Tektronix TDS784D vs. Siglent 2000X HD - Page 1
Forum section: electronics / testgear

author: Martinn
author_rank: Frequent Contributor
timestamp: February 15, 2023, 12:42:00 pm
content: Hi all,I have been watching reports on the 2000X HD and am currently waiting on another "all-in" sale on the current €5k pricinghttps://www.batronix.com/versand/oszilloskope/Siglent-SDS2354X-hd.htmlSomehow I came across reports on the TDS784D and wondered if a used one might be an option. I'd probably go for a TDS754 (500 MHz version) as I don't need the GHz bandwitdth and as they are quite a bit cheaper (I know that those can be upgraded to 1 GHz, but the required calibration signals are way beyond my possibilities).I have used the TDS784 a long time ago but don't remember too much. What I recall is its fancy LCD switched color filter in front of a B/W CRT and the purple InstaVu button. As I remember the InstaVu was seldom more than a gimmick - which is clear on hindsight, had it been ready for everyday use, they would have integrated it as standard mode and not added a fancy button.So, what do you think? Spec differences are obvious (particularly lower noise and 12 bit on the Siglent), but taken that aside what about usability, noise, size, reliability, UI responsiveness, interfacing, failure due to old age?- Martin

author: nctnico
author_rank: Super Contributor
timestamp: February 15, 2023, 08:48:11 pm
content: I don't think the TDS784D is a good buy nowadays if you are going to spend more than a couple of hundred euro / dollar. These machine are like 25 years old by now and their CRT displays are prone to failures. You can buy much nicer and more versatile Lecroy scopes like the Wavepro 7k series if you need to measure high frequencies. And there are several nice options from Agilent as well. All with LCD displays.

author: Martinn
author_rank: Frequent Contributor
timestamp: February 15, 2023, 09:03:59 pm
content: I don't really need the 1 GHz bandwidth. 350 MHz would be fine for me.Currently there are many TDS754 and 784 on ebay, but most >$1000 if in decent condition (passing self test or signal compensation).Wavepro 7k are pretty rare and quickly > $3000.What Agilent models were you thinking of? A quick check on ebay showed the Infiniium series - but they seem to run Windows... not sure I like that...

author: nctnico
author_rank: Super Contributor
timestamp: February 15, 2023, 09:52:52 pm
content: Quote from: Martinn on February 15, 2023, 09:03:59 pmYou have to wait for a good deal and make a lowball offer. Asking prices ain't selling prices on Ebay. If you don't need the high bandwidth, you can buy a nice new oscilloscope with a whole lot better features for $3k. R&S RTB2004 comes to mind. Otherwise buy something with a cosmetic issue. I paid $450 for my Wavepro 7200A for which the most serious issue was a broken bezel. I spend around 90 euro on a 3D printed replacement bezel.

author: Martinn
author_rank: Frequent Contributor
timestamp: February 16, 2023, 06:08:36 pm
content: Quote from: nctnico on February 15, 2023, 09:52:52 pmGood point. Just realized there is a full package offerhttps://www.batronix.com/versand/oszilloskope/Rohde-Schwarz-RTB2K-COM4-SA.htmlfor around €4k. It is not 12 bit as the Siglent HD, but still better than older 8 bit scopes (not sure how much that matters).However I find it very difficult to find an overall statement on the RTB2k here in the forum. The "killer scope" thread has >3000 posts and is impossible to read.It seems you have been following this thread - what do you think about the RTB2k (maybe compered to the Siglent 200X HD)? Any major deficiencies? It seems decent, but surely R&S will have added limitations to set it apart from their higher end models.

author: 2N3055
author_rank: Super Contributor
timestamp: February 16, 2023, 06:17:14 pm
content: Make note RTB2000 has no 50 Ohm inputs...

author: Martinn
author_rank: Frequent Contributor
timestamp: February 16, 2023, 06:25:03 pm
content: Quote from: 2N3055 on February 16, 2023, 06:17:14 pmI know. That's the only real deficiency I am aware of. I also guess that for those cases a through terminator will work fine, just not as elegant. It also does not have probe interfaces, but I could not afford high end current or FET probes anyway (I have some Tek AM503 which are happy witha 50 ohms terminated BNC).

author: nctnico
author_rank: Super Contributor
timestamp: February 16, 2023, 06:49:04 pm
content: Quote from: Martinn on February 16, 2023, 06:25:03 pmA 50 Ohm through terminator works just fine. About 50% of the scopes with 50 Ohm inputs have a 50 Ohm resistor switchable across the 1M Ohm input where the other 50% has a true 50 Ohm path.

author: nctnico
author_rank: Super Contributor
timestamp: February 16, 2023, 06:58:49 pm
content: Quote from: Martinn on February 16, 2023, 06:08:36 pmOfcourse the RTB2004 is a more limited version compared to the higher end models but every oscilloscope manufacturer does that. What sets the RTB2004 apart is the user interface that has been build from the ground up to be touch screen based. There are many things in the UI that make it easy to use. I have an RTM3004 myself (which uses the same UI) and what I like about it, is that the protocol decoding 'trace' shows as much information as possible. If you make the trace high enough, the texts will be rotated 90 degrees so you can see a lot of data on screen and correlate that with slower events. It really gives you a good overview of what is going on in your circuit.