Bogner xtc 101b Marvel mod capacitor material suggestions

[lonetone83]

Hi guys I have a 96 to 97 Bogner Ecstasy 101b that I am going to perform the Marvel Mod on. In looking for the parts I came across two kinds of capacitors to use but was wondering if one was better than the other to use. Here are the links to the capacitors, if you guys could shine some light on the issue that would make things that much more easy to get this mod moving along.

http://www.amplifiedparts.com/products/C-T-630V

http://www.amplifiedparts.com/products/C-FS-630

Thanks

 

[Setneck]

To do a mod You don't need a cap with that high voltage parameters. Even 25V cap will do. Use 63V or 100V cap max.

I'd advise You to use polyester cap, film-to-foil being the best, but every metal film polyester cap will do fine. Avoid polypro caps, as they tend to be harsh in highs.

For bypass purposes I use exclusively ERO/Roederstein MKT1813 caps, which are very smooth and harmonically rich sounding. Strongly recommended. You may also use ERO MKT1822's, which are box-shaped caps made of the same material as 1813's.

Regards, Andy

 

[lonetone83]

To do a mod You don't need a cap with that high voltage parameters. Even 25V cap will do. Use 63V or 100V cap max.

I'd advise You to use polyester cap, film-to-foil being the best, but every metal film polyester cap will do fine. Avoid polypro caps, as they tend to be harsh in highs.

For bypass purposes I use exclusively ERO/Roederstein MKT1813 caps, which are very smooth and harmonically rich sounding. Strongly recommended. You may also use ERO MKT1822's, which are box-shaped caps made of the same material as 1813's.

Regards, Andy

Where can I source these in small quantities for the Marvel Mod? I can't really seem to find a place.

 

[Setneck]

Mouser, RS Components.. or Your nearest local electronic parts store

 

[lonetone83]

Ok I placed an order for all the components I need. However I did notice that on the Marvel Mod thread that you can only choose between 2 settings and I wanted to be able to keep my pre-2004 red channel as is but add the post-2004 and Cameron mod so I could have 3 options. I know I need a DPDT toggle switch with on-off-on selections but how would I go about wiring it in? Is it different from the diagram on the Marvel Mod thread? Do you happen to have a diagram for what I want? Thanks a lot so far for all the info.

 

[Setneck]

Off position of a switch allows You to keep Your pre2004 setting. Both on positions enable particular mods.

To wire a mod, solder in series 2.7K + 0.22uF for Factory mod and in series 10K + 1uF for Cameron Mod, then solder them to the left and right lugs od a switch. Link other sides of the mods and solder it with a wire to the one side of a R12 resistor. Then wire the second side with the moddle lug of a switch. And that's it .

You can do it using a board or without it, as I've done R19 mod. See below.



I'd advise You to try .68uF instead of 1uF in Cameron. More mids and less boomy sound.

Regards, Andy

 

[lonetone83]

Great looks easy enough. One quick question though, where do I solder the 1M resistors to reduce the popping sound when switching? Is it necessary as I do not see them in the picture you posted.

 

[Setneck]

They should be soldered in series with the mods, but I don't use additional resistors, as the amp isn't popping dramatically when switching mods.

And also because actually I don't switch it . I use tweaked Cameron only.

Regards, Andy

 

[_actual time_]

One quick question though, where do I solder the 1M resistors to reduce the popping sound when switching? Is it necessary as I do not see them in the picture you posted.

actually, in this case, you don't need any resistors to prevent popping. it took me a while to figure that out. all my early mod switches were DPDT with 10M resistors, but they didn't need to be.

if you look at a Marvel board, he does it with a SPDT and no resistors. this works because the amp resistors that you are adding these mods across, adding in parallel to, have one end of the resistor connected to ground. if you put the mod series resistor and cap in the correct order so that the cap is what gets connected to the ground end of the amp resistor (R12 in this case), then the cap has one end connected to ground all the time. and that prevents popping, without needing tie-down resistors.

so the signal path overall would be:

non-ground end of amp resistor --> a wire to center pole of mod SPDT switch -->
connection through switch to one of the other poles of the switch -->
mod resistor --> mod cap --> wire from the end of both mod caps to ground end of amp resistor

i used my voltmeter to double-check which end of the amp resistor was connected to ground, before i soldered my mod board across it. it is usually the end of the resistor that is toward the back of the amp. Setneck told me that and he's totally right.

here's a pic of my old Marvel board, next to one of my DPDT mods with unneeded tie-down resistors.

here's a pic of my homemade Marvel-type board, with the Cameron 1.0uF changed for a 0.68uF, like Setneck suggests, next to my R19 mod, which is two different caps. they both use SPDT switches for the same reason as the Marvel--one end of the amp resistor that they each get soldered across is connected to ground, and if you make sure that your mod is oriented so that the cap-end of the mod switch is soldered to that ground-end of the resistor, that will minimize or eliminate popping.

i did a Structure mod recently, across R11 IIRC, that works the same way. with Setneck answering lot of my questions! i need to play that some more and write up a post.

 

[_actual time_]

Where can I source these in small quantities for the Marvel Mod? I can't really seem to find a place.

Mouser, like Setneck says, works great for me (i'm in the USA). also in the USA is Newark, and they have a slightly different stock of these caps than Mouser.

it's almost as tough as sourcing 20 millicandella LEDs to make a custom XTC footswitch. but that would be a different post.

 

[lonetone83]

Ok so I just need to make sure that the cap come last in the mod components and those get wired to the resistor end facing the back of the amp? Is the SPDT switch on your mod a center off switch?

 

[_actual time_]

Ok so I just need to make sure that the cap come last in the mod components and those get wired to the resistor end facing the back of the amp?

yep, and that will keep that end of the caps from building up charge. wiring it that way, i have never had popping problems.

Is the SPDT switch on your mod a center off switch?

exactly right, center off, which in the center position gives no mod components added across the amp resistor, and so gives the pre-2004 gain sound.

 

[lonetone83]

Well I guess I messed up somehow and the caps I ordered say 310V on them. Can I still use these? I could have sworn I saw them with a rating of 63V

 

[Setneck]

Yes, you can use them

 

[lonetone83]

The mod went without a hitch! Now I have 3 flavors of the xtc red channel. One thing I did notice was the post 2004 mod didn't really make to much of a difference from my pre 2004 (stock). Is it one of thise mods that's not too noticeable but it gives it a different feel? The Cameron side is awesome. It's like it brought the red channel to life. I still wish I could squeeze out a little more gain over all from the channel though. Would the R19 mod do that and could I make it switchable like the Marvel Mod?

 

[Setneck]

The mod went without a hitch! Now I have 3 flavors of the xtc red channel. One thing I did notice was the post 2004 mod didn't really make to much of a difference from my pre 2004 (stock). Is it one of thise mods that's not too noticeable but it gives it a different feel?

If so, something might have gone wrong, possibly with the wiring. Post2004 Factory mod gives noticeably brighter and more saturated tone. It also gives lots of compression. You should hear the difference.

The Cameron side is awesome. It's like it brought the red channel to life. I still wish I could squeeze out a little more gain over all from the channel though.

Try .68uF cap instead of 1uF. It gives less bottom, so tighter sound, so an impression of more dynamic tone, so impression of having more gain on tap .

Would the R19 mod do that and could I make it switchable like the Marvel Mod?

Yes, see a photo I have attached, there's Marvel Mod and R19 mod showed in my amp. R19 mod affects both Blue and Red, gives some compression which You may like or not, but it is definitely a mod to try.

Regards, Andy

 

[_actual time_]

The mod went without a hitch! Now I have 3 flavors of the xtc red channel. One thing I did notice was the post 2004 mod didn't really make to much of a difference from my pre 2004 (stock). Is it one of thise mods that's not too noticeable but it gives it a different feel?

hmm. no, in my experience, it definitely is noticeable. it kicks the gain up a notch, like raising the Gain knob 2 or 3 "hours" of o'clock setting. it increases the amount of hiss noise in my amp when not playing; i can instantly tell when mine is on.

so i would recommend that you check your wiring. it seems like something might not be quite right.

The Cameron side is awesome. It's like it brought the red channel to life. I still wish I could squeeze out a little more gain over all from the channel though. Would the R19 mod do that and could I make it switchable like the Marvel Mod?

for your Cameron, did you use the 1.0 uF or Setneck's 0.68 uF? i've briefly tried both but prefer the post-2004 sound to the Cameron, for tone--it sounds tighter to my ears, and i just turn the Gain knob down.

if you want a bit more gain, the R19 will provide that. to my ears, it's a bit like the Boost function on the Blue and Red channels, except its amount of boost is about half as much as the boost of the Boost setting. it adds upper-mids bite, but also gain. it adds enough gain that i don't use the R19 and the post-2004 Red at the same time; it's too much gain for me.

the R19 can be wired switchable exactly like the Marvel mod. it's even easier, because it's only caps, with no resistors. i used a SPDT and two cap values, 0.68 uF and 1.0 uF IIRC. with the cap end of the mod connected to the ground end of the R19 resistor, to avoid popping. below is a pic of it next to my homemade Marvel with Setneck 0.68 uF cap in the Cameron.

i use the R19 mostly on un-Boosted Blue. i also use it when using my Creamback 65 speakers instead of my V30s; the Creamback 65s have less volume to them, so the sound has less gain; kicking in the R19 compensates for that. i ended up preferring the 0.68 uF of those two cap values.

 

[lonetone83]

Hmm...well I guess I'll have to double check my work on the Post-2004 side. Do you happen to have a picture of the R19 resistor on the actual xtc circuit board to see which one of the wires is green and red and which one is to ground? That would be a huge help. Thanks

 

[_actual time_]

which end of the R19 resistor goes to ground? IIRC it's the end toward the back of the amp; the same orientation as R12 has. i always double-check with my voltmeter before soldering my mod wires for which end of the resistor is connected to ground, but i'm that guy.

 

[lonetone83]

Thanks guys for all the help....both mods came out great.