I've been working on a power supply for a little tube amp, and the very last part on my list is for an IRF820B MOSFET transistor. Unfortunately, the minimum order for these things through mouser is about 1500 pieces-a bit more than I need considering I will only be using two. Transistors are new territory for me. Can anyone help find a replacement transistor for sale with similar characteristics?
Here is the data page link from mouser.com:
http://www.mouser.com/Search/ProductDetail.aspx?qs=TGPpmpbSrT6CKxW5JYO1AA%3d%3d
many thanks to any and all who can help me with this.
wade
Wade - Looks like you can purchase one of these transistors from www.newark.com for $1.18 plus shipping. Lead time is said to be 18 days, here is the direct link:
http://www.newark.com/73J5886/semiconductors-prototyping/product.us0?sku=STMICROELECTRONICS-STP4NK50Z&_requestid=47675
Robert H.
:Folks,
:
: I've been working on a power supply for a little tube amp, and the very last part on my list is for an IRF820B MOSFET transistor. Unfortunately, the minimum order for these things through mouser is about 1500 pieces-a bit more than I need considering I will only be using two. Transistors are new territory for me. Can anyone help find a replacement transistor for sale with similar characteristics?
:
:Here is the data page link from mouser.com:
:
:http://www.mouser.com/Search/ProductDetail.aspx?qs=TGPpmpbSrT6CKxW5JYO1AA%3d%3d
:
:many thanks to any and all who can help me with this.
:
:wade
I received several Power MOS FETS's from them recently. They must have made changes to their site. It was very easy to get around. Now it terrible. Might need to give them a call?
Looks like they don't stock the exact part you need so an order requires quantity. A similar part that I received recently could be bought in small quantity, one if you want. Part number is STP9NC60. It's rated N-Channel, 600 volts 9 amps.
Norm
:Folks,
:
: I've been working on a power supply for a little tube amp, and the very last part on my list is for an IRF820B MOSFET transistor. Unfortunately, the minimum order for these things through mouser is about 1500 pieces-a bit more than I need considering I will only be using two. Transistors are new territory for me. Can anyone help find a replacement transistor for sale with similar characteristics?
:
:Here is the data page link from mouser.com:
:
:http://www.mouser.com/Search/ProductDetail.aspx?qs=TGPpmpbSrT6CKxW5JYO1AA%3d%3d
:
:many thanks to any and all who can help me with this.
:
:wade
Lewis
Hi Wade
:
: I received several Power MOS FETS's from them recently. They must have made changes to their site. It was very easy to get around. Now it terrible. Might need to give them a call?
:
: Looks like they don't stock the exact part you need so an order requires quantity. A similar part that I received recently could be bought in small quantity, one if you want. Part number is STP9NC60. It's rated N-Channel, 600 volts 9 amps.
:
:Norm
:
:
:
::Folks,
::
:: I've been working on a power supply for a little tube amp, and the very last part on my list is for an IRF820B MOSFET transistor. Unfortunately, the minimum order for these things through mouser is about 1500 pieces-a bit more than I need considering I will only be using two. Transistors are new territory for me. Can anyone help find a replacement transistor for sale with similar characteristics?
::
::Here is the data page link from mouser.com:
::
::http://www.mouser.com/Search/ProductDetail.aspx?qs=TGPpmpbSrT6CKxW5JYO1AA%3d%3d
::
::many thanks to any and all who can help me with this.
::
::wade
The only thing odd was the B suffix version of the very common ‘820 version unit specified, which may have only been attributable to the “builders” stock “access” …Hmmmmm ? (read as free) from some aerospace/industrial/commercial concern’s supply bin.
With the unit used not being critical at all..BUT…with no knowledge of the circuit to be used in …I might surmise that if it is to be used with tube equipment , it would be used in a linear mode and not be the element of a “noisy” harmonic rich switch mode power supply design .
This submitted example is for one being used in a linear mode and with a cushioned / slow turn on characteristic…if you could be forthcoming with more data on the power supply / feeding tube equipment situation more exacting info could be supplied.
Reference:
73's de Edd
Edd, here is some info on the circuit to confirm what I am up to:
this is essentially a battery eliminator circuit, powering a series of 1u5s and 3v4s. The MOSFET drain side is connected to the positive side of a bridge rectifier, with the source pin running out to the B+ lead. I can't give away too much of what is in this thing, as it is a little 'above top secret', but hopefully there is enough here to tell you what you need to know.
I did see that the 820s are pretty common, it's just that darn 'B' designation that troubled me.
What new or more desirable features could be gained and would be "top secret" about using the mosfet in a battery eliminator circuit?
What major improvements would there be compared to say... an LM317 for instance ...that'll do that same job in spades?
:this is essentially a battery eliminator circuit, powering a series of 1u5s and 3v4s. The MOSFET drain side is connected to the positive side of a bridge rectifier, with the source pin running out to the B+ lead. I can't give away too much of what is in this thing, as it is a little 'above top secret', but hopefully there is enough here to tell you what you need to know.
:
No idea why the circuit if comprised of what it is-I'll go with Edd's theory about 'free parts' available to the designer.
An LM317 is used for the filmament side, however....Wish I could explain/understand the theory behind the circuit a bit more, but this is my first 'big' solid state project. I've really wanted to get this amp running for a long while, but it eats B batteries like nothing else-maybe thirty minutes running time before its spent. Hence my desire for a solid state alternative.
There was a tube powered battery eliminator constructed by the manufacturer for this device, and I recall in the literature that it required a great deal of current regulation and so forth in order to properly drive the amp. The resulting unit weighed in and looked like a small fridge.
:Hi Wade... I'm curious.
:What new or more desirable features could be gained and would be "top secret" about using the mosfet in a battery eliminator circuit?
: What major improvements would there be compared to say... an LM317 for instance ...that'll do that same job in spades?
:
:
::this is essentially a battery eliminator circuit, powering a series of 1u5s and 3v4s. The MOSFET drain side is connected to the positive side of a bridge rectifier, with the source pin running out to the B+ lead. I can't give away too much of what is in this thing, as it is a little 'above top secret', but hopefully there is enough here to tell you what you need to know.
::
:
Wonder if the supply is using a switching circuit to get plate voltage for the tubes? Maybe it starts with only filament voltage and steps it up with an oscillator using two MOS FETs?
Norm
:Peter
:
:No idea why the circuit if comprised of what it is-I'll go with Edd's theory about 'free parts' available to the designer.
:
:An LM317 is used for the filmament side, however....Wish I could explain/understand the theory behind the circuit a bit more, but this is my first 'big' solid state project. I've really wanted to get this amp running for a long while, but it eats B batteries like nothing else-maybe thirty minutes running time before its spent. Hence my desire for a solid state alternative.
:
:There was a tube powered battery eliminator constructed by the manufacturer for this device, and I recall in the literature that it required a great deal of current regulation and so forth in order to properly drive the amp. The resulting unit weighed in and looked like a small fridge.
:
::Hi Wade... I'm curious.
::What new or more desirable features could be gained and would be "top secret" about using the mosfet in a battery eliminator circuit?
:: What major improvements would there be compared to say... an LM317 for instance ...that'll do that same job in spades?
::
::
:::this is essentially a battery eliminator circuit, powering a series of 1u5s and 3v4s. The MOSFET drain side is connected to the positive side of a bridge rectifier, with the source pin running out to the B+ lead. I can't give away too much of what is in this thing, as it is a little 'above top secret', but hopefully there is enough here to tell you what you need to know.
:::
::
Oh, and while I did say I need two MOSFETs-they are in identical but unrelated circuits. The original amp used two ninety volt batteries, and the solid stater version remains true to that by having two ninety volt supplies-each with a single irf820b in it.
With my having so much else happening this weekend, I hadn't realized that I haven't really said what this amp is-it is an optical sound amplifier for an old 16mm newsreel camera. 4 1u5 and 4 3v4s drive a galvo and lamp in the camera to burn an optical soundtrack to the edge of your film as you shoot. The finished product is your own little newsreel-with sound! News equipment needing to be portable, the amp was battery powered. But since the camera is AC powered (to keep sync) and the whole mess weighing 100+ pounds-having a battery portable amp that costs about 100 dollars an hour to run just doesn't seem very appealing to me....
:You can also try an NTE 2398....I can buy NTE locally,,,but heck, anything less than a 75 mile round trip around Atlanta is considered local...I hate this place!
:Lewis
:
:
:
:Hi Wade
::
:: I received several Power MOS FETS's from them recently. They must have made changes to their site. It was very easy to get around. Now it terrible. Might need to give them a call?
::
:: Looks like they don't stock the exact part you need so an order requires quantity. A similar part that I received recently could be bought in small quantity, one if you want. Part number is STP9NC60. It's rated N-Channel, 600 volts 9 amps.
::
::Norm
::
::
::
:::Folks,
:::
::: I've been working on a power supply for a little tube amp, and the very last part on my list is for an IRF820B MOSFET transistor. Unfortunately, the minimum order for these things through mouser is about 1500 pieces-a bit more than I need considering I will only be using two. Transistors are new territory for me. Can anyone help find a replacement transistor for sale with similar characteristics?
:::
:::Here is the data page link from mouser.com:
:::
:::http://www.mouser.com/Search/ProductDetail.aspx?qs=TGPpmpbSrT6CKxW5JYO1AA%3d%3d
:::
:::many thanks to any and all who can help me with this.
:::
:::wade
OK now getting back to the business at hand, and not even being able to utilize my active COSMIC / NATO /SEATO / OAS / TOP SECRET / POLLUX / ADONIS / ATHENA / IRIS / NOFORN / EFTO clearance levels..… WHY ? because….its non military and even more so, because I just don’t have the need to know…LOL.
I initially had no idea what your voltage and current consumption parameters were…therefore referencing the very hefty voltage level of regulated B+ being derived from that piece of circuitry initially submitted.
The use of an IRF820 as the linear pass element would still be all dependent upon the drive / voltage corrective circuitry feeding into it. A sole IRF820 is an ~70 watt device, somewhat overkill on the end use that you are describing .
With the fact of it not being a brute force HV power requirement, I can see it being an AC line powered and creating dual 90 VDC supplies then. And a question about that….are they isolated or do they share a common grounding?
Also , how about each supplies current requirements, as I seem to perceive of a mere decade or so of B+ current required
for those particular mentioned tubes.
If my situation to solve, I would use a variant of the tried and proven old work horse LM317, which you seem to already be using for the filament supply portion.
Check out this end reference for the NATIONAL application note, describing the manner of doing so.
I have a high respect for that unit, for its good control of line and load regulation along with its current and thermal sensing circuitry to protect the end connected equipment.
linked DA-DA sheet reference:
http://www.national.com/ms/LB/LB-47.pdf
73's de Edd
Unfortunately, Edd's advice came a little late, as I had already ordered the nte2398s to give it a go. Well, got those little mosfets earlier this week and just placed them in the circuit, and I'm getting 90 volts dc at the power rating I need, so looks likely that we have a good match. Thanks for all of your help in this first solid state project o' mine.
It's all hooked up now and it works great! The amp is powered perectly and driving the camera's galvonometer. It is so wonderful to have this all working after picking up various parts for this project over the past few years. I just had a 400' film magazine arrive today, so it is ready to load with film. Probably all told, there is about sixty pounds of gear here, so lets give a salute to those early news cameramen and their dedication to hauling this hefty Auricon gear around!
:To all-
:
: Unfortunately, Edd's advice came a little late, as I had already ordered the nte2398s to give it a go. Well, got those little mosfets earlier this week and just placed them in the circuit, and I'm getting 90 volts dc at the power rating I need, so looks likely that we have a good match. Thanks for all of your help in this first solid state project o' mine.