Audio advice and discussions with audiophiles and professionals. Free discussion forums, open to all and frequented by industry experts. Ask questions and get advice on stereos, speakers, hi-end amplifiers, pre-amps, home theater, tube hi-fi, turntables, vinyl, tweaks, music, films, video, DVDs and more.
Hi Everyone, My latest project... A stereo integrated amp with full remote control. Class A pp u/l with up to 25 watts per channel. I do admit to cheating on the remote control section. It is modular and does all the volume, source selection and muting functions. It is the same as the one I had at LSAF in the preamp. This project is not finished yet and it probably will take me a month to get it to the level that I can post the schematics and details. A fun if not particularly inexpensive project (about $200 in trannies alone). For all you folks that can't or won't diy it, I suspect in about 6-9 months my commercial side will be issuing it as either a kit or built (maybe both). Sadly it won't be cheap there either.
Hi Everyone, Updated Amp Photo:
I am so envious of people that are electronically blessed. I am electronically challenged. This is a great example of DIY it looks very complicated. Thanks for the pictures.
Hi, Everyone starts somewhere. Diy is IMO a learning process. Find a simple project and preferably a mentor or at least assistant and go for it.
Bruce, that looks stunning! Your amps sound great too - That model is a game changer!
Which model is that? It looks like the "podwatt", but that's only 5watts per channel. I'm looking to build another tube amp (kit) this winter, to power a pair of 7pi I'm building. Perhaps I can go with some mono blocks. Wayne, if you don't mind me asking, which "Oddwatt" amps have you listened to with your 7pi corner horns or your 4pi's?
I've run Bruce's Podwatt and Oddblock amps. The Oddblock had KT120 tubes in it. Both are really good amps. Like you've said, the Podwatt is a relatively low-power amp, but it's enough for any models of my speakers. I still like the Oddblock better because of its ability to deliver more dynamic range. But the Podwatt will surprise you. Bruce's amps all sound like SET amps, but they're less finicky than many of the SET amps on the market. Many SET amps have a tendency to drift as their tubes age, sometimes to the point of overheating biasing resistors and popping coupling or bypass caps. Bruce's amps don't do that.
Hi Folks, Thanks for the kind words. In a way it is a shame that the middle sized amps don't get more interest. The KT77/EL34/KT88 amps are quite the same in sound and have lots of punch. The nice thing about them is that you can roll all sorts of tubes. Anything in either size range can be used. The parts to build them is significantly lower as well. The difference between 28-30 watts rms and 40-42 is not going to be heard. With the smaller tubes it is 15-18 watts rms. Still plenty for most uses. The KT120 mono blocks can also use KT88/KT90 and similar tubes as well. With the present possibility of lots of bum KT120s and KT150 running around I personally would either wait for it to sort out or go for the mid size amps. BTW I was running my system just yesterday with the mini mono blocks which are really 1/2 each of the newest Poddwatt. I have always loved the sound of EL84s and these amps don't disappoint. They are just sufficient to drive my Martin Logan ESLs to a comfortable level...I would not use them for loud rock as they don't have that level of power.
Bruce... When you say "mid size amps" are you referring to the series 2 Octals? Those are the mono blocks I was considering, using kt88's. Wayne's 7pi's are 101db sensitivity, so I'm guessing that's plenty of power.
Hi, That is correct. The Octals are excellent amps and there is no likelihood of running out of power tubes that work in them.
I really like the 6550 / KT88 tubes. And with what Bruce has found on the larger tubes, that makes it even more of a sweet spot for me.
I like the kt88 tubes as well. I would think the current troubles with the kt120's will pass. Is TUNG-SOL the only current manufacturer? I have decided to go ahead with a pair of OddWatt Odd Block series 2 octal using kt88s. It looks like it should be a fun build. I agree with you about some current SET amps being fickle. I've had my own issues with a kit I built, started blowing fuses (after around 200 hrs.), needing a very specific rectifier tube to correct it (EH 5U4GB). Regards!