The comment about resistors in parallel suggest to me that the OP is right at the very beginning of learning about electronics. The start of a long, but fascinating, journey. If so, Morgan Jones' book and valve electronics might not be the best place to start. Better to read Horowitz and Hill, and in parallel with that build a chip amp kit. Learn about high voltage safety via a mains PSU for that before looking at valves.
There are some things you can only learn by making and debugging an amp. Before you do that, there are some things you can only learn by reading a good book and scribbling on lots of paper. After a while these two activities can run in parallel and reinforce each other. Some people imagine they can avoid one by doing more of the other - it doesn't work like that, except to a rather limited extent.
There are some things you can only learn by making and debugging an amp. Before you do that, there are some things you can only learn by reading a good book and scribbling on lots of paper. After a while these two activities can run in parallel and reinforce each other. Some people imagine they can avoid one by doing more of the other - it doesn't work like that, except to a rather limited extent.
+1 on starting out with low power DC. That's how I started. I build Rod Elliott's P05 (power supply) & P06 (phono preamp). Very easy basic stuff, learn to solder, learn to read schematic to some degree etc. The thing when I went from low power DC to HV is SAFETY. You must learn proper safety practices. My only goal in building tube amps now and when I started out is not getting jolted with electricity. That takes patience AND practice and reading about it. Safety first (it's not a cliche).
If you're dead set on going to a power amp as a first build, as has been mentioned, SE (single ended) is a good place to start. Low parts count, easiest circuit, modest cost. Beware tho you may get hooked on SE. Take a look at some SEUL (single ended ultra linear) amp builds. Thats what I like the sound of and they are easy to build point to point. Like I said tho... the sound of SE can get you hooked.
With SE you will achieve you goals cept for the 40w/ch thing, with tube amps is expensive and more difficult. It's all about the output iron, the bigger the more expensive.
You may have to read Morgan Jones a few times, and it's best to read it build something then go back and re-read it again. All that math will start to hit home after a little practice.
Your real worries:
HV can kill .... one hand only inside the amp after it's been powered on the first time, even with the power off and get alligator clips for your DMM.
Cheers,
Bob
well spotted, I admit begginer with electronics. Although the more I read the more comes back to me. I have read the first chapter though 3 times now and am starting to get a feel for the maths.... there is however a big difference between understanding maths and understanding how much electric shocks hurt/kill... and both can be learnt in different ways... my question involves an aid to help me understand the maths as I am much more of a practicle learner but understand that books and academia have it's place.
Thankyou for looking after my safety once it's been said I don't need patronising with further mothering. I don't mean to be arogant or dismissive but please trust me I know already about the high voltages involved with valve amps and have become tired of every time I ask a begginer to valves question having to put up with every other reply being telling me to try learning electronics with a lego motor kit.
Thankyou for looking after my safety once it's been said I don't need patronising with further mothering. I don't mean to be arogant or dismissive but please trust me I know already about the high voltages involved with valve amps and have become tired of every time I ask a begginer to valves question having to put up with every other reply being telling me to try learning electronics with a lego motor kit.
No one here is saying anything but be carefull !!
A solidstate amp with +/-70V rails will kill you to so anything above 50V and 30mA is what i consider lethal.
A solidstate amp with +/-70V rails will kill you to so anything above 50V and 30mA is what i consider lethal.
So you already know how to calculate bleeder resistance values and know how long to wait before touching anything in a valve amp after powering off? You know that fuses (when carefully chosen) may prevent your house from burning down but probably won't protect you from electrocution? You know about the difference between Class I and Class II equipment? You know what a Class X capacitor is, and where a Class Y capacitor must be used?just an idea said:
Please reassure us that you don't need any help with safety issues. We don't like to lose forum members so we tend to be cautious when someone appears to be inexperienced.
Most here I suspect have scary stories to tell of how close they have come to getting a lethal shock. Better to learn by our mistakes.
Here's something easier to read to start you off. It good for hifi amps as well as guitar amps. It looks at the small circuits that can make up an amp schematic. Should give you a start understanding your own Mingda schematic.
How to design valve guitar amplifiers
Here's a link to the Baby Huey thread.
http://www.diyaudio.com/forums/tubes-valves/72536-el84-amp-baby-huey.html
I'm not suggesting you should build it ( although it is a very good amp) You don't even need to read it all, just the first 100 posts or so. You will find the designer providing you with the schematics which you can study. People will talk about which components to use in their builds. You can view pictures of their builds. There are examples of people making mistakes and getting advice on how to fix them. There will be mathematics....😱
Finally here's a link to Duncans' power supply simulator where you can dream up your perfect power supply in complete safety, much better than Lego 😉
Download
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df96, nope I don't know any of that stuff, but i do know when i touch stuff that is connected to electrical stuff and even some other stuff that was connected a while ago to electric stuff can kill me.... so thats why I'm reading a book and not just sticking random bits of metal in a plug socket. If all you want to do is show off how much you know and make a begginer feel bad about wanting to learn then I would appreciate if you found a different thread to pick on.
Soonerorlater, thats good stuff. eventually my GCSE maths will come back to me, I'm sure. I'm keen to pick this up, and am doing my homework, practicing the problems set for me by morgan jones. I might look into the recommended book to read first, but 'valve amplifiers' was quite expensive and I'm just starting to get the hang of it.
Soonerorlater, thats good stuff. eventually my GCSE maths will come back to me, I'm sure. I'm keen to pick this up, and am doing my homework, practicing the problems set for me by morgan jones. I might look into the recommended book to read first, but 'valve amplifiers' was quite expensive and I'm just starting to get the hang of it.
I´m pretty sure DF96 isn´t picking on you.
Just take it slow and get the basic stuff like croc leads for your DMM before starting to measure live circuits.
Building it is pretty safe but if you have an experienced friend to assist at startup and debugging the first times it´s a great help.
The advices is not to scare people off but out of concern.
Just take it slow and get the basic stuff like croc leads for your DMM before starting to measure live circuits.
Building it is pretty safe but if you have an experienced friend to assist at startup and debugging the first times it´s a great help.
The advices is not to scare people off but out of concern.
Tube project suppose something like +350V-450V DC that needs special care, discharging power supply capacitors especially. So it is important to mention.
While SS beginners project is something about +-35V-45V DC (yes it is current that is lethal and every electric circuit has to be treated right) but touching 35V cap most likely would not kill but 350V charged cap that is very-very bad for sure.
Regarding rectifier I might suggest using SS diodes (MUR860 is popular but any appropriate hi voltage Schottky will do the job) . L-C-L filter that is where "tube sound" coming from and magnetic field charged choke (flux capacitor 🙂 ) provides so called micro-dynamics.
And yes tube project needs quality expensive components like chokes, OTs, foil decoupling capacitors in order to outperform SS amps.
Lowther or Fostex Fe206 might be good companion speaker project.
While SS beginners project is something about +-35V-45V DC (yes it is current that is lethal and every electric circuit has to be treated right) but touching 35V cap most likely would not kill but 350V charged cap that is very-very bad for sure.
Regarding rectifier I might suggest using SS diodes (MUR860 is popular but any appropriate hi voltage Schottky will do the job) . L-C-L filter that is where "tube sound" coming from and magnetic field charged choke (flux capacitor 🙂 ) provides so called micro-dynamics.
And yes tube project needs quality expensive components like chokes, OTs, foil decoupling capacitors in order to outperform SS amps.
Lowther or Fostex Fe206 might be good companion speaker project.
I don't want to get to far off subject and too argumentative, but it's a point that often puts me off using forums. I think you're right, DF96 is not picking on me, but he has along with many in the past fallen into the classic forum 'expert' role. Concern has nothing to do with it, but a desire to feel important through demonstrating their superiority... and most importantly maintaining that difference by making begginers feel lesser and trying to scare them away from reaching the same knowledge base and therefore removing the small amount of usefullness they have in this world. Do you really think it's the first time I've been told how dangerous high voltage is? and as all this thread is asking for is an easy circuit diagram to follow while I learn how to do it all safely, are the repeated messages needed? At this stage my biggest risk is if I print it off and get a paper cut. Leave the high horses at home and either help me in respect to me question or not.
at this ealry stage lets please just keep things light hearted. when I start to build then I promise to welcome all the saftey advice you can throw at me... and I'll keep both hands behind my back then nothing can go wrong.
+1 on the PSUD-2 - it's the best tool in my tool box. It's a bit tricky to get going at first. Try it (it does the math you're reading about for you) for the power supply part. Ask your questions here for getting going I'm sure folks here will be glad to help.
RE: electric shock warning... not meant to be condescending or anything close to that at all. There's a sticky on this forum, highly suggest you read thru that. There's some good stories of folks with LOTS of experience getting a good smack as well as tips to help avoid them. You work with tubes long enough you will get a shock, how much depends on your safety practices.
Cheers,
Bob
RE: electric shock warning... not meant to be condescending or anything close to that at all. There's a sticky on this forum, highly suggest you read thru that. There's some good stories of folks with LOTS of experience getting a good smack as well as tips to help avoid them. You work with tubes long enough you will get a shock, how much depends on your safety practices.
Cheers,
Bob
If you display the same attitude on other forums I'm not surprised you get put off when people try to help. If I wanted to demonstrate my superiority I can assure you I would talk about much more esoteric things than bleeder resistors. I wanted to confirm my suspicion that you are not aware of safety issues, apart from the simplistic "don't touch" which will not get you far with valve circuits - to debug you have to touch but you need to know what to touch and when.just an idea said:
My advice still stands: start with low voltage circuitry, where mistakes don't matter too much.
In case you have central heating radiators around your working place you should avoid leaning on them while probing you tube amp with one hand. That is more applicable to northern countries of course.
And no it is not funny tube amp bites nasty and can kill easily a way more efficient than 240V AC from receptacle. And once tube amp is working it very tempting to make a quick tweak hear or there right after unplugging it from receptacle and then plug it back quickly in order to hear the difference while forgetting about charged caps in PSU. So that is when good advice from forums helps slow down a bit and rethink stuff carefully.
Well I might suggest read the whole book first. Afterwards you may figure out what schematic looks more appealing for your needs clearly.
Roughly there are two major tube amplifier categories: tube amps with OTs (output transformer) and OCL-OTL ams (output capacitor-transformer less, OTL amps more applicable to headphone amps).
OTL-OCL (Atmosphere kits, Transcendent Sound DIY, Graaf) are probably most resolving tube amps (BW up to 500KHz). Exotic stuff.
OT's amp provides excellent speaker protection so there are suitable for DIY and are most common tube amps.
OT's amp can be SE or PP.
SE (Single Ended) can be with gaped OT or zero gaped OT ( so called parafeed). In most cases both are using triodes or triode strapped beam pentode output tubes.
Parafeed zero gap OT SE amps delivers up to 100KHz BW (SACD BW).
Gaped OT SE delivers 50KHz BW (LP MC cartridge delivers 30-45 KHz BW).
PP (Push-Pull) commonly use beam output pentodes (EL84, KT88)) and many commercial amps can be switched from triode to ultra-linear mode.
PP amp delivers BW slightly better than a gaped OT but less than zero gaped OT since PP OT has very minor gap.
Then you might consider global feedback if you need it or not. Something like that.
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