The only time I would use PayPal would be when I buy things on ebay. Seeing as how I only do so once or twice a year on average, the money would just sit there and sit there and sit there. I expect my money to earn interest at the very minimum. As of this writing (4/9/06) I regard any account earning less than 4% to be dead money and prefer 4.5%. (I have an entirely different set of guidelines for the equity market [i.e. stocks]--I'm just talking about passive money sitting there earning interest just for existing.) My expectations along those lines will rise along with interest rates as we are entering a high inflation era for our economy. It won't be long before we're looking at 4 to 5% as hopelessly behind the curve, but that's another matter for another day.
I also disapprove of PayPal charging fees. What, they're not making enough interest holding your money? Harrumph!
Yes, PayPal is convenient, but it's highway robbery.
All I can say is that I'm jealous that I didn't think of it first. I'd retire and use dump trucks to move my money around.
I wish my bank hadn't gotten weird on me about out-of-the-US checks. When I started this, I envisioned that Canadians and Mexicans would be able to send me personal checks just the way US buyers do. It didn't work out that way. I realize that getting a money order of some sort entails extra hassle and a fee on the buyer's end, but it's still less than this absurd $16.75 add-on my bank wants for cashing a Canadian check. And $75.00 for cashing one from Europe? You must be kidding!
If I don't watch t, I'll get up on my soapbox and start ranting again. You guys have heard it all before so I'll desist. So all I'll say is that it's a cryin' shame and let it go at that.
Grey
P.S.: The moon's phase has come 'round again and I'm getting another wave of orders that don't cover the basics:
(everyone repeat after me...)
--Your DIY username
--Your real name
--Your mailing address
--How many devices you want
--Matched or unmatched
And again...there's no need to ask me if I've got devices. Just order. There's a pile of them sitting here smiling at me, ready to go.
I also disapprove of PayPal charging fees. What, they're not making enough interest holding your money? Harrumph!
Yes, PayPal is convenient, but it's highway robbery.
All I can say is that I'm jealous that I didn't think of it first. I'd retire and use dump trucks to move my money around.
I wish my bank hadn't gotten weird on me about out-of-the-US checks. When I started this, I envisioned that Canadians and Mexicans would be able to send me personal checks just the way US buyers do. It didn't work out that way. I realize that getting a money order of some sort entails extra hassle and a fee on the buyer's end, but it's still less than this absurd $16.75 add-on my bank wants for cashing a Canadian check. And $75.00 for cashing one from Europe? You must be kidding!
If I don't watch t, I'll get up on my soapbox and start ranting again. You guys have heard it all before so I'll desist. So all I'll say is that it's a cryin' shame and let it go at that.
Grey
P.S.: The moon's phase has come 'round again and I'm getting another wave of orders that don't cover the basics:
(everyone repeat after me...)
--Your DIY username
--Your real name
--Your mailing address
--How many devices you want
--Matched or unmatched
And again...there's no need to ask me if I've got devices. Just order. There's a pile of them sitting here smiling at me, ready to go.
Since there is reason to beleive that the Lovoltech's will arrive in EU shortly, here is an update to round 1 of the EU part.
Device prices listed here: Round 1 prices
Postage prices here:
Postage
If you pay by Paypal, they charge a fee of 3,4%+0,35Euro that you need to add (Dont ask me how they ended up with those figures) You will also need to add a 2Euro fee that my bank charges for exchanging the Euro's to Danish money.
If you pay by banktransfer, remember that you will pay all fee's, both in your end and in mine. You will have to tell your bank that.
If you pay by snailmail, you will have to add the 2Euro exchange fee only. You can add up the prices yourself to get a final price, if you want.
I will send an email to everyone of you that ordered, with bank details, paypal handle, and so on. Once your payment is safely on my bankaccount, I will send out the fets.
Now to round two
I am slowly gearing up to do a second round.
The interest is there, counting the emails requesting J-fets, so I will do another round Those of you wanting to join in are welcome to send me an email with your request. Remember to tell me if you want matched or unmatched devices. As usual, I expect you to buy the devices you order The terms will be like the first round, if everything turns out right. If not, there might be some adjustments to the whole thing.
For now I am counting the orders over the next few days to try and figure out how many devices that will be needed.
If you have questions, just shoot..
Steen
Device prices listed here: Round 1 prices
Postage prices here:
Postage
If you pay by Paypal, they charge a fee of 3,4%+0,35Euro that you need to add (Dont ask me how they ended up with those figures) You will also need to add a 2Euro fee that my bank charges for exchanging the Euro's to Danish money.
If you pay by banktransfer, remember that you will pay all fee's, both in your end and in mine. You will have to tell your bank that.
If you pay by snailmail, you will have to add the 2Euro exchange fee only. You can add up the prices yourself to get a final price, if you want.
I will send an email to everyone of you that ordered, with bank details, paypal handle, and so on. Once your payment is safely on my bankaccount, I will send out the fets.
Now to round two
I am slowly gearing up to do a second round.The interest is there, counting the emails requesting J-fets, so I will do another round
Those of you wanting to join in are welcome to send me an email with your request. Remember to tell me if you want matched or unmatched devices. As usual, I expect you to buy the devices you order The terms will be like the first round, if everything turns out right. If not, there might be some adjustments to the whole thing. For now I am counting the orders over the next few days to try and figure out how many devices that will be needed.
If you have questions, just shoot..
Steen
I have had a few inquiries from the other side of the world. One the other day from Malaysia, I think, and a couple of other points scattered about the Pacific. If anyone wants to start another buy for that part of the planet, please step forward. I think I still have some of the e-mail inquiries. I can forward those to anyone brave enough to do the job.
Note that I have deleted European e-mail inquiries after suggesting that the sender contact Steen and/or watch this thread. I had to jettison some stuff in order to keep my e-mail account from overflowing. For some reason I had a burst of interest from guys in Italy. Not Germany, not France, not Norway, the UK, or Belgium...Italy. Must be something in the water over there. Okay, all you Italian guys, it's time to make yourselves known. Contact Steen, okay?
On to other things...
I have, as of an hour ago, finished messing with income taxes. Now, if I can only get rid of the germs my 3 year-old bestowed upon me, I can get back to the amplifier circuit I've been working on.
As things stand now I'm in trouble-shooting mode. The amp worked on the punch board. I made circuit boards and it quit working. Bummer. Obviously something didn't translate properly from the original point-to-point prototype, but I haven't had time to figure out what happened. Sometimes life throws curve balls at you just to see if you're paying attention. Hopefully, it's something simple like a wire in the wrong place, but I don't know yet.
I haven't yet taken the time to work up a headphone amp. I've got ideas, just need time. Haven't done anything on preamps or phono stages either, for that matter.
Between taxes, plumbing, and work, not to mention getting a few of these silly little JFETs out, I've barely had time to scratch. I've got another plumbing problem pending, but I'm ignoring it, hoping it will go away (it won't, but I can pretend, can't I?).
Anyway, let me get a few hours of sleep, then get through tomorrow. Perhaps tomorrow night I can get down in the Dungeon and look at that confounded amp. I had hoped to post the thing back in January. Ha! Running a wee bit late, are we, Grey? Yup. I'll get there.
Oh yeah, and I've got to get a story written, soonest. Stan went and sent two contracts at the same time, and I don't have anything on the spike ready to go.
Yikes!
Man, I put in an order for 48 hour days ages ago and they haven't shown up yet. Maybe tomorrow the UPS man will deliver them.
Grey
Note that I have deleted European e-mail inquiries after suggesting that the sender contact Steen and/or watch this thread. I had to jettison some stuff in order to keep my e-mail account from overflowing. For some reason I had a burst of interest from guys in Italy. Not Germany, not France, not Norway, the UK, or Belgium...Italy. Must be something in the water over there. Okay, all you Italian guys, it's time to make yourselves known. Contact Steen, okay?
On to other things...
I have, as of an hour ago, finished messing with income taxes. Now, if I can only get rid of the germs my 3 year-old bestowed upon me, I can get back to the amplifier circuit I've been working on.
As things stand now I'm in trouble-shooting mode. The amp worked on the punch board. I made circuit boards and it quit working. Bummer. Obviously something didn't translate properly from the original point-to-point prototype, but I haven't had time to figure out what happened. Sometimes life throws curve balls at you just to see if you're paying attention. Hopefully, it's something simple like a wire in the wrong place, but I don't know yet.
I haven't yet taken the time to work up a headphone amp. I've got ideas, just need time. Haven't done anything on preamps or phono stages either, for that matter.
Between taxes, plumbing, and work, not to mention getting a few of these silly little JFETs out, I've barely had time to scratch. I've got another plumbing problem pending, but I'm ignoring it, hoping it will go away (it won't, but I can pretend, can't I?).
Anyway, let me get a few hours of sleep, then get through tomorrow. Perhaps tomorrow night I can get down in the Dungeon and look at that confounded amp. I had hoped to post the thing back in January. Ha! Running a wee bit late, are we, Grey? Yup. I'll get there.
Oh yeah, and I've got to get a story written, soonest. Stan went and sent two contracts at the same time, and I don't have anything on the spike ready to go.
Yikes!
Man, I put in an order for 48 hour days ages ago and they haven't shown up yet. Maybe tomorrow the UPS man will deliver them.
Grey
Email with instructions on payment is sent to everyone of you, participating in the first EU round. Please check your mailboxes.
Some of you have more than one, so check them all
As soon as I have your payment, the Fets will fly out to you.
Thanks to Grey for doing a great job. The fets were well packed and easily sorted out
Steen
Some of you have more than one, so check them all
As soon as I have your payment, the Fets will fly out to you.
Thanks to Grey for doing a great job. The fets were well packed and easily sorted out
Steen
The USPS, in its inimitable manner, delivered the shipment to Steen in less than half the time it took to deliver the UK parts. Don't ask why or how, as I have no answers. Glad they arrived okay, though.
As for the amp circuit, the problem I mentioned above was simple--a ground wire had come loose. Easily fixed, once noticed. Just spent a luxurious two whole consecutive hours on the circuit. I think I mentioned that one version of the output stage is done. I'm just fiddling with different front ends. The plan is to offer one output (for now) with a succession of different front ends. I have several variants on the output stage and several front ends. It's all pretty much mix and match. For instance, I had a 2SK389/2SJ109 front end close to finished all the way back in January. Then I read three or four unrelated posts bemoaning the difficulty in finding those parts. I can hardly expect people to build amps if they can't find the parts. Well, that sent me back to the bench with an eye towards coming up with a front end that can be built with parts that are currently available. What I really wanted to do was a J310/J271 front end, but the only J271s I can find are the Fairchild version. For reasons unknown, the Fairchild is labelled on the spec sheet as a switch. The Vishay version of the same part is labelled as an amplifier. Since I have the Vishay J310 on hand, I wanted the Vishay J271, but I can't seem to find them at retail. Damn. Another unobtanium part. The annoying thing is that I got into solid state because I was tired of exspensive, hard-to-find tubes. Little did I know that things were as difficult in the solid state world. Oh, well. I went ahead and built an N-ch front end with the J310 only, no J271s. Just for giggles, I'm back piddling with the '389/'109 front end, mainly because I'm a masochist.
With luck I'll start a post on the amp within a week. That's assuming that I don't have any more plumbing problems, etc.
Grey
As for the amp circuit, the problem I mentioned above was simple--a ground wire had come loose. Easily fixed, once noticed. Just spent a luxurious two whole consecutive hours on the circuit. I think I mentioned that one version of the output stage is done. I'm just fiddling with different front ends. The plan is to offer one output (for now) with a succession of different front ends. I have several variants on the output stage and several front ends. It's all pretty much mix and match. For instance, I had a 2SK389/2SJ109 front end close to finished all the way back in January. Then I read three or four unrelated posts bemoaning the difficulty in finding those parts. I can hardly expect people to build amps if they can't find the parts. Well, that sent me back to the bench with an eye towards coming up with a front end that can be built with parts that are currently available. What I really wanted to do was a J310/J271 front end, but the only J271s I can find are the Fairchild version. For reasons unknown, the Fairchild is labelled on the spec sheet as a switch. The Vishay version of the same part is labelled as an amplifier. Since I have the Vishay J310 on hand, I wanted the Vishay J271, but I can't seem to find them at retail. Damn. Another unobtanium part. The annoying thing is that I got into solid state because I was tired of exspensive, hard-to-find tubes. Little did I know that things were as difficult in the solid state world. Oh, well. I went ahead and built an N-ch front end with the J310 only, no J271s. Just for giggles, I'm back piddling with the '389/'109 front end, mainly because I'm a masochist.
With luck I'll start a post on the amp within a week. That's assuming that I don't have any more plumbing problems, etc.
Grey
Thr J270 and J175 series are pretty much the same - the names are changed to protect the guilty, etc. You can get the Vishay J175 and 176 from Mouser. They will serve your purposes just fine, even though they are called switches. The only rub may be that the spread for Vg and IDSS may be larger for the switch-numbered parts than for the amplifier versions. For Vishay/Siliconix at least, it's the same process for both series.
The PN4393 is also called a switch, but it makes a dandy low noise amp...
The PN4393 is also called a switch, but it makes a dandy low noise amp...
What I've got on the bench right now is a power amp. Currently it's running with 25V rails, which brings it in around 30W or so. The project is easily scalable--as long as your front end can swing sufficient signal voltage, you can ramp up the rails to get more wattage with no other changes necessary. It's class A, self-biasing, so there's no fiddle-factor on the output stage. Some of the input stages I've done are fiddly, some aren't. I'm going to start with a non-fiddly one that most folks can run up from parts they already have on hand. They'll get steadily more complicated after that.
The fact that this amp is so modular means that other folks are welcome to post their own front ends. The only requirements are that the front end should have a balanced output and reasonable current delivery. I've seen several schematics here recently that should do as well as anything I've put together.
From the very start I found myself intrigued by some of the biasing options for the Lovoltech parts. I've got at least ten or fifteen different ways to bias the things so far. Obviously, the bias circuits require an output stage to go into, and that in turn implies a front end. I settled on one bias scheme--mainly for simplicity--back in December and have been tied up with various front ends since then. That's unfortunate from my point of view, because what I really wanted to do was play with bias and here I am getting further and further afield.
Why the devil bias appealed to me, I can't say. It just did.
I'll try to start the writeup this weekend, but I already know Saturday is a lost cause. Maybe Sunday.
Grey
The fact that this amp is so modular means that other folks are welcome to post their own front ends. The only requirements are that the front end should have a balanced output and reasonable current delivery. I've seen several schematics here recently that should do as well as anything I've put together.
From the very start I found myself intrigued by some of the biasing options for the Lovoltech parts. I've got at least ten or fifteen different ways to bias the things so far. Obviously, the bias circuits require an output stage to go into, and that in turn implies a front end. I settled on one bias scheme--mainly for simplicity--back in December and have been tied up with various front ends since then. That's unfortunate from my point of view, because what I really wanted to do was play with bias and here I am getting further and further afield.
Why the devil bias appealed to me, I can't say. It just did.
I'll try to start the writeup this weekend, but I already know Saturday is a lost cause. Maybe Sunday.
Grey
These guys in Vancouver list the 2SK389 and 2SJ107, although I don't know what their stock level is. Pricing is $4.89 and $4.27 respectively (CDN$ I think).
I've bought from here before, and thought I had picked up a few of these FETs but can't find them.
http://www.mainelectronics.com/bulksemi.htm
I'll try to do a little parts searching to help the cause.
Paul
I've bought from here before, and thought I had picked up a few of these FETs but can't find them.
http://www.mainelectronics.com/bulksemi.htm
I'll try to do a little parts searching to help the cause.
Paul
Typo, that should have said 2SK389 and 2SJ109 (not 107). I sent them an inquiry.
I also found a company with stock on the 2SJ109:
http://www.bdent.com/search/part.jsp?partnum=2sj109
And of course there is the LSK389 replacement part:
http://www.linearsystems.com/press_release.html#GlossA
Pricing says $3 in 1K quantities.
I also found a company with stock on the 2SJ109:
http://www.bdent.com/search/part.jsp?partnum=2sj109
And of course there is the LSK389 replacement part:
http://www.linearsystems.com/press_release.html#GlossA
Pricing says $3 in 1K quantities.
If there is sufficient interest, I would consider a buy for the Linear Systems LSK389 "C" which is, I believe, their equivalent for the "VI" Toshiba '389.
The problem with Linear Systems is that they don't offer P-ch devices to match their '170 and '389. Bummer.
Their 2SK389 equivalent is a seriously different case configuration from the Toshiba part, hence not a 1:1 replacement mechanically. I have some parts on hand and will be testing them when I have time.
One possibility for the headphone amp (which I think Paul expressed interest in) is a '389 followed by a '1014 or two. I have at least three headphone topologies in mind. This is of more than passing interest to me since I find myself listening to headphones more now than I used to. I have a decent pair of Grados and am willing to undertake the design stuff inherent for the higher voltage models like Senheisers and such. There have been times recently when I've been tempted to set aside the amp circuit in order to begin a headphone amp.
Speaking of the amp project, I spent another hour on it this afternoon and have everything in line now except the gain, which is too high (of all things). Given that I don't want to burn it off as feedback, I'll have to jiggle this and that and reduce it in other ways. My goal, for the time being, is a 0dB NFB amp, although I'd be willing to go as far as 6dB NFB in a pinch. This is all in terms of the front end, obviously.
Yes, the amp will easily support "X" NFB for those who wish it. And if I use feedback, that's the way it will go.
I've got a large pair of heatsinks (courtesy MikeW) that cry out for a nice project. I think it's time.
(Thanks, Mike...have a nice time at the beach, man...)
Grey
The problem with Linear Systems is that they don't offer P-ch devices to match their '170 and '389. Bummer.
Their 2SK389 equivalent is a seriously different case configuration from the Toshiba part, hence not a 1:1 replacement mechanically. I have some parts on hand and will be testing them when I have time.
One possibility for the headphone amp (which I think Paul expressed interest in) is a '389 followed by a '1014 or two. I have at least three headphone topologies in mind. This is of more than passing interest to me since I find myself listening to headphones more now than I used to. I have a decent pair of Grados and am willing to undertake the design stuff inherent for the higher voltage models like Senheisers and such. There have been times recently when I've been tempted to set aside the amp circuit in order to begin a headphone amp.
Speaking of the amp project, I spent another hour on it this afternoon and have everything in line now except the gain, which is too high (of all things). Given that I don't want to burn it off as feedback, I'll have to jiggle this and that and reduce it in other ways. My goal, for the time being, is a 0dB NFB amp, although I'd be willing to go as far as 6dB NFB in a pinch. This is all in terms of the front end, obviously.
Yes, the amp will easily support "X" NFB for those who wish it. And if I use feedback, that's the way it will go.
I've got a large pair of heatsinks (courtesy MikeW) that cry out for a nice project. I think it's time.
(Thanks, Mike...have a nice time at the beach, man...)
Grey
If a GB is comming up on those rare 2SJ109 and 2SK389's, maybe these guys would be a possible supplier?
http://www.1sourcecomponents.com/search/search.htm Choky posted the link in another thread.
Seems they have plenty of the real things. I dont know if they do business with private persons though.
I managed to find some of them with the help of nice people here on the forum. These are from a german supplier.
Steen
http://www.1sourcecomponents.com/search/search.htm Choky posted the link in another thread.
Seems they have plenty of the real things. I dont know if they do business with private persons though.
I managed to find some of them with the help of nice people here on the forum. These are from a german supplier.
Steen
Attachments
My problem with the Toshiba parts--aside from the fact that they're out of production--is that we have little or no control over the grade (GR, BL, VI). I've seen one or two places that claim to have separate inventory categories for the grades, but they only ever seem to show GR parts. What a surprise. The vast majority of places simply say 2SK389...if you ask which grade they act like you kicked their cat. It's only after you place your order and get the parts in that you find out what you've got. That, to me, is unacceptable.
Of course, there's always the fact that the prices keep rising as the dwindling inventory gets depleted.
Linear Systems appears to be currently manufacturing the parts and you can specify the grade up front. I, for one, don't mind the different casing as long as it's for a new circuit board. If I know going in that I need to allow for a different pinout, then it's all the same to me when I'm doing the artwork. I've always found the Toshiba case to be a bit of a pain, due to the offset pins in front.
I have a small stock of Toshiba '389s, '170s, '109s, and '74s. They're nice parts, but they're too hard to get for me to get excited about using them for many projects. I've begun leaning towards the J310, etc. which I can order by the pound if I want. They're also much cheaper.
Incidentally, the Toshiba duals aren't as tightly Vgs matched as I would like for use in a balanced circuit. It doesn't matter so much for a single-ended circuit where you're using the two halves of the differential in different ways, but if you're trying to get DC to balance in a symmetrical circuit with the Toshiba duals, you're in for some fiddling. I have no opinion yet on the Linear Systems '389s. As I said, I have some on hand, but haven't begun testing them yet.
Grey
Of course, there's always the fact that the prices keep rising as the dwindling inventory gets depleted.
Linear Systems appears to be currently manufacturing the parts and you can specify the grade up front. I, for one, don't mind the different casing as long as it's for a new circuit board. If I know going in that I need to allow for a different pinout, then it's all the same to me when I'm doing the artwork. I've always found the Toshiba case to be a bit of a pain, due to the offset pins in front.
I have a small stock of Toshiba '389s, '170s, '109s, and '74s. They're nice parts, but they're too hard to get for me to get excited about using them for many projects. I've begun leaning towards the J310, etc. which I can order by the pound if I want. They're also much cheaper.
Incidentally, the Toshiba duals aren't as tightly Vgs matched as I would like for use in a balanced circuit. It doesn't matter so much for a single-ended circuit where you're using the two halves of the differential in different ways, but if you're trying to get DC to balance in a symmetrical circuit with the Toshiba duals, you're in for some fiddling. I have no opinion yet on the Linear Systems '389s. As I said, I have some on hand, but haven't begun testing them yet.
Grey
It doesn't really make sense for a new design to use discontinued parts. I would lean towards the new devices, meself.
And yes, I am still interested in a headphone amp, though I probably wouldn't start it until the fall. I can perhaps help with some prototyping and testing, if you like.
Paul
And yes, I am still interested in a headphone amp, though I probably wouldn't start it until the fall. I can perhaps help with some prototyping and testing, if you like.
Paul
J310: is that a 2SJ310? I found both numbers as FETs, although I couldn't seem to find a datasheet for the latter. J310 shows up as an RF amplifier.GRollins said:
http://www.fairchildsemi.com/ds/J3/J310.pdf
Just "J310" and yes, it's rated for high frequency use. It's not the be-all, end-all, but it's an interesting part. The J271, which I mentioned above, isn't exactly specified as a complement, but the two are very close in behavior. But note that the Fairchild and Vishay J271 spec sheets tend to lead your thinking in different directions.
Grey
Grey
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