Extortion
I thought that too. But I've just had to pay £25.50 to get parts totalling $100 into the UK. £12 was Customs, and the other £13.50 was Parcelforce's hit for paying Customs. I was not amused.
I will need an extremely good reason to order anything from the USA again. Oh, and Mouser stitched me $36.50 postage for something that must have weighed, oooh, 1kg.
woodturner-fran said:
I thought that too. But I've just had to pay £25.50 to get parts totalling $100 into the UK. £12 was Customs, and the other £13.50 was Parcelforce's hit for paying Customs. I was not amused.
I will need an extremely good reason to order anything from the USA again. Oh, and Mouser stitched me $36.50 postage for something that must have weighed, oooh, 1kg.
OK, then, Mr. Grumpy, who would be the European equivalents to Mouser or Digikey? Farnell? Maplin? RS? Some I'm missing?
When you think about it, I'm an even worse courier than UPS; at least they leave after they've dropped the box off and they don't drink your beer and frighten your cats.
When you think about it, I'm an even worse courier than UPS; at least they leave after they've dropped the box off and they don't drink your beer and frighten your cats.
yeah, you need to be careful or else factor in the possible hit. I just find that to me here in Ireland, USPS is the best solution. I rarely get hit for duties, my regular postman delivers. If I'm not around, he'll drop the parcel into my brother a mile up the road, if he's not around (rare) he'll put it behind a pot on the deck (I live in the sticks)!
Far better than a crappy note saying "we called and missed you ring me to get your stuff - and by the way you owe us €10 duties and €25 for us collecting your taxes"
So if it can't come USPS then I'm not too interested. All the sweeter if the seller marks it to <$50 when it 99% of the time passes under the radar!
Fran
Far better than a crappy note saying "we called and missed you ring me to get your stuff - and by the way you owe us €10 duties and €25 for us collecting your taxes"
So if it can't come USPS then I'm not too interested. All the sweeter if the seller marks it to <$50 when it 99% of the time passes under the radar!
Fran
SY said:
But nobody at UPS has offered to cook us dinner. By the way, you will be distraught to learn that I have not been able to get any Summer Lightning. We will have to drink Heineken. Or Miller Light. Sue will probably stick to gin and tonic.
Well, that's good- it will keep us sober for a change. It's Sue's turn to be loud, sloppy, and obnoxious.😀
Hi Fran,
I ordered my HPLM6000 from RS who in turn ordered from Allied, they turned up in an Allied bag. I thought they may be cheaper for you by going straight to Allied. I think they are a good led for the RLD, I like them cos they are small and lay flat and you can get 2 legs down the one pcb hole and they sit still which makes it a lot easier to solder. They also measure very well, the best of any led I could get my hands on.
I ordered my HPLM6000 from RS who in turn ordered from Allied, they turned up in an Allied bag. I thought they may be cheaper for you by going straight to Allied. I think they are a good led for the RLD, I like them cos they are small and lay flat and you can get 2 legs down the one pcb hole and they sit still which makes it a lot easier to solder. They also measure very well, the best of any led I could get my hands on.
to kopite: OK, I'll do some more searching for them. The ebay ones only cost me $10 anyways, and I'll always have them if HLMP6000 don't turn up. EDIT: would you have the RS number for the HLMP6000 that you got?
To SY et al:
A bunch of questions on component choice:
1. Are the likes of 1/4W MF resistors OK except where you have specified differently (eg the CC ones for grid leak). and 1/4W carbon film in the PS except where specified?
2. Can I use Wima FKP everywhere except in the PS?
3. In the prototype in Bas mag, you have 2 caps in the heater supply "OuO1" one on each leg centred to ground - excuse my ignorance but what does this do?
4. For the output coupling caps (Ou1) are 0.1uF FKP OK?
5. Is there any merit in going to DC with the heaters eg ala MJ in valve amplifiers? (even if they weren't regulated just put a R in series to get 6.3V from a 9V secondary)
6. I know I kinda asked this before but..... Would I get away with using 2 x 240 isolating transformers for each of the B+ supplies. I reckon I might be able to make the B+ plus for the output stage and screen voltage OK, but will the approx 300-320V be OK for the drivers? Or should I be considering a voltage doubler. (sorta stuck with these Tx or else project cost really climbs!)
2 more quick Qs: Has anyone got a BOM for the RLD and are there photos anywhere showing peoples layout?
thanks in advance I'm sure I must be driving you mad with all the stupid questions!
Fran
To SY et al:
A bunch of questions on component choice:
1. Are the likes of 1/4W MF resistors OK except where you have specified differently (eg the CC ones for grid leak). and 1/4W carbon film in the PS except where specified?
2. Can I use Wima FKP everywhere except in the PS?
3. In the prototype in Bas mag, you have 2 caps in the heater supply "OuO1" one on each leg centred to ground - excuse my ignorance but what does this do?
4. For the output coupling caps (Ou1) are 0.1uF FKP OK?
5. Is there any merit in going to DC with the heaters eg ala MJ in valve amplifiers? (even if they weren't regulated just put a R in series to get 6.3V from a 9V secondary)
6. I know I kinda asked this before but..... Would I get away with using 2 x 240 isolating transformers for each of the B+ supplies. I reckon I might be able to make the B+ plus for the output stage and screen voltage OK, but will the approx 300-320V be OK for the drivers? Or should I be considering a voltage doubler. (sorta stuck with these Tx or else project cost really climbs!)
2 more quick Qs: Has anyone got a BOM for the RLD and are there photos anywhere showing peoples layout?
thanks in advance I'm sure I must be driving you mad with all the stupid questions!
Fran
1. Use something heavier duty for the plate resistors and the cathode resistor of the split-load inverter. 2W (or higher) metal film or wirewound are ideal. Carbon comps for grid-stopping.
2. Yes, they're great caps.
3. Those caps are to bypass common mode noise on the heater lines. This is particularly important when the heater winding is shared with the main B+; diode noise and hash becomes much less of an issue.
4. See number 2.
5. It won't hurt but it's totally unnecessary. In my versions, the output hum is below 1mV despite the AC heaters.
6. The driver stage current requirements are really, really low (like 10mA total for two channels). But it does need voltage. You don't need a big transformer by any means, but you do need more than 300V.
I've got a few photos of the bottom posted in the Photo Gallery thread. If you want to get a better look at anything, let me know and I'll snap a photo. There's nothing exotic about the layout- tight twisting of heater leads, power and output transformers with cores perpendicular to one another, bus grounding, all very standard practice.
2. Yes, they're great caps.
3. Those caps are to bypass common mode noise on the heater lines. This is particularly important when the heater winding is shared with the main B+; diode noise and hash becomes much less of an issue.
4. See number 2.
5. It won't hurt but it's totally unnecessary. In my versions, the output hum is below 1mV despite the AC heaters.
6. The driver stage current requirements are really, really low (like 10mA total for two channels). But it does need voltage. You don't need a big transformer by any means, but you do need more than 300V.
I've got a few photos of the bottom posted in the Photo Gallery thread. If you want to get a better look at anything, let me know and I'll snap a photo. There's nothing exotic about the layout- tight twisting of heater leads, power and output transformers with cores perpendicular to one another, bus grounding, all very standard practice.
Many, many thanks SY,
as you can imagine I'm getting my act together a bit more here! I got my chassis aluminium on friday and I am planning on getting the rest of the components in the next week or so. So hence all the questions!
I downloaded PSUD last night and came up with a PSU for the power tubes. I ended up with 310 for the B+ after a RC-RC filter post rectification via a bridge (my Tx has only 0-240V as sec).
I also came up with a voltage doubler circuit for the driver stage B+ and ended up with 360V for that. This was using the standard load resistor in PSUD of 5K - what would you think? Heres what they look like:
and
The learning curve is pretty steep! So If I've done something stupid, please bear with me!!
Fran
as you can imagine I'm getting my act together a bit more here! I got my chassis aluminium on friday and I am planning on getting the rest of the components in the next week or so. So hence all the questions!
I downloaded PSUD last night and came up with a PSU for the power tubes. I ended up with 310 for the B+ after a RC-RC filter post rectification via a bridge (my Tx has only 0-240V as sec).
I also came up with a voltage doubler circuit for the driver stage B+ and ended up with 360V for that. This was using the standard load resistor in PSUD of 5K - what would you think? Heres what they look like:
An externally hosted image should be here but it was not working when we last tested it.
and
An externally hosted image should be here but it was not working when we last tested it.
The learning curve is pretty steep! So If I've done something stupid, please bear with me!!
Fran
You really want to put a load in there that looks like the circuit you want to drive. Model the output stage as a stepped current source going from 0.160A to 0.220A (i.e., idle to full power). Then run the sim for a second before the step and a few seconds afterward. That will show you whether or not the supply will tend to ring or droop too much under drive. The input stage is more like a constant 10mA load.
OK,
just running out the door here, but after doing that it doesn't look nearly so good now. Seems like it ain't gonna be easy to get away with using the simple Tx! I'll need to think about this for a while....
Fran
just running out the door here, but after doing that it doesn't look nearly so good now. Seems like it ain't gonna be easy to get away with using the simple Tx! I'll need to think about this for a while....
Fran
Just for fun, I used a WAG for your transformer off-load voltage, then used a FWB rectifier feeding a 47uF- 1.5H (30R)- 220uF CLC filter to power the output stage. It looks pretty good: the voltages are where you want them, the ripple is low, and the sag after current step shows no instability.
real ignorance being shown here, but WAG??
I tried to run that in PSUD but must be doing something stupid, I can only get 275V at the load? But it should work from reading MJ.... will need to learn more! However, your reply is now saved and will be what I use!!
But as for the driver voltage, I think the only way now is to lay hands on a Tx with higher output. EDIT - a thought just struck me.... how about a variac... goes to 270V output at 0.75A?
....... off to the 'bay.....
Fran
I tried to run that in PSUD but must be doing something stupid, I can only get 275V at the load? But it should work from reading MJ.... will need to learn more! However, your reply is now saved and will be what I use!!
But as for the driver voltage, I think the only way now is to lay hands on a Tx with higher output. EDIT - a thought just struck me.... how about a variac... goes to 270V output at 0.75A?
....... off to the 'bay.....
Fran
EC8010,
I felt certain that a man of your experience would have come across that precision engineering term a "WAG". Perhaps it is known by some other name in your part of the world.
A "WAG" design is slightly to the left of a design based upon the "TLAR" principal (That looks about right), being based instead upon a Wild A..ed Guess.
Cheers,
Ian
I felt certain that a man of your experience would have come across that precision engineering term a "WAG". Perhaps it is known by some other name in your part of the world.
A "WAG" design is slightly to the left of a design based upon the "TLAR" principal (That looks about right), being based instead upon a Wild A..ed Guess.
Cheers,
Ian
You can use a second, smaller 240V transformer and stack a small 36 volt (or thereabouts) transformer on top of it, then rectify and filter your virtual 256V unit.
The key to getting a reasonably accurate voltage from PSUDII is putting in accurate transformer parameters. GIGO.
EC, do I need to explain GIGO to you? How about the smallest unit of mechanical adjustment, the RCH?
The key to getting a reasonably accurate voltage from PSUDII is putting in accurate transformer parameters. GIGO.
EC, do I need to explain GIGO to you? How about the smallest unit of mechanical adjustment, the RCH?
since we;re talking crap, how about the shortest measurable unit of time?
defined from time immemorial as that distance from "maybe to too tired........."😀
Favourite saying around here for that little bit more yet to be removed, the instruction is to remove a "bees wing". Larger amount for removal is referred to as "the butt of a cigarette".
Just got a site from Italy that has chokes and Tx for reasonable money, have sent them and email and will see how we get on! Their site is very much in Italian and my email was in english, so we'll see!
SY - by stacking you mean paralleling the 2 TX (or at least connecting the output in parallel?)
Fran
defined from time immemorial as that distance from "maybe to too tired........."😀
Favourite saying around here for that little bit more yet to be removed, the instruction is to remove a "bees wing". Larger amount for removal is referred to as "the butt of a cigarette".
Just got a site from Italy that has chokes and Tx for reasonable money, have sent them and email and will see how we get on! Their site is very much in Italian and my email was in english, so we'll see!
SY - by stacking you mean paralleling the 2 TX (or at least connecting the output in parallel?)
Fran
The primaries in parallel and the secondaries in series. Once you have the primary hooked up, there are two possible relative polarities for the two series secondaries- one direction will reduce the voltage, the other will increase it. (This is a good and often useful trick to know)
yeah, sorry its late, hands didn't type what head was thinking. pri in parallel and secs in series... Actually I can get 24-0-24 secs and end up with c. 230-240 + 48 to give 278-288 or thereabouts. Think this si the route I will go - unless I get a good response from the Italians....
Been reading MJ and like the part where he says 11pm at night is not the time to start wiring!
Fran
Been reading MJ and like the part where he says 11pm at night is not the time to start wiring!
Fran
Where do you get those transformers
I have been looking for the James transformers which were suggested in the DIYMAG article. The exact model number is not given but I assume its the 6228HS. James does not seem to have a North American distributer that I can find. Is there one? Would anyone care to comment on their luck with any of James Distributers? I think I remember reading mixed things about some of them long ago
Steve
I have been looking for the James transformers which were suggested in the DIYMAG article. The exact model number is not given but I assume its the 6228HS. James does not seem to have a North American distributer that I can find. Is there one? Would anyone care to comment on their luck with any of James Distributers? I think I remember reading mixed things about some of them long ago
Steve