Hi.
I have had a GM2 for 6 years and i can testify to about everything that has been said about it in the earlier posts.
The sound is big, smooth, fast, detailed, controlled. Never heard better, but I have not heard the Joules and Tenors. What I know is that everything else I have heard in comparison sounds slow and syrupy.
But owning the GM20 is not without hassle. You HAVE to buy matched output tubes. That is a must. You have to adjust the BIAS an DC offset about every 2-3 month. For that the amp must be turned up side down, the lid under unscrewed, warmed up, and then adjusted. (So watch out, you may kill yourself if you are really unlucky.)
You also have to replace the large electrolytics resting on top of the amps every other year. They last for about 3-5000 hours. Better replace them in advance in the summertime, before the listning season begins.
And then there is the 8 ohm issue. Take that serious.
And to make it sound the best I can tell you right away: Run it balanced. Do not waste your time using singel ended preamps. It may sound sweet, but you loose the bottom end control.
The best combo I have heard is the GM 20 and the GM13.5B. That is magic.
I also sounds very good if u run it balanced from a Wadia CD player.
But as of January this year, Graaf does not make it any more, so if you want one, you better hunt down a used one. (And then look for the newer types with metal bars on the tube pins. Look inside.) On the older ones, the PCB tends to be destroyed around the tube sockets due to the heat.
I have learned to live with the "trouble". I do most of the service work myself, so I don´t have to ship it away for repairs. Then it works very reliable. I use to say that if you own and drive a Ferrari, you don´t take it to the garage for service with a two year interval. A race car needs service more often to work reliable. But then again, driving a Ferrari is certainly not the same as driving a SUV.
So until I hear something that equals my GM20, that is my dream amp and it rests in my living room.
(Forgive my bad inglish, it is not my native language :-)
Theo
