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jakwb
02-04-2009, 19:31
Now that Marco upgraded to the Time Step PSU, his KAB PSU found a new home in the US.

I opened the box, and it's not obvious (to me at least) on what to do to get this thing converted to 120V.

Appreciate any help and instructions. :)

Here's a pic of the innards.

http://i723.photobucket.com/albums/ww237/jakwb/KAB-PSU.jpg


Jason


I expect it's just a matter of connecting the transformer primaries in parallel instead of series.
__________________
"There's no point being grown up if you can't be childish, sometimes"


Kevin

jakwb
02-04-2009, 19:41
Hi Kevin,
Thanks for your input.
I'm really inexperienced in this area.
How would I go about changing the transformer primaries from series to parallel? :scratch:

Thanks
Jason

Marco
02-04-2009, 20:50
Hi Jason,

I had a word with Dave earlier and he's going to draw up a diagram for you to follow and post it here :)

Have you tried the 103R yet? :smoking:

Marco.

jakwb
02-04-2009, 22:59
Great! Thanks Marco and Dave. :cool:

I have not tried the 103R yet. I am going to mount it up tonight and give it a listen. It does look pretty minty. :)
I will pass on my impressions compared to my 103.
:gig:

Jason

Marco
03-04-2009, 21:13
Great - keep us posted, Jason :)

Marco.

Marco
06-04-2009, 09:40
How's the 103R, Jason? :smoking:

Marco.

jakwb
07-04-2009, 07:25
Marco,
The 103R is great. :) It really is beautiful. :smoking:

When I make cartridge change or really change anything, I like to listen to certain LP's and certain "test" tracks that I'm very familiar with. I suspect this is what everyone does to evaluate a change. The 103R is very much like the 103 with regard to the impact and presence, but the high end clarity and definition is much improved. I really like the 103, but the 103R is definitely an improvement.

Speaking of my "test" tracks, I love "The Battle of Evermore" from Zep IV. It sounds so good on my set up now, I just sit there and smile. I haven't listened to CD's for a while now, but tried the same track for comparison, but there was none. The LP beat it hands down!

On the topic of the PSU, I did some elementary reading this weekend as it's been 20+ years since I took an EE course, but now I understand about changing the wiring of primaries on the transformer. I just have to change the wiring on the taps out of the transformer - correct? It still would be a help if Dave could tell me which colors to match.:)

Jason

jonners
07-04-2009, 08:29
On the topic of the PSU, I did some elementary reading this weekend as it's been 20+ years since I took an EE course, but now I understand about changing the wiring of primaries on the transformer. I just have to change the wiring on the taps out of the transformer - correct? It still would be a help if Dave could tell me which colors to match.:)

Jason

The primary of the mains transformer will probably have two 110V windings. At present they are probably connected in series (for UK mains voltage). As Kevin said earlier, you need to connect them in parallel instead. The colour coding may be different on different transformers. Do consult someone with more experience if you can because of the potential danger of mains voltages.

jonners
07-04-2009, 14:56
Jason -

A couple of further thoughts:

1. After rewiring the transformer, do check with a meter that you are getting the correct volts DC out before connecting to the Technics.

2. Have you tried asking KAB if they can help?

jakwb
08-04-2009, 06:58
John,
Thanks for the inputs. I tried calling Kevin but always get the answering machine. I did check his website and he discusses what brand transformer is in the PSU (Amveco) so I checked out their catalogue for the wiring diagram. I should be able to get it right, but will confirm by measuring the output voltage prior to connecting. I should be getting 21V, correct?

On another note, how is the Jelco and 103 combo working for you? :eyebrows:
Do you have any pics of the wooden spacer you were making?

Jason

Dave Cawley
08-04-2009, 07:08
Hi Jason

It's difficult to see the transformer wires, they all look yellow! Could you separate them into maybe to areas, just by hand, and do a new photo please?

:bag:

Thanks

Dave

jonners
08-04-2009, 07:47
I should be able to get it right, but will confirm by measuring the output voltage prior to connecting. I should be getting 21V, correct?



No - the KAB doesn't bypass the internal regulator, so I think it supplies something in the region of 33-35V DC.

jakwb
09-04-2009, 06:51
Hi Dave,
See if this pic is any better. I've tried to take a close-up and label the colors of the wires. This is how it came connected for 220V.
Thanks,
Jason :)

http://i723.photobucket.com/albums/ww237/jakwb/KAB-PSU-labeled.jpg

StanleyB
09-04-2009, 09:11
Hi Jason,

can you:
1. unscrew the cap that covers the orange and black cable ends.
2. Separate the two cables from each other. If they are soldered together you'll have to desolder them.
3. Measure for me with a multimeter on the Ohms range if there is a low resistance between:
3a. The orange cable from point 2 and the purple cable.
3b. The black cable from point 2 and the purple cable.

From the answers in 3 I should be able to tell you which wires go where in order to turn it into 110V operation.

STan

Dave Cawley
09-04-2009, 11:38
Stan

You beat me to it!

Dave

StanleyB
09-04-2009, 14:15
We call that team work;).;)

jakwb
10-04-2009, 02:55
Thanks Stan & Dave. You guys are a good team. :)

From orange cable to purple is 52 ohms.
From black to purple is no reading.

Jason

P.S. I'll be traveling for the next 4 days and not on the forum till I'm back in town.

Prince of Darkness
10-04-2009, 07:16
Did a search for Amveco and found this.

http://www.powertransformer.us/amvecotransformers.htm

Scroll down to find dual primaries.:)

On second thoughts, this appears to be a different colour code.:confused:

jakwb
16-04-2009, 07:13
Hi Stan, Dave,
I'm back in town and online. Can you let me know if the resistance readings from the orange and black leads give you an idea of next step. :)

Kevin,
Yes, I was also confused by the color coding shown on the Amveco site compared to what I'm seeing. Maybe it's a different brand. :confused:

Thanks guys!
Jason

Ritch
16-04-2009, 07:50
The following may help (on the other hand it may not. No responsibility for the contents of this message. Use the information as you see fit but at your own risk):

1) Separate the Red/Brown and Orange/Black wires.

2) Use a test meter to check continuity of the Red/Brown and Orange/Black wires. Make a note of the reading.

3) Use the test meter to see if there is any continuity between Purple and one of the other split wires (ie: Red, Black, Orange and Brown). Make a note of the reading.

4) Repeat this for the Yellow wire. Make a note of the reading.

5) If for example in 2) above there is continuity between Red/Brown and Orange/Black, this tells you each is a winding. Then it is likely they have been wired in series for 220v. They will require wiring in parallel for 110v.

6) Use the readings obtained in 3) to determine final winding phase connection. If for example the Purple wire reads zero ohms to the Red wire and the Yellow wire reads zero ohms to the Black wire then the Red wire will become the "DOT" or "LIVE" phase connection and the Black wire the "RETURN" connection. The Black wire will connect to the Brown wire and the Orange wire will connect to the Red wire in this instance.

7) if for example all in 6) above is true then check continiuty reading across the Red wire and the Brown wire is NOW approximately half the reading obtained in 2) above.

Check and double check your readings before making final connections to the power line.

StanleyB
16-04-2009, 09:44
Hi Jason, since this is a safety issue, I decided to make a drawing that is easier to follow, I hope...

Before doing anything else, check and confirm that the resistance between Black and Yellow is also 52 Ohms. If it is then use the following diagram to wire it from 220V to 110V.

Stan

http://www.beresford.me/images/mods/KABPSU.png

I can't figure out why it doesn't display, but the direct link is at
http://www.beresford.me/images/mods/KABPSU.png

Stan

jakwb
17-04-2009, 06:52
Ritch, thanks for the instructions.
&
Stan, thanks for the diagram. It's showing up fine to me.:)

I'll have some time this weekend to play around with the PSU and I'll report back with my findings.

Cheers, Jason

jakwb
21-04-2009, 06:50
Stan, Ritch,
You guys were right on. Did some tinkering this weekend and I think we're on the right path.
Found this on the Amveco website and wiring diagram shown on this page matches what we have in the KAB:

http://www.powertransformer.us/amvecominiaturelowprofiletransformers.htm

Have a friend here going to wire up the primaries in parallel and confirm what output voltage we're getting off the secondaries to the board. Report back with some pics when we're done.

Thanks again. :cool:
Jason