Running 110v Adcoms in Sweden - safest way?

donjansson

donjansson

Member
Made an impulse buy on Ebay a couple of weeks ago; most to determine how electronics handle transportation across the Atlantic. I bought an Adcom-amp, the classic GFA-555, and matching preamp (GFP-555). These two fell within the scope of what I thought the "experiment" could cost.

I knew that both were 110v versions. Totally forgot to check the solutions available to run those in the Swedish grid.

There is no particular budget; I just want the amps to run without interruptions.

- Is a step-down transformer the only alternative? Which type? Post a link?
- Is it possible to "rebuild" the amps for 230v?

Thanks in advance!
Oscar

P.S I've had a hard day, felt to lazy to translate; therefore the text is run (with some mods) through Google translate :nono:
 
Greetings;

I don't think a fix unless we see the transformer layout. schematic. maybe rebuilt the circuit as some schematics have poles for changes but there is no switch on the back for EU 220 service and no open poles on the transformer probably fixed. And don't quote me on it...
 
If I recall; the Achille's heel of the Adcoms was their complete lack of Voltage Regulation.
When retrofitted with a decent VR design/setup they became Much better sounding Gizmos.
Likely what they should have been, before short sighted cost cuttings.
Given that you will need to do some significant work 'in there' for the power input changes...
I would suggest doing the regulation upgrade and enjoy the Much improved performances resulting.
Might then even be Keepers ?
 
take note of the hz ..u.s units will be 60hz .. your supply i don't know but suspect its 50hz so the transformer will run hotter . whether it wont mind so much i wouldnt know either .
sorry couldn't be any more helpful . maybe the info is in the manual .
 
I found info on the upgrade, first posted in '89. Is it possible to find these circuit birds second-hand or am I obliged to do this myself?

I'll do anything in order to prevent me trying to run this project on my own. It's waaaaaay beyond my knowledge.
 
Check first for dual voltage switch, the GFA-635 had one inside undercover for instance.

Sent from my SM-N900V using Tapatalk
 
Hi Oscar,

The power transformer can be re-wired for 220 or 240 volts. You can find the service manual with the information at the following site. Free to download with free registration. No affiliation.

www.hifiengine.com

Also, make sure you change out the AC mains fuse for one of a smaller value.


-bob
 
donjansson said:
I found info on the upgrade, first posted in '89. Is it possible to find these circuit birds second-hand or am I obliged to do this myself?

I'll do anything in order to prevent me trying to run this project on my own. It's waaaaaay beyond my knowledge.
Click to expand...

Welll it is a bit involved.. but not overly difficult without time pressures and using reasonable caution :)
Everybody needs start somewhere.. Long dark winter in your future.. use it?
Adcoms are powerful but clumsy things sonically.
Refined they are Not.. period.
Circuit boards can be made from prints from a desktop printer.. easily/inexpensively (learn a new skill?)
You would find the improvement as worth the effort.
Your choice of course :)
 
If the units transformers can be "strapped" for 220 Volts, you are good to go as far as power is concerned, as for sonic qualities no clue here.

Mark T.
 
FYI In Sweden we use 230V

There's no way I will attempt this myself. However; I have this very nice hifi repair-man just around the corner. Will call him on Monday and hear what he thinks.

I've downloaded manuals for both GFA and GFP.
1. Make a list of all the parts I need, please.
2. What will they cost me?
3. Is the upgrade "necessary" for both the pre- and the poweramp? Is method the same?
 
Co incidentally I've located a 'How to' for the GFA 555 in one of my old Audio Amateur magazines 4/1989. I can scan then post or email(?) it.
Give me a day or 2 though.
Pre doesn't make nearly as heavy a demand on it's power supply so adding a regulated stage is less rewarding. Still a usable improvement though, but I have no info, as few modded that unit.
 
Don't know either. But I'm sure it will do some help for the mechanic, if he wants to give the project a try. Thanks!
 
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