The "Sussex" Homebrew Valve Tester. - Page 10 - UK Vintage Radio Repair and Restoration Discussion Forum

Stockden · 21st Feb 2010, 4:53 pm

I see that the recommended meter modules state a power supply requirement of "9V-12V DC OR AC" whereas the original design (and Ed's transformer) provides them with 6v AC. I assume that experience has shown that they're fine with a 6v supply but I though I'd ask before placing an order (or have I missed something?).

Hugh

ahjohn002 · 21st Feb 2010, 5:08 pm

Mike and Les,
Thanks for your suggestions. The regulator is working properly now after replacing the IRF730 (it's brand new) with an IRF820. After setting the anode voltage at 250 vdc, a 12AU7 is inserted and the voltage only dropped to 247 vdc, with both sections of the dual triode connected for test. The reading remained stable even with variations on -ve grid voltage.
One observation though. There was a 1 vac present, noise and hum presumably, on the anode after a tube is inserted with grid input coupling capacitor grounded. I just wonder would it affect the gm measurement because a 1 khz sine wave should be injected at the grid which would be amplified at the anode. The amplified signal together with the noise signal would affect the gm measurement. Wouldn't it?
Regards,
John

swordholder · 21st Feb 2010, 5:47 pm

Hugh,
I have had them running OK on 6v since I built the tester. I worked on the principle that the module has a full wave bridge recifier on board (in fact the DC still goes through the recifier) so there will be enough voltage to run the module which has proved to be the case.

Mike

Stockden · 21st Feb 2010, 5:51 pm

Thanks Mike, I'll get on and order them.

Hugh

Ed_Dinning · 21st Feb 2010, 10:00 pm

Hi Gents all remaining transformers will be posted out this coming week; I notify people indivually by PM.
Orders still being accepted if anyone else wants one.

Ed

real2real · 22nd Feb 2010, 3:11 pm

Looking at cases, I found the RS 222-064, it has dimensions of 133mm H x 305mm W X 280 D, would this be ok with Ed's transformer, its circa £28.0.
Not sure about the height though, I have ordered the Chinese DVM's and have all the other parts barring Ed's transformer.
Andy

Andymic · 22nd Feb 2010, 3:21 pm

From Ed....

Tx is on an 80 * 100mm lam with a 37mm stack, dimensions over belly are 75mm, all leads out of one side.
Angle bracket feet are fitted to the shorter dimension

real2real · 22nd Feb 2010, 3:50 pm

Cheers Andy
Other case sizes are available at slightly higher cost 222-086 and 224-010.
I will order something appropriate when I have ALL the bits.
Andy

Andymic · 23rd Feb 2010, 12:02 am

Hmmm...

I was thinking maybe something like this for the case...
http://cgi.ebay.co.uk/NICE-QUALITY-H...item1c0cffd4f9

real2real · 23rd Feb 2010, 9:54 am

Yes, nice, but mines staying in my workshop/shack and I like mine screened fully, I might get one for all my video gear !
Andy

swordholder · 27th Feb 2010, 4:39 pm

Hi All,
Andy has requested a copy of the front panel, unfortunately I don't know how to attach to a PM so I am posting it here for anyone interested

Regards
Mike

FRANK.C · 27th Feb 2010, 5:41 pm

Hi Mike
I've come late to this thread but I would just like to echo what everyone has said. What a brilliant design.
I hope to build one sometime in the future.
I can see it proving to be one of those classic designs that will be built by many for years to come.

Well done and thanks for sharing it with us.
Frank

Andymic · 27th Feb 2010, 8:13 pm

Quote:

Originally Posted by swordholder

Andy has requested a copy of the front panel, unfortunately I don't know how to attach to a PM so I am posting it here for anyone interested

Thanks Mike.

Much appreciated

One more point.
On the photos you posted early on in the thread, there appears to be an LED on each pin selector switch. I don't see those on the circuit diagram and I'm trying to work out what they indicate.

Andy

swordholder · 27th Feb 2010, 8:26 pm

Andy,
Yes I did fit a 3mm LED to each switch as an indicator to show which position of the knob was selected. Originally I wanted something "more professional" than a simple felt tip mark as I was not sufficiently adept with a small paintbrush to paint a spot.
I did originally glue the LEDs in place, but decided to light them up as a bit of "flash". They are connected in series across the LT supply, with , if I remember rightly a 2k2 reistor in series.
They serve no other purpose other than to show the switch position and could be omitted and another method used.

Regards
Mike

jakamp58 · 27th Feb 2010, 9:49 pm

Mike,

Thanks for sharing this with us. What a great project! I was searching the internet for a vintage tube tester, when i came accross this project. I'm looking over the project at the moment and i'm very much interested in making the tester instead of bying a vintage one.
Are the the tranny and PCB still available?

Regards,
Jan

swordholder · 27th Feb 2010, 11:30 pm

Jan
Look through the posts from the beginning, both PCB and transformer should still be available. Contact Martin for the PCB and Ed for the transformer.

Regards
Mike

G8UWM-MildMartin · 28th Feb 2010, 2:31 am

37 PCBs still available...
Turns out that postage to the EU was just 62p dearer than for UK on Friday.
(I was told 90p more last week, though the rates shouldn't have changed. Oh well...)

Andymic · 28th Feb 2010, 4:13 am

Mike,

I'm looking at options for the grid voltage pot. I know you used a 30k one but would this part be OK. http://www.rapidonline.com/sku/Elect.../65229/68-1310

Andy

Andymic · 28th Feb 2010, 5:31 am

Actually.....

This one might be better....

http://www.rapidonline.com/Electroni...29588#techspec

swordholder · 28th Feb 2010, 9:19 am

Andy,
Use Rapid 65-1060 50k 10t pot
Mike

21st Feb 2010, 4:53 pm	#181
Stockden Heptode Join Date: Mar 2008 Location: Forest of Dean, Gloucestershire, UK. Posts: 634	Re: The "Sussex" Homebrew Valve Tester. I see that the recommended meter modules state a power supply requirement of "9V-12V DC OR AC" whereas the original design (and Ed's transformer) provides them with 6v AC. I assume that experience has shown that they're fine with a 6v supply but I though I'd ask before placing an order (or have I missed something?). Hugh

21st Feb 2010, 5:08 pm	#182
ahjohn002 Retired Dormant Member Join Date: Feb 2010 Location: Hong Kong, China. Posts: 5	Re: The "Sussex" Homebrew Valve Tester. Mike and Les, Thanks for your suggestions. The regulator is working properly now after replacing the IRF730 (it's brand new) with an IRF820. After setting the anode voltage at 250 vdc, a 12AU7 is inserted and the voltage only dropped to 247 vdc, with both sections of the dual triode connected for test. The reading remained stable even with variations on -ve grid voltage. One observation though. There was a 1 vac present, noise and hum presumably, on the anode after a tube is inserted with grid input coupling capacitor grounded. I just wonder would it affect the gm measurement because a 1 khz sine wave should be injected at the grid which would be amplified at the anode. The amplified signal together with the noise signal would affect the gm measurement. Wouldn't it? Regards, John

21st Feb 2010, 5:47 pm	#183
swordholder Rest in Peace Join Date: Aug 2009 Location: East Preston, Sussex Posts: 162	Re: The "Sussex" Homebrew Valve Tester. Hugh, I have had them running OK on 6v since I built the tester. I worked on the principle that the module has a full wave bridge recifier on board (in fact the DC still goes through the recifier) so there will be enough voltage to run the module which has proved to be the case. Mike

21st Feb 2010, 5:51 pm	#184
Stockden Heptode Join Date: Mar 2008 Location: Forest of Dean, Gloucestershire, UK. Posts: 634	Re: The "Sussex" Homebrew Valve Tester. Thanks Mike, I'll get on and order them. Hugh

21st Feb 2010, 10:00 pm	#185
Ed_Dinning Dekatron Join Date: Jan 2004 Location: Newcastle upon Tyne, Tyne & Wear, UK. Posts: 8,010	Re: The "Sussex" Homebrew Valve Tester. Hi Gents all remaining transformers will be posted out this coming week; I notify people indivually by PM. Orders still being accepted if anyone else wants one. Ed

22nd Feb 2010, 3:11 pm	#186
real2real Retired Dormant Member Join Date: Jul 2005 Location: Barnham, Nr Bognor Regis, West Sussex, UK. Posts: 40	Re: The "Sussex" Homebrew Valve Tester. Looking at cases, I found the RS 222-064, it has dimensions of 133mm H x 305mm W X 280 D, would this be ok with Ed's transformer, its circa £28.0. Not sure about the height though, I have ordered the Chinese DVM's and have all the other parts barring Ed's transformer. Andy

22nd Feb 2010, 3:21 pm	#187
Andymic Retired Dormant Member Join Date: Jan 2010 Location: Harrow, London, UK. Posts: 78	Re: The "Sussex" Homebrew Valve Tester. From Ed.... Tx is on an 80 * 100mm lam with a 37mm stack, dimensions over belly are 75mm, all leads out of one side. Angle bracket feet are fitted to the shorter dimension

22nd Feb 2010, 3:50 pm	#188
real2real Retired Dormant Member Join Date: Jul 2005 Location: Barnham, Nr Bognor Regis, West Sussex, UK. Posts: 40	Re: The "Sussex" Homebrew Valve Tester. Cheers Andy Other case sizes are available at slightly higher cost 222-086 and 224-010. I will order something appropriate when I have ALL the bits. Andy

23rd Feb 2010, 12:02 am	#189
Andymic Retired Dormant Member Join Date: Jan 2010 Location: Harrow, London, UK. Posts: 78	Re: The "Sussex" Homebrew Valve Tester. Hmmm... I was thinking maybe something like this for the case... http://cgi.ebay.co.uk/NICE-QUALITY-H...item1c0cffd4f9

23rd Feb 2010, 9:54 am	#190
real2real Retired Dormant Member Join Date: Jul 2005 Location: Barnham, Nr Bognor Regis, West Sussex, UK. Posts: 40	Re: The "Sussex" Homebrew Valve Tester. Yes, nice, but mines staying in my workshop/shack and I like mine screened fully, I might get one for all my video gear ! Andy

27th Feb 2010, 5:41 pm	#192
FRANK.C Heptode Join Date: Feb 2006 Location: Roscommon, Ireland Posts: 722	Re: The "Sussex" Homebrew Valve Tester. Hi Mike I've come late to this thread but I would just like to echo what everyone has said. What a brilliant design. I hope to build one sometime in the future. I can see it proving to be one of those classic designs that will be built by many for years to come. Well done and thanks for sharing it with us. Frank

27th Feb 2010, 8:26 pm	#194
swordholder Rest in Peace Join Date: Aug 2009 Location: East Preston, Sussex Posts: 162	Re: The "Sussex" Homebrew Valve Tester. Andy, Yes I did fit a 3mm LED to each switch as an indicator to show which position of the knob was selected. Originally I wanted something "more professional" than a simple felt tip mark as I was not sufficiently adept with a small paintbrush to paint a spot. I did originally glue the LEDs in place, but decided to light them up as a bit of "flash". They are connected in series across the LT supply, with , if I remember rightly a 2k2 reistor in series. They serve no other purpose other than to show the switch position and could be omitted and another method used. Regards Mike

27th Feb 2010, 9:49 pm	#195
jakamp58 Retired Dormant Member Join Date: Feb 2010 Location: Groningen, Netherlands. Posts: 3	Re: The "Sussex" Homebrew Valve Tester. Mike, Thanks for sharing this with us. What a great project! I was searching the internet for a vintage tube tester, when i came accross this project. I'm looking over the project at the moment and i'm very much interested in making the tester instead of bying a vintage one. Are the the tranny and PCB still available? Regards, Jan

27th Feb 2010, 11:30 pm	#196
swordholder Rest in Peace Join Date: Aug 2009 Location: East Preston, Sussex Posts: 162	Re: The "Sussex" Homebrew Valve Tester. Jan Look through the posts from the beginning, both PCB and transformer should still be available. Contact Martin for the PCB and Ed for the transformer. Regards Mike

28th Feb 2010, 2:31 am	#197
G8UWM-MildMartin Heptode Join Date: Jan 2004 Location: Stockport, Greater Manchester, UK. Posts: 822	Re: The "Sussex" Homebrew Valve Tester. 37 PCBs still available... Turns out that postage to the EU was just 62p dearer than for UK on Friday. (I was told 90p more last week, though the rates shouldn't have changed. Oh well...)

28th Feb 2010, 4:13 am	#198
Andymic Retired Dormant Member Join Date: Jan 2010 Location: Harrow, London, UK. Posts: 78	Re: The "Sussex" Homebrew Valve Tester. Mike, I'm looking at options for the grid voltage pot. I know you used a 30k one but would this part be OK. http://www.rapidonline.com/sku/Elect.../65229/68-1310 Andy

28th Feb 2010, 5:31 am	#199
Andymic Retired Dormant Member Join Date: Jan 2010 Location: Harrow, London, UK. Posts: 78	Re: The "Sussex" Homebrew Valve Tester. Actually..... This one might be better.... http://www.rapidonline.com/Electroni...29588#techspec

28th Feb 2010, 9:19 am	#200
swordholder Rest in Peace Join Date: Aug 2009 Location: East Preston, Sussex Posts: 162	Re: The "Sussex" Homebrew Valve Tester. Andy, Use Rapid 65-1060 50k 10t pot Mike