
To answer your direct question: Yes, but imho, you don't need it to start, and when you do, there are other ( maybe better ) ways of doing it. You'll just have to experiment ....
edit: there are a handful of practical ways to adjust your B+ up or down: You can get a power transformer with multiple high voltage secondaries; you can change the value of the first capacitor in the power supply ( or omit it entirely ), or you can use different rectifier tubes which have different internal voltage drops, or use a solid state rectifier.
Win W5JAG
The B+ goes to the primary of the output transformer, the Plate connects to the plate lead of the OPT. The screen grid can be connected in three ways: 1) it can go to a separate lead on the OPT (UltraLinear or "UL"), 2) it can be jumpered to the plate to make a triode connection, or 3) it can be jumpered to the B+ to make a pentode connection, thus your SSE board is already adapted for pentode mode; it does not need to be added. Most people use connection 1 or 2.
For the common tubes the board was designed for, such as 6550, 6L6GC, EL34, KT88, etc., screen voltage is a non isssue - the screens can handle whatever B+ ( within reason ) that you are supplying the board. You may find that you like this pentode sound - or not. I personally think that - with the tubes I've used as pentodes - the onboard cathode feedback is inadequate and more feedback must be added. This is an entirely different subject, sometimes lightning rod polarizing. The Edcor OPT's I am familiar with do have UL taps.
You sound like you want to experiment, and the SSE board is terrific for that - it's like a tube amp lab on a printed circuit board ("PCB"). Everything I kow about tube amps - which is honestly very little - has come from abusing my SSE board(s). But you must be aware that experimenting can come with a price - some experiments can go really wrong and cause significant damage. I have first hand experience with this. If you get careless around the voltages commonly used in tube amplifiers, it can be lethal. High voltages are a bit like aviation - really bad things can happen really fast, and when they do, they can be very unforgiving.
This is why the best advice is to always build your board in a stock configuration as specified, and leave it alone.
But once you get it working properly, and if for some reason that is not entirely satisfactory to your particular situation, then carefully consider what changes you want to make ( experiment ) with. There is a wealth of information on this sub forum with ways people have adapted their SSE and TSE boards to their unique needs.
To answer your direct question: Yes, but imho, you don't need it to start, and when you do, there are other ( maybe better ) ways of doing it. You'll just have to experiment ....
edit: there are a handful of practical ways to adjust your B+ up or down: You can get a power transformer with multiple high voltage secondaries; you can change the value of the first capacitor in the power supply ( or omit it entirely ), or you can use different rectifier tubes which have different internal voltage drops, or use a solid state rectifier.
Win W5JAG
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Firstly thank you for your reply. I did state I intended to get my sse up and running first, meaning a stock version but at some point, yes, I intend to experiment. How else will I learn more about Tubes? I am a hands on type of learner. I know things can go wrong very quickly when it comes to any higher voltage electronics.
I was a electromechanical field engineer for 16 years and am very familiar with things going wrong, it was my job to fix them when they did. But modern equipment is very different from tube electronics. I am not worried about the possibility of damaging my sse, if during my investigations it happens well I learned what not to do. Lol and I intend to do it safely on a breadboard.
I understand the Sse can be jumpered for pentode mode but that provides the same b+ my question was to enable a second separate b+ one hopefully adjustable. This way I could use tubes that require different voltages on the screens. I am still learning and had no idea that it could cause stress on any other parts like the capacitor you mentioned. Could you point me to a thread that explains this stress?
Let me just say that most of my questions are for future expansion and experimentation not to build into the Sse in one go. I intend to take it slow and in well thought out steps. Getting a stock working board is step one, waiting for my transformers is keeping me from that at the moment. But I know myself and after listening to it for awhile I will begin to wonder what that "other" tube would sound like. Asking questions now will allow me to be better prepared for the changes to come.
Sent from my SM-T810 using Tapatalk
I was a electromechanical field engineer for 16 years and am very familiar with things going wrong, it was my job to fix them when they did. But modern equipment is very different from tube electronics. I am not worried about the possibility of damaging my sse, if during my investigations it happens well I learned what not to do. Lol and I intend to do it safely on a breadboard.
I understand the Sse can be jumpered for pentode mode but that provides the same b+ my question was to enable a second separate b+ one hopefully adjustable. This way I could use tubes that require different voltages on the screens. I am still learning and had no idea that it could cause stress on any other parts like the capacitor you mentioned. Could you point me to a thread that explains this stress?
Let me just say that most of my questions are for future expansion and experimentation not to build into the Sse in one go. I intend to take it slow and in well thought out steps. Getting a stock working board is step one, waiting for my transformers is keeping me from that at the moment. But I know myself and after listening to it for awhile I will begin to wonder what that "other" tube would sound like. Asking questions now will allow me to be better prepared for the changes to come.
Sent from my SM-T810 using Tapatalk
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