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Power Supply for Gram Slam 1
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Brennythefox View Drop Down
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    Posted: 14 Feb 2023 at 12:40pm
Hi. I am a newbie to Graham Slee products and have been given a Gram Amp 1 phono stage without a power supply. I can see no information on the device as to what is required and don't want to just assume that it is the same as the current phono stages. It looks like a Gram Amp 2 Communicator exterior but clearly an older or more budget model. I have tried looking on this forum but unable to find the information I require. All help greatly appreciated.

Edited by Brennythefox - 15 Feb 2023 at 7:34am
Brendan

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ICL1P View Drop Down
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I’m guessing you mean Gram Amp (not Slam) 1 like this: https://www.lpgear.com/product/GA1.html
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Reflex M & ACCESSION M, CuSat50, Majestic DAC, a Proprius pair.
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Welcome aboard Brendan. It probably needs a 24 volt power 'green' supply like the current models. If you give us the serial number Graham or John will confirm what is needed.
Jon

Open mind and ears whilst owning GSP Genera, Accession M, Accession MC, Elevator EXP, Solo ULDE, Proprius amps, Cusat50 cables, Lautus digital cable, Spatia cables and links, and a Majestic DAC.
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Points: 9 		Post Options Post Options   Thanks (1) Thanks(1)   Quote Brennythefox Quote  Post ReplyReply Direct Link To This Post Posted: 15 Feb 2023 at 7:16am
Sorry about my mistake, post corrected, it is a Gram Amp 1 and also has Bridge written on it. Serial number is 0506-53

Thanks


Edited by Brennythefox - 15 Feb 2023 at 7:37am
Brendan

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Brennythefox View Drop Down
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Hi. Currently I am powering my Gram Amp 1 with a 15v supply. I believe from reading here that it should be a 24v supply. Will buying the 24v supply bring a noticeable improvement to the sound?
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Fatmangolf View Drop Down
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Please proceed. It will give more headroom for the signal peaks and also means your Gram Amp is getting the 24 volts it was designed for.
Jon

Open mind and ears whilst owning GSP Genera, Accession M, Accession MC, Elevator EXP, Solo ULDE, Proprius amps, Cusat50 cables, Lautus digital cable, Spatia cables and links, and a Majestic DAC.
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The Bridge version of the Gram Amp 1 has an internal 18V regulator, so running it at 15V means the regulator isn't working.

But is that 15V really 15V?

There were two types of "wall wart": 1. the unregulated; 2. the regulated.

The unregulated would do 20% more volts offload, and seeing the Gram Amp load is very light, it's classed as offload.

So 15V plus 20% which represents 3V, makes it up to 18V. Still not enough as the built-in regulator needs 3V more than its 18V rating.

As for the regulated variety, there's no mileage there as it just does the voltage written on the can.

So, we would send them out with 18V unregulated "wall warts", because that 20% extra took it to 21.6V, which is 3.6V more, and plenty to do the job.

So why not 24V? Well, at the time, it was legal to sell transformer type wall warts, and SMPS types weren't very popular especially for audio, and in the main SMPS didn't exist.

So, at 24V plus 20%, that was 28.8V, which was still OK.

BUT! There were some 24V unregulated wall warts that did 50% more, making 36V, and that exceeded the on-board regulator's limit, so that's why I specified 18V unregulated.

And then in 2010, the Governator, and the European Union banned transformer wall warts, so that makers of SMPS wall warts could have all the money.

Now, SMPS just come as regulated, so the voltage is exactly what's written on the can.

So if it's a SMPS, the voltage needs to be 24V.

Confusing? Yes, definitely, but that's not my fault. Blame Arnie and his fellow European politicians.
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