This is my first completed tube amp. Sounds awsome, I'm very happy with it.
(schematic removed by moderators for safety reasons)
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
(schematic removed by moderators for safety reasons)
Have you designed the circuit? I see there is no power transformer used 
That can be fine for you, but actually it is pretty dangerous. A newbee can just look at it and think: "nice, project without power trafo, that will save me some bucks". I would at least put a remark about this issue on the schematic.
That can be fine for you, but actually it is pretty dangerous. A newbee can just look at it and think: "nice, project without power trafo, that will save me some bucks". I would at least put a remark about this issue on the schematic.
The "euro - style" barrier strips, as they are often called in the states actually work pretty well as no solder terminal strips. The ones sold here at Radio Shack are rated to 450 volts. I have cranked 550 volts through them without issue, and the nylon dielectric material should have no loss at audio frequencies. They should work as well as any other solderless connector. I have an 80 watt push pull breadboard amp that is entirely assembled on these connectors, and it works well.
The no line isolation part is what scares me. A miswired electrical outlet could put the line voltage on the case of your CD player!
This is a total death trap. DO NOT BUILD ANYTHING LIKE THIS CIRCUIT!
I have to agree with tubelab. I am now in the tube diy for about 3 years, shown by my date of registration at diyaudio. After building some amplifiers and noting that after one week I started asking myself if it could be done better I started thinking about ways to make prototyping easier. I have spent the last year on that, thinking about an easy but reliable way of prototyping tube circuits. I finally came up with some building blocks that allows the combination of different tubes in different circuits. I don't have a digital camera, so I can't post pictures, but as soon as I get one I will do so.
I am using the euro-style terminal strips. Mine are also rated 450V and I think that it is actually no problem to go to 550V. I assume this based on the fact that 450V is the rating for use with high currents. Also, I have got two kinds of connectors. The first have a 10mm spacing between the copper 'tubes', the second have about 7mm...but are also rated 450V... higher spacing = higher insulation!
Erik
(I once sent some earliers version pictures to tubelab, but probably he has thrown them away - and I changed my PC)
I am using the euro-style terminal strips. Mine are also rated 450V and I think that it is actually no problem to go to 550V. I assume this based on the fact that 450V is the rating for use with high currents. Also, I have got two kinds of connectors. The first have a 10mm spacing between the copper 'tubes', the second have about 7mm...but are also rated 450V... higher spacing = higher insulation!
Erik
(I once sent some earliers version pictures to tubelab, but probably he has thrown them away - and I changed my PC)
Banned
Joined 2002
Jeb-D. Can you share that schematic or email it to me ? I have a pair of them tubes if i can't use them i should sell them.. I have a brand new pair of 6C33-cb with ceramic socket's if i can id like to build a amp..
Oh BTW looks really nice.. Expencive ? How does it sound so far ?
Oh BTW looks really nice.. Expencive ? How does it sound so far ?
An externally hosted image should be here but it was not working when we last tested it.
Contrary to what some of you say, it is safe. By looking at the wiring it "appears" that the components are grounded to the chassis via the neutral line. The neutral line and the star ground of the amp are actually isolated from the chassis. There is a plastic mounting block that has that screw stud sticking out of it. The chassis, transformer housings, cap clamps, VC, ect are grounded by the third, ground prong, on the 3-prong plug. If the hot or neutral were to come loose and touch the chassis the breaker would go off. I do have an isolation transformer with an ungrounded secondary, but I only have to use it when using a grounded output signal source, such as a computer. People died in the past because they were using 2-prong plugs and grounding chassis with the neutral. Some people would put the plug in reverse polarity and "zap". Or if the neutral line were to open then it would leave the chassis at 120V and "zap". This grounding scheme prevents either of those circumstances. If any of you can come up with a logical reason why this is dangerous let me know. Because saftey is my first priority. Obviously a new-B that mis-wires something is dangerous regarless of topology.I would put a disclaimer and specify the grounding details in the original post but it is too late to edit it. Mods took the schematic down anyhow.
Yeah, the CD player does suck. It used to resonate, untill I stacked the heavy amp on it. Now it sounds good, for a hand-me down.
As for the chassis I got it from this website http://www.yaegeraudio.com/
The OPT's are from some guy in Hong Kong he sells them for like $50 each. If any of you are looking for a 6c33c transformer I'll hook you up with his e-mail. Don't let the low price tag fool you, the quality is probably better than any EI type that i've messed with before. But shipping time to the states is long. Shelling out extra for express shipping would be worth it.
Specs: 600ohm primary, 4&8 ohm secondaries, primary DCR 15ohms. The max DC current was either 250 or 300mA, I forgot though.
The plate voltage on the 6c33c is roughly 150V, but will vary depending upon how high the idle current is set, because of the DCR of the choke and the xfmr. Playing with the bias on the output stage changes the way it sounds. Just slightly more, than enough idle current, to deliver full power at max drive is what I perfer. It gives a grounded-cathode like mids but with much better bass. Since Zout of the cathode follower is much lower. Also output gain doesn't fluctuate as much with reactance, as opposed to the grounded cathode. It handles 2&3 way speakers fine unlike alot of grounded cathode SET's.
Yeah, the CD player does suck. It used to resonate, untill I stacked the heavy amp on it. Now it sounds good, for a hand-me down.
As for the chassis I got it from this website http://www.yaegeraudio.com/
The OPT's are from some guy in Hong Kong he sells them for like $50 each. If any of you are looking for a 6c33c transformer I'll hook you up with his e-mail. Don't let the low price tag fool you, the quality is probably better than any EI type that i've messed with before. But shipping time to the states is long. Shelling out extra for express shipping would be worth it.
Specs: 600ohm primary, 4&8 ohm secondaries, primary DCR 15ohms. The max DC current was either 250 or 300mA, I forgot though.
The plate voltage on the 6c33c is roughly 150V, but will vary depending upon how high the idle current is set, because of the DCR of the choke and the xfmr. Playing with the bias on the output stage changes the way it sounds. Just slightly more, than enough idle current, to deliver full power at max drive is what I perfer. It gives a grounded-cathode like mids but with much better bass. Since Zout of the cathode follower is much lower. Also output gain doesn't fluctuate as much with reactance, as opposed to the grounded cathode. It handles 2&3 way speakers fine unlike alot of grounded cathode SET's.
You are operating under the presumption that Neutral is Neutral and Line is Line. Consider the situation where the socket is wired incorrectly... and this DOES happen. Or the case where someone uses a 2 conductor extension cord and casually hangs the ground prong over the end of the receptacle on the extension cord.
The trouble comes when you hook to another piece of gear.
Check this out!
This is supposed to be Plug and Play with multiple layers of protection... your implementation is Plug and Poof.
The trouble comes when you hook to another piece of gear.
Check this out!
This is supposed to be Plug and Play with multiple layers of protection... your implementation is Plug and Poof.
An input transformer could make this amp safe - transformer isolated from source and speakers. If the transformers will pass a 1000V isolation test, it could even be approved by a safety agency.
An example of this type of design is on Steve Bench's page here: http://members.aol.com/sbench/50c5.html
I helped my bother-in-law wire an addition to his cottage... but FIRST, I rewired all the outlets that were wired backwards - HALF of them! Neutral must always be isolated, because sometimes it's HOT!
An example of this type of design is on Steve Bench's page here: http://members.aol.com/sbench/50c5.html
I helped my bother-in-law wire an addition to his cottage... but FIRST, I rewired all the outlets that were wired backwards - HALF of them! Neutral must always be isolated, because sometimes it's HOT!
Thanks for the input guys. I suppose the fact that the input and output to speakers are referenced to the neutral could potentially cause a problem. Of course I metered the outlets first. I found that with all the appliances and lights in the house turned on the neutral only has a 1Vpk sine wave due to the resistance in the house electrical. Which isn't enough to really do anything, and I don't rewire things with it plugged in anyhow. But still, I suppose a potenially hazardous circumstance could occur. Instead of floating the output and putting in input transformer. I decided to ground the secondary of my 1:1 isolation transformer and run it off of that. Luckily I already had one lying around from previous experimentation.
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