Hello folks,
I want to make a preamp using tubes. I have no idea where to start though. Should I buy one of those really old radios and take the tubes/transformer from those, or should I buy all components one-by-one?
I have plenty of electronics experience, but the field of tubes is very new to me. I was first going to make a complete amp with tubes but I think I'm going to keep it solid state for now - let's first get a preamp running.
Any help would be greatly appreciated.
Regards,
-- Charl
I want to make a preamp using tubes. I have no idea where to start though. Should I buy one of those really old radios and take the tubes/transformer from those, or should I buy all components one-by-one?
I have plenty of electronics experience, but the field of tubes is very new to me. I was first going to make a complete amp with tubes but I think I'm going to keep it solid state for now - let's first get a preamp running.
Any help would be greatly appreciated.
Regards,
-- Charl
From recent threads on the same subject, a single 12B4 per channel is a good way to go... most of the work is in the power supply, which for a really good pre should be regulated -- i'd use a choke loaded supply running into a Vacuum State SuperReg (a shunt reg kit).
IIRC Gary Pimm (check for some of Brett's posts) has a good site on building regulators.
There is also a thread "Frank's Ultimate Pre" that has another take on the subject.
dave
IIRC Gary Pimm (check for some of Brett's posts) has a good site on building regulators.
There is also a thread "Frank's Ultimate Pre" that has another take on the subject.
dave
Hey,
Thanks for referring me to that post. It does have a lot of schematics though, so again I wouldn't know which one to (try) to start building.
Also, it would be nice if my preamp would have some gain, maybe 2.
Perhaps I should just look for some tubes, buy them, then build something based on that instead of trying to build something based on a certain schematic?
-- Charl
Thanks for referring me to that post. It does have a lot of schematics though, so again I wouldn't know which one to (try) to start building.
Also, it would be nice if my preamp would have some gain, maybe 2.
Perhaps I should just look for some tubes, buy them, then build something based on that instead of trying to build something based on a certain schematic?
-- Charl
Cost no object?
What does your line stage need to do? More to the point, do you really need it? If it's simply feeding a nearby stereo power amplifier, why not simply add input slection and volume control to the power amplifier? The very best line stage is always inferior to a piece of wire. (Farewell, Peter Walker.) On the other hand, if you need to drive remote power amplifiers, then a carefully designed cathode follower is required. I can't believe that you need gain? Think hard. All line stages cost money and degrade the sound, so you need a very good reason for using one...
What does your line stage need to do? More to the point, do you really need it? If it's simply feeding a nearby stereo power amplifier, why not simply add input slection and volume control to the power amplifier? The very best line stage is always inferior to a piece of wire. (Farewell, Peter Walker.) On the other hand, if you need to drive remote power amplifiers, then a carefully designed cathode follower is required. I can't believe that you need gain? Think hard. All line stages cost money and degrade the sound, so you need a very good reason for using one...
Line stage
Yes, if the amp already has enough gain, then the preamp is actually built into the amp so to speak. Why duplicate. Always keep the number of stages low and accurate if possible.
I took a different approach and outboarded the first stage. This was to decouple the amp from the preamp. However, it would be very difficult to rewire your existing amp.
Happy new year.
Yes, if the amp already has enough gain, then the preamp is actually built into the amp so to speak. Why duplicate. Always keep the number of stages low and accurate if possible.
I took a different approach and outboarded the first stage. This was to decouple the amp from the preamp. However, it would be very difficult to rewire your existing amp.
Happy new year.
Hello fellows,
Yes, of course I could just tweak my (solid state) amp a bit. But I want to make a versatile pre-amp with equalizer and volume control - both computer (software) operated. I thought it would be a nice learning experience to do it with tubes. And let's face it, wouldn't they look gorgeous behind some plexiglass?
This amp won't last that much longer too, I will be upgrading it in a couple of years. This way I don't have to do any modification to the preamp, I can just leave it where it is and replace the amp itself.
Still don't know what to do - find a good schematic and search for the tubes that it uses, or find good tubes and search for a schematic or design my own schematic for them?
-- Charl
Yes, of course I could just tweak my (solid state) amp a bit. But I want to make a versatile pre-amp with equalizer and volume control - both computer (software) operated. I thought it would be a nice learning experience to do it with tubes. And let's face it, wouldn't they look gorgeous behind some plexiglass?
This amp won't last that much longer too, I will be upgrading it in a couple of years. This way I don't have to do any modification to the preamp, I can just leave it where it is and replace the amp itself.
Still don't know what to do - find a good schematic and search for the tubes that it uses, or find good tubes and search for a schematic or design my own schematic for them?
-- Charl
Fact 1: Valves can look gorgeous.
Fact 2: Valves can sound gorgeous.
Fact 3: Valves are expensive. (Apologies Sch3mat1c, but it's true unless you spent lots of money acquiring the knowledge of how to design with cheap valves.)
Fact 2 is not absolute.
Careful software control could allow a beautifully ergonomic pre-amplifier. Have you listened to a valve amplifier and been seduced? If you haven't, why bother? If you have, get into design and build a purpose-built stunner!
Fact 2: Valves can sound gorgeous.
Fact 3: Valves are expensive. (Apologies Sch3mat1c, but it's true unless you spent lots of money acquiring the knowledge of how to design with cheap valves.)
Fact 2 is not absolute.
Careful software control could allow a beautifully ergonomic pre-amplifier. Have you listened to a valve amplifier and been seduced? If you haven't, why bother? If you have, get into design and build a purpose-built stunner!
EL34 is a power amplifier valve...
The classic Mullard 5-20 is a good starting point, but there are plenty of recent designs. Better driver circuitry can be designed, but the final limiting factor is always the output transformer, so you need a good one, and they can be very expensive...
6SN7 and 7N7 are very linear pre-amplifier valves.
The classic Mullard 5-20 is a good starting point, but there are plenty of recent designs. Better driver circuitry can be designed, but the final limiting factor is always the output transformer, so you need a good one, and they can be very expensive...
6SN7 and 7N7 are very linear pre-amplifier valves.
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