Building an amplifier. Class D.

[NancyJohnson]

I have a question (or ten).

 

I'll admit that for a while I've not been 100% happy with my head (Darkglass AO900); I mean it's certainly got more than enough oomph, but the drive element is too aggressive. 

 

In my head, my ideal is a one box solution of a small chassis class D amp with a similar/adequate output to the AO900 with a Sansamp BDDI at the front end; following a thread elsewhere, I'm actually giving some thought to getting something built.

 

Spec-wise, I'd be happy with all the controls and input jack on the top (similar to the Victory Kraken units) and round the back, 240v in,  a single Speakon output and an XLR/DI output.  As the pre-amp/BDDI will always be on and I don't use any outboard stuff, there's be no requirement for effects sends/return, aux inputs.   As an afterthought an always on tuner might be nice.

 

Looking around, there does seem to be a few BDDI clones about, but to be honest, if it's as easy to facilitate, I'd be OK butchering a Sansamp for it (so getting the top fascia laser cut so the unit simply bolts in and is always on).  Obviously if the unit is having holes laser cut, it's a no brainer to get the control function laser etched as well.

 

Is this all feasible?  Where do I start?

 

 

 

 

[nekomatic]

Well. You can buy yourself an ICEpower Class D module from Profusion in the UK and some of them are all-in-one units that simply need connecting to line level input, speaker output and mains power, but the thing that would (and has) put me off a DIY with one of these is the thermal design - I assume commercial designers using these modules will have done proper engineering calculations and maybe simulations to verify that the thing won't overheat under the expected use conditions, or at least they will have built up experience of what they need to do in practice, but I don't have either the knowledge to do that or the time and money to figure it out - and you don't want to worry that your homebuilt amp is going to crap out on you on a gig.

 

How about building the preamp stage in a case that would stack neatly on top of a GR Bass Pure Amp 800 - which has a 9 volt power output so you'd only need the one mains lead to power the combination?

[Dan Dare]

2 hours ago, nekomatic said:

Well. You can buy yourself an ICEpower Class D module from Profusion in the UK and some of them are all-in-one units that simply need connecting to line level input, speaker output and mains power, but the thing that would (and has) put me off a DIY with one of these is the thermal design - I assume commercial designers using these modules will have done proper engineering calculations and maybe simulations to verify that the thing won't overheat under the expected use conditions, or at least they will have built up experience of what they need to do in practice, but I don't have either the knowledge to do that or the time and money to figure it out - and you don't want to worry that your homebuilt amp is going to crap out on you on a gig.

 

How about building the preamp stage in a case that would stack neatly on top of a GR Bass Pure Amp 800 - which has a 9 volt power output so you'd only need the one mains lead to power the combination?

 

Great advice. ICEPower, Hypex and similar quality modules aren't cheap, either, so you're unlikely to save a lot by going the DIY route. Selling it on could be tricky, too. GSS power amps are essentially class D modules in a box. I'd be inclined to look at one of theirs.

[NancyJohnson]

2 hours ago, nekomatic said:

Well. You can buy yourself an ICEpower Class D module from Profusion in the UK and some of them are all-in-one units that simply need connecting to line level input, speaker output and mains power, but the thing that would (and has) put me off a DIY with one of these is the thermal design - I assume commercial designers using these modules will have done proper engineering calculations and maybe simulations to verify that the thing won't overheat under the expected use conditions, or at least they will have built up experience of what they need to do in practice, but I don't have either the knowledge to do that or the time and money to figure it out - and you don't want to worry that your homebuilt amp is going to crap out on you on a gig.

 

How about building the preamp stage in a case that would stack neatly on top of a GR Bass Pure Amp 800 - which has a 9 volt power output so you'd only need the one mains lead to power the combination?

 

It's surprising how when you get an idea in your head how quickly you start accumulating intel.  I've already skirted around the Profusion site.

 

[Bolo]

Hot-glue a sansamp to the gss (baby) sumo. Done.

[Downunderwonder]

You could put a RBI combo style in the front or top-back of the speaker box and strap any little class D amp with fx loop to the top, or even always on inside the box.

 

All power wired from the one jug cord socket input.

 

RBI xlr out.

 

Your choice if the cab has a speakon parallel AMP out or not but you wouldn't ever plug another amp into it.

[Phil Starr]

We've been looking at designing a self build BC design active speaker for a while and there is no real shortcut or financially sensible way of going about this that we have found. The cheap chinese amp modules are just a lottery to buy, quality of fitted components is usually poor and very variable anbd quality control seemingly non-existent. They do make high quality reliable amps too but these are approaching the cost of the ICE Power amps. @Chienmortbb is our expert in this area.

 

I concluded that the cheapest way of getting this power was to buy a PA amp and build it into a speaker and I've experimented with using this approach with multi-way speakers both for PA and for bass. You can certainly drive them directly from a SansAmp. I've also considered just ripping the plate amp off an active speaker whose drive units/speakers have died. The other alternative would be to use something like a Bugera Veyron as a pedal board amp with the SansAmp feeding into the aux input.

[bremen]

I've been using Connex class D amps and smps without issues; they are made in China but the owner of the company has always helped when I've asked for help.

 

This was a few years ago though, and whether his customer service is currently scintillating or dismal very much depends on which online review you read.

 

https://connexelectronic.com/

[Passinwind]

3 hours ago, Phil Starr said:

We've been looking at designing a self build BC design active speaker for a while and there is no real shortcut or financially sensible way of going about this that we have found.

I'll be doing one for myself quite soon, but mainly for acoustic guitar. Supporting ground-up DIY active speaker builds for others would be utterly daft in my case, simple pedals are already a huge hassle.😉

[Owen]

Do you deeply love your present cab? I put a preamp into an active PA cab and could not be happier. 

[joel406]

Who uses amps anymore?

[tauzero]

5 hours ago, joel406 said:

Who uses amps anymore?

 

You were just as tedious the last time you started this off.

[crazycloud]

Buy a HB Block 800B and go into the FX return from the BDDI. Uses an Icepower 700AS module. No fabrication or soldering needed, working within 10 mins of the parts arriving and has resale. And this is from an EE who can, and does, design a lot of electronics; current project is a pair of 3 way bass (guitar) speakers and a very large 10ch Hypex NCore powered hi-fi system.

[Tech21NYC]

22 hours ago, joel406 said:

Who uses amps anymore?

Most people on this side of the pond. When you play without an amp you are totally at the mercy of the sound tech. Live sound mixing is a skill that takes years to master. I saw a 10 piece band over the weekend. Guitar, bass drums, percussion, horn section, 2 keys and vocals. The guitarist and keyboard player both went direct without stage amps, bass player had an amp. The guitarist had two sounds off and kind of sorta could hear him. The keys were anemic. The bass player sounded great. Just sayin'

[bremen]

5 minutes ago, Tech21NYC said:

When you play without an amp you are totally at the mercy of the sound tech

I endured a gig not long ago where no-one had their own amp: guitar, bass, vocals, backing track. You couldn't actually hear which note the bass was playing. Sound guy spent most of the gig in headphones.

 

Kick drum was lovely and loud though.

[Chienmortbb]

18 hours ago, bremen said:

Kick drum was lovely and loud though

As ever, the first lecture on the Sound Tech Course is obviously Kick Drum and they drop out after that. In saying that I saw a Soul band, 9 piece  laat year at my local British Legion. The sound tech used an iPad to mix and was continually listening form all angles and occasionally making small tweaks. Best live sound I have hear except for Black Country Communion at the Hammersmith Odean (can't be assed to check on it's current name). 

Edited September 27 by Chienmortbb

[Tech21NYC]

20 hours ago, bremen said:

I endured a gig not long ago where no-one had their own amp: guitar, bass, vocals, backing track. You couldn't actually hear which note the bass was playing. Sound guy spent most of the gig in headphones.

 

Kick drum was lovely and loud though.

 

The sound tech that our band hires to setup the PA and mix works for a large sound company in NYC. He tells us that most sound techs don't even "mix", they set levels and that's about it. We've been on shows where the supplied sound tech is sitting by the mixer playing with his phone... This is not to say that all sound techs are clueless but just like many musicians on the aggregate they are mediocre at best.

 

Our band brings our own monitor mixer so at least we don't have to depend on supplied sound for that. 

[orangepeelneil]

Hi,

 

I’ve put together a few DIY amps using class D modules with a simple preamp or as you suggest a something like a Sansamp as a preamp would work fine. 

 

You can purchase a simple Class D IC and module for tens of pounds on ebay/Amazon/Aliexpress etc to do have a try. 

 

As mentioned, cooling is very important, good electronics “best practice” for minimising noise and last but not least power supply consideration..

 

You may need a DC bipolar +/- 30V  —>  +/- 100V at several Amps (at least) to power the class D module (depending on type) most of the class D OEMs go for switch mode PSU for this. 

So check the spec of the module you a planning to buy and confirm you have a suitable PSU or it has a PSU onboard so you can connect 230V AC mains directly to it. 

 

Years ago I experimented with the IRS2092 which can deliver 350W+ into 8 Ohms, this guy is really good to watch ... 

 

 

 

If I can find my modules in the shed, I’ll take some photos, I just screwed to a bit of ply with a simple preamp as as above DC PSU. Worked better than expected, but I never got around to putting it in an enclosure…. Life got in the way

 

 

 

Thanks Neil 

Edited September 28 by orangepeelneil

[bremen]

The connex ones I use are IRS2092 based. Haven't managed to kill them yet. Top tip for cooling: bigger fans are quieter for a given airflow.

 

I also got a super cheap one similar to the one Neil pictured from Fleabay, terrible construction quality and over a volt switching noise at the output. I definitely wouldn't trust it at a gig.

[Beer of the Bass]

On 25/09/2024 at 17:14, bremen said:

I've been using Connex class D amps and smps without issues; they are made in China but the owner of the company has always helped when I've asked for help.

 

This was a few years ago though, and whether his customer service is currently scintillating or dismal very much depends on which online review you read.

 

https://connexelectronic.com/

 

I have a Connex power amp module and power supply that I bought a few years ago and never quite got around to doing anything with. I never managed to get even a basic spec sheet for it from them, stuff like input impedance and sensitivity, cooling requirements etc. Literally the modules in a box with no info even when I emailed them asking for it. The website still says "more details soon" for that model, and it must be getting on for 10 years.

Edited September 28 by Beer of the Bass

[Chienmortbb]

On 28/09/2024 at 12:08, Beer of the Bass said:

 

I have a Connex power amp module and power supply that I bought a few years ago and never quite got around to doing anything with. I never managed to get even a basic spec sheet for it from them, stuff like input impedance and sensitivity, cooling requirements etc. Literally the modules in a box with no info even when I emailed them asking for it. The website still says "more details soon" for that model, and it must be getting on for 10 years.

What module is it?

[Beer of the Bass]

41 minutes ago, Chienmortbb said:

What module is it?

 

It's this one, 600 watt version, plus the recommended power supply. I'm sure it'll be fine if/when I get around to doing something with it, but a succession of house moves and band changes disrupted what projects I'd been getting up to.

 

https://connexelectronic.com/product/irs2092-modular-amplifier/

Edited September 29 by Beer of the Bass

[bremen]

I'm sure it will be fine, your experience of Cristi's customer service is quite common, we eventually had some useful conversations.

 

Which power supply do you have?

[Beer of the Bass]

19 hours ago, bremen said:

I'm sure it will be fine, your experience of Cristi's customer service is quite common, we eventually had some useful conversations.

 

Which power supply do you have?

 

I'd have to check, it's the one they recommended with it, one of the SMPS800 variants. Amidst all the "heft" discussions on bass forums I liked the concept of using a more than ample power supply.

[JPJ]

On 25/09/2024 at 13:41, Phil Starr said:

I've also considered just ripping the plate amp off an active speaker whose drive units/speakers have died.

You don’t have to rip one out of a dead box. When the amp blew in one of my EV ZX15’s I was able to source a complete new plate amp (including the dsp) for around £250. Not sure what the crossover point is, but I have used one of my ZX15’s as a bass monitor driven by my EBS Stanley Clarke pre and it sounded great.