Cute that you guys are discussing my auction and my knowledge on this forum.
Alexi's amp tech himself said this about the mod and this is a direct quote:
Me: Replacing the 1,25kohm and 22uF with 825 ohm and 0.68uF resistor and capacator C1. This will smooth out the brightness some and free a tiny bit more distortion/gain.
Tech: *This is done already in some units. ( Factory installation). So actually ity's not a mod, it's an update.
This is Lee Jackson's own suggested mods page from his metaltronix homepage.
http://metaltronix.net/metaltronix-modification.htm
"PERFECT CONNECTION GP-1000 PRE-AMP MODIFICATION: Change the cathode circuit on the first gain stage from 1.5k ohm/22uF to 825 ohm/.68uF. This mod gives a little extra gain and reduces the scratchy character of the distortion timbre."
So don't come teaching me about the GP-1000, I've dealt with the amp and it's possibilities for more than a decade now.
Now it is easy to misunderstand the unit, because it is very unique. It is a mixture of all the amps Lee Jackson has worked with throughout the years and at the time amps with a overdrive pedal in front was the thing, and everybody used it in that way. What Stone and Alexi wanted with the unit was keeping the mid-rage and getting rid of some of the treble as well as adding modern gain and bass response.Remember this was the first mass produced Guitar rack preamp. So it need some heavy modification on almost all stages.
But the most important thing in this case is that Bodom's tone comes from the pickup and on-board preamp they use with it, Jackson JE-1000 or ESP MM-04. Alexi's signature pickup package (EMG) aren't used by the man himself.
Changing C18, 19 to 100n/200n are done to the 1988 version as stock as well, not always, but in 90% of the cases.
C6 should be 2.2n and C8 should be 100n, which should be stock in most units. It gives output #2 more bass frequency and if you've played it you know what I'm talking about. But this wasn't even touched in Bodom's units. As of 2004 Bodom only used output #2 anyways.
R15: Adding a larger resistor here only enhance the volume on the unit, which could be done with the trimpot beneath it anyways. It's helps nothing in this situation.
Now a clarification from an article in Premier Guitar of an interview with Lee Jackson about the extra gainstage in 88 units:
http://www.premierguitar.com/articles/G ... ack_Preamp
"So, I quickly went to my lab and started designing a change to the GP-1000 that would satisfy that need. I had parameters that I needed to stay in, like the number of tubes, controls, power transformer etc., especially if we were going to make the change on the next production run. I needed more gain stages, and the only place I could get it was from the tube-driven XLR balanced out, so away it went. On the first batch, we put a metal plate over the holes until the new metal arrived, when it was removed all together."
The same article shines light on my insight between 87 and 88 model as well.
Edit: And I have a whole offical Bodom forum to proof that I know the mods Alexi had/have in his now retired GP-1000.