Taming the Bass in My Splawn Comp

[Junk Yard Dog]

We all love the Splawn's for the bass/punch, which is way above other amps that cost at least twice as much. That said, sometimes the bass is too much on Gear2 & 3 and when in the "Old" mode. I find myself using Gear 1, Old or Gear 2, New to cut the bass back a bit and get some of the clarity at lower volumes.

What are you guys doing to mitigate this? I've seen it in a few other posts that others sometimes struggle with it.

I just retubed my Comp with JJ EL34 II's and it seems to have gotten worse...Maybe the bias is off or the these tubes dont' work.

Thoughts and suggestions?

 

[311splawndude]

We all love the Splawn's for the bass/punch, which is way above other amps that cost at least twice as much. That said, sometimes the bass is too much on Gear2 & 3 and when in the "Old" mode. I find myself using Gear 1, Old or Gear 2, New to cut the bass back a bit and get some of the clarity at lower volumes.

What are you guys doing to mitigate this? I've seen it in a few other posts that others sometimes struggle with it.

I just retubed my Comp with JJ EL34 II's and it seems to have gotten worse...Maybe the bias is off or the these tubes dont' work.

Thoughts and suggestions?

I have JJ EL34 IIs in my QR and I agree they add more bass or lower mids for sure. I dig that bass and punch for my chugga stuff but lots if other tones, 80s rock/metal in particular, I agree it can be a bit much. EL34Ls = same thing.

Have you tried an EQ in the loop?

 

[Junk Yard Dog]

I have JJ EL34 IIs in my QR and I agree they add more bass or lower mids for sure. I dig that bass and punch for my chugga stuff but lots if other tones, 80s rock/metal in particular, I agree it can be a bit much. EL34Ls = same thing.

Have you tried an EQ in the loop?

Yup, EQ in the loop works great. But sometimes wish I had a bit more control over the bass without having to use EQ in the loop.

I think I'm going to rip out the JJ II's and go back to TAD BTSR's or even EH C6CA7's, which were fantastic in my Comp.

What do you think about Old/New? Those make a big impact on the amp's tone and feel. Love Old with Gear 1, don't love it with Gear 2.

 

[motorboy1]

I found at low volumes the old setting is a little thick sounding, sounds great at louder volumes though. Try setting your mids higher, I run mine at 5 or 6 and this will lean out the bass. Also no b+ or mid cut at low settings. V2 tube stage 1 makes a difference. The stock Chinese 12ax7b adds low end, I put in a nos RCA and this leaned out the bass quite a bit. Eq in the loop or any boost in front will cut the bass also. I have a 100 fully loaded quick rod.

 

[Junk Yard Dog]

I found at low volumes the old setting is a little thick sounding, sounds great at louder volumes though. Try setting your mids higher, I run mine at 5 or 6 and this will lean out the bass. Also no b+ or mid cut at low settings. V2 tube stage 1 makes a difference. The stock Chinese 12ax7b adds low end, I put in a nos RCA and this leaned out the bass quite a bit. Eq in the loop or any boost in front will cut the bass also. I have a 100 fully loaded quick rod.

Ok, thanks. I'll try the mids higher. Mine is a 50w Comp, so it's always in B+ mode. ...V2 currently has a TAD 7025; I could try a lower gain preamp tube. Thanks for he suggestions!

 

[311splawndude]

I have an older QR and have never tried the old/new switch

 

[hammered]

Eq in the loop or a clean boost like the Friedman Buxom Boost, MXR Modified OD or Boss SD-1 out front . I just mention those boosts cause that's what I'm using. What speakers are you using ?

 

[Junk Yard Dog]

Eq in the loop or a clean boost like the Friedman Buxom Boost, MXR Modified OD or Boss SD-1 out front . I just mention those boosts cause that's what I'm using. What speakers are you using ?

V30 / CBH75 mix in Friedman 2x12.

 

[hammered]

V30 / CBH75 mix in Friedman 2x12.

I’ve had good results with those speakers in the past. I’d recommend a boost up front. Friedman Buxom boost doesn’t color the tone like a lot of TS type pedals and it’s got come cool features with a ton of boost on tap if needed. Me personally I’ve never did a preamp tube swap to get the results your after but ya never know it could work. FWIW I've had the JJ EL34 ll in my EL34 Super Sport for a while and they work really good

 

[harddriver]

There is a lot of bass frequencies passed in the stock Splawn circuit so I don't know how you mitigate besides turning down the bass pot without making the amp sound empty.

There is a .22uf cap in series after a 220K NFB resistor on the 4 ohm tap in the NFB circuit that gives a fixed bass response which you may feel it too much at times.

You can always lower the value of that .22uf capacitor and it should change the corner frequency giving less bass.

Probably the best way to deal with this is removing the .22uf and replacing with a depth mod where you can dial in how much bass response you want but you will need to drill a hole in the chassis. You can also change the NFB resistor from 47K(plexi) to 100K(Marhsall SL) or if you like the 220K splawn value.

You can also install a NFB(variable resistor) pot instead of a fixed NFB resistor where you can dial it in clean tight plexi @ 47K to a Ratty more aggressive but looser @100-220K. Depends on if you want to drill holes or not to add them.

The Variable NFB and Depth mod are very powerful ways to adjust any amp. I had both NFB and Depth on one of my HG build amps and it was crazy how I could dial in different feel, ie tight/loose and aggression with both of those controls.

I'd say the Depth Mod pot would be the best solution for you and you can play with the fixed NFB resistor values to see what you like from 47K-220K on the existing circuti board. This would be the easiest and most productive mod to do for any decent tech.

 

[morgansbluff]

There is a lot of bass frequencies passed in the stock Splawn circuit so I don't know how you mitigate besides turning down the bass pot without making the amp sound empty.

There is a .22uf cap in series after a 220K NFB resistor on the 4 ohm tap in the NFB circuit that gives a fixed bass response which you may feel it too much at times.

You can always lower the value of that .22uf capacitor and it should change the corner frequency giving less bass.

Probably the best way to deal with this is removing the .22uf and replacing with a depth mod where you can dial in how much bass response you want but you will need to drill a hole in the chassis. You can also change the NFB resistor from 47K(plexi) to 100K(Marhsall SL) or if you like the 220K splawn value.

You can also install a NFB(variable resistor) pot instead of a fixed NFB resistor where you can dial it in clean tight plexi @ 47K to a Ratty more aggressive but looser @100-220K. Depends on if you want to drill holes or not to add them.

The Variable NFB and Depth mod are very powerful ways to adjust any amp. I had both NFB and Depth on one of my HG build amps and it was crazy how I could dial in different feel, ie tight/loose and aggression with both of those controls.

I'd say the Depth Mod pot would be the best solution for you and you can play with the fixed NFB resistor values to see what you like from 47K-220K on the existing circuti board. This would be the easiest and most productive mod to do for any decent tech.

THIS . the bass can get out of hand quickly. I did a slight mod to gear 2. I Put a variable resistor trim pot inside to fiddle with til it sounded right. Gear 1 and 2 now have similar bass response. I must say the biggest change I've heard is new power tubes. The stock psvanes flashed one day but my amp tech said they were fine. I finally changed the tubes to mullards and the amp sounds like it was when I bought it new. I think the stock tubes got damaged somehow and were not reproducing bass and treble properly. I came way down on my treble knob and up on the bass knob after replacing the power tubes.

 

[Bash_Man]

so I had a similar "issue" with my Splawn Nitro.. i ended up taking it to a local amp tech who added a toggle switch with some a cap value (no idea what it is), and with it ON, it takes away that boomy low end. it allows me to turn up the bass dial a bit more. I didn't want it to take away too much, just mainly that boomy sound.

he did the mod on both the clean and OD channel. Works great.

 

[reignman454]

We all love the Splawn's for the bass/punch, which is way above other amps that cost at least twice as much. That said, sometimes the bass is too much on Gear2 & 3 and when in the "Old" mode. I find myself using Gear 1, Old or Gear 2, New to cut the bass back a bit and get some of the clarity at lower volumes.

What are you guys doing to mitigate this? I've seen it in a few other posts that others sometimes struggle with it.

I just retubed my Comp with JJ EL34 II's and it seems to have gotten worse...Maybe the bias is off or the these tubes dont' work.

Thoughts and suggestions?

*I am not a tech* I do know that there is usually a cap that can be clipped to remedy this (at least in some of my amps) I've had my tech clip it. Perhaps someone more knowledgeable can chime in.

Doesn't change the voicing, just takes some of the woofiness away

What year is your comp? I can ask. Im 99% sure it's not just on the Marshall Mods, I have a handful of splawns, modded and Splawn production and did it to all of them.

 

[motorboy1]

Try a different tube in the PI slot. I sdded a Sovtek LPS and it helped with the bass issue. Amp sounds more open and clear.

 

[SpiderWars]

I thought I read that he puts a really big bass cap in the tone stack and that’s why they have so much bass.

If there is a 0.22uF cap in series with the NFB that should just block any DC and isolate. It shouldn’t sound any different because that cap is passing all frequencies all the way down to really low sub frequencies.

Seems you could add a cap right on the bass pot which would be in series with the existing cap, cutting the value to something lower.

 

[Junk Yard Dog]

There is a lot of bass frequencies passed in the stock Splawn circuit so I don't know how you mitigate besides turning down the bass pot without making the amp sound empty.

There is a .22uf cap in series after a 220K NFB resistor on the 4 ohm tap in the NFB circuit that gives a fixed bass response which you may feel it too much at times.

You can always lower the value of that .22uf capacitor and it should change the corner frequency giving less bass.

Probably the best way to deal with this is removing the .22uf and replacing with a depth mod where you can dial in how much bass response you want but you will need to drill a hole in the chassis. You can also change the NFB resistor from 47K(plexi) to 100K(Marhsall SL) or if you like the 220K splawn value.

You can also install a NFB(variable resistor) pot instead of a fixed NFB resistor where you can dial it in clean tight plexi @ 47K to a Ratty more aggressive but looser @100-220K. Depends on if you want to drill holes or not to add them.

The Variable NFB and Depth mod are very powerful ways to adjust any amp. I had both NFB and Depth on one of my HG build amps and it was crazy how I could dial in different feel, ie tight/loose and aggression with both of those controls.

I'd say the Depth Mod pot would be the best solution for you and you can play with the fixed NFB resistor values to see what you like from 47K-220K on the existing circuti board. This would be the easiest and most productive mod to do for any decent tech.

Have you done this before? I am interested in any of these options. I wouldn’t do the work myself, and maybe have a local tech do it.

 

[Junk Yard Dog]

THIS . the bass can get out of hand quickly. I did a slight mod to gear 2. I Put a variable resistor trim pot inside to fiddle with til it sounded right. Gear 1 and 2 now have similar bass response. I must say the biggest change I've heard is new power tubes. The stock psvanes flashed one day but my amp tech said they were fine. I finally changed the tubes to mullards and the amp sounds like it was when I bought it new. I think the stock tubes got damaged somehow and were not reproducing bass and treble properly. I came way down on my treble knob and up on the bass knob after replacing the power tubes.

So the trim pot you added is on the inside of the chassis? …I just put JJ EL34 II’s in there and noticed the bass got worse. I may need different tubes in mine.

 

[Junk Yard Dog]

so I had a similar "issue" with my Splawn Nitro.. i ended up taking it to a local amp tech who added a toggle switch with some a cap value (no idea what it is), and with it ON, it takes away that boomy low end. it allows me to turn up the bass dial a bit more. I didn't want it to take away too much, just mainly that boomy sound.

he did the mod on both the clean and OD channel. Works great.

If you can find out the details, if it’s no trouble, that would be great. My tech might be able to do something similar for me.

 

[Junk Yard Dog]

*I am not a tech* I do know that there is usually a cap that can be clipped to remedy this (at least in some of my amps) I've had my tech clip it. Perhaps someone more knowledgeable can chime in.

Doesn't change the voicing, just takes some of the woofiness away

What year is your comp? I can ask. Im 99% sure it's not just on the Marshall Mods, I have a handful of splawns, modded and Splawn production and did it to all of them.

Mine is a 2015,

 

[Junk Yard Dog]

Try a different tube in the PI slot. I sdded a Sovtek LPS and it helped with the bass issue. Amp sounds more open and clear.

Yup, that’s what I have in the PI slot of all my heads