Sammelbestellung Dexter's Preamp (Alembic F2B Clone)

Good morning guys,
A little update on the work i'm doing regarding the bass preamps. Right now the MK-1 V2 is out of the design state.
The V2 will keep the same tone quality (of course will keep the high-voltage design) but will have some new features that were asked by some bass players:
- -6db input pad
- bright switch
- high-cut switch
- -20db output pad
Soon the first prototype will be ready, until then just a little bit of sneak and peek on the PCB
BPRE_V1.png
 
I would like to see the deep switch (like fender baseman), too. Just one more 47nF capacity and of course a switch.
Are the Dipswitvhes only placeholder or do I have to open the case for adjustment?
 
@Willie - those are dip switches. Because of the small footprint is quite impossible to add toggle switches on the top end of the enclosure... so the MK-1 / V2 will have those controls inside.

Regards,
DeX

I would like to see the deep switch (like fender baseman), too. Just one more 47nF capacity and of course a switch.
Are the Dipswitvhes only placeholder or do I have to open the case for adjustment?
 
As i see the PCB is smaller than that what we have.
I just make the modification on mine and i think there is not plenty but enough room beside the lower 2 Pots to fit 2 switches on both sides.
But on the V2 PCB there are the jacks.
 
@Willie - the PCB on V2 is the exact (100%) dimensions with the V1 :-) I've kept the same layout, only the jacks are a little bit down, because i've used PCB mounted pots.
And between the pots there is some room but is very very tight and would violate some ... design rules.
 
Hi @DeXTeR
as you discribed > in the new PRE version all additional functions can be operated by using inside installed DIP switches.
What´s the plan to grant access to them ?
Maybe positioned holes on the backside/cover ??

My concern is the mechanical quality of those components.
 
@lila_vila - the access will be like when you change the tube, you put the lid out (4 screws) and you can change the settings. The quality is quite ok as the dip switches are made by omron and that basically dip switches are for this type of action.
There will not be any type of holes in the enclosure (except for the 3 ones that are on the side for vent).
Usually those settings are set and forget, and adding 4 switches on the top ... would be almost an impossible mission with this footprint.
 
@DeXTeR
ah, i understand.
Your idea is to install all components on "one" side.

What speaks against the idea to place all DIP switches opposite on the PCB ??
Drill holes on backcover exactly placed over the DIP Switches > for the user it´s not necessary to open the PRE.
You can see this style of "adjustment access" on many devices on the market.
 
That is correct, but high voltage and open holes is not something that i would do, dust ...moisture and other things can go inside and cause trouble...i will give it a thought.
But, on the MK-II all controls will be on the panel, but the footprint is bigger (twice as bigger than the MK-I)
 
@DeXTeR
maybee there is anough space to create some kind of plastic tube guided / protected access through the adjustment holes ??
Plasic tubes could be glued on backcover.

It could also be a kind of square plasic profil what you can find in most OBI or BAUHAUS shops
 

Hello guys,
I would like to ask an opinion from you all and see how it goes.
I had a discussion with @f_luxus and @lila_vila regarding the MID control on the preamp.
The MID control on this preamp at this particular time has a value of 250K (some Alembic F2B units were using this value), having this value on the MID pot would have the following consequences:
- in the first 10-15% of the MID pot, the MID pot will act like a normal MID pot, the rest of the travel will act like let's call it a gain pot that minimize the loss on the tonestack and that would give you a more raw sound, punchier and will increase the gain, but that also will have a downside: will minimize the effect of the treble pot (with the MID pot going over 50% the treble pot will not have a lot of influence on the sound)
The original Fender / Marshall amps are using 10K to 25K as a MID pot.
The question is this: would you like it like it is now or would you like it with a 10K MID pot (that would take the grit a little bit as the loss would be bigger in the tonestack)
Thank you for taking the time to read this and answering.

Regards,
DeX
 
I think it shouldn't be an big issue to announce with the order the preferred Tone Stack configuration > why not ?
 
Ist jemand so nett und klärt mich Unwissenden im Fachenglisch auf, was Dex da mit dem Update vorhat?
Handelt es sich um deinen gleichen Preamp, den wir erhalten haben oder um ganz was Neues?
Ich verstehe da nur ungenügend, was ihr redet.
Danke! :-)
 
Hallo @bassdscho, es wird eine MK2 Version geben die etwas anders aufgebaut sein wird.
Außerdem wird die MK1 Version noch mit dem Brightcap-Switch und einem -10dB Eingangswiderstand ausgerüstet werden.

Der MK2 Preamp wird teurer sein und eine andere Klangreglung haben, so wie die Möglichkeit bestimmte Voreinstellung mithilfe eines Dip-Switches im Inneren voreinzustellen ohne am Preamp rumlöten zu müssen.

Das klassische Tonestack wird so wie es immoment aussieht bis auf den Mid Poti weichen, während es stattdessen ein parametrisches Band geben wird, ebenso wird eine DI Box integriert sein.
Es wird der moderne große Bruder des "normalen" Preamp sein. Der klassische Preamp wird weiterhin erhältlich sein.

Die Frage die Dexter gestellt hat, war ob er den Wert des Mid Potis beibehalten soll.
Der 250k sorgt dafür dass man ziemlich weit zurückschrauben muss um überhaupt was von den Höhen regeln zu können, andererseits fungiert er ab 11 Uhr ca. als eine Art Midgain, was meiner Meinung nach auch den guten Klang des Preamps fördert.
 
Mit meiner Wortmeldung habe ich lediglich gemeint, dass der Kunde bei der Bestellung vorgibt ob er den F2B Tonestack (So wie jetzt erhältlich) oder eventuelle die Fender Dual Show/Bassman Variante haben möchte.
 

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