Building my first project a Mullard 3-3. I'm building it to see If I like the valve sound. It has a primary impedance of 22,800 where are the Mullard states I should use an output transformer with a primary impedance of 5000 ohms.
What would I see with the increase of impedance, an severely decreased frequency response? If so do you think there would still be enough of the spectrum test the water with the valve sound?
What would I see with the increase of impedance, an severely decreased frequency response? If so do you think there would still be enough of the spectrum test the water with the valve sound?
Hi.
What are you building? Is it a guitar amp? It seems that transformer is meant to drive a guitar reverb tank circuit. Too high a primary impedance will step down the output of the tube too much and give you a very low power output.
Cheers.
Rolf.
What are you building? Is it a guitar amp? It seems that transformer is meant to drive a guitar reverb tank circuit. Too high a primary impedance will step down the output of the tube too much and give you a very low power output.
Cheers.
Rolf.
Okay I see what this is.
http://www.r-type.org/static/3-3.htm
Try Edcor Transformers. They make excellent and inexpensive small output transformers. Are you going to make a stereo version? With or without the tone controls?
Good luck with your project. I don't know how good an amp this is but the sound will probably surprise you if get it working right and use good parts. The Edcor XSE15-8-5k Transformer would be an excellent choice assuming you are running 8 ohm speaker(s).
Cheers.
Rolf.
http://www.r-type.org/static/3-3.htm
Try Edcor Transformers. They make excellent and inexpensive small output transformers. Are you going to make a stereo version? With or without the tone controls?
Good luck with your project. I don't know how good an amp this is but the sound will probably surprise you if get it working right and use good parts. The Edcor XSE15-8-5k Transformer would be an excellent choice assuming you are running 8 ohm speaker(s).
Cheers.
Rolf.
Thanks for the reply rolf. Those transformers are so cheap! It's going to be one mono-block with a volume control. I'm going to use it as a platform to see If I want to build a stereo pair of valve amps and pre-amp (may or may not be based on Mullard 3-3).
What's the best site to deal with in the UK for valve stuff? Also what's the general consensus on the Hammond transformers?
What's the best site to deal with in the UK for valve stuff? Also what's the general consensus on the Hammond transformers?
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Have fun building this amp and learn from it but I wouldn't judge tube gear in general based on what you hear from it. this amp uses a fair bit of negative feedback to linearize inherent distortions. Most modern DIY tube stuff is made to be low in unpleasant harmonic distortion. with little or no added feedback.
Maybe someone else reading this knows this amp and how it sounds? Alternatively If you are not too far along with this project you could get suggestions for other simple but very nice sounding amplifiers. my personal suggestion would be this. http://the-planet.org/6EM7.html
Sorry I can't answer your other questions
Cheers.
Rolf.
Have fun building this amp and learn from it but I wouldn't judge tube gear in general based on what you hear from it. this amp uses a fair bit of negative feedback to linearize inherent distortions. Most modern DIY tube stuff is made to be low in unpleasant harmonic distortion. with little or no added feedback.
Maybe someone else reading this knows this amp and how it sounds? Alternatively If you are not too far along with this project you could get suggestions for other simple but very nice sounding amplifiers. my personal suggestion would be this. http://the-planet.org/6EM7.html
Sorry I can't answer your other questions
Cheers.
Rolf.
I've thought about it, I think I might as well build something high quality. What do you think about the Mullard 5-10? Or the 5-20? I'm quoting Mullard designs because I have the book in-front of me and the details of construction are quite complete, which I think will help overcome the learning curve. I can even make the chassis in a metal working shop I have access too. However I like the look of that SET project!
http://www.r-type.org/static/5-10.htm
http://www.r-type.org/static/5-20.htm
http://www.r-type.org/static/pre.htm (preamplifier for 5-20)
http://www.r-type.org/static/5-10.htm
http://www.r-type.org/static/5-20.htm
http://www.r-type.org/static/pre.htm (preamplifier for 5-20)
I'm pretty sure the Fender transformer you have is designed for a single ended amp and the Mullard design is push-pull. Likely you would be able to hear sounds but it would be a poor test of wetter you like the "tube sound" as it would be badly distorted.
Also, if you look at the Fender design they purposely filter out the lows before they send the signal to the transformer, that transformer is not designed for anything below about 200Hz. So no bass. After all the goal was to drive a spring reverb tank not a hifi speaker
For a three watt push pull look for a transformer rated at about 15W.
save that transformer. It would make a good headphone amp. Drive it with a 12AU7 tube and at 1/2 watt or less it would have decent bass but at three watts no.
Good idea. But build a high qualiity SIMPLE design. The mullard push-pull has lots of parts and many ways to go wrong.
Try building a single end (SE) design. These amps arguably sound better than push pull and have about 1/2 the number of parts. The cost is that SE amps have less power. You can build a low power SE stereo amp with three tubes. Start with something the uses one 6V6 or EL84 per channel.
Basic rule: Do NOT build anything you can not diagnose and debug. I'd actually recommend a low power, low gain guitar amp as your first project but that's useless if you don't play guitar, so the next simplest thing is a small SE stereo amp.
Hi.
I agree with Chris with the exception that he is wrong the 3-3 being Push Pull.
When I Googgled it and found that link I put in post three, the Schematic clearly shows it to be single ended. Maybe all their other designs are push pull?
Cheers.
Rolf.
I agree with Chris with the exception that he is wrong the 3-3 being Push Pull.
When I Googgled it and found that link I put in post three, the Schematic clearly shows it to be single ended. Maybe all their other designs are push pull?
Cheers.
Rolf.
I built that 6em7 dc amp as my first project. It is dead simple. Really about as simple as an amplifier can get. The sound is truly excellent as well, it will really give you the tube sound you want to hear. The only reason you might need to build a replacement for it, besides having gotten the Diy bug, would be if you really needed more power.
Use those Edcor transformers, and try to get new old stock tubes. If you have to use used tubes, get several so you can match up a pair that give at least close to the specified voltages and are not to different from each other. you can use a 5ar4 rectifier tube, they are still being made and are common.
Cheers.
Rolf.
Use those Edcor transformers, and try to get new old stock tubes. If you have to use used tubes, get several so you can match up a pair that give at least close to the specified voltages and are not to different from each other. you can use a 5ar4 rectifier tube, they are still being made and are common.
Cheers.
Rolf.
Sorry I read "Mullard" and assumed the classic "Mullard Amp"
But that 3-3 has to be one of the more complex SE amps I've seen. I was thinking about something simple like this....
http://diyaudioprojects.com/Tubes/KT88/F01-KT88-Amplifier.png
But I'd suggest a 6V6 in place of the KT88 to save a pile of money on not only the tubes but the three transformers. Use Edcor transformers and normal caps and you might get it done for under $200.
If you are building an SE amp a tube rectifier does not contribute to the sound you can use solid state diodes unless you just like the idea of "all tubes". You can buy both an 12AX7 and 6v6 as new production tubes and not have to pay a premium price. The JJ versions are very good and reasonably priced at $10 or $12
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Edcor aren't replying to my e-mails, so I'm going with a company called VVT Transformers. They offer transformers with and without bell caps. Bell caps are to shield from RFI am I right? Is it worth getting bell caps? I can save quite a bit on the overall cost of the transformers if I get the C-Clamp style transformers.
The Edcor transformers are open frame and work well so I guess they should be alright without. I have a transformer on order from Edcor that I ordered by telephone. They said two to three weeks for shipping so I guess they are pretty busy. I hope the vvt ones work out well for you. Are they English?
What amplifier did you end up deciding to build?
Cheers.
Rolf.
What amplifier did you end up deciding to build?
Cheers.
Rolf.
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