No shortcuts. You can learn it in a couple hours of playing with it. That's how I did it.
Your dad is wise.
If you take shortcuts building this amp you could end up dead. Take your time, test each assembly thoroughly before moving on. Test the amp as each stage is added. Have a fire extinguisher handy and an escape route planned. The time invested in doing it right is worth it in the end.
i hear you loud and clear i know this is a very dangerous voltage to work at and im going to be taking my time as theres going to be a lot of money involved in building this amplifier but the end result will be very worth im going to get going now its 23.21pm here in the uk its been an absolute pleasure speaking to you until next time take care and good night.
Hi Guys i thank you all very much indeed but to me the 833 is the way forward for me i dont care if this thing costs me £10,000 to build i need to build it i have seen the midlife crisis end result very impressive indeed will probably need some guiding but in the end i will get there lol!
its the look of the tube that does it for me its amazing!
just trying to find the.sch files for eagle to see how this thing works before i start ordering the bits and putting this thing together.
How about just hooking up the filaments, but not the plates.
(and then running something else to handle the actual sound, mounted off to one side).
That you you get the coolest looking tube ever, but you don't have to cobble together a supply capable if putting out 1 Amp at 3000 Volts.
I'm just trying to figure out why you are so set on building something that pumps out 200 watts. A 200 watt amp is only twice as loud as a 20 watt amp.
Lets put this into perspective.... with a normal amp at NORMAL listening levels, meaning something that won't tick off the parents of have your wife filing for divorce.... you may be using something like 1 watt, maybe less. That is at ambient levels. If you are in a room in your house and you actually try to use 200 watts, you won't enjoy much after that because you will likely be either deaf or at least very hard of hearing.
I have a 12 watt 6v6 pp amp that I built last year. These are running B&W DM330i speakers. Not overly efficient but not that bad either with a 92db spl rating. So, I put on shooters head phones for hearing protection and started turning up the volume. Even with the level of hearing protection that I was using, it was uncomfortably loud.
When picking an amp to build, the folks here have given you quite a bit of good information. If you don't know what you are doing with high voltage, and I mean REALLY know what you are doing, then leave that alone. Like one poster hear said you will not get a second chance. Build something reasonable like a 6l6 based amp and see how you like it.
After reading your posts about wattage requirements, I am pretty sure that at this point you are looking at wattage thinking "more is better".... not so much. Wattage ratings on commercial amps that you find in your local stereo store are a great marketing ploy for those who don't know the math behind it.
To start with, Edcor OPT, power, and chokes are good buys. So are Transcendar OPT. I have both in my amps and am very satisfied with them. You can pick up Russian tubes with no issues and they do sound good. What's better is that you can experiment with different brands of the same tube to see what sounds better to you.
If this is your first amp, and I don't know what your building expertise is, don't be surprised if a cap explodes, resistors smoke, etc... It's far less dramatic blowing up a cap at 300v than it is at over 1kv, not to mention far less expensive. Once you get over 500v with electrolytics, then you will be spending quite a bit more money on them.
Start small, see how it sounds and then go from there. My 2 cents.....
Lets put this into perspective.... with a normal amp at NORMAL listening levels, meaning something that won't tick off the parents of have your wife filing for divorce.... you may be using something like 1 watt, maybe less. That is at ambient levels. If you are in a room in your house and you actually try to use 200 watts, you won't enjoy much after that because you will likely be either deaf or at least very hard of hearing.
I have a 12 watt 6v6 pp amp that I built last year. These are running B&W DM330i speakers. Not overly efficient but not that bad either with a 92db spl rating. So, I put on shooters head phones for hearing protection and started turning up the volume. Even with the level of hearing protection that I was using, it was uncomfortably loud.
When picking an amp to build, the folks here have given you quite a bit of good information. If you don't know what you are doing with high voltage, and I mean REALLY know what you are doing, then leave that alone. Like one poster hear said you will not get a second chance. Build something reasonable like a 6l6 based amp and see how you like it.
After reading your posts about wattage requirements, I am pretty sure that at this point you are looking at wattage thinking "more is better".... not so much. Wattage ratings on commercial amps that you find in your local stereo store are a great marketing ploy for those who don't know the math behind it.
To start with, Edcor OPT, power, and chokes are good buys. So are Transcendar OPT. I have both in my amps and am very satisfied with them. You can pick up Russian tubes with no issues and they do sound good. What's better is that you can experiment with different brands of the same tube to see what sounds better to you.
If this is your first amp, and I don't know what your building expertise is, don't be surprised if a cap explodes, resistors smoke, etc... It's far less dramatic blowing up a cap at 300v than it is at over 1kv, not to mention far less expensive. Once you get over 500v with electrolytics, then you will be spending quite a bit more money on them.
Start small, see how it sounds and then go from there. My 2 cents.....
Yes, been there built that. I have built several amps using the 6LW6 tube since it is the biggest sweep tube available, but the days of finding then cheap or even in reliable supply are gone. The 525 watt version of Pete's amp ran 35LR6's since I got a bunch of them cheap at a hamfest.
Pete's amp was designed for a very conservative 18 WPC. Yes, I squeezed 525 watts out of a board in mono block configuration, but I wouldn't recommend running the board that hard for long term reliability. There are some traces on the PC board that are too close together for comfort at the kilovolt levels that they will see. 125 WPC is reliable, and relatively easy. The details are somewhere in the long thread.
Most commercial speakers, especially big ones, were designed to be driven from a solid state amp, since big tube amps are not common in the commercial market. This means a decent damping factor in needed for tight well controlled bass.
Magz has proven that it is possible to build a big Single Ended tube amp with the 833A that works well for him. It took considerable effort, and a large cash outlay......maybe "cheaper than a Corvette" but, not something that should be attempted as a first amp build. Would you attempt to restore a classic Corvette if you have never changed a head gasket?
The 833A is a BIG awesome looking tube. I liked its looks, and wanted to build a big HiFi amp several years ago. The 833A was designed for an RF amplifier in a radio transmitter. It is also used as the modulator (a big audio amp) in the same radio transmitter, but it is really not the ideal tube to use in an amplifier that runs a speaker particularly if good bass is a primary consideration.
The 833A has a Mu of 35 which results in a high plate resistance. Using this tube in an audio amp will result in a low damping factor unless a lot of feedback is applied. Some of this can be mitigated by using a higher impedance OPT and a lot of plate voltage. I believe MAGZ amp used 2200 volts and 10,000 ohms, but I really don't remember, read the entire thread. This makes the OPT design far more difficult, and EXPENSIVE!
I chose the more common 1500 volts and 5,000 ohms and discussed my plans with a well known transformer designer who makes OPT's for a lot of the amps seen on this forum including several of mine. He agreed to make me a sample transformer for my 833A amp for the cost of time and material, so I got one OPT. The results were NOT suitable for use in a HiFi amp, and we agreed not to pursue this plan any further.
The 833A does exhibit a behavior that would work awesome in a SE guitar amp, so I tested the setup with a guitar preamp, and it does work quite well for that application! I may build one some day.
The results are here, but DO NOT duplicate my high voltage testing practices unless you really understand all the different ways this kind of power can kill you or burn your house down!
Understand that under NORMAL HiFi listening conditions your OPT, and your amps wiring will see voltages equal to TWICE the B+ voltage, and under clipping or mismatched load conditions, this can be 3 or 4 times the B+ voltage. I have seen over 2 KV in a guitar amp cranked to full tilt into a normal guitar speaker near resonance....from a B+ of 430 volts!
833 SE | Tubelab
I have build DHT (833A, 845, 211, 300B, 45 tubes) amps in both SE and P-P, conventional audio tube (KT88, EL34, 6L6GC) amps in SE and P-P, and amps with all sorts of oddball tubes, including TV sweep tubes.
If I were to try to choose which of all of these would be the best choice for a first time builder that wants big bass at 100+ WPC levels, it would be the 125 WPC version of Pete's design that I posted in his thread. At least a dozen of these were build and none have blown up that I know of, and the construction costs are quite reasonable.
Once you have succeeded, and you want to build a BIG push pull amp that costs less than a used Honda.....look at the 845's and 211's. These aren't as awesome as the 833A, but actually work better for audio and a pair in push pull will still make over 200 watts. A single tube will make 40 watts in SE. Either way, a GOOD OPT is a must. It will see several KILOVOLTS!
845 SE | Tubelab
The plate voltage is 2300V, the OPT is 12k:4.
I also found that adding an autoformer between the amps and the speakers (to raise the speakers' nominal impedance from ~3-4ohm to ~12-16ohm)made everything sound a whole lot better. One of these days I plan to build some 16 ohm speakers just to see how they'll sound; I just love the sound of those old Infinity amp-killers, though!
"I also found that adding an autoformer between the amps and the speakers (to raise the speakers' nominal impedance from ~3-4ohm to ~12-16ohm)made everything sound a whole lot better."
That sounds suspiciously like what I've heard before for OTL amplifiers. A huge initial effort to avoid an OT, then they find it sounds better when they put it through an autoformer. I assume that's because the bass got better with a lower output Z.
That sounds suspiciously like what I've heard before for OTL amplifiers. A huge initial effort to avoid an OT, then they find it sounds better when they put it through an autoformer. I assume that's because the bass got better with a lower output Z.
If you like the looks of the 833, check out the Philips TB3/1000
http://www.diyaudio.com/forums/tubes-valves/111971-tb3-1000-alive-european-833a.html
The amp now sees 12 to 16 ohms, so the 833A now sees about 48K ohms. Yeah the damping factor just got a whole lot better. You probably lost some output power, but with 200 watts available, who cares.
There was an auto-former called the Zero several years ago that was marketed as an improvement for OTL's.
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