Re: The 6550 Experience
Posted: Thu Jul 11, 2019 7:58 pm
More experiments today...
I swapped out the 100pf disk bright cap and put the 4700pf back in and also swapped the 470pf dog bone in the tone stack for a 500pf silver mica.
Quite interesting, the bright cap definitely gave it alot more presence in the room. When I kicked the wah on with the guitar volume full up it would go into feed back, I think on a big stage this would be completely useable. I'm quite convinced it was a big bright cap, that said for my needs I'm going to try a dog bone I have that reads 2600pf. I really enjoyed the 100pf but I did feel it needed a bit of a lift and I also felt the 4700pf was a bit much so i ll see how the 2600pf works out. I think in the days before sound reinforcement you'd definitely want the 4700/5000pf in there, especially on the bigger stages it would have space to breath.
I generally prefer the bigger caps but for this amp I think its maybe a bit much for where I'll be using it.
The silicon fuzz is doing what it should, I'm getting fat cleans up to 7. Then rock n roll 7 to 8, it starts hotting up 8 to 9 and then over the top rawk from 9 to 10. With the germanium fuzz I prefer it with more fuzz and less volume but the silicon is just right the other way round. I'm amazed at how fat and sweet the clean tone gets with the guitar rolled back compared to the amp on it's own.
At the moment I can see the fuzz being on all the time with this amp.
So far i think the 100pf bright cap and dog bone in the tone stack sounded best with the fuzz and the wah. The 500pf mica was better when it was just the amp but it lacked some of the really tasty overtones or magic I was getting with the fuzz but the draw back with the bone was it could sound a bit harsh with just the amp so i had to really work the guitar volume and tone to get the sweet spots but when I hit them it sounded great.
I don't know exactly what the dog bone cap does whether it blocks more bass or allows more mids through but it definitely imparts some magic it was alot of fun to play and I was getting a familiar vibe from it although it can be a bit harsh at times.
So at this point I'm thinking I'm facing a balancing act between bright cap and the tone stack cap. I'm going to swap out the 500pf for a 560pf mica and see how it goes. I'm hoping the 2600pf bright cap will be somewhere in between the extremes of the 100pf cap and the 4700pf. Also hoping the 560pf in the tone stack will give a slight mid lift like I was getting from the bone but with out the harshness.
I'm up for trying all the combos I can at the moment with what I have to hand. I've never tried a bone on the mixer or even the 560pf on the mixer. I don't really know what to expect so I should just give it a go and find out.
I have been looking on amp archives to try get a feel for what type of caps generally went into the 69's for the mixer and stack but they all seem to be every possible combination under the sun.
I'd be interested to know if Dave can remember what type or combos of cap types turned up in the "Jim Morrisson" shipment.
I am concerned about the electrolytics like I said the other day I was getting 478vdc on the plates, I need to up the voltage handling. I'm going to remove the pre amp cap and mount a small board on top so I can take the wires back through the hole. So I'll have the screens P.I and pre amp on top. Theres not really enough room inside. I took a long look at it but I think the caps will get too hot from the P.T and the P.T needs all the air circulation it can get.
I'm going to stick to essentially the same values a dual 50uf for pre, a 16/32uf for 48uf on th P.I 2x dual 50uf for 50uf on the screens and 2x dual 100uf for 100uf on the mains. All the other caps are ARS but I could only get F&T for the dual 100's. So far I really like the ARS, I have no idea how or why but I think they some how sound better at least as far as current production goes. Anyway hope it doesn't muck things up because it's really getting there.
I swapped out the 100pf disk bright cap and put the 4700pf back in and also swapped the 470pf dog bone in the tone stack for a 500pf silver mica.
Quite interesting, the bright cap definitely gave it alot more presence in the room. When I kicked the wah on with the guitar volume full up it would go into feed back, I think on a big stage this would be completely useable. I'm quite convinced it was a big bright cap, that said for my needs I'm going to try a dog bone I have that reads 2600pf. I really enjoyed the 100pf but I did feel it needed a bit of a lift and I also felt the 4700pf was a bit much so i ll see how the 2600pf works out. I think in the days before sound reinforcement you'd definitely want the 4700/5000pf in there, especially on the bigger stages it would have space to breath.
I generally prefer the bigger caps but for this amp I think its maybe a bit much for where I'll be using it.
The silicon fuzz is doing what it should, I'm getting fat cleans up to 7. Then rock n roll 7 to 8, it starts hotting up 8 to 9 and then over the top rawk from 9 to 10. With the germanium fuzz I prefer it with more fuzz and less volume but the silicon is just right the other way round. I'm amazed at how fat and sweet the clean tone gets with the guitar rolled back compared to the amp on it's own.
At the moment I can see the fuzz being on all the time with this amp.
So far i think the 100pf bright cap and dog bone in the tone stack sounded best with the fuzz and the wah. The 500pf mica was better when it was just the amp but it lacked some of the really tasty overtones or magic I was getting with the fuzz but the draw back with the bone was it could sound a bit harsh with just the amp so i had to really work the guitar volume and tone to get the sweet spots but when I hit them it sounded great.
I don't know exactly what the dog bone cap does whether it blocks more bass or allows more mids through but it definitely imparts some magic it was alot of fun to play and I was getting a familiar vibe from it although it can be a bit harsh at times.
So at this point I'm thinking I'm facing a balancing act between bright cap and the tone stack cap. I'm going to swap out the 500pf for a 560pf mica and see how it goes. I'm hoping the 2600pf bright cap will be somewhere in between the extremes of the 100pf cap and the 4700pf. Also hoping the 560pf in the tone stack will give a slight mid lift like I was getting from the bone but with out the harshness.
I'm up for trying all the combos I can at the moment with what I have to hand. I've never tried a bone on the mixer or even the 560pf on the mixer. I don't really know what to expect so I should just give it a go and find out.
I have been looking on amp archives to try get a feel for what type of caps generally went into the 69's for the mixer and stack but they all seem to be every possible combination under the sun.
I'd be interested to know if Dave can remember what type or combos of cap types turned up in the "Jim Morrisson" shipment.
I am concerned about the electrolytics like I said the other day I was getting 478vdc on the plates, I need to up the voltage handling. I'm going to remove the pre amp cap and mount a small board on top so I can take the wires back through the hole. So I'll have the screens P.I and pre amp on top. Theres not really enough room inside. I took a long look at it but I think the caps will get too hot from the P.T and the P.T needs all the air circulation it can get.
I'm going to stick to essentially the same values a dual 50uf for pre, a 16/32uf for 48uf on th P.I 2x dual 50uf for 50uf on the screens and 2x dual 100uf for 100uf on the mains. All the other caps are ARS but I could only get F&T for the dual 100's. So far I really like the ARS, I have no idea how or why but I think they some how sound better at least as far as current production goes. Anyway hope it doesn't muck things up because it's really getting there.