I am in a preliminary phase and considering to release a DIY kit series with tubes.
The kits will be shipped to EU countries.
Pre-drilled aluminum chassis, toroidal power transformer, quality input/output connectors.
First kits to be released will be a valve pre-amp and buffer and a Push-Pull power amplifier utilising 2 EL34's per channel. These will be new designs, not clones of classic products.
The pricing would be competitive, not down to Chinese prices of course.
I would like to hear your views and opinions. Thanks for your time.
The kits will be shipped to EU countries.
Pre-drilled aluminum chassis, toroidal power transformer, quality input/output connectors.
First kits to be released will be a valve pre-amp and buffer and a Push-Pull power amplifier utilising 2 EL34's per channel. These will be new designs, not clones of classic products.
The pricing would be competitive, not down to Chinese prices of course.
I would like to hear your views and opinions. Thanks for your time.
make mains adjustable in steps of 20v 200-220-240 don't include a thermal fuse that renders the transformer inoperable . its DIY after all
Fuse the HT CT and maybye design a PCB for the mains wiring its likely safer that way .
chassis power cord fuse and HF suppression on a little PCB that has jumpers for the correct mains voltage
use some good sockets not chinese those ruin valve pins use NOS /nice fitting stuf
hum pot would be nice
v4lve
Fuse the HT CT and maybye design a PCB for the mains wiring its likely safer that way .
chassis power cord fuse and HF suppression on a little PCB that has jumpers for the correct mains voltage
use some good sockets not chinese those ruin valve pins use NOS /nice fitting stuf
hum pot would be nice
v4lve
1. All screws and bolts will be metric
2. My little research states that UK and Cyprus is 240 V and mainland Europe is 230 V, except Russia/ Lithuania /Ukraine which are 220 V.
So I believe that a heater regulator is the solution (for the preamp)
Thanks!
You mean PMPO watts, which, according to Morgan Jones, means Purely Mythical Power Output?
Best regards!
UK law is 230v +10% - 6% 50 Hz
Here it's usually 225 whilst about three miles away it's 245!
Paul
You mean PMPO watts, which, according to Morgan Jones, means Purely Mythical Power Output?
Best regards!
Hi Folks,
I found another funny definition:
Panel Melting Power Once
@Paul , 7N7
Whole Europe, North Africa and even Russia turned to 230V. Here in Germany we are changed since 1985 from 220V to 230V , at first -10% - +6% and from Januar this Year -10% - +10% tolerance. In my place I got most time of the day 235V and late night 240V. The mains transformer is 150m apart from my place.
73
Wolfgang
How's the leg?
Meanwhile I think I made a mistake - as you say it should be -10% +6% here in England.
It was quite a problem when I made my 813 amplifier, since the mains supply varied between 219v to nearly 250! I was using an HT of around 850, so this varied quite a bit...
Paul
Hi Paul,
no, you were right to what you stated. GB had 240V before they turn down to 230V so they had to have the tolerance limits set to +10% and for 220V countries -10%. The point to do so is that after changing the voltage, many appliances which meet the old standard stay in use by its owner for many years . The max. voltage at 230V +10% were 253 V. An appliances made for 220 V could be overload if 253v is present in a socket. On the other direction a consumer device designed for 240V could possible run out of proper or unsafe operation when it see only 230V -10% which is 207V. AC Motors for example can be damaged if running on undervoltage.
The EEC had the asymmetric tolerance scheme for 20 Years, which come to an end on the first January this year . Now we have in Britain, Germany or elswhere in EU 230V -10 to +10% that means the mains voltage may varying from 207V to 253V or 360V to 440V between to phases.
cheers
Wolfgang
First of all thanks to all for your keen interest!
I ll try to answer your questions.
Since EU is the target market, the power supply will have 230V as design center. 240 and 220 supply voltages are +- 6% off that.
Possibly have a different power transformer for UK and Cyprus. In this small scale, this is feasible.
CE certification applies to finished products, i.e. consumer products I believe. Since it is a kit, it is a bunch of parts, a PCB, and an aluminum box. As an example, the prominent electronic kit manufacturer in EU, Velleman Velleman nv does not mention any CE certification on their kits that are mains-powered
Of course there will be all safety measures in place, fuse, protective ground earth etc
Most important all of the "big" parts will be sourced locally. This will increase the price, do you think people will accept the price difference with the Chinese kits that flood e-bay?
Thanks you all again for your time and thoughts.
I ll try to answer your questions.
Since EU is the target market, the power supply will have 230V as design center. 240 and 220 supply voltages are +- 6% off that.
Possibly have a different power transformer for UK and Cyprus. In this small scale, this is feasible.
CE certification applies to finished products, i.e. consumer products I believe. Since it is a kit, it is a bunch of parts, a PCB, and an aluminum box. As an example, the prominent electronic kit manufacturer in EU, Velleman Velleman nv does not mention any CE certification on their kits that are mains-powered
Of course there will be all safety measures in place, fuse, protective ground earth etc
Most important all of the "big" parts will be sourced locally. This will increase the price, do you think people will accept the price difference with the Chinese kits that flood e-bay?
Thanks you all again for your time and thoughts.
The UK has not "turned down to 230V". The official standard has changed, but nobody has gone out to change distribution transformer taps. The UK government position seems to be that an increase in voltage is more likely, especially in the rest of Europe. This is because utilities get paid for power yet part of their distribution costs relate to current so it is in their interests to raise voltage and reduce current. So as transformers get replaced a gradual rise in 220V is more likely than a reduction in 240V. They won't do a sudden rise as that would cause complaints as lightbulbs start exploding prematurely.
The big problem is that the EU has given permission for a degradation in voltage tolerance from +-6% to +-10%. This makes equipment design more difficult, unless an SMPS is used. Fortunately in practice most locations will not see such a wide swing except under fault conditions.
My mains voltage this morning is 243V.
The big problem is that the EU has given permission for a degradation in voltage tolerance from +-6% to +-10%. This makes equipment design more difficult, unless an SMPS is used. Fortunately in practice most locations will not see such a wide swing except under fault conditions.
My mains voltage this morning is 243V.
I am sorry for my late replies, I am still under moderation it seems. I will try to answer your questions in one post.
StigErik , I do not wish to make the kit Class II (who doesn't want to see a valve glow), but your recommendation is very good, a ground lift switch will be included.
DF96: The power amplifier will be rated in Soviet Watts
Artosalo: I have contacted a specialised lawyer about required CE certification, if applicable.
For now I am concentrating the the effort on the preamp kit. It will be a low price DIY kit, made in EU, competently designed, with decent quality components, not available preassembled.
My concern is if there is interest in the market segment that usually buys the chinese um, offerings. I am also exploring alternate advertising channels.
Your thoughts and opinions are welcome!
Thanks to all.
StigErik , I do not wish to make the kit Class II (who doesn't want to see a valve glow), but your recommendation is very good, a ground lift switch will be included.
DF96: The power amplifier will be rated in Soviet Watts
Artosalo: I have contacted a specialised lawyer about required CE certification, if applicable.
For now I am concentrating the the effort on the preamp kit. It will be a low price DIY kit, made in EU, competently designed, with decent quality components, not available preassembled.
My concern is if there is interest in the market segment that usually buys the chinese um, offerings. I am also exploring alternate advertising channels.
Your thoughts and opinions are welcome!
Thanks to all.
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