Re: [time-nuts] Anybody want a Thunderbolt power supply?

Hi > On Oct 23, 2016, at 2:12 PM, Scott Stobbe wrote: > > I would certainly hope a 7912 would be good enough, because at 1ppm rms in > 0.1 Hz to 10 Hz there is maybe a little over one order magnitude left with > a dedicated low-noise reference. In all likely hood the

Re: [time-nuts] Anybody want a Thunderbolt power supply?

I would certainly hope a 7912 would be good enough, because at 1ppm rms in 0.1 Hz to 10 Hz there is maybe a little over one order magnitude left with a dedicated low-noise reference. In all likely hood the reference on board the thunderbolt likely has 1ppm pk-pk over 0.1 to 10 Hz band. Tempco for

Re: [time-nuts] Anybody want a Thunderbolt power supply?

Hi The op amp has a PSRR of roughly 90 db at 1 Hz. As frequency goes up, the PSRR gets worse. What frequency is your “signal” at? A very normal 7912 fed by a normal supply will not produce a noticeable degradation in phase nose on the TBolt. Putting an un-filtered switcher on any of the lines

Re: [time-nuts] Anybody want a Thunderbolt power supply?

At this point, I have three prototype boards that are functional as far as I can tell. Unfortunately I don’t have a better reference which would allow me to make comparisons. If someone with a better reference could make a proper comparison, I’d be happy to send them a prototype. > On Oct

Re: [time-nuts] Anybody want a Thunderbolt power supply?

I think we are coming up to the noise floor here. We have identified a potential signal A from a 7912 (likely similar to a 7812, no guarentee). The remaining question is if you apply signal A to the power pin of a thunderbolt what is signal B added to the output. We know where we want signal B to

Re: [time-nuts] Anybody want a Thunderbolt power supply?

Hi There is an *enormous* difference between regulation and it’s impact on stability (which is what this drifted off into) and PSRR and it’s impact on phase noise (which got lost at the tread moved on). PSRR does indeed matter, but a fairly simple linear regulator (or pair of cheap ones or coil

Re: [time-nuts] Anybody want a Thunderbolt power supply?

Bob, this is good data and insights thanks for taking the time to share. Ultimately the question Nick is hoping to answer is what is the point of diminishing returns for voltage regulation. I think there are plenty of folks on this list that have shared data suggesting a switching regulator which

Re: [time-nuts] Anybody want a Thunderbolt power supply?

Hi The -12 V line is not the reference for the EFC. It *is* one supply into the op amp circuit that drives the EFC. Since the EFC is +/- 5V, there must be both a positive and a negative supply into the driver circuit for full output swing. The -12 can be anything between about -13 and -7

Re: [time-nuts] Anybody want a Thunderbolt power supply?

It all depends what the -12V rail is for, some have said it directly references the EFC dac. I would hope an ocxo would have a better tuning gain on its efc pin than supply pin but maybe that's not always true. On Saturday, 22 October 2016, Bob Camp wrote: > Hi > > The +12 goes

Re: [time-nuts] Anybody want a Thunderbolt power supply?

Hi The +12 goes straight to the OCXO. All OCXO’s have a voltage sensitivity. That sensitivity is much higher than voltage sensitivity is much higher than what you see on the other two supply pins. Bob > On Oct 21, 2016, at 11:06 PM, Scott Stobbe wrote: > >

Re: [time-nuts] Anybody want a Thunderbolt power supply?

Interesting, I would have thought that the +12V input would be extremely well regulated since its shared with the oven heater, I*R drops are going to show up every where, if your looking for uV levels of stability. Just a connector has milliohms of contact resistance, let alone routing and

Re: [time-nuts] Anybody want a Thunderbolt power supply?

Hi > On Oct 21, 2016, at 7:44 PM, Scott Stobbe wrote: > > A little more data on the 7912. > > The first plot shows the tempCo of the 7912 measured with ambient > temperature swings "7912_TempCo.png". Which is -150 ppm/degC. > > The second plot is off a 7912 logged

Re: [time-nuts] Anybody want a Thunderbolt power supply?

On Fri, 21 Oct 2016 10:59:59 +0200, you wrote: >On Fri, 21 Oct 2016 00:20:43 -0400 >Scott Stobbe wrote: > >> The bad side of a 7912 is in long-term stability and tempCo, the sample I >> tested had at least a 150 ppm/degC tempCo, which is going to put a serious >>

Re: [time-nuts] Anybody want a Thunderbolt power supply?

On Fri, 21 Oct 2016 06:14:03 -0700 Nick Sayer via time-nuts wrote: > Well, because it's easily an order of magnitude more expensive than a 7912. > $5 instead of 50¢ (Q:1). > > If it *matters*, then fine, but I am sensitive to cost efficiency in addition > to efficacy.

Re: [time-nuts] Anybody want a Thunderbolt power supply?

Hi At least in terms of voltage regulation (as opposed to noise), the -12V input on the TBolt is the *least* sensitive input on the TBolt. It’s issue is only in terms of PSRR. The internals of the unit take care of any drift or really low frequency stuff on the -12 input. Bob > On Oct 21,

Re: [time-nuts] Anybody want a Thunderbolt power supply?

Well, because it's easily an order of magnitude more expensive than a 7912. $5 instead of 50¢ (Q:1). If it *matters*, then fine, but I am sensitive to cost efficiency in addition to efficacy. If you put the board in a box in a stable temperature environment (which I'd kind of assume you'd do

Re: [time-nuts] Anybody want a Thunderbolt power supply?

Hi > On Oct 21, 2016, at 12:20 AM, Scott Stobbe wrote: > > Nick had mention that the -12V rail on the thunderbolt has the poorest PSRR > with respect to frequency output, so I first took a look at the venerable > 7912. > > The first data-set was taken with a -13.5 VDC

Re: [time-nuts] Anybody want a Thunderbolt power supply?

On Fri, 21 Oct 2016 10:59:59 +0200 Attila Kinali wrote: > And while you are at it, use three LT3090 for the positive supplies :-) Ermm... LT3045 Attila Kinali -- Malek's Law: Any simple idea will be worded in the most complicated way.

Re: [time-nuts] Anybody want a Thunderbolt power supply?

On Fri, 21 Oct 2016 00:20:43 -0400 Scott Stobbe wrote: > The bad side of a 7912 is in long-term stability and tempCo, the sample I > tested had at least a 150 ppm/degC tempCo, which is going to put a serious > lump/bump in the 10s tau to gps crossover point on an allan

Re: [time-nuts] Anybody want a Thunderbolt power supply?

Nick had mention that the -12V rail on the thunderbolt has the poorest PSRR with respect to frequency output, so I first took a look at the venerable 7912. The first data-set was taken with a -13.5 VDC input. Attached is the 0.1 Hz to 10 Hz noise of an essentially quiescently loaded 7912, only a

Re: [time-nuts] Anybody want a Thunderbolt power supply?

I'm sure I have some 7805s lying around, maybe a 7812/7912. I'm interested to see the 1/f noise of a classic regulator, what load current do you expect? I can bias a 7805 for the same load and measure the 0.1 to 10 Hz noise. Also if you have a digital scope without a very good builtin FFT, octave

Re: [time-nuts] Anybody want a Thunderbolt power supply?

Just an update. I’ve built the second prototype board (I skipped over the first design), and it’s powering my tbolt right now. The design calls for 15v in (though it would also work with 13.8v). The +12 output comes from a D2PAK 7812. For +5, there is an AP1509 buck converter to make around

Re: [time-nuts] Anybody want a Thunderbolt power supply

Am 01.09.2016 um 06:56 schrieb Gerhard Hoffmann: Am 01.09.2016 um 05:35 schrieb Charles Steinmetz: The suggestion to use LT3042s is a good one, but note that it has an output current rating of 200mA. The Tbolt needs ~250mA at +5v, and ~700mA at +12v [at startup -- but only ~150mA

Re: [time-nuts] Anybody want a Thunderbolt power supply?

James wrote: Is there a problem running more than one Thunderbolt off of the same linear supply (assuming the supply can support the current demands) or does each Thunderbolt require its’ own separate linear supply? I do not anticipate that multiple Tbolts would interact in a negative

Re: [time-nuts] Anybody want a Thunderbolt power supply?

Jim, I use a HP 6236B triple power supply to drive 2 each T'Bolts. Works fine after the T'Bolts warm up, with limitations on a cold start up. But once they warm up all is OK. Using a common outside puck antenna and a HP RF distribution block I can run 3 T'Bolts and get essentially the same

Re: [time-nuts] Anybody want a Thunderbolt power supply

Am 01.09.2016 um 16:36 schrieb jimlux: On 8/31/16 10:24 PM, Gerhard Hoffmann wrote: Am 01.09.2016 um 06:07 schrieb Bruce Griffiths: I have a quad LT3042 PCB that I must get around to assembling.One potential issue with the LT3042 is the relatively high noise at low frequencies when the

Re: [time-nuts] Anybody want a Thunderbolt power supply?

s a Hammond >> box, the price moves into new territory and nobody's interested. >> >> Bob >> >> >> From: Charles Steinmetz <csteinm...@yandex.com> >> To: time-nuts@febo.com >> Sent: Wednesday, August 31, 2016 4:24 PM >> Subject: Re

Re: [time-nuts] Anybody want a Thunderbolt power supply?

Hi The gotcha is that an OCXO acts as a negative resistance load (current goes up as voltage goes down). That makes wiring up multiple units problematic. It is not impossible to do, but you can get in trouble. Putting regulation at each device eliminates the problem. It may be overkill, but

Re: [time-nuts] Anybody want a Thunderbolt power supply

On 8/31/16 10:24 PM, Gerhard Hoffmann wrote: Am 01.09.2016 um 06:07 schrieb Bruce Griffiths: I have a quad LT3042 PCB that I must get around to assembling.One potential issue with the LT3042 is the relatively high noise at low frequencies when the capacititve bypassing of the resistor that sets

Re: [time-nuts] Anybody want a Thunderbolt power supply

Dave wrote: The problem on eBay is "tested" means something quite different to what I know as "tested' Well, yes, but that's well-known. Ebay is what it is and ebay sellers are what they are. No use grousing about it, just deal with it. The important thing is to make sure you have a

Re: [time-nuts] Anybody want a Thunderbolt power supply?

Hi For multiple TBolts, the simple answer is local regulation. LT1764’s work fine for the +12 and +5 side. A well bypassed 79L12 can do the trick for the -12. Feed them all of of a bulk +15 (high current) llinear supply and a -15 with the lowest output you can find. The gotcha is that if you

Re: [time-nuts] Anybody want a Thunderbolt power supply?

Is there a problem running more than one Thunderbolt off of the same linear supply (assuming the supply can support the current demands) or does each Thunderbolt require its’ own separate linear supply? Jim Robbins ___ time-nuts mailing list --

Re: [time-nuts] Anybody want a Thunderbolt power supply

Mike wrote: I use the TAPR HPSDR LPU I was unfamiliar with the LPU, so I took a look at the docs. It develops several voltages, all from a +13.8v source. This means that the -12v supply necessarily is a switching supply (to get the polarity reversal). It is unfortunate that the power

Re: [time-nuts] Anybody want a Thunderbolt power supply

On 2016-09-01 05:35, Charles Steinmetz wrote: Bruce wrote: Low noise regulators for the +12V and +5V outputs would also be useful. Very true. By focusing on the -12v supply, I did not intend to suggest that low noise is unimportant on the +12v and +5v supplies. The suggestion to use

Re: [time-nuts] Anybody want a Thunderbolt power supply

Am 01.09.2016 um 07:44 schrieb Charles Steinmetz: The datasheet shows both NPN and PNP current multipliers. Just curious -- did you choose the NPN circuit for theoretical considerations, and if so what was your reasoning -- the lower open-loop output impedance? More belly feeling. The PNP

Re: [time-nuts] Anybody want a Thunderbolt power supply?

Original message From: Charles Steinmetz Date:09/01/2016 06:07 (GMT+00:00) To: time-nuts@febo.com Subject: Re: [time-nuts] Anybody want a Thunderbolt power supply? Randall wrote: > Tested and guaranteed samples of all of these can be bought for $25-100 if

Re: [time-nuts] Anybody want a Thunderbolt power supply

Bruce wrote: It will show up if the value of the voltage setting bypass capacitor is reduced. Both the Johnson and excess noise in this resistor coupled with the current source flicker noise should become evident. The datasheet graphs indicate that the Johnson noise of the voltage setting

Re: [time-nuts] Anybody want a Thunderbolt power supply?

Post should have been: Acts like noise current flowing in the voltage setting network (R || C).Flicker noise appears to kick in below 1Hz or so. Bruce On Thursday, 1 September 2016 8:23 PM, Bruce Griffiths wrote: Acts like current  noise flowing in the

Re: [time-nuts] Anybody want a Thunderbolt power supply

I wrote: I have converted a number of them by replacing the DC-DC converters and feeding the circuitry from a mains-operated linear DC supply This should read, "I have converted a number of them by *removing* the DC-DC converters and feeding the circuitry from a mains-operated linear DC

Re: [time-nuts] Anybody want a Thunderbolt power supply

Gerhard wrote: I have made a stamp-sized layout for LT3042 + external npn power transistor as shown in the data sheet. Not fabricated, let alone tested. Nice! The datasheet shows both NPN and PNP current multipliers. Just curious -- did you choose the NPN circuit for theoretical

Re: [time-nuts] Anybody want a Thunderbolt power supply?

Randall wrote: Wow, given all the responses about the cleanliness of the power into a Thunderbolt, I would be even more interested in a power supply that did *not* leave the "last mile" up to me. I would be more interested in a "pretty clean" power supply that I could just plug in and go.

Re: [time-nuts] Anybody want a Thunderbolt power supply

Dave wrote: Getting the required Thunderbolt supply rails from a nominal 12v dc supply of doubtful cleanliness is an issue that also needs to be addressed. I'm still mulling over that one. (and using a triple output switcher from an inverter backed mains supply meantime!) The ex-telco GPSDOs

Re: [time-nuts] Anybody want a Thunderbolt power supply

It will show up if the value of the voltage setting bypass capacitor is reduced. Both the Johnson and excess noise in this resistor coupled with the current source flicker noise should become evident. The datasheet graphs indicate that the Johnson noise of the voltage setting resistor(33k2

Re: [time-nuts] Anybody want a Thunderbolt power supply

Bruce wrote: Low noise regulators for the +12V and +5V outputs would also be useful. Very true. By focusing on the -12v supply, I did not intend to suggest that low noise is unimportant on the +12v and +5v supplies. The suggestion to use LT3042s is a good one, but note that it has an

Re: [time-nuts] Anybody want a Thunderbolt power supply

Am 01.09.2016 um 05:35 schrieb Charles Steinmetz: The suggestion to use LT3042s is a good one, but note that it has an output current rating of 200mA. The Tbolt needs ~250mA at +5v, and ~700mA at +12v [at startup -- but only ~150mA steady-state, depending on ambient temperature]. LT3042s

Re: [time-nuts] Anybody want a Thunderbolt power supply?

; > From: Charles Steinmetz <csteinm...@yandex.com> > To: time-nuts@febo.com > Sent: Wednesday, August 31, 2016 4:24 PM > Subject: Re: [time-nuts] Anybody want a Thunderbolt power supply? > > Mark wrote: > > > Some times a full linear supply is not a

Re: [time-nuts] Anybody want a Thunderbolt power supply

Just split  the 1uF coupling cap into 2x 2u2 in series in the Cuk dc-dc converter add a 1:1 transformer (should be small at 2MHz) between the pair of 2u2 caps to produce a floating output and use an LT3042 as a post regulator.With a mains transformer input supply a separate isolated winding for

Re: [time-nuts] Anybody want a Thunderbolt power supply

ubject: Re: [time-nuts] Anybody want a Thunderbolt power supply Bruce wrote: Low noise regulators for the +12V and +5V outputs would also be useful. Very true. By focusing on the -12v supply, I did not intend to suggest that low noise is unimportant on the +12v and +5v supplies. The sug

Re: [time-nuts] Anybody want a Thunderbolt power supply

HI Just get a linear supply from somebody you have heard of before and it will do fine. The key point is to avoid a switcher. There are still lots of linears out there. The designs have not changed much for the last 40 years. They pretty much all do it the same way. Bob > On Aug 31, 2016,

Re: [time-nuts] Anybody want a Thunderbolt power supply?

/jeff/ac0c www.ac0c.com alpha-charlie-zero-charlie -Original Message- From: Bob kb8tq Sent: Wednesday, August 31, 2016 7:49 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Anybody want a Thunderbolt power supply? Hi It is not that hard to do. Use a linear r

Re: [time-nuts] Anybody want a Thunderbolt power supply

With the talk of Thunderbolt power supplies and their qualities, and after seeing the post about the TAPR HPSDR LPU... I am beginning to wonder about the power source I have for mine, as the "Temp" field shown on the following link has always been funny. It seems to track and keep the outputs up

Re: [time-nuts] Anybody want a Thunderbolt power supply?

Bob wrote: I don't mean to cause offense, but is everything you don't like crap? The reality is that whatever the market will bear is what determines what comes to market. If you can find high quality goods on ebay that can be modified to fit your needs, then you win. There is a

Re: [time-nuts] Anybody want a Thunderbolt power supply?

boun...@febo.com] On Behalf Of Bob Stewart > Sent: Wednesday, 31 August, 2016 15:29 > To: Discussion of precise time and frequency measurement <time-nuts@febo.com> > Subject: Re: [time-nuts] Anybody want a Thunderbolt power supply? > > OTOH, how many time-nuts have any interest

Re: [time-nuts] Anybody want a Thunderbolt power supply

If onen is going to use a dc-dc converter the Cuk converter used here is a nice topology in that it can have low input and output ripple currents. However input and output filters like the Murata BNX002/BNX005 series would have been useful as would an LM3042 linear post regulator for the -12V

Re: [time-nuts] Anybody want a Thunderbolt power supply?

Bob wrote: OTOH, how many time-nuts have any interest in paying for a power supply that's up to time-nuts standards? It's really not easy to bring a small product to market at a small price. Even if you completely discount the personal effort of design, construction, and marketing, there's

Re: [time-nuts] Anybody want a Thunderbolt power supply

I use the TAPR HPSDR LPU: < https://www.tapr.org/kits_lpu.html > I run two Trimble Thunderbolts on a LPU that uses the house 13.6 Volt supply that is backed up with two 6 Volt golf cart batteries in series. I didn't bother installing the Anderson Power Pole and ATX connectors, but wired

Re: [time-nuts] Anybody want a Thunderbolt power supply?

Chris wrote: Did you try any passive filters between the switchers and linear regulators? Yes, I *always* use passive filters on the outputs of switching regulators. As others have posted, it's not just a matter of the conducted noise on the supply rail -- switching noise propogates on the

Re: [time-nuts] Anybody want a Thunderbolt power supply?

When I began the design process, I assumed - as would be reasonable - that ~30 mV P-P of noise and ripple were acceptable for input power supplies, and that before they were used for a precision purpose within the device that there would be further filtering if for no other reason that you’d

Re: [time-nuts] Anybody want a Thunderbolt power supply?

Mark wrote: Some times a full linear supply is not a viable option due to power dissipation/size issues or the utter convenience of using a switching wall wart. In the context of the present discussion -- powering a Tbolt for time-nuts use -- the first consideration would just be laughable

Re: [time-nuts] Anybody want a Thunderbolt power supply?

jim wrote: with the venerable 2n3055 (1960s!) as the series pass device, and an exotic TIP29 (my 1985 databook has it, but the original datasheet says 1968) to drive it.. They probably used the 1970s versions of the transistor, of course, since the 723 didn't come out til early 70s..

Re: [time-nuts] Anybody want a Thunderbolt power supply?

box, the price moves into new > territory and nobody's interested. > > Bob > > > From: Charles Steinmetz <csteinm...@yandex.com> > To: time-nuts@febo.com > Sent: Wednesday, August 31, 2016 4:24 PM > Subject: Re: [time-nuts] Anybody want a Thunderbolt power

Re: [time-nuts] Anybody want a Thunderbolt power supply?

unit. Bob - AE6RV.com GFS GPSDO list: groups.yahoo.com/neo/groups/GFS-GPSDOs/info From: Charles Steinmetz <csteinm...@yandex.com> To: time-nuts@febo.com Sent: Wednesday, August 31, 2016 5:02 PM Subject: Re: [time-nu

Re: [time-nuts] Anybody want a Thunderbolt power supply?

ednesday, August 31, 2016 5:02 PM Subject: Re: [time-nuts] Anybody want a Thunderbolt power supply? Bob wrote: > OTOH, how many time-nuts have any interest in paying for a power supply > that's up to time-nuts standards?  It's really not easy to bring a small > product to marke

Re: [time-nuts] Anybody want a Thunderbolt power supply?

ust 31, 2016 4:24 PM Subject: Re: [time-nuts] Anybody want a Thunderbolt power supply? Mark wrote: > Some times a full linear supply is not a viable option due to power > dissipation/size issues or the utter convenience of using a switching wall > wart. In the context of the pre

Re: [time-nuts] Anybody want a Thunderbolt power supply?

Mark wrote: You have to be careful choosing a linear regulator to clean up a switching supply. Many just wind up passing the noise through. Pay attention to the noise, PSRR and CMRR vs frequency specs, etc Precisely the reason to avoid switchers entirely and use linear-only voltage

Re: [time-nuts] Anybody want a Thunderbolt power supply?

On Wed, August 31, 2016 2:16 pm, Charles Steinmetz wrote: > I had to use two stages of well-designed linear regulation to > make any switching supply acceptable (at a time-nuts level) for use with > a Tbolt. Did you try any passive filters between the switchers and linear regulators? -- Chris

Re: [time-nuts] Anybody want a Thunderbolt power supply?

On 8/31/16 1:52 PM, Adrian Godwin wrote: I'm being Devil's Advocate here because I certainly realise switchers do generate high frequency noise. But wasn't the intention of them to make filtering easier, with smaller filter components, exactly because they operate at higher frequencies ? So why

Re: [time-nuts] Anybody want a Thunderbolt power supply?

I'm being Devil's Advocate here because I certainly realise switchers do generate high frequency noise. But wasn't the intention of them to make filtering easier, with smaller filter components, exactly because they operate at higher frequencies ? So why do they fail ? Is it cost-cutting to make

[time-nuts] Anybody want a Thunderbolt power supply?

Yes, at times I used a two stage linear regulator. The first stage had excellent low freq rejection and the final stage too care of the high freq stuff. Some times a full linear supply is not a viable option due to power dissipation/size issues or the utter convenience of using a switching

Re: [time-nuts] Anybody want a Thunderbolt power supply?

Have a look at Linear Application Note 101 by Jim Williams: Minimizing Switching Regulator Residue in Linear Regulator Outputs Edésio On Wed, Aug 31, 2016 at 07:01:44PM +, Mark Sims wrote: > You have to be careful choosing a linear

Re: [time-nuts] Anybody want a Thunderbolt power supply?

Jerry wrote: Charles, do you have the schematic for the HTAA-16W-A ? The KO4BB mod has limited info Clint wrote: >> Ah, these are the LM723 based linear supplies, Lambda Coutant made >> variants as did Farnell, they're renowned as high reliability, low noise >> supplies. >> >> There

Re: [time-nuts] Anybody want a Thunderbolt power supply?

On 8/31/16 12:01 PM, Mark Sims wrote: You have to be careful choosing a linear regulator to clean up a switching supply. Many just wind up passing the noise through. Pay attention to the noise, PSRR and CMRR vs frequency specs, etc Indeed.. a lot of monolithic regulators have a

Re: [time-nuts] Anybody want a Thunderbolt power supply?

On 8/31/16 11:22 AM, Charles Steinmetz wrote: Jerry wrote: Charles, do you have the schematic for the HTAA-16W-A ? The KO4BB mod has limited info Clint wrote: Ah, these are the LM723 based linear supplies, Lambda Coutant made variants as did Farnell, they're renowned as high

[time-nuts] Anybody want a Thunderbolt power supply?

You have to be careful choosing a linear regulator to clean up a switching supply. Many just wind up passing the noise through. Pay attention to the noise, PSRR and CMRR vs frequency specs, etc Take a look at the "voltage regulation" section of that home built VNA page for an example:

Re: [time-nuts] Anybody want a Thunderbolt power supply?

x > > Jerry > k1...@arrl.net > > > -Original Message- > From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Charles > Steinmetz > Sent: Wednesday, August 31, 2016 4:49 AM > To: time-nuts@febo.com > Subject: Re: [time-nuts] Anybody want a Thunderbolt power sup

Re: [time-nuts] Anybody want a Thunderbolt power supply?

Subject: Re: [time-nuts] Anybody want a Thunderbolt power supply? Nick wrote:> > I’m going to shoot for <= 35 mV P-P. If you need better than that, > then it probably turns into a hybrid switching+linear system It's been years since I played with Tbolts (as opposed to just using them

Re: [time-nuts] Anybody want a Thunderbolt power supply?

gt; Subject: [time-nuts] Anybody want a Thunderbolt power supply? > > A little board to generate -12 and +5 from a 15 watt 12 VDC > input wouldn't be too hard to design. If I put one out for > $25, would anyone like one? > ___ > time-nut

Re: [time-nuts] Anybody want a Thunderbolt power supply?

...@febo.com] On Behalf Of Nick Sayer via time-nuts Sent: Tuesday, 30 August, 2016 20:23 To: Discussion of precise time and frequency measurement <time-nuts@febo.com> Subject: [time-nuts] Anybody want a Thunderbolt power supply? A little board to generate -12 and +5 from a 15 watt 12 VDC

Re: [time-nuts] Anybody want a Thunderbolt power supply?

> On Aug 30, 2016, at 9:26 PM, Mark Sims wrote: > > The -12V is used to drive the RS-232 signals... it also eventually gets to > the EFC dac so it can swing below ground. Also, the +12V gets to the DAC. > Pay close attention to generating noise on these lines. I’ve

[time-nuts] Anybody want a Thunderbolt power supply?

The -12V is used to drive the RS-232 signals... it also eventually gets to the EFC dac so it can swing below ground. Also, the +12V gets to the DAC. Pay close attention to generating noise on these lines. Also, when I did Lady Heather's temperature control PID (with great help from Warren

[time-nuts] Anybody want a Thunderbolt power supply?

A little board to generate -12 and +5 from a 15 watt 12 VDC input wouldn’t be too hard to design. If I put one out for $25, would anyone like one? ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to