Using a classic Heathkit WA-1 (circa 1950's) Williamson design audio amplifier and investigating its performance using different power supply rectifiers.
Sorry I haven't been watching videos lately. My summer up here in Pa has been really busy. Just trying to get everything ready for winter again. Great video. I recently cleaned out a house of a gentleman that passed away. Had one whole room in his house floor to ceiling with boxes of tubes. One tube there were a few dozen of was the 5R4 GY. That would have been an interesting one to try. I love when you compare tubes like this. I have a lot of different amps I want to build. Really wish or need a distortion analyser. Would like to get one like you have, but haven't found one I can afford. Going to go back and see the videos of yours I missed. Also, just had a 6 week old kitty show up at our place. He's our new baby. Getting too many, but we love them all.
I did this conversion on one of the old Altec amplifiers that uses the 6ca7 output tubes. Distortion dropped by an order of magnitude and power output increased by about 38%. The thing that you have to watch out for with these solid state rectifiers is that they come up instantly and if the surge capacity of the filter capacitors can't handle the voltage you may have Arc over. The other issue is that the tubes run much hotter so you may have to adjust the screen grid voltage to keep the plate current from running away.
The last scene of the MV rectifier and your equipment in the dark was FUN and impressive! Thank you for that. You have some very nice equipment.... jealous here hehe!
Your cat looks like a real sweetie, I happen to have two pet cats of my own, or rather they "own" me, one is a female calico named Holly, the other is a male dark grey and white named Gengle.
This kitty in the video, Angel, is the gentlest and sweetest cat I have ever had. Never once scratched or bit me to draw blood. I have another (feral) outside mother cat that gave me kittens 10 weeks ago and Angel, is so happy with them. She is not the mom but I let them in the house to keep them socialized so hopefully... someone will really want the kittens soon. I am keeping one, a little female, so Angel will have a friend inside. I am sure Holly and Gengle keep you busy. Thanks for your nice comment.
Some data that can be gleaned from this experiment is the DC voltage output, under proper load, of the various rectifiers working into a Pi filter, (capacitor input) sometimes known as a CLC filter is as follows: With 411 RMS AC volts input to the rectifier plates (822 volts, CT grounded, also known as a FWCT rectifier circuit): The 5V4 voltage gain of 116%, (478 VDC) The 5U4 voltage gain of 108%, (442 VDC) The 1N2632 voltage gain of 125%, (512 VDC) The 83 Hg voltage gain of 119%. (488 VDC)
David, I think many of the Hickok testers operated the 83 sideways as well. I have a bunch of Heath amps that I have not gotten around to yet, so thanks for this.
I have a loving feline family. My Pale Pussy is ALWAYS meowing like that. He does it when he wants to be fed. He doesn't stop until he is. And he ALWAYS wants to be fed.
I really wish you would do one more video on this amp after u recap it those red caps are killing that amp I have 25 of them that leak like crazy I took out of my old hp gear
I tell u what just unsolder one and read the leakage across it just for kicks lol I mean if those coupling caps completely go that might be the end of that beautiful little peerless transformer. It's worth a check. I can almost promise u they are terrible and this amp is even better than u think.
I just know that amp is being held back in a big way the fact that it performs as well as it does just makes wonder how good it really is. Ok for real I'll shut up.
I apologize if I missed it, but when you were discussing putting caps in series in order to get the additive effect of the WVDC of each cap, I don't think you mentioned how you would calculate the effective capacitance. Most of us know this, but the effect of adding caps in series regarding capacitance is the same as the effect of adding resistors in parallel for the total resistance. It's the product of the two caps divided by the sum (C1 x C2 / C1 + C2), or an alternate way to calculate and if you're using more than two caps 1/ (1/C1 + 1/C2 + 1/C3 + ...)
Thanks, Fred. Totally forgot to address that issue. I remember as a kid getting my ham license and looking at that reciprocal of the sum of the reciprocals formula and just trembling at the thought of having to do that longhand. Slide rules didn't help with that problem but with today's calculators, it's a quick job for any number of capacitors in series and as you mentioned, I think most know that any number of, equal capacitance, capacitors in series, is just the the capacitance of one divided by the number of capacitors.
@@ElPasoTubeAmps Funny you should mention having to do it long hand back in the day. I did that as well and didn't care for the effort involved, mostly with resistors. Sometimes I would get lazy and ballpark it and then measure the resistor network instead.. 😊😊
Cats are cool, imo. Mine are characteristically curious. Keep her out of the HV. I keep anything exposed under 50 volts or so. Had to rewire 77 volt lighting. Curiosity killed the cat - don't repeat 😺
I am sorry to hear that about you kitty- I hope I misunderstood that your cat was harmed. I certainly understand and just recently made sure my 833A amplifier is completely enclosed as it has 4000 volts on it. Every piece of equipment in my ham radio room is totally enclosed and - as far as I can assess it - and is completely safe from the outside with one exception - my AM transmitter. It is safe from the front but not the back so if I operate it I make sure my cat is locked out of the basement. It would be difficult to make this piece of equipment cat-proof. Stay safe...
Here is a nice datasheet for the 83 that is worth reading and the advantages of this tube can easily be seen. frank.pocnet.net/sheets/021/8/83.pdf Hi power Hg rectifiers like the 866A and larger, specify vertical, base-down mounting position only. Apparently, this is not required for the 83 and as mentioned in the video, the TV-7 tube testers operate it in a horizontal position. So, I don't see why it can't be operated upside down. I haven't looked but there may be a 4-pin to octal adapter on Ebay.
That Tektronix model (DMM 4020) has the option for reading watts and impedance values and can be selected between 2 ohms and some high value I don't remember at the moment. It is a very nice meter to have. The HP 8903 will display watts also. Here is a link to Ebay. www.ebay.com/itm/115134925876?hash=item1ace938c34:g:RsYAAOSw-pdhssKl&amdata=enc%3AAQAHAAAAoGLRK8xpGEQLaY%2BqFXdiwfCQOm8XpX3juIlIHpL7wjyLeMpbGc7UbA57dE2L5bDhnUcWM0S2sCSDkysl2Nh1idxuNcvd3T%2FEtVWMjEuwlEKnrDtjRYjVWcIhLPf0C78y7npskYNJnqAaCtqlMkqZC4%2Bukd4eBqOrvhPr0pU%2F4DupoGkm%2F0Lh0KW5%2BCeqUGMT7uSyiHng5Wn2WL%2F%2F0PyaSP8%3D%7Ctkp%3ABk9SR-LQgaSSYQ
