Adcom help needed - GFP 750

[AndyGwis]

Hey All,

I have a GFP 750 in my possession and want to check on a minor issue before putting it in my system.

I am looking to use my CD player's unbalaned/RCA output to the Adcom's unbalanced/RCA CD input. From the manual, looks like I should have some pins inserted in the Balanced/XLR input of the Pre in order to use the unbalanced/RCA inputs.

I do not have said pins. Can I not use the unbalanced inputs until I get some the pins? Does anyone happen to have another pair of these pins laying around that I could purchase or know if you can still get them from Adcom?

I'll email Adcom but thought I would check with you trusted advisors first!


Thanks!

[ben62670]

Congrats on a great Pre. I would just use an axillary input till you get a hold of Adcom. Their CS is top notch. If they don't have the jumpers they can easily be made from some XLR plugs

[AndyGwis]

Hey Ben,

Adcom (unfortunately) does not have/sell the pins anymore. How "easily" are we talking about in regards to making a pair myself? Are we talking soldering and such? I have zero talent / competence / patience for soldering, especially for anything that would potentially be used for high end audio.

[heiney9]

Hey Ben,

Adcom (unfortunately) does not have/sell the pins anymore. How "easily" are we talking about in regards to making a pair myself? Are we talking soldering and such? I have zero talent / competence / patience for soldering, especially for anything that would potentially be used for high end audio.

Check around at some on-line audio suppliers. Actually contact Pass Labs as I thought I needed the same jumpers for my Aleph and I read somewhere they could get them. Otherwise you'll need to make some. The pre won't have the proper impedance if running unbalanced cdp input minus the shorting pins in the balanced input connector.

They are just U shaped jumpers made out of gold platted copper usually. The thing is all balanced connectors are the same so any pair would work....they aren't unique to each piece of equipment.

I don't think you'll do any damage running unbalanced with the jumpers missing............the gain will be way off however, and might not get the dynamics or output needed to sound good.

H9

[heiney9]

Congrats on a great Pre. I would just use an axillary input till you get a hold of Adcom. Their CS is top notch. If they don't have the jumpers they can easily be made from some XLR plugs

How would you make them from XLR plugs?

[ben62670]

Just jump the correct pins with a small wire.

[GV#27]

Short pieces of wire with bared ends will do in a crunch.

[heiney9]

Short pieces of wire with bared ends will do in a crunch.

Something like Romex bent in a U-shape will do in a pinch. I thought about giving the measurements from my GFP-750 but they are so small I don't really have any sort of scale to give accurate to the millimeter measurements.

[Gadabout]

Andy,

If you can get the plugs and find out what pins need to be jumped. I'd be happy to drop by and solder them for you. Should take all of about 10 minutes. I carry a couple soldering irons with me, for work, all the time.

Let me know,
Scott

[ben62670]

Just run to Rat Shack and get two XLR plugs. The pins that are shorted are easily viewed at Adcom.com in the manual section for the GFP-750
http://www.adcom.com/data/manuals/gfp_750manual.pdf
Page 3;)
Pop the XLR's in to jump, and pop them out if you go balanced:)

[heiney9]

BTW, just checked my 750 and I've been running unbalanced at the cd input and my pins are missing as well. I do have some XLR plugs that I will use.

I'll let you know any difference, if there is one. The manual specifically states the pins need to be in place, w/o them they seem to sound fine. I'll report back when I can.

H9

[GV#27]

Using without the jumpers inplace will likely mean that the source component will see a lower input impedance than it would otherwise.

[heiney9]

I put the shorting plugs in and it does sound better.

[AndyGwis]

Thanks for checking on that for me, Troy. I'll look into getting something in place to short them as previously stated.

Thanks again, everyone.

[heiney9]

No problem Andy, shorting them like they are supposed to be really helped. Btw, I'm Brock :D

[heiney9]

Andy,

I found these. I ordered 2 pairs to have an extra.

http://www.dedicatedaudio.com/inc/sdetail/5158

Hope this helps

H9

[AndyGwis]

Wow, that is awesome Troy. I'm going to grab a pair or two myself.

Thanks for the link and for your help!