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Old 22nd Jun 2016, 7:41 pm   #1301
Mark James
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Default Re: The "Sussex" Homebrew Valve Tester.

Thank you. Hopefully there will be others interested.

Mark
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Old 25th Jun 2016, 4:39 pm   #1302
G3VFB_Anton
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Default Re: The "Sussex" Homebrew Valve Tester.

Having browsed through the whole thread this looks like a fantastic project. I notice the original inventor G8JVE is 'silent key' but it's wonderful how his memory will live on with the Sussex Project.

Still doing a huge turn out of valve equipment prior to a move but there are a few things I cannot part with and they will become 'projects' at the new abode!

To start project No.1 - I would like to purchase the main PCB in readiness and put my name down for the switch PCBs.

Will send PM to G8UWM-MildMartin to order
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Old 25th Jun 2016, 7:55 pm   #1303
Mark James
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Default Re: The "Sussex" Homebrew Valve Tester.

That's 2 for the switch PCB's - just need another eight!

Mark
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Old 29th Jun 2016, 7:48 am   #1304
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Default Re: The "Sussex" Homebrew Valve Tester.

Just to inform anyone interested, a set of four small round PCBs (Anode & Screen-volts, Electrode and Function switches) for the switches will cost approximately as much as the main PCBs if someone in the UK can handle the shipping to interested members.

It would be prohibitively expensive to ship them from Sweden so someone in the UK must help to manage the shipping. Unfortunately I can't fund these PCBs myself so there will have to be at least 10 interested parties for those to be made professionally.
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Old 1st Jul 2016, 2:53 pm   #1305
G8UWM-MildMartin
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Default Re: The "Sussex" Homebrew Valve Tester.

List of suggested component values for the new PCBs is attached.
Attached Files
File Type: txt Sussex new board Components.txt (1.2 KB, 424 views)
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Old 1st Jul 2016, 3:52 pm   #1306
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Default Re: The "Sussex" Homebrew Valve Tester.

Hi Martin

Thanks for the new component list.

Bob
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Old 1st Jul 2016, 6:36 pm   #1307
G8UWM-MildMartin
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Default Re: The "Sussex" Homebrew Valve Tester.

One mistake spotted so far:
RV1 2320R should read 220R.
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Old 15th Sep 2016, 10:44 pm   #1308
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Default Re: The "Sussex" Homebrew Valve Tester.

The last batch of main PCBs plus a batch of switch PCBs were shipped to Martin yesterday, see the last photo for their looks.

This newer design incorporates a snubber for the HV relay and the relay contacts have been put in series. I also updated the two trim potentiometer footprints so they will accept a lot of different types of trim potentiometers. I also changed the footprints for all of the electrolytic capacitors so that different types of capacitors could be used, even press-fit types for some of the large electrolytics will fit. To make space for all of these changes I had to move a lot of components around on the PCB so it looks somewhat different from the first edition. I also included silkscreen print for the numbers on the connectors.

The snubber design used is shown here: http://sound.whsites.net/articles/relays2.htm#srsc under "Diode Suppression Circuits". It uses a resistor, a capacitor and a diode to protect the relay contacts while they switch the HV-voltage. A resistor of some 390 Ohm, a capacitor of some 220nF @ 630V or 1kV and a diode like UF4007 (or some better diode with higher current rating) will work fine for this snubber.

I've only tried the round switch PCBs to make sure that the switches fit, I have not tested them to see that they work like they should as I don't have a Sussex valve tester at hand (I am right now building my second Roetest valve tester, version V9, www.roehrentest.de so I unfortunately I can't spend money on a Sussex).

There is one capacitor that should be mounted on the switch PCB, to get it to stand up straight you can use brass or tinned thin rivets and put them on the pins of the capacitor with the flange towards the PCB and then solder it in place, that will make sure that the capacitor pins don't bend.

Unfortunately the PCB manufacturer had some "problems" with their quality control so there were too few good PCBs manufactured compared to what I ordered so they made a second run for free which checked out OK. I sent both batches to Martin, marking the second batch "2ok" and the first batch either "1ok" or "1pm" for "poor mask". The faults were only with the solder mask so the PCBs are ok but they look ugly. They can of course be used without any problems but they won't win any beauty contests anytime soon.
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Old 17th Sep 2016, 2:37 am   #1309
G8UWM-MildMartin
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Default Re: The "Sussex" Homebrew Valve Tester.

The PCBs have arrived.
I'll work out costs over the weekend.
(There was a quantity discount, Customs charges from China to Sweden and higher Paypal charges this time, but some free extras due to the manufacturer making some poor ones, as Martin described.)
Postage will be bought and charged at the 100g+ rate since, despite them actually being just within the limits for letter post and verified by the recipients, two of eight posted from the last batch incurred postage surcharges and I can't be bothered to pursue the matter!
Regards,
Martin.
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Old 17th Sep 2016, 9:39 am   #1310
Colin G8TMV
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Default Re: The "Sussex" Homebrew Valve Tester.

Quote:
Originally Posted by Dekatron View Post
Unfortunately the PCB manufacturer had some "problems" with their quality control
Where did you get them made? I've been using Hackvana for my PCB production they offer excellent service and are the cheapest I've found. He even has online IRC chat so you can have a realtime conversation to work things out. The only disadvantage is that they are in the Far East and the shipping is obviously a bit slower.

http://www.hackvana.com/store/

No connection except as a very satisfied customer.

Colin
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Old 17th Sep 2016, 9:51 am   #1311
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Default Re: The "Sussex" Homebrew Valve Tester.

I don't want to publicly disclose whose quality control was poor.

But since there are many small companies who rely on the few big companies who manufacture the PCBs it is almost impossible to say who really manufactured the PCBs themselves (I have asked but I never got an answer as they don't want to disclose this). Many small companies buy board space from the larger companies and if you look carefully at the technical details that these smaller companies offer you can see that they are very limited compared to what a larger company offers, but the price is substantially lower. In this case I could have 20 boards made for less than the starting cost at a large company.

Now that they made 20 new PCBs without a hassle and shipped them for free I can't complain - we even got to keep all of the first batch for free, I think there were something like 6-7 PCBs that had a poor solder mask so we got something like 14 for free.

As soon as the first few have been built of this second batch with the new changes and someone have confirmed that the switch PCBs work I'll put all of the necessary files for making your own PCBs here on the forum. I'll have to clean up the schematics some as I just threw it together to have something to start the PCB drawing from. I used Designspark 7.2 when I made the PCB and schematic.
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Last edited by Dekatron; 17th Sep 2016 at 10:04 am. Reason: Wrong version of Designspark
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Old 20th Sep 2016, 9:56 pm   #1312
G8UWM-MildMartin
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Default Re: The "Sussex" Homebrew Valve Tester.

Sorry for the delay.
After some deliberation, prices are:
£5 for a PCB, also £5 for a set of 4 switch PCBs and £1.27 UK postage (Royal Mail 1st class large letter 101-250g) per order.

(The 7 ropey PCBs can go at £3 each including UK postage to anyone who wants to hack them around to try different oscillators or build HT PSUs, etc.)

Regards,
Martin.
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Old 2nd Oct 2016, 10:18 am   #1313
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Default Re: The "Sussex" Homebrew Valve Tester.

So, here are the files!

You can download them and unpack them, there are all of the files necessary to edit the design in Designspark V7.2.

There are also Gerber files in the folder "plots" which were made with Designspark V7.2. You can use for instance Gerbv 2.6.1 to view these plots. I used these plots for the manufacturing of all PCBs.

I haven't included any library files for the symbols that I changed myself but you can save those that are in the design and reuse them that way, if you wish.

I've been discussing a better library manager, or better option in saving a design, with RS but so far they have not had time to make one available. I wanted an ability to save a project including all the components that you have made yourself (or all used), so you don't lose them if your libraries crash, but you still have the design files accessible, saving the symbols from the design is the only option right now.
Attached Files
File Type: zip Sussex-UKVRRR-files.zip (322.2 KB, 376 views)
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Old 4th Oct 2016, 4:23 pm   #1314
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Default Re: The "Sussex" Homebrew Valve Tester.

Hello to everyone here. I'm new to the forum, but have been following for some time.

Thank you to everyone who has contributed to this excellent project. I've ordered a PCB and have started the quest for components. I look forward to seeing how things develop with the updated PCB.

I'm moving from the world of solid state to valves and learning what I can. With used valve testers demanding such extreme prices, this project is perfect for those of us starting out. Also hope to learn more by building one myself.

Ralph.
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Old 6th Oct 2016, 4:14 pm   #1315
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Default Re: The "Sussex" Homebrew Valve Tester.

Welcome Ralph.

If you have any problems with your tester, just ask on here. There are several of us who have built them, got them working and calibrated using a Standard Valve!

I hope it all goes well. Just remember, though, that the voltages used in the tester can bite. Quite hard.
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Old 7th Oct 2016, 7:06 pm   #1316
astrouk1
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Default Re: The "Sussex" Homebrew Valve Tester.

Richard,

Many thanks, slowly getting there with the parts. Where can a standard valve be purchased?

I hope to see many of you at Wootton Bassett on Sunday.

Ralph.
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Old 19th Oct 2016, 12:51 pm   #1317
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Default Re: The "Sussex" Homebrew Valve Tester.

Hi to everyone on the Forum. I am also a new user attracted initially by stumbling across this great project.

I have a Dynaquik tester but it is restrictive to what it tests and does not offer a Mutual conductance test. I have shied off buying an old tester again as the one I have shows its age and I ideally wanted a new build.

The orange tester, while great for current guitar audio needs, did not meed my needs for wider ranging valve types. This looks a great and affordable project and I have taken the plunge, already ordering the boards and transformer.

My thanks to everyone who has added to the initial project, its good to see it continue and is a great memorial to initial contributor. The PC board and tranformer availability really helps as well.

On a practical note.

On my tester there is a quick Bad - Suspect - Good indication does anyone have an ides how this relates to a percentage when compared to a gm rating? ( i have read reject is after a loss of 65% I would guess that suspect starts at a point less than this (40% to 50% ) is this a reasonable guess?

As to a standard test valve, which the previous poster asked about, I know Hotrox in the UK will test a valve for you on their calibrated AVO tester and from memory they don't charge a great amount to do this. Reading around the web an ECC82 (12AU7) seems to be a recommended choice and it should be burned in. Interesting article can be read here.

http://tone-lizard.com/testers-exposed/

Looking forward to getting more involved the forum. Dave
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Old 20th Oct 2016, 12:00 pm   #1318
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Default Re: The "Sussex" Homebrew Valve Tester.

Thought it would be useful to add a link to the Newest (that I could find) Avo valve Data version 23 this is a searchable pdf

https://www.vintage-radio.net/forum/...d.php?t=114306

I really struggled to decompress these on my Apple Mac and found a combined version that worked fine here. (This went into iBooks on my Mac and iPad).

https://frank.pocnet.net/instruments...R-20150222.pdf
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Old 20th Oct 2016, 1:12 pm   #1319
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Default Re: The "Sussex" Homebrew Valve Tester.

Hi Dave, with regards to gm pass and fail figures I use a rough approximation of the AVO Meter scale i.e. the Red and Green zones.
Using the gm figure published in the AVO test data let's say a valve is given a gm of 2.
A Pass would be acceptable as 2 x 0.7 to 2 x 1.3 that is a reading on the Sussex Tester as 1.4 to 2.6
A Fail would be indicated as 2 x 0.5 or less which would be a reading of 1 or below.
Rather than just test at one grid voltage as stated in the AVO test data, I like to run the valve above and below to obtain a set of curves. These I enter into an Excel spreadsheet to obtain a -Vg/Ia plot. It also indicates if a Pass or Fail around the AVO figure based on the above formula.
Les
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Old 20th Oct 2016, 6:58 pm   #1320
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Default Re: The "Sussex" Homebrew Valve Tester.

Thanks Les, that's really useful. Dave
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