Celsius Preamp (Boss CE-1 Preamp) -Update Noise issue FIX!

MichaelW

MichaelW

Well-known member
Build Rating
5.00 star(s)
Update: 12-16-22

@Robert has released a revised version of this board to address the "white noise" hiss reported by a number of folks.
The hiss was tolerable playing clean or with low gain but kick in a higher gain pedal and it got pretty distracting.

It was a shame because I really like the subtle coloring this pedal added as a boost. It wound up on the pedal shelf.

When revised pedal was released @Robert offered to send me a new board or try the mod to my existing build. Never one to back down from some squeamish surgery I decided to try the mod first.

I had forgotten that I had already semi-borked this board when I installed the wrong pot and pulled a pad removing it. So there was already a flying jumper to fix that. So what's a few more cowboy mods right? :ROFLMAO: .

Anyway, those of you that have built this pedal and want to try the mod, it's actually pretty simple and COMPLETELY addresses the "hiss" issue.

Here's the mod:

Screen Shot 2022-12-16 at 12.16.21 PM.png

So as I was removing the 470n cap at C3, of course I pulled another pad along with part of the trace.....ugh....so I had to run a small jumper underneath the board and run the C3 leg to R2 output.

IMG_4104.JPG

I decided to do the mod up top where I could have a little more room.

IMG_4105.JPG

I was surprised as all get out when I fired it up and it all worked! Hahaha....
There is a "slight" attenuation to the gain. But this pedal had TONS of gain to begin with. I could barely crack the knob at the "High Impedance" setting.

With the mod there is still a ton of gain to push an amp.
At the High toggle setting, unity is now around 3 on the knob.
At the Low toggle setting (where there is a bit more coloration) Unity is around 5.

All with no noise.
So glad to put this sweet boost back into rotation!

Thanks @Robert !!



Original post from 8-9-22 below:
******************************************************************************************************************************************
Double dipping on the build reports today.

I was originally planning to post a 2fer build report with these two pedals assuming they would be very similar.

But as I mentioned in my EV Preamp build report, the forum seemed kinda quiet this morning so I went ahead posted that build report separately.

Regarding the notion that these two pedals would be very similar, I could not have been more wrong. This is a very different pedal.

First off, there is a ton of gain in my build. To the point that I'm wondering if I did something wrong. I mean unity is literally about 2 on the amp knob that I used in Low mode. In High mode I can barely crack the pot and I'll be at unity. I don't know if swapping to a linear pot would help or not but I'm thinking about it.

Secondly, I am hearing a little bit of the white noise that @coltonius mentioned in his build report. It's in the background and is there when the pedal is engaged.
I can hear it when I play with my headphones but it's not noticeable through my amp or monitors, but it's definitely there.

Not sure if it's a charge pump issue or as @coltonius surmised a circuit noise floor issue. I don't find it distracting or anything but there is some hiss.
I imagine a real Boss CE-1 would probably do the same thing.

Tonally, it's what I expected, a subtle warmth to the tone and added girth. More noticeable playing clean than with drive. Paired with an overdrive or pushing an amp it sounds like a really hard punching boost.

I really like the way this sounds but somehow I need to tame the output, it's barely usable it's got so much volume.

Tight fit in a 1590B but mainly because my drilling was a skootch off, hence the toggle washer and slightly crooked PCB in the enclosure. Oh and I put one of the 470nf caps in upside down. These little things drive me nuts.

@Bricksnbeatles did you build yours yet? I'd love to hear how yours turns out.

IMG_3338.JPG

IMG_3337.JPG
 
Last edited:
Sharp build!

I haven’t built mine yet— power to my workspace is shut off for the moment until some electrical work gets done. In the meantime I’m just getting graphics together to get printed from Tayda.
 
When you say insane amounts of volume, is it just in the high mode? Based on this video (the Preamp Crunch+ *should* be exactly the same as the Celsius, just with a master volume on the output, and a selectable buffer on the input) it seems that in low mode unity should be around 3:00 and in high mode it should be around 9:00.

I think adding a 100k volume pot at the output should do the trick. You could probably fit it directly opposite the hi/lo switch if you use a small knob for the master level.
 
Bricksnbeatles said:
When you say insane amounts of volume, is it just in the high mode? Based on this video (the Preamp Crunch+ *should* be exactly the same as the Celsius, just with a master volume on the output, and a selectable buffer on the input) it seems that in low mode unity should be around 3:00 and in high mode it should be around 9:00.

I think adding a 100k volume pot at the output should do the trick. You could probably fit it directly opposite the hi/lo switch if you use a small knob for the master level.
Click to expand...
Yah both on High and Low settings. Low setting unity is (if I were using a normal knob with a pointer at 6:30 for full CCW) about 8 o'clock. High toggle setting unity would be about 7:30. I mean I can barely crack the pot on the High setting and hit unity, and turning it up any more clips my digital interface. I would say pretty insane amounts of volume hahaha.

Hmmm adding a master volume at the output you mean? I could probably try to do that in a non-destructive way with some alligator leads.

@PedalPCB is there a schematic available for this yet?
 
Robert said:
There is, give me just a bit and I'll send it over to you.

Coincidentally the earlier version of the Crunch Ensemble didn't have a master volume control... This might be why it was added.
Click to expand...
No rush dude, take your time.
 
Robert said:
There is, give me just a bit and I'll send it over to you.

Coincidentally the earlier version of the Crunch Ensemble didn't have a master volume control... This might be why it was added.
Click to expand...
could you pm the schematic to me too when you get around to it? No rush– except what I'm listening to (sorry. terrible attempt at a joke. I'm not even actually listening to Rush rn, so that was a bust.)
 
Ok I just watched this vid of the Triungulo version without the master vol. Very interesting the effect it has on the signal integrity in high impedance. I actually like it in High mode better except for the unmanageable volume.
There's a pretty significant level bump between low and high, which this video shows.

 
Bricksnbeatles said:
When you say insane amounts of volume, is it just in the high mode? Based on this video (the Preamp Crunch+ *should* be exactly the same as the Celsius, just with a master volume on the output, and a selectable buffer on the input) it seems that in low mode unity should be around 3:00 and in high mode it should be around 9:00.

I think adding a 100k volume pot at the output should do the trick. You could probably fit it directly opposite the hi/lo switch if you use a small knob for the master level.
Click to expand...
Ok, I just watched the full video, that selectable input buffer is interesting.
Here's some of my own findings messing around with different placement in my pedal chain.

The pedal in High mode sounds very different with or without a buffered pedal in front of it.
If I make it the first pedal in my chain it definitely sounds "to me" like a pretty dramatic loss of high end
Or put another way you can look at it as the "maximum sweetening effect" if that's what you what you're looking for.

If I put in the usual "boost" slot in my chain, which is after my compressor with buffered bypass, it's got much more clarity and sparkle to it.

I don't think I have enough room in this pedal for any mods, since I stuck it in a 1590B.

But it if I built it again, I'd do it in a 125B and it would be worth putting in the buffered input mod. You could used one of PPCB's simple jet buffers on a toggle switch. And put a master volume at the output.

After chatting with @PedalPCB he's getting unity at around 25% of the volume sweep. This is what I would have expected.
I need to pull mine apart and see if I didn't use the wrong value pot.

I have a feeling the volume issue on mine is an anomaly and probably something dumb I did.....:)

Edit: I just looked at the PastFX website and they mention the following:

"Buffer CircuitMany owners of the BOSS® CE-1 noticed that when selecting the high on the input sensitivity switch that some of the high frequencies of their signal was lost. This was a desirable outcome for some. To remedy this, some users would place a buffer before the BOSS® CE-1 to restore the high frequencies. The Preamp Crunch comes with an inbuilt buffer circuit which can be added or removed as desired."

So I guess my findings are consistent at least with regards to the buffered input.
 
Last edited:
Ok update:

Volume mystery solved!

And the answer is.................I'm a dumbass.......

@PedalPCB: "You DID use an A50k pot right?
Me: "Of COURSE I did, you think I'm an idiot?????"

Me: (quietly opens the enclosure, takes the board out and sees that in fact it's a B50k in there.....duh......)

With the proper log pot in there it now gets to unity at about 1/4 turn.
 
thewintersoldier said:
if you are taking a pot out of a board, sacrifice that 50 cent pot and snip all three legs and then go about removing the solder and what's left of each leg. Save the time, effort and pcb and no jumpers necessary.
Click to expand...
HAH, I actually did do that, yet still somehow borked the pad removing the pin. I was trying to figure out why the freaking pad wouldn't take solder when I put the new pot in. Then I looked down on my silicon work mat and saw this neat little round silver circle sitting there mocking me.......
 
thewintersoldier said:
what shape tip are you using for desodering? What temp are you running for desoldering? Pump or braid? and are you using additional flux?
Click to expand...
Conical tip, same temps that I solder at 715 degrees. Uber Super Solder Sucker first, then wiggle-wiggle-wiggle applying a little heat with a hemostat on the remaining pot tip from the other side.

Edit: Not that I've done this very often. I think this is maybe only 2nd or 3rd time I've had to yank a pot out.
 
Route14 said:
What are your thoughts on using 1590B enclosures on these smaller projects?
Click to expand...
I may be the wrong person to ask hahahaha, I really prefer the 1590B and will tend to use them whenever I can shoe horn a build into one. But I may be in the minority here.

There's nothing wrong with a 125B, but I hate seeing the wasted space of a small board in a larger enclosure. It's also gotten me into trouble a few times when I don't measure correctly. Drilling needs to be spot on, lot less margin for error.
 
If one is available for your soldering iron I highly recommend one of these tips for removing pots.

It literally takes about 5 seconds to remove a pot cleanly. No wick, no solder sucker, no damage to the PCB.

1660153080836.png
 
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