DIY bass preamp ?

[Geoff Wood]

Anybody know of kits or PCBs available for a straightforward solid-state bass preamp to build into a combo cabinet (I have an ICEPower 500A power module without a home !) ? Input with active/passive sensitivity switch, 4-band Low/Low-Mid/Hi-Mid/Hi EQ, and maybe compression ?

I could design or clone one myself, but too lazy and life's too short.

 

[Passinwind]

Anybody know of kits or PCBs available for a straightforward solid-state bass preamp to build into a combo cabinet (I have an ICEPower 500A power module without a home !) ? Input with active/passive sensitivity switch, 4-band Low/Low-Mid/Hi-Mid/Hi EQ, and maybe compression ?

I could design or clone one myself, but too lazy and life's too short.

Last time I checked there was still no PCB yet, but this is a pretty great jump off spot: Bass Guitar Amp 1

 

[Geoff Wood]

Thanks for the link, fantastic, but no PCB.

WRT you username, one band name I thought of was 'The Sphinctones' ;- )

 

[Passinwind]

Thanks for the link, fantastic, but no PCB.

I've used Rod's Project 27 and Project 94 board for bass preamp builds, both worked really well. P27 is essentially an impedance scaled Fender tone stack and P94 is Baxandall-ish. One of my DIY amp builds used the 500ASP module too, like so: A DIY 500 Watt Bass Head

For me rolling my own PCBs was just an inevitability. I'd love the re-do the one in that thread using SMDs and 21st century parts eventually, and maybe open sourcing it like some of my onboard electronics projects, but providing tech support to DIYers is a huge commitment that I'm not sure I can make at the moment.

 

[Roxbororob]

This might be of interest
360+ DIY Kit -
Been around for a while & proven. It's even been copied.

 

[spencejm]

If you haven’t already, you might want to check out Diyaudio. It’s mostly hi-fi stuff but they do have a forum for instrument amps. I think a lot of that is people messing with commercial amps but I would guess if there are any kits or boards out there, someone on that forum will know. I’m actually working on my 2nd audio amp that I built from their kits.

Joe

 

[Passinwind]

If you haven’t already, you might want to check out Diyaudio. It’s mostly hi-fi stuff but they do have a forum for instrument amps. I think a lot of that is people messing with commercial amps but I would guess if there are any kits or boards out there, someone on that forum will know. I’m actually working on my 2nd audio amp that I built from their kits.

Joe

Those guys seem to send people over here pretty regularly, FWIW. But I haven't been hanging there much for the last few years and certainly may have missed some relevant posts.

 

[Geoff Wood]

This might be of interest
360+ DIY Kit -
Been around for a while & proven. It's even been copied.

Looks possibble, but little info on what the 'Variamp' actually does over its range, and 'blend' (blend the effected 'Variamp' with the vanilla signal I guess. Would prefer something with a lo-mid and hi-mid EQ as well...

Might give it a try for $35 ...

 

[Geoff Wood]

Last time I checked there was still no PCB yet, but this is a pretty great jump off spot: Bass Guitar Amp 1

Perfect functionality, but I checked with ESP and sadly no plans for a PCB ;- (

 

[Roxbororob]

Looks possibble, but little info on what the 'Variamp' actually does over its range, and 'blend' (blend the effected 'Variamp' with the vanilla signal I guess. Would prefer something with a lo-mid and hi-mid EQ as well...

Might give it a try for $35 ...

The variamp is a reproduction of a feature on the original Acoustic 360 preamp. Its a 5 position, selectable range, cut/boost EQ (screen shot from OEM manual below). The blend is for the fuzz circuit, its an option that was not on the original.

 

[Geoff Wood]

The variamp is a reproduction of a feature on the original Acoustic 360 preamp. Its a 5 position, selectable range, cut/boost EQ (screen shot from OEM manual below). The blend is for the fuzz circuit, its an option that was not on the original.

View attachment 4671406

Ahaa - thanks for that. It would at least partially fulfill my needs. Maybe tack a comp on the end ...

Will order a PCB, and suggest that thhey put a bit more detailon the web-page.

geoff

 

[Steve Dallman]

I’ve used a couple of these. There seems to be some limiting when the overload light goes on. My only niggle is the 10k input impedance, but adding an input buffer is pretty easy.

Guitar/Instrument Pre-amplifier With 4 band Tone Control+Over Load Led | eBay

 

[agedhorse]

IMO, 10k input impedance is a non-starter with a passive pickup, and even some active pickups.

 

[beans-on-toast]

Not solid state but you could replace the tubes with transistors. See the Ampeg SBT schematic.

DIY bass preamplifier in the Ampeg SVT tradition


[Invalid or Expired Link Removed]

 

[fdeck]

Who needs a circuit board?
https://bassisttech.github.io/JFET-bass-preamp/index.html
Unfortunately, those JFETs have become hard to get, and I haven't tried building this circuit with surface mount types that are still available. It doesn't really have a use in my gigging life right now, so I haven't put a lot of miles on it.

 

[basscooker]

You could use that ice unit for small form general purpose power amp. No knobs...
Input impedance selector, hpf selector, A/C input, power switch, TS input, two NL-4. Done. Over-engineer the enclosure, use louvered venting for cooling (spills wash down and don't get in).

Call it the Grunt Runt. Send the info to a contract manufacturer. Blam you're a bajillionaire.

.....ooooor maybe just go with what the smart fellas above said. Prolly work out better.

 

[PeaveyPlayer]

I’d love if someone made an ampeg Pro 6 diy preamp

 

[byacey]

IMO, 10k input impedance is a non-starter with a passive pickup, and even some active pickups.

That looks like a Hifi preamp that they are trying to market to the MI crowd.

 

[PeaveyPlayer]

I was also looking a trying my hand in designing a preamp…

but not sure where to start?
Anyone have any advice

do I start with a schematic to copy?

 

[agedhorse]

I was also looking a trying my hand in designing a preamp…

but not sure where to start?
Anyone have any advice

do I start with a schematic to copy?

Best to start with an electronics education IME.