Sulzer Frequency Standards For Sale
Back in the 1960s, Peter Sulzer of Sulzer Laboratories designed some extraordinarily good crystal frequency standards. Their short term frequency stability, even by today's standards, was remarkable.I need to make room in the lab, and move from "collecting" toward "using" the gear I keep, so I've decided to look for new homes for the four Sulzer standards I still have.
The performance of the first three units is quite remarkable. The fourth works but clearly has a problem (maybe in the thermostat?) and is offered as a "technician special." I also have one complete Sulzer power supply that works and includes batteries in unknown condition, one Sulzer supply that works but does not have batteries or outer cover, and two rack panels each with cutouts for two units (either two OCXOs or power supply and OCXO). NOTE: I'd prefer to sell each power supply and panel together with an OCXO, and not separately.
I've measured these oscillators a number of times over the years -- I have data for runs in 2013, 2018, and just now in August 2023. The earlier data was collected using an Oscilloquartz 8607-008 "BVA" oscillator as the reference. The BVA has extraordinarily good short term stability, but also some drift at longer time intervals. For the most recent run I used a passive hydrogen maser as the reference. The maser probably limits the ADEV below about 10 seconds; the measurements against BVA are likely more accurate at short tau.
In the earlier runs all the standards had been running for months but in the 2023 run they had only been on for a few days. As a result the long interval ADEV shown in the 2023 run would probably improve with longer running time. The ADEV plots below show data from all three runs. The phase noise plots are from 2023.
To give an idea of what these look like, this is Sulzer #3 mounted in a panel with power supply.
You don't see a lot of these units on eBay, so I don't have much to go on in setting prices. These are what I came up with as units with both collector value and current excellent performance, but I'm open to negotiation. Prices do not include shipping. Please contact me if you're interested.
| Sulzer #1 (2.5 MHz) | $350 | |
| Sulzer #2 (5.0 MHz) | $350 | |
| Sulzer #3 (5.006 880 MHz) | $400 | See Note Below |
| Sulzer #6 (5.0 MHz; needs work) | $50 | |
| Sulzer Power Supply (Complete) | $50 | |
| Sulzer Power Supply (Head Only) | $25 | |
| Sulzer Rack Panel (2 available) | $25 |
Sulzer #1 -- Model 2.5A
Sulzer #2 -- Model 5A
Special Note About Sulzer # 3
This frequency standard is unique and likely has some time-nuts history. Note the 6.88 kHz offset from 5 MHz. That's not a random frequency error -- it is very nearly the 1836th subharmonic of the cesium resonance frequncy of 9. 192 631 680 GHz.I suspect this was used at one of the laboratories working on fundamental cesium clock research. When I visited NIST at Boulder in the early 1990s I saw a couple of Sulzer oscillators behind the glass wall on the tour of the cesium standards. Since it has a "Tracor" badge, it was built in 1964 or later.
The phase noise is better than typical of OCXOs of this vintage. It looks like there's a crystal filter to improve the noise floor beyond 1 kHz and remove spurs, which makes sense if you're going to multiply the output to 9 GHz!
TVB wrote a version of his PIC divider code to generate 1 PPS from this frequency. His source code explains the math and has pointers to a couple of NIST references:
https://tf.nist.gov/general/pdf/52.pdf
https://tf.nist.gov/general/pdf/79.pdf
Special Note About Sulzer # 6
This unit is in nice physical condition, but has a problem, likely related to its temperature control circuit. It's being offerred "as is" as a tech special.
