Rather sad GloBug. I pick some very legitimate safety concerns, and you see fit to defend the person who is selling these things commercially. I make some observations about the law, you challenge my knowledge and tell me to 'look it up'. I did, and confirmed my belief, and posted the appropriate link. Hopefully Steve reads it, fixes the safety issues affecting his customers and does not suffer under the law.
I am happy to address your statements towards me.
That link to the Rod Elliot site is a great resource for people trying to understand why safety ground is important, what a ground loop is and how to fix it safely. The very first not he makes is:
I am not too sure about your claim of using an 'uncertified imported amp with a 100v transformer'. If you elaborate, I will happily respond.
The issue with hum in a gainclone amp. Yes, I did get it. It was a result of ground loops, exacerbated by the design of the PC board. You will note the date of that build was around 2003? The problem led me to learn more about the problem. I ended up fixing it and helping others to do the same.
Glue for the filter caps. GUILTY AS CHARGED. Yep, I did it. It was around the same time, for a gainclone amp. It was the BAD experience with this build that sparked my concern seeing others commit the same offence. That amp is scrapped, the transformer is on my parts shelf. I learned lessons from experience due to helpful advice from DIYAudio.
Yes, my son's amp has an exposed transformer. The wires, however, have been double insulated, and there are grommets for the wires to the chassis.
I am not sure about the comment regarding the lack of power cord. I use IEC power receptacles on my amps.
Now I will address the photos:
The first shot is a 6BM8 amp I built as a building experience prior to building a 'Baby Huey' amp, about 5 years ago. The power transformer is mounted such that its wiring is not exposed, it exits directly under the chassis. The output transformers do pose a shock hazard. Someone on the forum pointed that out to me, as the wires connect to naked tabs. I have heat-shrinked them, and the wires (not double insulated) enter the chassis via a grommet, however, yes, there is still a problem. Since being made aware of the problem, I construct amps with these transformers by mounting them with the end containing the tabs inside the chassis. Kind of like how Steve has mounted the transformer in that orange amp getting some attention in the posts above. If you do a more complete search of my posts, you will see I pass this advice on regarding a safer way to mount them. BTW, that amp was salvaged after the build for parts.
The second amp is my first tube amp. It is a Tubelab Simple Single Ended amp. It still sounds great, though it has been re-housed to incorporate the safer output transformer mounting described above and to reduce the switching on the front, as I have found the topology that works best for the setup I have. That amp is in my other residence, so don't have a shot to prove this to you.
Third photo is a botched attempt at point to point. It was my first attempt at scratch building a tube amp after building the Tubelab amp. It did not work, hummed etc. It was dismantled straight away. I did learn some valuable building experiences from that. In fact if you look at the photo, that was prior to build. It is just a raw chassis with the parts sitting on the top to get an idea of placement. That is why there are wires everywhere 😉
Fourth shot was a scratch built gainclone. It was my first amp building exercise around 2003. Yes, I made mistakes! Look at the hot melt glue! You will note however, that there is a safety ground 🙂
The fourth photo is a shot of a guitar amp that I built with my son. If there are any safety issues with it, I would like to know (honestly!). All power leads are protected with grommets, it has an IEC power connector. Not sure what thread you found that on, but I am pretty sure I posted the completion of that project - the whole amp is enclosed in a wood cabinet. The amp hangs inverted in the cabinet, there is no exposed wiring and the valves and transformers are protected from mechanical interference.
In short, those who have seen me on these forums will have seen that I have developed as a builder. My first amps were not that great. I have taken the advice here to improve the standard of my work and have been grateful for it. In fact, I am very proud of my 6L6 push pull amps that were developed, for the most part, from the very generous help of Tubelab and others on this site. No exposed wires, in fact, not even any exposed nut or bolt heads. I have measured the distortion figures to the best of my ability (second hand HP distortion meter), and it performs well. There is no hum that I am able to measure or hear. They sound fantastic (to me) and I think they look good too. I don't make any claim to them being better than anything other than my own previous builds though 😉 Where things have been pointed out as safety deficiencies, I have rebuilt with those issues in mind. I don't have an ego to protect. Hopefully others can look at the mistakes I have made and learn from them.
BTW, love the mixed metaphors 😉
What is your problem with me?
Last edited:
833A runs properly when red-plating. There are many rf output tubes that are designed to red plate under normal operating conditions. Most use additional heatsinks on the anode for improved power dissipation as there is a limit to the- anode temperature that needs to be respected.
Wiki has a nice brief on it.
833A - Wikipedia, the free encyclopedia
It has been raining on-and-off here for weeks (13 years of drought, now 3 years of flood), so in a brief break in the weather I went out for a bike ride. While riding I was thinking about GloBugs comments, specifically the uncertified 100 volt imported amp comment. All I can think of is an Adcom 555 power amp that I bought wile I was working in the USA. It was also sold here in Australia, so I am not sure about the 'uncertified'. It has a multi tapped transformer made for worldwide voltages, so with the appropriate documentation, I was able to make the appropriate changes on the terminal strip to make it 240 volts compatible. I have also modded it with a grounded cable (original was two prong) and put a 555 timer circuit for turn-on delay so that I don't get a 'pop' out of my subwoofers (555 is a good subwoofer amp) when the active crossover powers up. BTW I believe the Adcom 555 is designed by Nelson Pass, a contributor to these forums.
I have nothing to hide, if I have made mistakes I am happy to learn by them and hope others can too.
Cheers,
Chris
I have nothing to hide, if I have made mistakes I am happy to learn by them and hope others can too.
Cheers,
Chris
Don't sweat it, I was referencing the amplifier you bought from Japan.
I did not read your whole thread, but it looks like it might have had the proper taps for your country.
Don't loose any sleep on my behalf.
I did not read your whole thread, but it looks like it might have had the proper taps for your country.
Don't loose any sleep on my behalf.
I did not buy one from Japan. I looked at some kits, but ended up not getting one due to incompatible power transformers.
This thread grows very fast! Man, I love this forum; plenty of nutters like me. I didn't try to reverse engineer Steve's circuit because his wiring is a mess but you guys are braver than me. Hmmmm I wonder why Lance lied about his 'secret' circuit. Who is he trying to fool? Wrong forum Lance! 😀
About paraphase - I've been building amps with different paraphase circuits for 3-4 years now. I don't sell amps, I like experimenting. My amp has a floating paraphase and it sounds great - better than anything I have tried. I agree with Lance here. Fancier circuits didn't make it, this one stayed. I have no doubt Steve's amps are good sounding, if he could only make them safer......
About paraphase - I've been building amps with different paraphase circuits for 3-4 years now. I don't sell amps, I like experimenting. My amp has a floating paraphase and it sounds great - better than anything I have tried. I agree with Lance here. Fancier circuits didn't make it, this one stayed. I have no doubt Steve's amps are good sounding, if he could only make them safer......
Perhaps if you are a hermit and there is no chance of anyone other than your self ever coming into contact with the said amp then you can make that statement (and be a contender for the next Darwin award). However this seems highly unlikely and therefore there is a chance that someone (perhaps a family member) could be killed by your negligence if you take this approach. I suggest you take note of rule number three.
Tony.
Just for interest,
Regs are different in other countries however this is common practice..
I would not try to create a double insulated situation its to difficult to meet the criteria (not impossible).
All extraneous metal work that could become live under fault conditions must be earthed. That includes base plates that should have a flexible earth connected should the screws become loose or corroded and transformer end bells etc. This is sometimes done with one of the bolts without insulators (the other three insulated to stop a shorted turn) and testing the Tx is at gnd after mounting. I have seen people put an earth on transformers via flying lead at the back.
The mains lead should have an inner and an outer insulating layer..double insulated.
The size of the mains conductor and earth must be able to carry the fault current and fuse rating to suite.
This was covered with earthed equipotential bonding and automatic disconnection of supply..now changed to automatic disconnection of supply (ADS) this can only happen if enough current flows to Gnd/Earth via a chassis connection under fault conditions (the fuse blows). Any resistance is not permitted in the path for removing ground loops etc. However a ground plane can be lifted above chassis.
Live conductors must be enclosed or out of reach, holes are permitted based upon IP of the location of a size to prevent you putting your fingers or a childs fingers into the enclosure (danger).
All conductors must be enclosed in earthed metal work or be double insulated.
There is much more you could add. If you sell an old piece of kit and it has no plug and is untested
And labled for spare parts that’s a different situation.
If you build the bits into a new upgraded/different item it must meet current regulations because it
Has been reworked.
The situation with no earth on a metal enclosure could end up relying on earth from audio connections via other equipment and ground loop prevention resistors. The danger with this is that when someone unplugs the audio connector they could get fault or leakage potential across their body..This is worse than to Gnd via your feet because it’s across the heart.
I guess I should add that a competent engineer will have ways to meet the regs using their own ideas..IE if the feet on Tx end bells are stripped of paint "underside" and bolted to earthed metal they are at earth potential. (normaly with nylock nuts or anti vibration fixings)
Regards
M. Gregg
Regs are different in other countries however this is common practice..
I would not try to create a double insulated situation its to difficult to meet the criteria (not impossible).
All extraneous metal work that could become live under fault conditions must be earthed. That includes base plates that should have a flexible earth connected should the screws become loose or corroded and transformer end bells etc. This is sometimes done with one of the bolts without insulators (the other three insulated to stop a shorted turn) and testing the Tx is at gnd after mounting. I have seen people put an earth on transformers via flying lead at the back.
The mains lead should have an inner and an outer insulating layer..double insulated.
The size of the mains conductor and earth must be able to carry the fault current and fuse rating to suite.
This was covered with earthed equipotential bonding and automatic disconnection of supply..now changed to automatic disconnection of supply (ADS) this can only happen if enough current flows to Gnd/Earth via a chassis connection under fault conditions (the fuse blows). Any resistance is not permitted in the path for removing ground loops etc. However a ground plane can be lifted above chassis.
Live conductors must be enclosed or out of reach, holes are permitted based upon IP of the location of a size to prevent you putting your fingers or a childs fingers into the enclosure (danger).
All conductors must be enclosed in earthed metal work or be double insulated.
There is much more you could add. If you sell an old piece of kit and it has no plug and is untested
And labled for spare parts that’s a different situation.
If you build the bits into a new upgraded/different item it must meet current regulations because it
Has been reworked.
The situation with no earth on a metal enclosure could end up relying on earth from audio connections via other equipment and ground loop prevention resistors. The danger with this is that when someone unplugs the audio connector they could get fault or leakage potential across their body..This is worse than to Gnd via your feet because it’s across the heart.
I guess I should add that a competent engineer will have ways to meet the regs using their own ideas..IE if the feet on Tx end bells are stripped of paint "underside" and bolted to earthed metal they are at earth potential. (normaly with nylock nuts or anti vibration fixings)
Regards
M. Gregg
Last edited:
Even though he likes to use the word cooking (tuning) he's no master chef like Shindo. He's more of a plumber - tweaks resistors values here and there. Has no taste for caps.
Last point,
Sometimes its not possible achieve some of the regs due to mechanical or other situations. Then a Competent engineer can do what they think would be considered OK under the regs. However they would have to prove that every and all effort was made to make the equipment safe.
What is a competent person (someone with sufficient technical knowledge or traing to be able to comply with the current regulations)
In DIY most will apply recognised practice and through that meet the requirements.
Any way back to paraphase because its realy interesting..🙂
Regards
M. Gregg
Sometimes its not possible achieve some of the regs due to mechanical or other situations. Then a Competent engineer can do what they think would be considered OK under the regs. However they would have to prove that every and all effort was made to make the equipment safe.
What is a competent person (someone with sufficient technical knowledge or traing to be able to comply with the current regulations)
In DIY most will apply recognised practice and through that meet the requirements.
Any way back to paraphase because its realy interesting..🙂
Regards
M. Gregg
Last edited:
Okay, I agree with you all about the three prong plug and I'll make it right. It had nothing to do with ground loops, it's just how I was taught, but after reading everything you posted and all the links, I have to agree and it will be corrected.
I'd like to thank those who were trying to be genuinely concerned for me and their advise did not fall on deaf ears. Thanks.
Steve
I'd like to thank those who were trying to be genuinely concerned for me and their advise did not fall on deaf ears. Thanks.
Steve
Steve,
I realy respect this post please stay with us and watch the fun..🙂
Welcome to DIY audio..
Regards
M. Gregg
I realy respect this post please stay with us and watch the fun..🙂
Welcome to DIY audio..
Regards
M. Gregg
Well, I'll try and see. There are some very nice and knowledgable people here, but there are some real bullies too. I'll sit here and see how things go. I love talking tubes and I love to share, but Remember when I first got here, I saw all of you nit picking my work apart, and I felt very violated. You all wouldn't like it either.
FYI- it was a lab that a customer sent a couple of my amps to that measured the THD, so I can't be 100% on that, but it did come back like that several times. Now, if you all start jumping down my throat again, I'll leave. Play nice, and I'll stay, simple.
Steve
FYI- it was a lab that a customer sent a couple of my amps to that measured the THD, so I can't be 100% on that, but it did come back like that several times. Now, if you all start jumping down my throat again, I'll leave. Play nice, and I'll stay, simple.
Steve
Excellent!
Yes, your work will be picked apart here. Mine is as well. That's the difference between a typical audiophile forum and this one, populated by fellows with engineering backgrounds and decades of experience. It makes my designs better, so I don't take any of that personally. My work has incorporated input from people like Morgan Jones, Jan Didden, Allen Wright, John Curl, and Nelson Pass (as well as lots of other incredibly smart and generous people that no-one has heard of)- where else could I have gotten such terrific design consultation, and at no cost?
- Status
- Not open for further replies.