Answer from ISO Tango re parallel winding…
You can use at 5kohm primary in parallel, confirmed.
As to 5687, its difficult to make a comment because we do not know this tube exactly.
It seems rather small μ, however its your choice.
I would trust them, but I am surprised. It is very close to a 6SN7G type and that's what I would normally use, maybe a 6SL7G might be better. Plate dissipation isn't as high, so depending where you run it on the curves ... You are also running open loop. I would tend to use some feedback and maybe that is their concern. This would normally be the driver with a gain stage and feedback with me.
Hello,
Hashimoto and Iso/ Tango both have chokes designed for choke input.
I only used the ones from Tango. Still have a few in the attic bought eight of them in Japan decades ago.
Which Lundahl and which Hashimoto did you use for choke input?
Greetings Eduard
http://vinylsavor.blogspot.com/2020/12/tube-of-month-5687.html
Both triode systems have an amplification factor of 17 and a plate resistance of about 3kOhm. This puts one half of the 5687 in the vicinity of a 6SN7 with both sections connected in parallel. It just has a tad less amplification factor
I found this comparison. I’m using half of the 5687 one half for each channel. I don’t need huge gain in my application…but it says 5687 just a tad less.
What is the book before this? He’s using terms that are not yet defined by him on page 2 😜
So I must also need another one where he introduces the things he is talking about in this book!
And I got through 3 pages 😎definitely not a ripper. You need to absorb as you say.
Tim De Paravaccini talked about choke in choke input suplly being bigger than power tansformer because it must deal with various heavy conditions after the rectification - here is the link where he talks about it and other things ( his philosophy of design ) :
The video starts around or just after the choke input talk - it is worth looking it from the beginning.
The video starts around or just after the choke input talk - it is worth looking it from the beginning.
Morgan has authored a few books. Each a valuable experience.
There is one on designing. Valve Amplifiers. I have them both (hot off the press at the time).
I was trained on tube technology by service people and engineers when I started, it was no longer taught in schools. Then years of my own experience and designing tube stages and amplifiers. Then Morgan's books after interacting with him here in the threads. Morgan summerized and tied up many loose ends for me. His books concentrate a lot of knowledge. RDH4 (Radiotron Designers Handbook, edition 4) is another, that's an RCA publication. You can download the PDF, I have paper versions. The normal RCA tube handbooks also have some great information. I would highly recommend you grab one, or download a bunch of PDF versions. They update it over the years, so just getting a late one means you may miss earlier information. My first books were some RCA tube handbooks, they were very helpful. I think I started with 1959 or 1957. Then I got the others. Yep have a set. They dropped older tubes or condensed the information. Some valuable information was the intended purpose of the tube.
Example, the 6DJ8 (garbage tuner tube) has an industrial equivalent (6922). Same specs. Totally different construction. The 6DJ8 has a normal spiral grid construction and designed for RF (lower B+, higher plate currents). It is microphonic as heck as a rule, and the specs are not tightly controlled. The 6922 has a frame grid, and the parameter spread isn't nearly as wide. They tend to be quiet and not very microphonic when it is a good brand. So reading in a chart you would think they are the same - not even close!
There used to be a difference between a 12AX7 and ECC83. The 12AX7A is equivalent to the ECC83. The difference?, the ECC83 was low noise and low microphonic. It is designed for audio (=low frequency) amplification. There is a good reason to use the tubes for the uses they were designed for. 6EU7 is a different tube, designed for even lower noise, hum and crosstalk. The broad characteristics are the same as a 12AX7A, different pin-out and 6.3 V heater only.
Unless a tube is poorly made, they do not have a "sound". They simply interact with the circuit they are in. Use the tube the circuit is designed for and you will have the lowest distortion if the circuit is designed properly. "Tube rolling" for different type numbers is a stupid practice, and some tubes have higher heater currents than others. If people understood what was actually going on, they would know enough to avoid this practice, or buy equipment from a designer who knows what they are doing (best idea).
The information is out there. Use the RCA books as a solid base, Morgan ties everything up wonderfully. He also has performed modern testing on tubes and circuits.
There is one on designing. Valve Amplifiers. I have them both (hot off the press at the time).
I was trained on tube technology by service people and engineers when I started, it was no longer taught in schools. Then years of my own experience and designing tube stages and amplifiers. Then Morgan's books after interacting with him here in the threads. Morgan summerized and tied up many loose ends for me. His books concentrate a lot of knowledge. RDH4 (Radiotron Designers Handbook, edition 4) is another, that's an RCA publication. You can download the PDF, I have paper versions. The normal RCA tube handbooks also have some great information. I would highly recommend you grab one, or download a bunch of PDF versions. They update it over the years, so just getting a late one means you may miss earlier information. My first books were some RCA tube handbooks, they were very helpful. I think I started with 1959 or 1957. Then I got the others. Yep have a set. They dropped older tubes or condensed the information. Some valuable information was the intended purpose of the tube.
Example, the 6DJ8 (garbage tuner tube) has an industrial equivalent (6922). Same specs. Totally different construction. The 6DJ8 has a normal spiral grid construction and designed for RF (lower B+, higher plate currents). It is microphonic as heck as a rule, and the specs are not tightly controlled. The 6922 has a frame grid, and the parameter spread isn't nearly as wide. They tend to be quiet and not very microphonic when it is a good brand. So reading in a chart you would think they are the same - not even close!
There used to be a difference between a 12AX7 and ECC83. The 12AX7A is equivalent to the ECC83. The difference?, the ECC83 was low noise and low microphonic. It is designed for audio (=low frequency) amplification. There is a good reason to use the tubes for the uses they were designed for. 6EU7 is a different tube, designed for even lower noise, hum and crosstalk. The broad characteristics are the same as a 12AX7A, different pin-out and 6.3 V heater only.
Unless a tube is poorly made, they do not have a "sound". They simply interact with the circuit they are in. Use the tube the circuit is designed for and you will have the lowest distortion if the circuit is designed properly. "Tube rolling" for different type numbers is a stupid practice, and some tubes have higher heater currents than others. If people understood what was actually going on, they would know enough to avoid this practice, or buy equipment from a designer who knows what they are doing (best idea).
The information is out there. Use the RCA books as a solid base, Morgan ties everything up wonderfully. He also has performed modern testing on tubes and circuits.
The choke is an engineering issue. You also have to watch out for coupled magnetics. Some designers take things to an extreme claiming benefits. Sorry, it's electrical engineering.
What you are talking about is inductance. Once you have enough, more is a pure waste of money. You also have leakage inductance and capacitance. That comes down to how the choke is made. Finally you look at the average current and min - max values in a power amp. If the inductance is too low, it will cease to function as an inductance and you'll end up with a capacitor input with higher voltages.
I know this from experience.
What you are talking about is inductance. Once you have enough, more is a pure waste of money. You also have leakage inductance and capacitance. That comes down to how the choke is made. Finally you look at the average current and min - max values in a power amp. If the inductance is too low, it will cease to function as an inductance and you'll end up with a capacitor input with higher voltages.
I know this from experience.
I received the Tocos Cosmos RV24 potentiometers today. I ordered from hificollective in the UK. They shipped from Germany. I ordered mono but received stereo. The site said they weren’t making stereo any longer due to the difference in db between left and right channel. But I received stereo anyway. I will wire them mono.
Super smooth operation and nice and firm
Super smooth operation and nice and firm
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Hello,
The French diy audio shop heavily related to Jean Hiraga used to sell them. They are carbon composition types and most of the time they were out of stock.
Very reliable.
This shop also sold Tango and Partridge transformers and some locally made ones before the www took over business.
Greetings,Eduard
P.s i am sure Allen Wright made the statement about the input choke being bigger than the power transformer. He passes away long time ago. I sometimes contacted him by fax machine !! Will look for his two books in my to big collection
The French diy audio shop heavily related to Jean Hiraga used to sell them. They are carbon composition types and most of the time they were out of stock.
Very reliable.
This shop also sold Tango and Partridge transformers and some locally made ones before the www took over business.
Greetings,Eduard
P.s i am sure Allen Wright made the statement about the input choke being bigger than the power transformer. He passes away long time ago. I sometimes contacted him by fax machine !! Will look for his two books in my to big collection
What's wrong with a good stereo control????
They don't track perfectly, but you can't set mono controls that close either, and two controls are a huge pain. Consider that speakers aren't matched perfectly, nor are the room acoustics. You probably aren't going to get the same SPL from each speaker anyway. I'm not even going to mention that circuits without feedback will vary in gain and that is also normal.
Maybe I know too much, but I'll opt for stereo controls given a choice. You can also use switched resistor networks, and a -20dB attenuator (level drop) becomes very handy with switched networks.
A decent stereo control tracks better than you can set mono controls. That's just a fact of life.
They don't track perfectly, but you can't set mono controls that close either, and two controls are a huge pain. Consider that speakers aren't matched perfectly, nor are the room acoustics. You probably aren't going to get the same SPL from each speaker anyway. I'm not even going to mention that circuits without feedback will vary in gain and that is also normal.
Maybe I know too much, but I'll opt for stereo controls given a choice. You can also use switched resistor networks, and a -20dB attenuator (level drop) becomes very handy with switched networks.
A decent stereo control tracks better than you can set mono controls. That's just a fact of life.
Well tango and hashimoto still make chokes specifically for choke input power supplies.they would be in the know rather than diy audio members.
So does Hammond and other manufacturers.
FYI, Hammond (and others) has a staff of engineers and has been in business longer than any of us have been alive. So these old manufacturers know more about this stuff than any modern "expert" could possibly know. Keep in mind that choke input power supplies were the normal practice for power supply design. It's been researched to death.
Power design for audio and instrumentation or anything else has to consider the same physics. Instrumentation has more stringent requirements than audio does.
FYI, Hammond (and others) has a staff of engineers and has been in business longer than any of us have been alive. So these old manufacturers know more about this stuff than any modern "expert" could possibly know. Keep in mind that choke input power supplies were the normal practice for power supply design. It's been researched to death.
Power design for audio and instrumentation or anything else has to consider the same physics. Instrumentation has more stringent requirements than audio does.
This above mainly. But it’s a great question of why? And I’ll give you all my considerations to date. I can always change it. Stepped attenuator had me interested.
How to get balance without a balance control? I understood and still find data that says balance controls are no good. And it adds extra circuitry. And I assumed these cosmos stereo must be way off spec if they don’t even sell them any more ( because they say they are too far off their spec) but somehow I got leftovers. And my listening room is requiring a “balance” unless I get that new house 🏡😎
I also play music and make guitars from scratch (12 to date). And the famous Les Paul I am used to playing (and have built 2 1959 replicas) have two volume controls. One for each pickup. And you balance the sound from the pickup coils with 2 volume pots. So it’s also a throw back to guitar 🎸 design. That’s why my mockup has chicken head knobs. Common on guitar amps and guitar controls.
And I like symmetry. The attenuators and ladder controls add more wire and more resistors and in the end more complexity?? You probably wouldn’t find them in a 1950s pre amp either. I’m not against digital or modern. I just built a streamer and a DAC.
I understand some of these things are preferences. Love this forum.
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Hi,
There is zero wrong with Balance controls. Some are used as additional volume controls electrically, others attenuate one or the other channel. But the idea that they are bad doesn't make sense. They are the same type of control as a volume control in that they are made nearly the same way. A wiper and resistive element - same exactly as a volume control. They became popular because they are the most logical and easiest way to accomplish that goal. They cost the same as using two duals, so they aren't a cheaper way to do this. Some people always say the way the industry does something is because it's cheaper. Not always, and things are done a certain way because it either works better or makes more sense.
On your pickups, those volume controls form a mixer. Same as a recording console except you aren't running each pickup to the amp (Two or three sets of cables that way). So your guitar controls are used in a completely different way.
You're going to find a great deal written out there as fact by people who haven't got the first clue what they are writing about. They get an idea and since they don't understand electronics and how each type of component is made, they can't really judge what the truth is. They hear something, think about it and decide without any understanding. However some will come across as experts and may even have a following in the audio industry. There is also a huge amount of fashion and whatever is the current fad in this industry. None of which has anything to do with reality.
One example, solid tantalum capacitors were supposed to be the best capacitor in the 1970s and early 1980's. They sounded terrible and even shorted. I knew this back then, but large, famous companies used them. Partially to get market share, partially because people making decisions didn't understand the part. Today we know better, the truth eventually came out. Another type, the wet slug tantalum, is a great capacitor. Expensive as sin. We have some new types that work as well. However, these are for specific applications. No part is good at every application.
There is zero wrong with Balance controls. Some are used as additional volume controls electrically, others attenuate one or the other channel. But the idea that they are bad doesn't make sense. They are the same type of control as a volume control in that they are made nearly the same way. A wiper and resistive element - same exactly as a volume control. They became popular because they are the most logical and easiest way to accomplish that goal. They cost the same as using two duals, so they aren't a cheaper way to do this. Some people always say the way the industry does something is because it's cheaper. Not always, and things are done a certain way because it either works better or makes more sense.
On your pickups, those volume controls form a mixer. Same as a recording console except you aren't running each pickup to the amp (Two or three sets of cables that way). So your guitar controls are used in a completely different way.
You're going to find a great deal written out there as fact by people who haven't got the first clue what they are writing about. They get an idea and since they don't understand electronics and how each type of component is made, they can't really judge what the truth is. They hear something, think about it and decide without any understanding. However some will come across as experts and may even have a following in the audio industry. There is also a huge amount of fashion and whatever is the current fad in this industry. None of which has anything to do with reality.
One example, solid tantalum capacitors were supposed to be the best capacitor in the 1970s and early 1980's. They sounded terrible and even shorted. I knew this back then, but large, famous companies used them. Partially to get market share, partially because people making decisions didn't understand the part. Today we know better, the truth eventually came out. Another type, the wet slug tantalum, is a great capacitor. Expensive as sin. We have some new types that work as well. However, these are for specific applications. No part is good at every application.
You have four Cosmos stereo pots - should measure them to see if they track both channels correctly - maybe they do.
Other han that there should be no problem using two volume controls - the man i know use it and says it is mostly matter of practice tu use for equal volume.
Other han that there should be no problem using two volume controls - the man i know use it and says it is mostly matter of practice tu use for equal volume.
The only “problem” with balance controls is the instant 6dB loss. You have to make up the gain somewhere. I can see where that sits wrong with some people, especially people who are allergic to feedback in their circuits.
I tested one of them. On a 10k pot, they are several hundred ohms out between the two channels. Percentage wise that one was about 3.5%, so if there is 40db of control, I guess that is about 1.5db. I know I can detect 1 db increments on my DAC volume which goes in 1db increments.
Hi wg_ski,
In all fairness, an iffy circuit seldom sounds better with feedback and often worse. Given they like these circuits I can understand the mindset. But get the circuitry and layout right (or even mostly right), feedback always improves things if you execute that even half right.
There are controls that suffer no loss at all in the centre position. Additionally, the -6 dB isn't an issue since you don't run your volume control full up. So that costs you absolutely zero.
The truth usually does! lol!
In all fairness, an iffy circuit seldom sounds better with feedback and often worse. Given they like these circuits I can understand the mindset. But get the circuitry and layout right (or even mostly right), feedback always improves things if you execute that even half right.
Hi fusion360guy,
Reading your post again. The additional circuitry isn't a factor unless you run the wiring totally incorrectly. In addition, some stepped attenuators are wired internally (Yamaha pro amps), and some use external resistors on terminals. These are equivalent to be honest, and I like the external resistors more. If the resistors are on a local PCB, no harm, no foul. I have no problem with that.
You seem to be concerned about ideas rather than the physical reality. I have decades of experience with separate volume controls vs a stereo control and balance pot. You can't set two mono controls even close, not nearly as close as a decent stereo control. The worst mistracking occurs at the bottom (min volume) so put a -20 dB attenuator in and you've solved that, plus made a convenient way to reduce volume to talk to someone as well. That entire argument is wishful thinking.
Even your new house will possibly need a balance adjustment. Sorry, speakers are not exactly the same sensitivity (designed speaker systems for over a decade professionally).
The huge factor is your line stage without feedback. Understand that a dual triode is really two independent tubes in one envelope. One has nothing to do with the other and they are not measured and matched. So think of them as two entirely different tubes of the same make. That is one very good reason to use feedback, the components in the circuit have a bigger say as to the total gain and frequency response. Tubes don't have high transconductance, not like solid state, so individual tubes will affect total circuit gain a bit as well.
Reading your post again. The additional circuitry isn't a factor unless you run the wiring totally incorrectly. In addition, some stepped attenuators are wired internally (Yamaha pro amps), and some use external resistors on terminals. These are equivalent to be honest, and I like the external resistors more. If the resistors are on a local PCB, no harm, no foul. I have no problem with that.
You seem to be concerned about ideas rather than the physical reality. I have decades of experience with separate volume controls vs a stereo control and balance pot. You can't set two mono controls even close, not nearly as close as a decent stereo control. The worst mistracking occurs at the bottom (min volume) so put a -20 dB attenuator in and you've solved that, plus made a convenient way to reduce volume to talk to someone as well. That entire argument is wishful thinking.
Even your new house will possibly need a balance adjustment. Sorry, speakers are not exactly the same sensitivity (designed speaker systems for over a decade professionally).
The huge factor is your line stage without feedback. Understand that a dual triode is really two independent tubes in one envelope. One has nothing to do with the other and they are not measured and matched. So think of them as two entirely different tubes of the same make. That is one very good reason to use feedback, the components in the circuit have a bigger say as to the total gain and frequency response. Tubes don't have high transconductance, not like solid state, so individual tubes will affect total circuit gain a bit as well.