Hybrid Bass Amp

[LeftyStrat]

My father-in-law has commissioned me to build him a bass amp. He's looking for a combo. Rather than all tube I was thinking about a hybrid with a tube preamp, based on the Alembic FB-2, and one of these class D power amps:

http://www.parts-express.com/pe/showdet ... er=320-311

It would be 200 watts into 8 ohms.

Anyone have suggestions for a neo bass speaker?

And what kind of combo cab?

[Cliff Schecht]

Be weary of neo speakers, I've heard that they don't hold up well in high power situations. A buddy of mine has tried multiple brands in a BF Twin and has ruined everyone he's tried so far.

[LeftyStrat]

Thanks for the tip. I guess since I'm saving a lot of weight by going with a solid state amp, I could go with something more substantial.

[JazzGuitarGimp]

I noticed one of the listed features of the power amp is "click and pop" reduction. What could this mean? Is your father in law a funk, slap & pop player?

[LeftyStrat]

I noticed one of the listed features of the power amp is "click and pop" reduction. What could this mean? Is your father in law a funk, slap & pop player?

Old school rock and country, so more a muffled p-bass tone.

I doubt he'll ever to crank it very loud.

He could probably spend less money buying something off the shelf, but he enjoys having me build him things. I built him a plexi 50-ish inspired amp that he loves.

[Reeltarded]

I wonder how hard I can hit the inputs of these things.

[briane]

My father-in-law has commissioned me to build him a bass amp.

HEy lefty - if you want to go all tube I have an awesome bass build I use.

Its a 100-200 watt, SVT power section with cathode follower PI, and a variety on the 1986 bass frontend.

Give me a call if you want me to track down the layout or schematic - its pretty simple - and sounds awesome! And its been tested by bass players - who love it.

[LeftyStrat]

My father-in-law has commissioned me to build him a bass amp.

HEy lefty - if you want to go all tube I have an awesome bass build I use.

Its a 100-200 watt, SVT power section with cathode follower PI, and a variety on the 1986 bass frontend.

Give me a call if you want me to track down the layout or schematic - its pretty simple - and sounds awesome! And its been tested by bass players - who love it.

I'm going to talk to him some more. I was looking at the fEARful bass cabs, and they look interesting. Might talk him into a separate cab and head.

I also have a transformer out of an old Sunn bass amp. I think it might be a later Schumacher transformer, rather than a Dynaco, since it is grey and branded "Sunn 3-60T."

[Structo]

The fEARFUl cabs look like variations of the EV Thiele cabs.

Like the TL806 and other Thiele cabs.

Pretty expensive for what they are.

[LeftyStrat]

The fEARFUl cabs look like variations of the EV Thiele cabs.

Like the TL806 and other Thiele cabs.

Pretty expensive for what they are.

They're similar, only designed for a different speaker. There is one vendor that sells precut kits with biscuit slots already cut for around $150.

[roberto]

This is the first prototype I did for a friend of mine some years ago:

[img:600:450]http://a4.ec-images.myspacecdn.com/imag ... 946b/l.jpg[/img]

A scoop on mids rotary, a bright switch, one 12ax7, one IRF820 to interface with a class D switching supplied power amp. Around 300W on 4 Ohm.

Sounds very good. Just limit the output from the preamp to the poweramp (a voltage divider and some diodes will work).

[sparrott]

The above mentioned class-D module is from Sure which also sells on ebay heavily. The dip switches on the board sets the gain and headroom. I used these modules for a surround sound amplifier with success. The highest gain setting is around 0.6 V rms and the lowest is 1.5 V rms or so, but check the technical reference pdf for the board. You have to be careful clipping class D modules as it can cause output stage failures. There are some better modules for more money. Bang & Olefsun sell ICEPower modules that have built in switch mode power supplies as well as higher input headroom and lower gain so they will work well with many preamps. The diyaudio forum has an entire section on various class D discussions. The click and pop reduction pertains to powering up and powering down so you don't the nasty thump as the power supply drains.

[cpollack]

For a speaker / cab combo consider an EV TL606 cab with an Eminence Delta Pro 15A. I have an original EVM-15L in an Audio Centron-built TL606 and it is thunderous even with a 50 watt BF Bassman. I've seen the Delta Pro 15A suggested as an EVM replacement for bass applications. The cab is fairly portable. It could be easily modified into a combo cab by adding an amp enclosure on to the top. A Parts Express plate amp bolted to the back of the cab might even handle the power amp duties for you.

[bal704]

How much did you have to knock the signal down?

This is the first prototype I did for a friend of mine some years ago:


A scoop on mids rotary, a bright switch, one 12ax7, one IRF820 to interface with a class D switching supplied power amp. Around 300W on 4 Ohm.

Sounds very good. Just limit the output from the preamp to the poweramp (a voltage divider and some diodes will work).