Xotic - AC Booster [ goop-alarm ]  [traced]

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quaternotetriplet
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Post by quaternotetriplet »

dont mind this pcb. there is a thread and someone posted a link. i think its on rc booster layout thread.

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Silent Fly
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Post by Silent Fly »

As far as I can understand, the IC should be the JRC4558D (?)

Does any one know the transistors? Someone said could read them...

Last but not least... can someone help me find a verified-ish schematics?

Thanks
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The Rotagilla
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Post by The Rotagilla »

Silent Fly wrote:As far as I can understand, the IC should be the JRC4558D (?)
The IC is believed to be a JRC4557D
The television will not be revolutionized.

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Silent Fly
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Post by Silent Fly »

The Rotagilla wrote:
Silent Fly wrote:As far as I can understand, the IC should be the JRC4558D (?)
The IC is believed to be a JRC4557D
That is what I though but I googled it and I got no results for JRC4557D :scratch:

Banzai stocks the JRC4558D and the higher gain version (JRC4558DD) though. JRC4557D or JRC4558D probably it doesn't make a huge difference.

I was more interested in the transistors... I gather nobody knows for sure.
"Remember - all I am offering is the truth, nothing more". Morpheus

lynessmy
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Post by lynessmy »

I build this with the info /sch shared by KUSI together with some folks posted here earlier....the transistor i used is 2sc1815. It work for me.
I'm using 4557 from NEC.

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Silent Fly
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Post by Silent Fly »

lynessmy wrote:I build this with the info /sch shared by KUSI together with some folks posted here earlier....the transistor i used is 2sc1815. It work for me.
I'm using 4557 from NEC.
[smilie=thanks.gif]

(I think the NEC version is the UPC4557)
"Remember - all I am offering is the truth, nothing more". Morpheus

Spazzmatazz
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Post by Spazzmatazz »

What's the difference between AC and RC booster??

is the AC booster layout verified?
is there any layout for the RC?

thanx

Spazzmatazz
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Post by Spazzmatazz »

Done! Find it other way.

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Post by pedjoh10 »

Hi, I've searched for the answer but no luck...
So, WHY do they bias the input trannie to 3 volt instead of 4.5? That would certainly give the circuit more headroom, or
are they just after the effect of an early clipping in the trannie?
Otherwise I would have guessed that the input T was a FET but it's not as it seems...

Would really appreciate some light on this...:)


//Peder

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Silent Fly
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Post by Silent Fly »

pedjoh10 wrote:Hi, I've searched for the answer but no luck...
So, WHY do they bias the input trannie to 3 volt instead of 4.5? That would certainly give the circuit more headroom, or
are they just after the effect of an early clipping in the trannie?
Otherwise I would have guessed that the input T was a FET but it's not as it seems...

Would really appreciate some light on this...:)


//Peder
I posted the same question a while ago (I can't find the original post) but as far as I can remember nobody could find any reason.

In theory the bias should be V/2 + 0.7V. I would understand if the bias was higher than 4.5V. Personally, I would have used a jFET at 4.5V.
"Remember - all I am offering is the truth, nothing more". Morpheus

pedjoh10
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Post by pedjoh10 »

Thanx for answer Silent Fly!
Well, that just confirm my thoughts more and more....could it be that this company just have cloned another pedal which is in fact is
using a FET at input and missed (?) that they use a bipolar? Bipolar's do work better at 1/2 vcc, but since they have copied the Boss FA-1 almost right off
(all they have added is the discrete output and another diode-layout) they simply forgot this?
I don't know.....;)


//Peder

pedjoh10
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Post by pedjoh10 »

also, can anyone confirm that this box is really 1.98" high? or is that including the plastic/rubber feet?

Thanx!
//Peder

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Post by Roa »

Hey I say I would but I never did put the transistors for AC and RC booster. There are 3 transistors and the ones close to the jacks are the kind C1815. I hope that helps someone out. Take care!

newly
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Post by newly »

With all other knobs at noon, Where did your build found the unity gain?
I found mine only happened after 9 or even max if the tone (T & B) knob is a tiny bit lower.
Is that normal?

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Post by gitaar0 »

Hi,

Anyone any experience with the perf board version posted in thie thread?

I build it. As fas as I can see the layout is corresponding to the posted schematic. It works but it sounds very dark.
Lots of bass and little high's.

Any suggestions or remarks?

Thanks, Marc

teddybear
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Post by teddybear »

gitaar0 wrote:Hi,

Anyone any experience with the perf board version posted in thie thread?

I build it. As fas as I can see the layout is corresponding to the posted schematic. It works but it sounds very dark.
Lots of bass and little high's.

Any suggestions or remarks?

Thanks, Marc
yes, ac like that kind sound.

SPeter
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Post by SPeter »

gitaar0 wrote:Hi,

Anyone any experience with the perf board version posted in thie thread?

I build it. As fas as I can see the layout is corresponding to the posted schematic. It works but it sounds very dark.
Lots of bass and little high's.

Any suggestions or remarks?

Thanks, Marc
http://proguitarshop.com/store/effects- ... oost-p-643

:)

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Post by gitaar0 »

[quote="SPeter"][quote="gitaar0"]Hi,

Anyone any experience with the perf board version posted in thie thread?

I build it. As fas as I can see the layout is corresponding to the posted schematic. It works but it sounds very dark.
Lots of bass and little high's.

Any suggestions or remarks?

Thanks, Marc[/quote]

http://proguitarshop.com/store/effects- ... oost-p-643

:)[/quote]
Thanks for reacting but the link confirms (as far as you can really tell from a Youtube movie) that either I have done something wrong or the schematic or layout is not correct. The Ac booster I build is really different. Darker almost muffled.
Did anyone build it frome the posted perf layout?

Marc

gitaar0
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Post by gitaar0 »

I worked some more on the AC booster as build according to the perf layout.

I changed C4 (.1uf) to 10nf and now it has a much better frequency range.
I would recommend putting C4 on a socket so you can adjust it to your taste.

Marc

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Post by cAMPus »

Hi,

anybody seen a pcb layout for the AC booster?
I didn't find any that was said to be verified.

Anyway: I made one with eagle that can be used for the AC booster and the RC booster as well (not verified yet).

If one would take a look at ...

Ulrich
Attachments
xotic-ac-rc-booster_layout.png
xotic-ac-rc-booster_schematic.png

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