Tube-Town Forum
Technik => Tech-Talk TT-Projekte => Thema gestartet von: shto am 25.10.2013 17:51
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Hi - I'm new to this forum, and don't have much experience with building circuits - I bought the Tube Town Reverb Kit, and, while its easy to follow the layout for building the main circuit board and tube sockets, I cant figure out how to wire the transformer - it's the TT T30 toroidal transformer - the project page clearly shows where the green and red wires go, but I dont know where to connect the purple, yellow, black and red wires that are wrapped together. I also need help to connect the switch. Does anyone have a layout diagram, or even some photos of a completed unit (or similar?)
Thanks
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Hi,
That's not good because it is the easiest part of the build.
Do you know someone with more knowledge in electrical engineering than you who can support you ? I highly recommend this.
Best regards, Dirk
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No, im afraid I dont. I dont have the money to bring it to a tech, and I've put most of it together, but I'm not sure where to put the last few connections. Honestly, I didn't realise it would come without any information. I'd rather not try to just guess, but I've already paid for it, so I can't just abandon it.
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Please see page 2 of the datasheet: https://www.tube-town.net/info/datenblaetter/kits/psu-mini.pdf
Regards, Dirk
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Thanks for the reply - I already downloaded the data sheet, unfortunately, it doesn't tell me what I need to know. Is there any way to access a layout diagram to build this kit?
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what else do you need ? all infos are given in the documents which you have already.
Regards, Dirk
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The 4 wires - purple,yellow, black & red - coming from the transformer, I can't see where they go. The datasheet shows where the red & green wires go, I can figure out the rest from the PDF and photos, but I can't see anything about the switch and the 4 wires.
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Hi,
have a look at the product page of the transformer:
https://www.tube-town.net/ttstore/product_info.php/language/en/info/p2192_Ringkern-Netztrafo-30VA.html
Knowing where the switch should be and which of the 4 wires are to be used for your local voltage is basic electrical engineering knowledge. Be aware that you handle high voltages capable of killing you instantly if you fail to meet security rules included in this basics.
greetings,
Sev
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Here's the thing, Shto. The questions you are asking demonstrate a significant lack of basic knowledge. If you were building a dirt box, this wouldn't be an issue, the worst that could happen would be you would blow a transistor or something. But this is a tube device, with several hundred volts DC running around in the amp. A mistake could seriously injure you, even kill you. If you can't figure out how to hook up the mains side of the transformer, we all have to ask what you have done on the secondary side. It's not even a PCB, so there are countless spots where you could have made a bad mistake (say, HV on the chassis). So Dirk is giving you the information you need - it is quite clear, really - and giving you a chance to figure it out. If you can't figure it out from the information you have, then you should get help - someone who knows more, and can not only help you hook up the mains, but also go through the reverb for you and check your work.
Nobody is willing to tell you step-by-step because nobody believes you are really ready to build this kit. Don't take it personally, but these aren't Lego sets, and if you are starting from zero (like I did) you should do a lot of reading before you pick up the soldering iron the first time (I read everything I could, and practiced my soldering, for 2 years before I built my first amp). You need to have a healthy respect for mains and B+ voltage - fear, really - and you should be aware of the safety precautions you have to take.
Now, to figure out how to hook up the mains, think about this -
What is your wall voltage? If you look at the spec for the tranformer, you have these choices:
Pri: 0 - 220 - 230 - 240 V (black-yellow-purple-red)
"Pri" means primary (mains side)
"0" - what could that mean? Figure it out.
What is your wall voltage? Which wire do you think is the right one?
Where do you hook up the fuse?
How do you hook up the mains switch? Hmm - it is a double-pole switch, so you will be switching two things at once.
How do you hook up the PE? What the heck is the PE? The PE is the single most important connection in your amp.
What do you do with the unused wires?
Once you have done all that - how are you going to test the unit? I'll give you a hint - this is the WRONG way -
put all the tubes in it, hook it up to a guitar and amp, and wail away.
Good luck. Find a friend.
steven
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Thanks guys. Obviously, im not an electrical engineer. If I'd realised that was a requirement, I never would have bought the kit. I'm aware of the dangers of working with high voltages, and im obviously not going to take any risks. But, I've bought tube amp kits online from 2 other companies in the last few years, and completed them safely and successfully. They both supplied schematics, layouts and detailed instructions, both companies recommended certain kits as suitable or not suitable for novices, and - guess what - they even offered customer support. Clearly I should have thought this purchase through a little more carefully.
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they even offered customer support.
There is a big difference between Customer Support and schooling. In you case basic skills are not given.
Regards, Dirk
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Look at it this way: for the first two kits, you were given fish to eat. We want you to learn to fish.
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Hi,
this helpful and important paragraph from the german offer of the Reverb Kit
"Zum Nachbau des Verstärkers sind elektrotechnische Kentnisse notwendig, Erfahung mit Hochspannungen, sowie das Lesen und Verstehen von Schaltplänen und der Umgang mit Meßgeräten.
Eine Schritt-Für-Schritt Anleitung für Anfänger gibt es nicht. Der Schalt und Layoutplan beinhaltet alle relevanten Informationen."
should be added to the English offer in the shop to avoid misunderstanding in the future.
my 2 ct.
mfg ernst
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Hi to all,
+1 for the suggestion of improvment of Ernst. Although it is hard to imagine, at least from my point of view, that someone, who has no knowledge how to connect a switch would try to build an amp.
I have taken a short look on the engish project pages, just at Lumex and Reverb. The Lumex site has a note on the bottom on warnings but not the Reverb. Maybe the notes should be placed on a more prominent location and on all project sites to avoid such situations in the future.
In order solve this particular problem, Steven already listed the required hints.
Regards and good luck,
Sepp
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The note might include something like the next sentences to avoid such situations:
"The kit includes, apart from the listed parts, just the information a service technican would need to service or recreate the amp. This information includes schematics and layouts but there are no step-by-step instructions included in the kit. In other words the kit is not aimed at beginners. Knowledge in reading schematics and knowledge in dealing with exposure to high voltages are mandatory."
BR,
Sepp
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Hi !
In fact the documentation and product descriptions needs an update and we will do this asap.
BUT even with a step-by-step instruction the risk is very high because the customer does righten know how to check the security of his build nor how to trace and solve problems in case the amp is not working.
@Sepp: Danke Dir für die Übersetzung. Die darf ich so übernehmen und muss mir die Arbeit nicht selbst machen ?
Gruß, Dirk
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You may take it as is or even better, maybe Steven can provide a better translation. Mine is no translation but my thought on how to avoid this situation. Fell free to take it.
@step-to-step instructions: Thats the reason why i mentioned "information a service technican would need to ...". This line includes, at least from my point of view, the postulate the buyer/builder/user has to have knowledge...
BR,
Sepp
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Hi !
In fact the documentation and product descriptions needs an update and we will do this asap.
I appreciate that, there's a huge amount of information on this site, it must be a lot of work keeping it updated. However, you can understand my frustration - I now have a half-built kit, and no idea how to proceed, and now, a week after I ordered it, I'm being told I shouldn't have bought it since I'm not a trained electrical engineer. If any other users on this forum have a completed Reverb kit, I'd really appreciate some photos, or useful information. Much as I'd love to train as an electrical engineer, it's not likely to happen any time soon. I do take your points about completing the project safely, and having the ability to troubleshoot, but Madamp, Ampmaker, Triode, and several other sites include all this information, and are happy to help with email support. I don't understand why it's such a problem here.
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Please find attached two pictures of the primary wiring on my TT Reverb kit.
There are three connectors on the mains socket. As already mentioned, the most important connection to make is the PE (yellow&green wire). This should go to chassis, using the hole drilled closed to the mains socket. Note that I left this wire quite a bit longer than the connection to the mains switch.
The other two connections (blue and black wires) go to the mains switch. Use the middle lugs on the switch.
Connect both the pilot light and the primary side of the transformer to the mains switch. Use the top two lugs for this. You can see I used the yellow wires for the pilot light and the black ("0") and red ("240V") wires from the PT.
You will have to select the correct wall voltage on the primary side of the transformer. This will leave you with two unused wires - cut them and insulate their ends, e.g. with heat shrinking tube. A good way to check the selected wall voltage is to check the heater voltage later on, this should be 6.3V +/- 10%. In my build, I get 6.6V AC.
On the secondary side, the green wires should go to the valve heaters. The red wires should go to the power supply - but connect one of them to the HT Fuse!
If you have built other amp kits before, please look at their schematics and try to match them with what you have here - it really should not be that different. Please also look at this web site: http://www.valvewizard.co.uk/fuses.html (http://www.valvewizard.co.uk/fuses.html). There are two schematics which show the exact wiring used in this kit.
Also, I would strongly suggest to have your wiring checked by a person with a background in electronics! Citing the "Valve Wizard" site:
Building and modifying amplifiers is DANGEROUS (like most fun things). Valve amplifiers invariably contain both very high voltages and high currents, capable of killing you. ... It is up to you to exercise caution and common sense at all times to avoid electrocuting yourself, and make your amplifiers safe to use. I am not responsible for your negligence.
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Hi, in this thread several people have given you the needed information and on this page are the photos you are looking for with again all the needed information in it:
https://www.tube-town.net/cms/?DIY/LoW-Projekte/Reverb
You only need to know how to isolate unused wire ends - which you should know after building two reverbs..
Kai
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The other two connections (blue and black wires) go to the mains switch. Use the middle lugs on the switch.
This makes the two unused lugs live when the amp is switched off. I prefer to connect the mains to the 'on' side of the switch when using a DPDT and go out the middle lugs. And paranoia leads me to shrink -wrap the unused lugs, just in case something unexpected happens. But usually I just use a DPST switch. Just to confuse things.
Pay attention to the markings on the back side of the IEC socket. The lug that goes through the built-in fuse is 'live' and should be connected to the 230/240 volt wire. The other 'N'eutral is connected to the black 0 volt lead (through the switch of course).
Making the yellow and green wire for the PE longer than the others ensures that when your drunk drummer trips over the power cable, ripping the IEC out of the hole, that the connection to ground is the last connection broken. The wire should be longer than any other wire connected to the IEC and it should be free to unwrap and come out the hole.
Steven
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@current - thanks very much, really helpful info - I will, of course, have the work checked out before I connect to the mains. Cheers
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Hallo!
As you are answering in english here, I have few (may be pretty stupid) questions myself (I am thinking about building my own Reverb with the schematic given):
- If the needed voltage for the project is close to the mains voltage - let's say 250V, which is close to our mains 230V - why not omit the transformer and connect the PSU directly to the mains (maybe through a noise surrpresor, if the neighbour is using the power drill). PT is one of the biggest and most expensive components of the project, what is the problem there? Is this trafo only used as an "isolation transformer" really? Or what is the point of the trafo in such circuit? I was thinking about this with another project, I am planning on constructing the Alembic. Surely I need the trafo for the filaments /heaters, but why for the line? Is it the safety issue described here: http://www.instructables.com/id/Isolation-transformer-upgrade-for-old-guitar-amps/ It doesn't look like. AC goes through the fuse directly to the diode bridge - and is nowhere connected to the ground - how could it come to the chassis in those cases? Only maybe with half waveor tube rectification ...
- If I use the trafo with the PSU from the site - which trafo to use? What is the required voltage of the trafo? As I see the "suggestions" on the PSU page, there are 30VA and 50VA toroids, but one has 200V and the other 250V primary - which to use - or it doesn't really matter?
- there is a possibility given on the PSU page to use the choke - which is the correct choke for the PSU to use - and then you omit R3, if I understand correctly.
- on the cathode bypass capacitors (C2, C6, C7) in the Reverb schematic there are no voltages given - other schematics on net use 25V, but I am not sure. Measured voltages in the schematic seem much smaller, so (because smaller voltage generally means smaller ESR and size / inductance) would it be better to use a lower voltage caps? Is 6,3V enough? Would you expect a noticable improvement in sound if using poly caps instead of elkos (C2 and C6).
- on the PSU (if I buy just the printed board and then components separately): would it be very messy to use F+T caps (they are axial and have a biiiig diameter)? What about using the can caps? Is there any noticeable improvement when using such better caps? Or is the exact purpose of that PSU that it is not so component-critical (because there is really a lot of them caps there, in the schematics of the same reverb on the net there are four 20/450 or three 40/450 and that's it)
Thank you for your kind answer.
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Hi,
just order the kit and you are happy because it comes with all items that you need to build the reverb.
Best regards, Dirk
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- If the needed voltage for the project is close to the mains voltage - let's say 250V, which is close to our mains 230V - why not omit the transformer and connect the PSU directly to the mains (maybe through a noise surrpresor, if the neighbour is using the power drill). PT is one of the biggest and most expensive components of the project, what is the problem there? Is this trafo only used as an "isolation transformer" really? Or what is the point of the trafo in such circuit? I was thinking about this with another project, I am planning on constructing the Alembic. Surely I need the trafo for the filaments /heaters, but why for the line? Is it the safety issue described here: http://www.instructables.com/id/Isolation-transformer-upgrade-for-old-guitar-amps/ It doesn't look like. AC goes through the fuse directly to the diode bridge - and is nowhere connected to the ground - how could it come to the chassis in those cases?
OMG, don't kill yourself! Never, ever connect your PSU directly to the mains! This would be really dangerous and stupid! Do yourself a favor and start with some low voltage projects and read some books. You are not ready for voltages above 50 Volts!
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I have made some Low Voltage projects and there are some books about Electronics waiting for me to read.
Scio mihi nihil scire - that is why I asked ... Is it really so hard to explain? Strike me with highly theoretical gibberish, just don't mock me for not knowing.
So, in short: what is the problem? I understand trafo is only a inductance based voltage transforming block and not some guardian angel ...
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Hello,
http://en.wikipedia.org/wiki/Galvanic_isolation#Applications (http://en.wikipedia.org/wiki/Galvanic_isolation#Applications)
Gruß, Peter
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Thank you! That is the answer I wanted. It would take some time to understand, but it's a starter ...
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first thing: does this "galvanic isolation work if the earthing from the socket is connected to the ground of the device (it is common, there are really scarce devices with some kind of separation, usually through cap and resistor, betwen "yellow-green" and "black" zone ...)
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I think this has nothing to do with the Reverb Unit and it might be better to start a new thread in the "Beginners" section.
BR, Dirk
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I finally built it ... http://www.tube-town.de/ttforum/index.php/topic,20728.msg210285.html#msg210285