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Group buy: α20 (formerly JISBOS)

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Group buy: α20 (formerly JISBOS)

Postby amb » November 6th, 2010, 5:03 am

Introduction

JISBOS (JFET Input Stage, BJT Output Stage) was best known as an upgrade output buffer for the SOHA-1 headphone amp (even though it was designed to be general-purpose). I designed the circuit but Steinchen gave it the name, tested it with the SOHA-1 and created the website.

Due to the association with SOHA-1, as the SOHA-1 fell out of favor so did the JISBOS. I discontinued the JISBOS due to low demand a little over one year ago.

As demonstrated with my new α10 preamp (pic gallery), JISBOS is an excellent unity-gain buffer stage for many uses. Some of you have expressed an interest in also building the α10.

So, I would like to "revive" the JISBOS and make it available again. I have upgraded JISBOS to add the option of voltage gain, so it is no longer just a unity-gain buffer (but unity gain is still supported). The new board is called α20 ("alpha 20"), and becomes an even more versatile little line stage module. The PCB dimensions, mounting holes and input/output/power supply terminals are unchanged from JISBOS v1.01, so α20 is plug-compatible. See the full announcement in this thread.

I don't know what the demand will be. Rather than just stocking up on them, I'll first try it as a group-buy.

α20 is one board per channel, so you need two boards for stereo. You could also build 3-channel "active ground" or 4-channel balanced configurations with three or four boards, respectively. The α10 preamp uses two boards.

Notes

- Dec 19, 2010: Boards have been shipped to participants.
- I will update this post with any news and updates.

Participants

id | # boards | notes
---------------------------
amc | 6 | shipped
Andersonix | 4 | shipped
Anonanimal | 4 | shipped
bada bing | 8 | shipped
beerad | 4 | shipped
Billyk | 6 | shipped
bk_856er | 6 | shipped
Blackbird09 | 15 | shipped
blip | 4 | shipped
deathg0d | 5 | shipped
DorkVader | 6 | shipped
dougigs | 2 | shipped
dwhat | 4 | shipped
Ferrari | 10 | shipped
fishski13 | 4 | shipped
Forte | 6 | shipped
giulio | 4 | shipped
goldkenn | 4 | shipped
grenert | 4 | shipped
hagak | 6 | shipped
hsyoo125 | 5 | shipped
Iniamyen | 4 | shipped
JamesL | 4 | shipped
jdkJake | 4 | shipped
jhead | 4 | shipped
jlefley | 6 | shipped
jpayton | 4 | shipped
jtostenr | 4 | shipped
K3cT | 4 | packing
knorthover | 2 | shipped
linux-works | 6 | pending
ltmon | 2 | shipped
Marcus | 12 | shipped
MASantos | 10 | shipped
mattcalf | 4 | shipped
MiniMe | 2 | shipped
MisterX | 6 | shipped
Nebby | 10 | shipped
onyu | 6 | shipped
particleman14 | 6 | shipped
Rabbit | 4 | shipped
sandbasser | 4 | shipped
Serenity | 6 | shipped
sds | 4 | shipped
Shaman | 4 | shipped
squiregeoff | 6 | shipped
suicidaleggroll | 6 | shipped
ujamerstand | 6 | shipped
unmatched | 4 | shipped
Viking87 | 4 | shipped
vixr | 6 | shipped
vt67 | 4 | shipped
wata | 4 | shipped
xt0rted | 6 | shipped
zaubertuba | 20 | shipped
----------------------------
total | 305

Dropped from group-buy due to non-payment

barkas | 4 | unpaid
Lil' Knight | 4 | unpaid
----------------------------
total | 8


Last update: Dec 21, 2010
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Re: Interest check: JISBOS

Postby Lil' Knight » November 6th, 2010, 5:12 am

I'm in for 4.
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Re: Interest check: JISBOS

Postby Billyk » November 6th, 2010, 5:20 am

I would like 4 please.
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Re: Interest check: JISBOS

Postby hagak » November 6th, 2010, 6:07 am

I am in for 4
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Re: Interest check: JISBOS

Postby Ferrari » November 6th, 2010, 7:11 am

I will take 10 boards.
Thanks for organizing this, Ti.
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Re: Interest check: JISBOS

Postby knorthover » November 6th, 2010, 8:02 am

2 boards for me
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Re: Interest check: JISBOS

Postby linux-works » November 6th, 2010, 8:05 am

put me down for 4 boards just to keep onhand ;)
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Re: Interest check: JISBOS

Postby MiniMe » November 6th, 2010, 10:30 am

2 for me
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Re: Interest check: JISBOS

Postby DorkVader » November 6th, 2010, 11:59 am

Edit: In for six.

I'm convinced you can never have enough of these, and am planning accordingly.
Last edited by DorkVader on November 21st, 2010, 9:19 pm, edited 2 times in total.
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Re: Interest check: JISBOS

Postby Blackbird09 » November 6th, 2010, 1:16 pm

I'll take 6-10 depending on the price.

Edit: Will these be updated with a configurable gain?
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