REVIEW (long): Caps, resistors & parts on my 1987x board
Posted: Wed Jan 21, 2004 7:04 pm
Greetings,
I just completed my first point to point board 3 weeks ago, and I'm still tweaking on a daily basis. But not because I'm unhappy with the sound ... just the opposite! I'm more intrigued with the endless tonal possibilities. I’ve swapped caps and combinations of caps at least three times, and I'm still trying out different resistors. I’ve made over 50 clips, documenting the different values and brands, so I thought I'd summarize my experiences in hopes that you guys can share as well. In fact I’m COUNTING on you to share, because my wife is at the end of her rope and might break my tubes if she hears me play the same damn riff again!
My benchmark tone is EVH's magic Marshall, and in particular, the tones off of VHII. So with that in mind, and volume on ten, here are my impressions. Remember that tone is subjective, so what I find pleasing, you might hate … especially if your idea of a pleasing Marshall tone is along the lines of C.C. DeVille. Isn’t it ironic that my wife finds none of it pleasing. She often refers to my amp as “the bomb”. “Hey, how’s your bomb coming along?”. “Are you going to come up for dinner, or are you still working on your bomb?”
On with the review ...
CAPS
Mallory 150s:
I didn’t like these, even though they seem to be the standard replacement cap for Marshall. Everyone else seems to love em, so hey, what do I know!! I thought they were grainy with a pronounced midrange. The low end was soft and the words plastic and chewy come to mind. The notes also seemed blurry and confused compared to the other caps I tried. They were darker than the Orange Drops and less detailed. They didn't do anything wrong ... they just weren't very inspiring.
Sprague Orange Drops:
These had a flatter frequency response and a much tighter low end. I could get a nice "thunk" out of my cab when hitting the low E that I couldn't get out of the Mallorys. There was also more clarity and detail, but this came at the expense of added brightness. I’d almost say the treble was “spitty”. They definitely had more character than the Mallorys and the tone seemed more alive and touch responsive, even when blazing through lame renditions of “Eruption”.
Mystery Cap (X):
Okay, I hate to do this, but the person that told me about these made me promise not to reveal the name. That being said, the X caps flat out rule!!! They have all the good characteristics of the Orange Drops, but sound smoother and more refined. Kind of like comparing wine to beer. Yeah I know, you’re saying, “Beer and Van Halen are a perfect mix” … but you should try wine while playing “Beautiful Girls” and “DOA”! They just sound more pleasing to the ears. The low end stays smooth, but retains a tight feel that doesn’t get flubby. The grain that I heard with the Mallorys is totally absent … almost like the caps have less of a sonic signature than the others.
I also tried every possible combination of Mallory/Sprague, Mallory/X, Sprague/X, Mallory/Sprague/X, and the X caps always came out on top.
Silver Mica vs. Ceramic disk:
My Metroamp board originally had Silver Mica caps throughout, but I changed them for ceramic disks. I think they sound smoother and less gritty. Seems like the Silver Mica disks pass along every single anomally in the chain, and that’s not always a good thing in my book. I made one clip where I swapped out the Silver Mica above the output coupling caps for ceramic, and the difference was quite noticeable. I was actually quite shocked at how much smoother the ONE ceramic cap sounded. I intend to play around with this a little more because it seems like a good way to fine-tune the sound of the other caps. For instance, if the Orange Drops sound too bright, you can knock em down with a ceramic disk, or visa versa with the Mallorys. I’m totally guessing here, so if I’m off my rocker, feel free to correct me.
Xicon vs. Sprague Cathode Bypass Caps:
The verdict is still out on this one, but I think I like the Xicon’s better! Remember I’m trying to duplicate EVH’s amp, and he had a 330uf cap on V1 AND V2. I’ve been told that the value of these caps are so high that it doesn’t really matter if you use a 250uf or a 300uf. I had some Spragues and thought they looked really cool with their black barrels and green writing. They looked like something from the Green Hornet TV series. Just for the hell of it, I tried using one of the ugly baby blue Xicon’s I had laying around. Well, I might be smoking crack (or moved my mic by mistake), but I think the Xicon’s sounded better. They didn’t have any more gain, but I did hear the mid frequency shifting. They also have a hollow sound that seems to have more personality than the flatter response of the Sprague’s. Think VH1 vs. VHII. I need to do a test with both Xicon’s in place before I make too much of a deal out of this.
Next came varieties of .022, .0022, .68, and .1 caps (and all the different combos). I ended up with .022s throughout, with .1s for the output coupling caps. My 50 watter tends to sound “smaller” than my ’74 Super Lead, so I’m always yearning for more beef. Using .0022s made the amp sound too lean. Interestingly, with the Mallorys, I felt the need to go to .0022s, but with the X caps and their added clarity, I could stay with .022s and .1s!! Don’t you wish I could reveal the name!
RESISTORS
I can’t really say I hear the difference between carbon comp and carbon film throughout the board, so no comment! That being said, I did try a gain mod that required the use of a 1M resistor, and I did swap that one in and out with carbon comp and carbon film. Carbon comp sounded SLIGHTLY smoother than carbon film. “Slightly” is the operative word here.
I’ve changed a few other values throughout, but again it’s a subjective thing because I’m going for a particular tone.
FILTERING
I tried lowering the filtering but found that the sound was too soft for my tastes. I cut the jumper wire on the 50/50uf cap closest to the edge of the chassis by the HT fuse (see how little I know), so it lowered it down to 25uf (or so I’m told). I just got a 32/32uf cap that I might try out, but I’m not holding my breath. I’ve heard that the 50 watters are much different than the 100 watters, and filtering is a different beast with those amps.
NEGATIVE FEEDBACK
This is another area where I went mad scientist and tried every conceivable combination of resistor values and impedence tapping. I connected the negative feedback wire to the 4, 8, and 16ohm speaker taps, and also raised and lowered my negative feedback resistor from 47k to 100k. I finally settled on the 100k resistor connected to the 8ohm tap. How’s that for original!
RECTIFIER DIODES
Wow, am I a geek or what!! Never in my wildest dreams did I ever think I would get excited about rectifier diodes. I just read an article by Don Butler, and he said that he prefers using FRED diodes in place of the cheapy IN4007s that are found in the typical Marshall. Don used words, like “improved harmonics, better touch sensitivity, and improved dynamics”. I could feel the excitement building and sure enough, I started having wet dreams of FRED diodes! Damn, I just HAVE to try them! I’m waiting to confirm the type with George before I buy them, and then I’ll report back.
Lastly, I bought a Mercury Magnetics choke. Curiosity got the better of me, and since they’re not that expensive I’m going to try it out. It’s still not here yet, so I’ll report back if it sounds any different from the stock choke. I’ve already got a OEI output transformer so I couldn’t really justify buying a MM just to see if it was different. Someone posted some clips comparing the two, and as fate would have it, I preferred the MM. We’ll see if I cave in and buy one later on.
There you have it. Thanks to George for answering all my stupid questions. You have to remember that 6 weeks ago, I didn’t even know what a multimeter was, or how to use a bias probe, so his patience was beyond the call of duty. Also thanks to Stan (bmf5150) for encouraging me to build a kit and for listening to 50 clips of the same riff over and over and over again!
chris
I just completed my first point to point board 3 weeks ago, and I'm still tweaking on a daily basis. But not because I'm unhappy with the sound ... just the opposite! I'm more intrigued with the endless tonal possibilities. I’ve swapped caps and combinations of caps at least three times, and I'm still trying out different resistors. I’ve made over 50 clips, documenting the different values and brands, so I thought I'd summarize my experiences in hopes that you guys can share as well. In fact I’m COUNTING on you to share, because my wife is at the end of her rope and might break my tubes if she hears me play the same damn riff again!
My benchmark tone is EVH's magic Marshall, and in particular, the tones off of VHII. So with that in mind, and volume on ten, here are my impressions. Remember that tone is subjective, so what I find pleasing, you might hate … especially if your idea of a pleasing Marshall tone is along the lines of C.C. DeVille. Isn’t it ironic that my wife finds none of it pleasing. She often refers to my amp as “the bomb”. “Hey, how’s your bomb coming along?”. “Are you going to come up for dinner, or are you still working on your bomb?”
On with the review ...
CAPS
Mallory 150s:
I didn’t like these, even though they seem to be the standard replacement cap for Marshall. Everyone else seems to love em, so hey, what do I know!! I thought they were grainy with a pronounced midrange. The low end was soft and the words plastic and chewy come to mind. The notes also seemed blurry and confused compared to the other caps I tried. They were darker than the Orange Drops and less detailed. They didn't do anything wrong ... they just weren't very inspiring.
Sprague Orange Drops:
These had a flatter frequency response and a much tighter low end. I could get a nice "thunk" out of my cab when hitting the low E that I couldn't get out of the Mallorys. There was also more clarity and detail, but this came at the expense of added brightness. I’d almost say the treble was “spitty”. They definitely had more character than the Mallorys and the tone seemed more alive and touch responsive, even when blazing through lame renditions of “Eruption”.
Mystery Cap (X):
Okay, I hate to do this, but the person that told me about these made me promise not to reveal the name. That being said, the X caps flat out rule!!! They have all the good characteristics of the Orange Drops, but sound smoother and more refined. Kind of like comparing wine to beer. Yeah I know, you’re saying, “Beer and Van Halen are a perfect mix” … but you should try wine while playing “Beautiful Girls” and “DOA”! They just sound more pleasing to the ears. The low end stays smooth, but retains a tight feel that doesn’t get flubby. The grain that I heard with the Mallorys is totally absent … almost like the caps have less of a sonic signature than the others.
I also tried every possible combination of Mallory/Sprague, Mallory/X, Sprague/X, Mallory/Sprague/X, and the X caps always came out on top.
Silver Mica vs. Ceramic disk:
My Metroamp board originally had Silver Mica caps throughout, but I changed them for ceramic disks. I think they sound smoother and less gritty. Seems like the Silver Mica disks pass along every single anomally in the chain, and that’s not always a good thing in my book. I made one clip where I swapped out the Silver Mica above the output coupling caps for ceramic, and the difference was quite noticeable. I was actually quite shocked at how much smoother the ONE ceramic cap sounded. I intend to play around with this a little more because it seems like a good way to fine-tune the sound of the other caps. For instance, if the Orange Drops sound too bright, you can knock em down with a ceramic disk, or visa versa with the Mallorys. I’m totally guessing here, so if I’m off my rocker, feel free to correct me.
Xicon vs. Sprague Cathode Bypass Caps:
The verdict is still out on this one, but I think I like the Xicon’s better! Remember I’m trying to duplicate EVH’s amp, and he had a 330uf cap on V1 AND V2. I’ve been told that the value of these caps are so high that it doesn’t really matter if you use a 250uf or a 300uf. I had some Spragues and thought they looked really cool with their black barrels and green writing. They looked like something from the Green Hornet TV series. Just for the hell of it, I tried using one of the ugly baby blue Xicon’s I had laying around. Well, I might be smoking crack (or moved my mic by mistake), but I think the Xicon’s sounded better. They didn’t have any more gain, but I did hear the mid frequency shifting. They also have a hollow sound that seems to have more personality than the flatter response of the Sprague’s. Think VH1 vs. VHII. I need to do a test with both Xicon’s in place before I make too much of a deal out of this.
Next came varieties of .022, .0022, .68, and .1 caps (and all the different combos). I ended up with .022s throughout, with .1s for the output coupling caps. My 50 watter tends to sound “smaller” than my ’74 Super Lead, so I’m always yearning for more beef. Using .0022s made the amp sound too lean. Interestingly, with the Mallorys, I felt the need to go to .0022s, but with the X caps and their added clarity, I could stay with .022s and .1s!! Don’t you wish I could reveal the name!
RESISTORS
I can’t really say I hear the difference between carbon comp and carbon film throughout the board, so no comment! That being said, I did try a gain mod that required the use of a 1M resistor, and I did swap that one in and out with carbon comp and carbon film. Carbon comp sounded SLIGHTLY smoother than carbon film. “Slightly” is the operative word here.
I’ve changed a few other values throughout, but again it’s a subjective thing because I’m going for a particular tone.
FILTERING
I tried lowering the filtering but found that the sound was too soft for my tastes. I cut the jumper wire on the 50/50uf cap closest to the edge of the chassis by the HT fuse (see how little I know), so it lowered it down to 25uf (or so I’m told). I just got a 32/32uf cap that I might try out, but I’m not holding my breath. I’ve heard that the 50 watters are much different than the 100 watters, and filtering is a different beast with those amps.
NEGATIVE FEEDBACK
This is another area where I went mad scientist and tried every conceivable combination of resistor values and impedence tapping. I connected the negative feedback wire to the 4, 8, and 16ohm speaker taps, and also raised and lowered my negative feedback resistor from 47k to 100k. I finally settled on the 100k resistor connected to the 8ohm tap. How’s that for original!
RECTIFIER DIODES
Wow, am I a geek or what!! Never in my wildest dreams did I ever think I would get excited about rectifier diodes. I just read an article by Don Butler, and he said that he prefers using FRED diodes in place of the cheapy IN4007s that are found in the typical Marshall. Don used words, like “improved harmonics, better touch sensitivity, and improved dynamics”. I could feel the excitement building and sure enough, I started having wet dreams of FRED diodes! Damn, I just HAVE to try them! I’m waiting to confirm the type with George before I buy them, and then I’ll report back.
Lastly, I bought a Mercury Magnetics choke. Curiosity got the better of me, and since they’re not that expensive I’m going to try it out. It’s still not here yet, so I’ll report back if it sounds any different from the stock choke. I’ve already got a OEI output transformer so I couldn’t really justify buying a MM just to see if it was different. Someone posted some clips comparing the two, and as fate would have it, I preferred the MM. We’ll see if I cave in and buy one later on.
There you have it. Thanks to George for answering all my stupid questions. You have to remember that 6 weeks ago, I didn’t even know what a multimeter was, or how to use a bias probe, so his patience was beyond the call of duty. Also thanks to Stan (bmf5150) for encouraging me to build a kit and for listening to 50 clips of the same riff over and over and over again!
chris