Power supply for Dr Boogey

[ghostsauce]

So I'm running a little radio shack adapter split 3 ways right now to power 1/2 my board.. and it's putting a lot of hum into my DB, and the SHO is almost unusable due to large hum when switched on.. Am in desperate need of something else! Been looking at the 1spot. I know it's supposed to be quiet, but how does it really stack up with the Dr Boogey? Cause if anything could make a power supply cry for mama, this beast can!

[FiveseveN]

Just add a 7809 or similar voltage regulator. See datasheet for details.

[ghostsauce]

http://www.fairchildsemi.com/ds/LM/LM7805.pdf

Oh, interesting.. Legs are Input, Ground, and Output... if I'm reading this right it'll take 9v in and output a regulated 9v... so no hum and really it's just one part so I could stick it inside these two troublesome pedals...

[FiveseveN]

I'm reading this right it'll take 9v in and output a regulated 9v

No, it has a dropout voltage of about 2 V, so you have to supply at least 11 V. Also note that the unregulated supply's output voltage drops as you suck more current out of it, so measure it under a typical load.

[ghostsauce]

Ah.. sadly I can't adjust the voltage on the adapter so I don't see how I could do this then...

[J0K3RX]

A possible problem with daisy chains is hum caused by ground loops. Your pedals will now have contact with ground not only through your signal cables, but also through the adapter cables, you are most likely creating a ground loop. This manifests itself as hum/noise etc. It can happen between pedals in a normal pedal chain, but the most common cause is when people power both pedals that go in front of the amp and pedals that go in the amp's effects loop from the same source.  If one pedal has any DC noise, it will spread across all of your pedals causing hiss and hum that may drive you nuts. Just because you get a 1 Spot will not solve your problem... You should split the power, but also isolate the outputs from each other. This will prevent any ground loops, as the pedals all think they are alone.

Maybe consider something like this?
http://www.generalguitargadgets.com/diagrams/ss-ps4_lo.gif

[FiveseveN]

Have you measured your supply's actual output voltage when loaded?

[lonewolf]

use an isolated power supply and you shouldnt have hum problems..

[J0K3RX]

If a wall plug transformer has safety agency approvals (UL, TUV, CUL, etc.) the input windings of the transformer will be isolated from the output windings, so there's your isolation...  However, there is a capacitance between the windings which could result in a small AC leakage current to ground. Because a wall wart "should be properly isolated" there is no need for a polarized connector, or a "three pin plug." In short, your AC/DC power adapter should be isolated... You may have one that is unregulated?  The 1 Spot is regulated, your Radio Shack special may not be...? Measure it with no load and if it reads considerably higher than the specs then bingo, you got yourself an unregulated supply...

A given unregulated power adapter has an output rating of 9 volts DC at 500ma (500 milliamps = 0.5 Amps). This rating means that the unregulated voltage output of the power adapter will be 9 volts DC when it is under the full rated load of 500ma. Many people are surprised when they plug an unregulated power adapter into a wall outlet and measure the DC output voltage of the power adapter with a volt meter. While the adapter is providing no power to a load device, the measured output voltage is several volts higher than the rated voltage of the power adapter. Often, people jump to the conclusion that something is wrong with the power adapter, while the simple explanation is that the power adapter has no voltage regulator, and this is normal. But if the same unregulated power adapter is connected to a load which draws 500ma of current, the measured output voltage of the power adapter would drop to the rated 9 volt DC output level as it should.

[ghostsauce]

I appreciate the input! That isolated power supply is something I'll have to consider building if this doesn't work out:

I plugged in a 1spot and the hums are all gone, however my dr boog is gating/farting so it would seem I need to re-bias. Not really sure what this indicates though... maybe the other supply was not providing enough voltage?  I'll have to re-bias and see what happens. Any thoughts? That other supply is about 16+ years old, maybe it is just no good... It's pretty beaten up.

@FiveseveN: No, I haven't.. So maybe it was a bad supply?

[ghostsauce]

@J0K3RX: Not sure if the other supply is regulated.. sure doesn't say it is.

[lonewolf]

what I meant to say was a multiple output Isolated power supply ..a transformer  for each output filtered and regulated..voodoo lab makes one....pretty expensive....I built one using the tonepad schematic...cost less than half the price of the ISO-5..no hum ....plenty of power..

[ghostsauce]

Woot! I rebiased the DB with the 1spot, and the hum is still non-existant! Ok, so good wiring on the DB + power supply that doesn't suck = no noise. I mean sure there is a little hissing but nothing I'm not ok with.. nothing like before.

The DB doesn't quite have the same quality of sound as it did before though.. gonna mess with different transistors and bias. I think it was getting more voltage before, because I noticed now the battery check on the Boss TU-2 (the LED glowing a little when it's not on) is now not lighting up at all when not engaged. Maybe I want my DB running over 9v. I could Y the 1spot with the RadioShack special to get 18v, wonder if the hum would come back.

[J0K3RX]

Woot! I rebiased the DB with the 1spot, and the hum is still non-existant! Ok, so good wiring on the DB + power supply that doesn't suck = no noise. I mean sure there is a little hissing but nothing I'm not ok with.. nothing like before.

The DB doesn't quite have the same quality of sound as it did before though.. gonna mess with different transistors and bias. I think it was getting more voltage before, because I noticed now the battery check on the Boss TU-2 (the LED glowing a little when it's not on) is now not lighting up at all when not engaged. Maybe I want my DB running over 9v. I could Y the 1spot with the RadioShack special to get 18v, wonder if the hum would come back.

or you could build a voltage doubler...?

[rousejeremy]

maybe one of these could help http://www.beavisaudio.com/projects/Huminator/index.htm

[ghostsauce]

You guys just want to spend my money!

Hehe, actually I was pleasantly surprised this morning when I continued to tweak the bias on the DB and was able to get a better tone than ever before! This required very frequent and minor adjustments on Q1 & Q2 mostly, but it sounds gorgeous now. Gonna buy the 1spot and seal the deal.

Also, I wonder now that I'm using a proper regulated supply if my troubles of the DB not sounding the same depending on the location will go away. Between at home, at the church, or the church campgrounds, or at other churches the DB always seemed to behave differently. And I don't mean just the different room = different tone, I mean.. seemed like the bias was off everywhere but at home because the characteristics of it was not the same, and the hum would vary in loudness. I'll know Sunday morning when I play at the campgrounds, I guess... I usually had a ridiculous hum out there and the DB would be more fizzy on the top end.

[J0K3RX]

You guys just want to spend my money!

Hehe, actually I was pleasantly surprised this morning when I continued to tweak the bias on the DB and was able to get a better tone than ever before! This required very frequent and minor adjustments on Q1 & Q2 mostly, but it sounds gorgeous now. Gonna buy the 1spot and seal the deal.

Also, I wonder now that I'm using a proper regulated supply if my troubles of the DB not sounding the same depending on the location will go away. Between at home, at the church, or the church campgrounds, or at other churches the DB always seemed to behave differently. And I don't mean just the different room = different tone, I mean.. seemed like the bias was off everywhere but at home because the characteristics of it was not the same, and the hum would vary in loudness. I'll know Sunday morning when I play at the campgrounds, I guess... I usually had a ridiculous hum out there and the DB would be more fizzy on the top end.

What are you running your DB into? An amp, PA..? Power at campgrounds and other places may vary, may have grounding issues, over power, under power etc... uneven power. I don't see how the pedal would be changing but I do see how whatever you may be running it into could be!? Especially if you are running it into a tube amp!!! Those can be real moody depending on the humidity, heat, cold etc.. speakers also react differently to different changes in the air  as well.. That may not be your problem but worth considering? You may want to run your pedal on battery when playing out just to give it clean DC..?  

If you are going to be playin out at gigs you really need some sort of rack mount line conditioner like Furman or whatever...! You never know what kinda crap you are gonna be hooking into!?
http://www.zzounds.com/item--FURM8X2

[ghostsauce]

Hrm, that's a very good point.. I'm running it into a Marshall Class5, so I suppose it's quite possible. It's a great lil' amp but I'm still a bit of a noob when it comes to tube amps, as far as gigging them in different locations, etc. I've got a JCM900 that I've been using for a year, but this one has only started getting out of the basement in June.

It has been very hot and humid lately. I played the amp out there for all last week, and it sat under a sturdy roof, but exposed to the open air the whole time. It didn't seem to change much once it was out there, but every time I plug in for the first time out there it doesn't sound the same. I've also used it a two different churches recently and both times it kinda took all the guts out of the DB.


Oh wow, that power conditioner is amazing for the price! I'm so putting this on my Christmas wishlist.

[ghostsauce]

IT'S MY CABLE!

/facepalm!!!

I've been using a long cable at the campgrounds and a short one at home.. so just out of curiosity I plugged in the long cable and sure enough it sounds like crap again. Wow.. could this have been my problem? It's not even that it's got a bad connection, it just seems to suck all the tone out.. It makes my DB's gain knob act like a volume, and it sounds gated/farty at the same setting as the other cable.  I've been using this cable everywhere I took the amp in the last month, so one church and the campgrounds can all be accounted for with it.

It's probably a good 10 years old, and has probably been stepped on 195 too many times... wow. The newer cables I'm using seem to just transmit more signal.  Now.. I should probably just clip the ends off of the cable, throw them in a drawer and toss the rest right? I can't think of a way to salvage it without cutting it all to bits.

////EDIT: I should be more clear - the humming issues were not solved this way, only by using the 1spot could I resolve that. But this fixes the DB reacting differently.

[J0K3RX]

IT'S MY CABLE!

/facepalm!!!

I've been using a long cable at the campgrounds and a short one at home.. so just out of curiosity I plugged in the long cable and sure enough it sounds like crap again. Wow.. could this have been my problem? It's not even that it's got a bad connection, it just seems to suck all the tone out.. It makes my DB's gain knob act like a volume, and it sounds gated/farty at the same setting as the other cable.  I've been using this cable everywhere I took the amp in the last month, so one church and the campgrounds can all be accounted for with it.

It's probably a good 10 years old, and has probably been stepped on 195 too many times... wow. The newer cables I'm using seem to just transmit more signal.  Now.. I should probably just clip the ends off of the cable, throw them in a drawer and toss the rest right? I can't think of a way to salvage it without cutting it all to bits.

Yeah "good" cables are a HUGE part of your rig believe it or not! Good catch!