R&S PSU number of channels needed - Page 1
Forum section: electronics / testgear

author: salomonander
author_rank: Regular Contributor
timestamp: October 09, 2024, 12:29:29 am
content: Hey,I often need voltages like +-15v and +-18v. Will i need to get at least a two channel psu? Or can the r&s supplies do it with one channel?Thanks

author: tautech
author_rank: Super Contributor
timestamp: October 09, 2024, 01:35:52 am
content: Split rail designs normally need a 0V reference where a 2ch PSU in Series mode/configuration is the normal solution although a on-board voltage divider or LM78**/79** regulators are sometimes also used.18V spit rail will require 36V or more with is a value beyond what is normally considered the 'industry safe' of ~30V.Best versatility will be provided with a 2ch PSU providing 30V/channel.

author: salomonander
author_rank: Regular Contributor
timestamp: October 09, 2024, 10:30:22 am
content: Thanks!

author: pdenisowski
author_rank: Super Contributor
timestamp: October 09, 2024, 10:31:19 am
content: Pretty much all R&S supplies can output at least 20 volts, and several go up to 32, 64, or 100 voltshttps://www.rohde-schwarz.com/us/products/test-and-measurement/dc-power-supplies_64067.htmlWe also sell a four-quadrant SMU (the NGU) that directly supports -20 volts to +20 volts. If you want to do it all with one channel on one supply, that would be the easiest way to do it.

author: coromonadalix
author_rank: Super Contributor
timestamp: October 09, 2024, 11:50:42 am
content: you have many who track rails IE adjust them simultaneously ... 1 master the other channel as slaveunless you go with fixed ones too ... ? it depends of your current requirements0-30vdc (per channel) models are the most common, some have switches to do single/ separated, in serial or in parallel, but a positive and negative one at the same time, haven't seen a lotas Tautech wrote, you need a ground reference and isolated supplies from each other .... and you put them as attached image, nothing fancy, but you need to adjust them separately ...

author: salomonander
author_rank: Regular Contributor
timestamp: October 09, 2024, 05:32:21 pm
content: Sorry i did not think this throughi work in pro audio and often repair gear from the early transistor age. Switching power supplies are a no go in my field. Do the oldschool R&S psus with VU meter behave more like an old fashioned transformer/regulator power supply? They would also cost a fraction on ebay.

author: coromonadalix
author_rank: Super Contributor
timestamp: October 09, 2024, 06:16:37 pm
content: the less noisy psu's are toroid based x-formers

author: salomonander
author_rank: Regular Contributor
timestamp: October 10, 2024, 10:30:21 am
content: Thanks,yes after some research i realized that R&S have transformer based versions as well. Its just hard identifying them. So far im pretty certain that HMP2000, NGA100, HM8143 and the old NGE100 are transformer based. But some seem to still have a switching element like the NGE100 series. Im wondering if its the same for NGA100? Can anyone confirm which ones are linear transformer based without any switching element? ThanksAnd another noob question: does the arbitrary mode in some psus allow me to use one channel as a sinus generator? Or am i understanding that wrong?

author: salomonander
author_rank: Regular Contributor
timestamp: October 10, 2024, 11:11:02 am
content: Did more reading. Looks like the NGA is the only true linear psu they build. All others mentioned claim a mixed architecture. A transformer into a rectifier and the into switching mode circuit. I honestly dont know if hybrid will work for me. And please correct me, if i did my research wrong.

author: glitchcatcher
author_rank: Contributor
timestamp: October 10, 2024, 01:12:49 pm
content: They have some nice documents explaining a lot:https://www.rohde-schwarz.com/products/test-and-measurement/dc-power-supplies_64067.htmlOn that site, click:Fundamentals of DC Power supplies – output characteristicsandFundamentals of DC Power supplies – measurement & monitoringFind a compilation of characteristics attached.

author: salomonander
author_rank: Regular Contributor
timestamp: October 10, 2024, 01:20:51 pm
content: Thanks Flo, thats awesome! I have never seen that comparison list.Is there a similar one for the older models? From the newest versions it would be the NGA102 for me. It seems to perform well from the charts.

author: glitchcatcher
author_rank: Contributor
timestamp: October 10, 2024, 02:57:53 pm
content: Yeah I also discovered this just recently.The only other datasheets I have is a PDF with many older models, see file attached.

author: salomonander
author_rank: Regular Contributor
timestamp: October 10, 2024, 03:22:15 pm
content: Thanks!Im pretty set on a NGA102 now. But i could get the HMP2030 for a fraction of the price. Its one of the hybrid ones. And im not educated enough in order to tell if this will work just as well as the NGA for audio. Can anyone else tell? If its suitable it would be a no brainer (i can get it for 500€ new).There is a little info on construction on page 34:https://cdn.rohde-schwarz.com/hameg-archive/HAMEG_MAN_DE_EN_HMPSeries.pdfAccording to Flos document, ripple on the HMP is a lot higher though. Maybe due to the hybrid design?