On Friday, 31 December 2021 at 03:04:48 UTC, jla...@highlandsniptechnology.com wrote:> On Thu, 30 Dec 2021 18:26:39 -0500, Phil Hobbs > <pcdhSpamM...@electrooptical.net> wrote: > > >Dimiter_Popoff wrote: > >> On 12/30/2021 22:17, Phil Hobbs wrote: > >>> Dimiter_Popoff wrote: > >>>> On 12/30/2021 20:28, John Larkin wrote: > >>>>> On Thu, 30 Dec 2021 18:47:34 +0200, Dimiter_Popoff <d...@tgi-sci.com> > >>>>> wrote: > >>>>> > >>>>>> On 12/30/2021 18:09, jla...@highlandsniptechnology.com wrote: > >>>>>>> On Thu, 30 Dec 2021 19:39:51 +1100, marty <ma...@invalid.net> wrote: > >>>>>>> > >>>>>>>> On 30/12/21 13:54, jla...@highlandsniptechnology.com wrote: > >>>>>>>>> On Wed, 29 Dec 2021 21:16:34 -0500, Phil Hobbs > >>>>>>>>> <pcdhSpamM...@electrooptical.net> wrote: > >>>>>>>>> > >>>>>>>>>> John Larkin wrote: > >>>>>>>>>>> Does anyone use Apex parts? > >>>>>>>>>>> > >>>>>>>>>>> https://www.mouser.com/c/semiconductors/amplifier-ics/operational-amplifiers-op-amps/?marcom=184808364 > >>>>>>>>>>> > >>>>>>>>>>> > >>>>>>>>>>> The companion heat sink is > >>>>>>>>>>> > >>>>>>>>>>> https://www.mouser.com/ProductDetail/Apex-Microtechnology/HS11?qs=TiOZkKH1s2RwK46pUwsmlQ%3D%3D > >>>>>>>>>>> > >>>>>>>>>>> > >>>>>>>>>>> > >>>>>>>>>> > >>>>>>>>>> Sure, for one-offs. Last one I used was in about 1989, as the > >>>>>>>>>> output > >>>>>>>>>> stage of a piezo driver for a prototype atomic force > >>>>>>>>>> microscope. IIRC > >>>>>>>>>> it was a PA85, which was a beefier replacement for the Burr-Brown > >>>>>>>>>> 3584--higher voltage (450V vs 300V) and much faster (1 kV/us vs > >>>>>>>>>> 150 V/us). > >>>>>>>>>> > >>>>>>>>>> The Apex parts were very noisy, iirc, but since it was the > >>>>>>>>>> output stage, > >>>>>>>>>> I didn't care very much. > >>>>>>>>>> > >>>>>>>>>> I really doubt I'd use one in any design that was going to be > >>>>>>>>>> replicated > >>>>>>>>>> more than 20 times. OTOH the quickish slew rate is worth a fair > >>>>>>>>>> amount > >>>>>>>>>> sometimes. > >>>>>>>>>> > >>>>>>>>>> Cheers > >>>>>>>>>> > >>>>>>>>>> Phil Hobbs > >>>>>>>>> > >>>>>>>>> Did you look at the price on that heat sink? > >>>>>>>>> > >>>>>>>>> Even boring heat sinks are priced at kilobucks these days. > >>>>>>>>> > >>>>>>>>> https://www.mouser.com/ProductDetail/Aavid/602151F00000G?qs=KrMmfw1gsVf%2FvbGzFuwJMg%3D%3D > >>>>>>>>> > >>>>>>>>> > >>>>>>>>> > >>>>>>>>> > >>>>>>>> Free shipping though! > >>>>>>> > >>>>>>> I'd hate to pay shipping for parts that are out of stock. > >>>>>>> > >>>>>>> I see insane pricing on some parts, factors of 10 and sometimes 100x > >>>>>>> reasonable. > >>>>>>> > >>>>>>> > >>>>>>> > >>>>>> > >>>>>> The pricing on these opamps may be insane but so are the parts, I > >>>>>> never > >>>>>> knew things like that were on offer (2.5kV peak to peak output!). > >>>>>> I have not done more than 200V peak to peak, was some 10 years ago, I > >>>>>> did it with discrete parts though. The project could not have afforded > >>>>>> opamps like these anyway. > >>>>> > >>>>> You can make your own kilovolt-level opamps pretty easily. There are > >>>>> some nice HV mosfets like IXTY02N120 and 2SK4177 and the IXTT02N450HV. > >>>>> If you optocouple up into the fets, it avoids all sorts of ugly level > >>>>> shifting. > >>>>> > >>>> > >>>> Well I have never needed that sort of thing so I never thought of it > >>>> really, my HV experiences are by just making HV sources (up to 5kV) > >>>> which only need HV diodes at the HV side apart from caps etc. (I got > >>>> some really good - fast, small etc. - HV diodes on ebay, can you believe > >>>> it). > >>>> The opto-level shifting is an interesting idea indeed, one could easily > >>>> overlook it and go into that "ugly level shifting", I had not thought of > >>>> it. I did "normal" level shifting on that +/- 100V thing back then but > >>>> it was not too ugly, getting the thing stable with optocouplers might > >>>> have been a challenge (unless one can get decent spice models, never > >>>> looked for any). But even without models one can manage it with some > >>>> trial and error of course. > >>> > >>> Slow HV isn't too hard, if you don't mind a few watts' quiescent > >>> dissipation. You can put HV transistors in series, for instance, with > >>> a resistive voltage divider driving the bases. > >>> > >>> Fast HV is another thing. Last time I needed to do that, I used an > >>> 811A. (It was about 1990.) > >>> > >>> Cheers > >>> > >>> Phil Hobbs > >>> > >> > >> Well obviously the slower the easier :-). My 200V p-p output stage (I > >> think it did up to 100 mA, it was for a one-off thing for a > >> plasma-physics lab) did something like 2300V/s which is not too fast > >> for a 200V peak to peak (and it needed much less than that). > >> They wanted to drive the voltage and monitor the current IIRC. > >> Then 200V really is not HV, just the highest V I have designed some > >> driver for. > >> What is this 811A, is it the valve which I kept finding? > > > >Yup. > > > >Cheers > > > >Phil Hobbs > I did some fun stuff with a TV HV rectifier tube, 1B3 I think, as an > amplifier, with the input going into the filament. Voltage gain around > 50K, bandwidth not so good. > > It's amazing that I survived childhood.Yes, a rectifier diode operated like that would make a good X-ray source. John
Apex
Started by ●December 29, 2021
Reply by ●December 31, 20212021-12-31
Reply by ●December 31, 20212021-12-31
On Thursday, December 30, 2021 at 4:49:54 PM UTC, jla...@highlandsniptechnology.com wrote:> On Thu, 30 Dec 2021 10:44:45 -0500, Phil Hobbs > <pcdhSpamM...@electrooptical.net> wrote: > > >Joe Gwinn wrote: > >> On Wed, 29 Dec 2021 18:54:34 -0800, jla...@highlandsniptechnology.com > >> wrote: > >> > >>> On Wed, 29 Dec 2021 21:16:34 -0500, Phil Hobbs > >>> <pcdhSpamM...@electrooptical.net> wrote: > >>> > >>>> John Larkin wrote: > >>>>> Does anyone use Apex parts? > >>>>> > >>>>> https://www.mouser.com/c/semiconductors/amplifier-ics/operational-amplifiers-op-amps/?marcom=184808364 > >>>>> > >>>>> The companion heat sink is > >>>>> > >>>>> https://www.mouser.com/ProductDetail/Apex-Microtechnology/HS11?qs=TiOZkKH1s2RwK46pUwsmlQ%3D%3D > >>>>> > >>>>> > >>>> > >>>> Sure, for one-offs. Last one I used was in about 1989, as the output > >>>> stage of a piezo driver for a prototype atomic force microscope. IIRC > >>>> it was a PA85, which was a beefier replacement for the Burr-Brown > >>>> 3584--higher voltage (450V vs 300V) and much faster (1 kV/us vs 150 V/us). > >>>> > >>>> The Apex parts were very noisy, iirc, but since it was the output stage, > >>>> I didn't care very much. > >>>> > >>>> I really doubt I'd use one in any design that was going to be replicated > >>>> more than 20 times. OTOH the quickish slew rate is worth a fair amount > >>>> sometimes. > >>>> > >>>> Cheers > >>>> > >>>> Phil Hobbs > >>> > >>> Did you look at the price on that heat sink? > >>> > >>> Even boring heat sinks are priced at kilobucks these days. > >>> > >>> <https://www.mouser.com/ProductDetail/Aavid/602151F00000G?qs=KrMmfw1gsVf%2FvbGzFuwJMg%3D%3D> > >> > >> I'd read that as Aavid has decided to drop that product, but for $3K, > >> they will pull the tooling out of storage and make a run. Once going, > >> they will make many, and sell you the first. > >> > >> Joe Gwinn > >> > > > > > >Might well be. Drilling a few more holes in a TO-3 heatsink is pretty > >simple--that $3k is more of a stupidity tax. ;) > > > >Distributor prices for heatsinks are pretty high in general. (Not > >usually as high as that, of course.) > > > >Cheers > > > >Phil Hobbs > We designed our own box to replace the ugly awkward Hammond things. We > designed a custom extrusion and had a bunch extruded and machined and > anodized, and still saved money. > > https://www.dropbox.com/s/rathfqgnng2r7gt/T2box_2.jpg?raw=1 > > https://www.dropbox.com/s/43gma000fpuocyf/T130_box.jpg?raw=1 > > > Commercial heat sinks cost crazy multiples of the cost of extruding > aluminum. > -- > > I yam what I yam - PopeyeNot that it explains All the cost, but heatsinks like these do require the footprint area to be machined to a certain flatness and roughness (which then incurs QA work) So the added labor cost could be major. cheers, RS
Reply by ●December 31, 20212021-12-31
On Fri, 31 Dec 2021 09:24:38 -0800 (PST), Rich S <richsulinengineer@gmail.com> wrote:>On Thursday, December 30, 2021 at 4:49:54 PM UTC, jla...@highlandsniptechnology.com wrote: >> On Thu, 30 Dec 2021 10:44:45 -0500, Phil Hobbs >> <pcdhSpamM...@electrooptical.net> wrote: >> >> >Joe Gwinn wrote: >> >> On Wed, 29 Dec 2021 18:54:34 -0800, jla...@highlandsniptechnology.com >> >> wrote: >> >> >> >>> On Wed, 29 Dec 2021 21:16:34 -0500, Phil Hobbs >> >>> <pcdhSpamM...@electrooptical.net> wrote: >> >>> >> >>>> John Larkin wrote: >> >>>>> Does anyone use Apex parts? >> >>>>> >> >>>>> https://www.mouser.com/c/semiconductors/amplifier-ics/operational-amplifiers-op-amps/?marcom=184808364 >> >>>>> >> >>>>> The companion heat sink is >> >>>>> >> >>>>> https://www.mouser.com/ProductDetail/Apex-Microtechnology/HS11?qs=TiOZkKH1s2RwK46pUwsmlQ%3D%3D >> >>>>> >> >>>>> >> >>>> >> >>>> Sure, for one-offs. Last one I used was in about 1989, as the output >> >>>> stage of a piezo driver for a prototype atomic force microscope. IIRC >> >>>> it was a PA85, which was a beefier replacement for the Burr-Brown >> >>>> 3584--higher voltage (450V vs 300V) and much faster (1 kV/us vs 150 V/us). >> >>>> >> >>>> The Apex parts were very noisy, iirc, but since it was the output stage, >> >>>> I didn't care very much. >> >>>> >> >>>> I really doubt I'd use one in any design that was going to be replicated >> >>>> more than 20 times. OTOH the quickish slew rate is worth a fair amount >> >>>> sometimes. >> >>>> >> >>>> Cheers >> >>>> >> >>>> Phil Hobbs >> >>> >> >>> Did you look at the price on that heat sink? >> >>> >> >>> Even boring heat sinks are priced at kilobucks these days. >> >>> >> >>> <https://www.mouser.com/ProductDetail/Aavid/602151F00000G?qs=KrMmfw1gsVf%2FvbGzFuwJMg%3D%3D> >> >> >> >> I'd read that as Aavid has decided to drop that product, but for $3K, >> >> they will pull the tooling out of storage and make a run. Once going, >> >> they will make many, and sell you the first. >> >> >> >> Joe Gwinn >> >> >> > >> > >> >Might well be. Drilling a few more holes in a TO-3 heatsink is pretty >> >simple--that $3k is more of a stupidity tax. ;) >> > >> >Distributor prices for heatsinks are pretty high in general. (Not >> >usually as high as that, of course.) >> > >> >Cheers >> > >> >Phil Hobbs >> We designed our own box to replace the ugly awkward Hammond things. We >> designed a custom extrusion and had a bunch extruded and machined and >> anodized, and still saved money. >> >> https://www.dropbox.com/s/rathfqgnng2r7gt/T2box_2.jpg?raw=1 >> >> https://www.dropbox.com/s/43gma000fpuocyf/T130_box.jpg?raw=1 >> >> >> Commercial heat sinks cost crazy multiples of the cost of extruding >> aluminum. >> -- >> >> I yam what I yam - Popeye > >Not that it explains All the cost, but >heatsinks like these do require the footprint >area to be machined to a certain flatness >and roughness (which then incurs QA work) >So the added labor cost could be major. >cheers, RSIn my experience, the big heat sink extrusions are not usually very flat. We often do our own secondary machining to get them flat. -- If a man will begin with certainties, he shall end with doubts, but if he will be content to begin with doubts he shall end in certainties. Francis Bacon
Reply by ●December 31, 20212021-12-31
> >> > >> Commercial heat sinks cost crazy multiples of the cost of extruding > >> aluminum. > >> -- > >> > >> I yam what I yam - Popeye > > > >Not that it explains All the cost, but > >heatsinks like these do require the footprint > >area to be machined to a certain flatness > >and roughness (which then incurs QA work) > >So the added labor cost could be major. > >cheers, RS > In my experience, the big heat sink extrusions are not usually very > flat. We often do our own secondary machining to get them flat.Sure, I accept that. A former colleague of mine designed his audio amps to push the limits. (these were full production commercial units). the output devices ran as hot as possible, and to ensure adequate heat removal, he left out the insulators. Devices were mounted "metal -on-metal" - so flatness mattered. I assume they ordered the heatsinks already machined as needed. Yes, the heatsinks were electrified, one at +100V and the other -100V. Very tricky to work on... Of course, the flatness need not be too low if we're using a thermal pad or compound to fill the small gaps.
Reply by ●December 31, 20212021-12-31
On Friday, December 31, 2021 at 11:33:53 AM UTC-8, John Larkin wrote:> In my experience, the big heat sink extrusions are not usually very > flat. We often do our own secondary machining to get them flat.Yeah, you squeeze a toothpaste tube, it's not straight. For the aluminum extrusions, each length is pulled (stretched) by a few percent while it's still hot. A couple of passes with a flycutter after anodizing is not a hard task. Any good heatsink manufacturer could/would do that.
