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Hoffman Amps Forum image Author Topic: Do I need a coupling cap on the output of this circuit?  (Read 2280 times)

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Offline markmalin

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Do I need a coupling cap on the output of this circuit?
« on: January 08, 2019, 06:28:11 am »
Hey all,


I've built this pedal which is the "183" D-style pre-amp. I don't have an accurate schematic drawn yet, but here's a hacked up schematic if you'll ignore the power section.  I have implemented my tube pre-amp pedal pretty much just like this, except with a bypass DPDT switch.  My question is, do I need a cap before the output to bock DC?  I've been running it as-is and it works fine, but woke up in the middle of the night thinking "dang! I think I need something to block DC on the output before going in to an amp input!"


Humbly,
Mark
"... there are Flying V's and then there are the ones shaped like peanuts..."  - my son at age 9

Offline sluckey

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Re: Do I need a coupling cap on the output of this circuit?
« Reply #1 on: January 08, 2019, 06:40:57 am »
No need for a cap. C10 and C16 have already blocked any dc from the output jack.
A schematic, layout, and hi-rez pics are very useful for troubleshooting your amp. Don't wait to be asked. JUST DO IT!

Offline markmalin

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Re: Do I need a coupling cap on the output of this circuit?
« Reply #2 on: January 08, 2019, 06:42:30 am »
No need for a cap. C10 and C16 have already blocked any dc from the output jack.


Thanks, Slucky. I'll go back to bed now :)
"... there are Flying V's and then there are the ones shaped like peanuts..."  - my son at age 9

Offline DummyLoad

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Re: Do I need a coupling cap on the output of this circuit?
« Reply #3 on: January 08, 2019, 07:04:31 am »
the fuse block - zip tied to a filter cap... lol!


--pete

Offline markmalin

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Re: Do I need a coupling cap on the output of this circuit?
« Reply #4 on: January 08, 2019, 07:16:21 am »
the fuse block - zip tied to a filter cap... lol!

--pete


I know, I know...I was impatient to get it up and running and there's so little room in there!  lol.
Here - I'll post a picture of the "other side" to redeem myself...
"... there are Flying V's and then there are the ones shaped like peanuts..."  - my son at age 9

Offline markmalin

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Re: Do I need a coupling cap on the output of this circuit?
« Reply #5 on: January 08, 2019, 07:18:39 am »
so Pete....other than that, if you see anything blatantly stupid in there, please point it out!  I'm always open to advice :)  (just ignore the fuse for now!)
"... there are Flying V's and then there are the ones shaped like peanuts..."  - my son at age 9

 


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