After Eighty - Small Ashdown Combo On Steroids

[nilebodgers]

8 minutes ago, Passinwind said:

Agreed, but in many parts of the world including the US it would be sketchy to even publish anything with the usual SMPS supply format that so many Class D amps use. DIYaudio used to explicitly forbid it, not sure if they're still held to that or not though.

For my part, I'm deep into a tube bass amp build at the moment. Just about everything about it is a real shock after all the battery powered stuff I've been doing for the last few years, hopefully not literally though!

Yes, I was.a pro elec engineer and there is no way I’d go anywhere near an amateur designed SMPS, there are an large number of failure modes and non-obvious design considerations that can be traps for the unwary. Ditto with amateur class-d power amps.

[Chienmortbb]

I hope I did not suggest the use of some of the suspect eBay amplifiers and power supplies. I am only using ICEPOWER modules as they are properly certified for EMC/EMI and safety. 

My two concerns with ClassA/Band a linear Power supply  are excess weight and heat. Following the ICEPower Designers manual allows that. 

[Chienmortbb]

On 06/07/2020 at 22:36, stevie said:

Aha. Your link said £75, which is why I asked. 😄

Wrong link, here is the correct one https://www.stakesys.co.uk/hole-punches-hole-saws/q-max-cutters/q-max-cutter-round-metric

[Chienmortbb]

 @Passinwind and @nilebodgers have valid points above and I would hate to think I have encouraged anyone to rush headlong into building a low cost, home brew amp from modules purchased from Ebay, Ali Express or Bangood. I have added a safety warning to the first post. Please read it.

 

John

[nilebodgers]

2 hours ago, Chienmortbb said:

 @Passinwind and @nilebodgers have valid points above and I would hate to think I have encouraged anyone to rush headlong into building a low cost, home brew amp from modules purchased from Ebay, Ali Express or Bangood. I have added a safety warning to the first post. Please read it.

 

John

That's an unmissable warning!

The Icepower modules are a fantastic thing that solve all the issues with SMPS and Class D in one hit for an amateur designer. The only snag is the difficulty of getting ones with known provenance at a sensible price given how much fakery goes on.

[Chienmortbb]

8 hours ago, nilebodgers said:

That's an unmissable warning!

The Icepower modules are a fantastic thing that solve all the issues with SMPS and Class D in one hit for an amateur designer. The only snag is the difficulty of getting ones with known provenance at a sensible price given how much fakery goes on.

True. The prices charged by ProFusion in the UK are eye watering.
 

 

[Chienmortbb]

Painting has commenced. Three coats of Tufcab. 

Edited July 9, 2020 by Chienmortbb
Duplicated images

[Chienmortbb]

Thinking outside the box?

I was thinking about the port. I will not move it now but adding 600 grams to the from (the new speaketr is much heavier than the old) and taking out thetransformer and heatsink from the rear, the balance will have shifted forward. It may well be that I have to move the handle forward. That would have alloud the top port I had originally planned. I could also have put the handle(s)  front to back or even on one side.

Today I will check the paint job and decide whether I need another coat. If not, I will fit the port and connect the amplifier to hear the real sound of the new rig fo the first time.

[Chienmortbb]

The. cabinet is now complete and even SWMBO is impressed.

The last thing is the grille but as the new speaker is deeper than the original one, it has to be farther away. I Have an idea but will sleep on it.I also need to fit the cabinet corners if I can find the black wood screws. 

I have decided to replace the External Speaker Jack with a Speakon. I would have preferred the ext speaker connection to be on the back but I found I could cut the hole for a Speakon so that the legend is visible.  
So the only things on the rear panel are the male XLR out and the ground lift switch. All to be fitted tomorrow. Tomorrow.....I must stop promising progress the next day. Something always pops up but hopefully there will be progress today
 

Edited July 10, 2020 by Chienmortbb

[SpondonBassed]

10 hours ago, Chienmortbb said:

I must stop promising progress the next day. Something always pops up but hopefully there will be progress today

Although you have ten eager followers on this thread, none of us are cracking a whip... at least not in your direction.

[stewblack]

What a wonderful, fascinating and dare I say it beautifully quixotic build this is. 

I love the way we get to 'see' your thoughts and ideas as they form. 

And to get approval from She Who Must... Well, that in itself is a great achievement. 

Will the finished article be present at the Bass Bash? 

[Chienmortbb]

2 minutes ago, stewblack said:

What a wonderful, fascinating and dare I say it beautifully quixotic build this is. 

I love the way we get to 'see' your thoughts and ideas as they form. 

And to get approval from She Who Must... Well, that in itself is a great achievement. 

Will the finished article be present at the Bass Bash? 

Oh yes and as this project is a parallel project to the Active version of Stevie's 1x12 FRFR, most of the work I have done will find its way into that project ban hopefully that will be at the bash

At the moment the my lady is having coffee with a friend in the workshop AKA the conservatory so there is no progress although the DI board is out ready to have the phantom power protection mods fitted.

[stewblack]

God, you'd think she could find somewhere else to entertain other than your workshop. 

 

[stevie]

Very nice paint job.

[Chienmortbb]

Yes even her friend likes it.

[Passinwind]

On 08/07/2020 at 01:06, Chienmortbb said:

 @Passinwind and @nilebodgers have valid points above and I would hate to think I have encouraged anyone to rush headlong into building a low cost, home brew amp from modules purchased from Ebay, Ali Express or Bangood. I have added a safety warning to the first post. Please read it.

 

John

I wasn't calling you out in any way John, I think you're doing it just right. Rod is in a position of extreme responsibilty and potential liability, and he did offer a Class D module as part of one or more projects a few years ago, but apparently doesn't anymore. I've purposely kept a lot of details of my DIY builds a bit vague in forum posts, but as always I'm happy to share more in PMs.

I'm always surprised not to see more mention of Hypex. They make great sounding stuff and are happy to support DIY'ers fully. In the US the ICEpower rep is a great guy and has helped me a lot, but tech support comes from Denmark and  IME those guys are pretty much all business. They changed their presence at NAMM from a public booth to appointment-only in a private office this year and I can't say I blame them. My first module came from a gray market source (lightly used evaluation kit) and was pretty expensive, but the guy was very helpful and made me a nice cable set on his nickel. For the last three I called in favors, schmoozed the right people, and so on, and the price for 700ASCs was very reasonable.

[nilebodgers]

20 minutes ago, Passinwind said:

I wasn't calling you out in any way John, I think you're doing it just right. Rod is in a position of extreme responsibilty and potential liability, and he did offer a Class D module as part of one or more projects a few years ago, but apparently doesn't anymore. I've purposely kept a lot of details of my DIY builds a bit vague in forum posts, but as always I'm happy to share more in PMs.

I'm always surprised not to see more mention of Hypex. They make great sounding stuff and are happy to support DIY'ers fully. In the US the ICEpower rep is a great guy and has helped me a lot, but tech support comes from Denmark and  IME those guys are pretty much all business. They changed their presence at NAMM from a public booth to appointment-only in a private office this year and I can't say I blame them. My first module came from a gray market source (lightly used evaluation kit) and was pretty expensive, but the guy was very helpful and made me a nice cable set on his nickel. For the last three I called in favors, schmoozed the right people, and so on, and the price for 700ASCs was very reasonable.

The NC500MP OEM and NC502 MP OEM look interesting as integrated modules (having a separate psu like the others is a step backward IMO).

A quick google didn't reveal any street prices though.

[Passinwind]

5 minutes ago, nilebodgers said:

The NC500MP OEM and NC502 MP OEM look interesting as integrated modules (having a separate psu like the others is a step backward IMO).

A quick google didn't reveal any street prices though.

I believe the NC500MP OEM is the one my friend Jule Potter is using in his new "pedalboard" power amp. I'm in no hurry to do any more Class D builds but it could be fun to give a different brand a try eventually. That said, both the Icepower 500ASP and 700ASC modules were pretty easy to work with beyond the cable fabrication end, but even that just takes a few Web clicks and a few weeks waiting time under normal circumstances. I just got in an order for something else from that vendor in the ROC, it took about 5-6 weeks this time around.

[Mottlefeeder]

Apologies for the slight thread diversion, but are any of you Class D module users aware of a 50-100W Class D module with a separate power supply, and a 12V dc SMPS to suit, to allow something like a PJ briefcase design to be built. The nearest I have got is a car stereo booster amp  with a SMPS and a pair of bridged Class AB amps.

Thanks

David

[Chienmortbb]

9 hours ago, Mottlefeeder said:

Apologies for the slight thread diversion, but are any of you Class D module users aware of a 50-100W Class D module with a separate power supply, and a 12V dc SMPS to suit, to allow something like a PJ briefcase design to be built. The nearest I have got is a car stereo booster amp  with a SMPS and a pair of bridged Class AB amps.

Thanks

David

Can you explain what you are trying to do? Is it solely run on12V or dysl 230ac/12dc?

 

Edited July 11, 2020 by Chienmortbb

[Mottlefeeder]

21 hours ago, Chienmortbb said:

Can you explain what you are trying to do? Is it solely run on12V or dysl 230ac/12dc?

 

I'm hoping for something modular so that I can fit the amp into the speaker casing, and power it from 12 Vdc when there is no supply available, or 230 Vac when there is.

In the briefcase,  PJ drops the mains down to 12 Vdc and feeds that, or the battery into a +/-X volt SMPS to power his class D amp. On 12 Vdc you have one voltage conversion, but on mains you have two in a row. It's inefficient having two conversions, but with mains power it is not that important.

Looking at what is readily available, you can use a pure sine inverter with a 230 Vac rig, but that is one voltage conversion on mains, and two on battery, so it is inefficient and it is using up your battery power. As an example, my Ashdown MyBass Mk1 is Class D and with an inverter, it draws about an amp at 12 Vdc while idling, which is about a third of the capacity of an easy carry 7AHr battery. You can also use an automotive booster amp with an SMPS feeding a class AB amp, which  has a lower quiescent current, but takes more on peaks. In summary, an automotive class D amp fed from a 12 Vdc SMPS would be the optimal solution. Unfortunately they don't do them in smaller power output units, and with a bigger unit you are back into the wasted power problem again.

David

[Chienmortbb]

Yesterday I had some successes and a few issues. The Speakon fitted nicely  in the hole I cut with my new QMax cutter and I was so pleased with myself. That was until I tried to reinstall the power module. The Speakon was so tight on one of the coils that I dare not try that. So the Speakon had to be installed from the front. It covers the legend slightly and does not hide my drilling inaccuracies and does not look so good.
 

So I either accept it and move on or move the supports for the power board. If I do, I will lose the ability to install a fan if needed.  While I have tried to keep the thermal design that Ashdown employed, and that Class D is more efficient than Class AB, the static power consumption of the ICEPower  module is slightly higher than the original 15W amp. The difference is only likely to be a watt or two and I do have another fan option. Looking back, I should probably used the more powerful 125ASX2 module. It lends itself to static cooling  better than the 50ASX2. 

I will look at cooling and moving the module tomorrow. 

 

 

Edited July 11, 2020 by Chienmortbb

[Chienmortbb]

17 hours ago, Mottlefeeder said:

I'm hoping for something modular so that I can fit the amp into the speaker casing, and power it from 12 Vdc when there is no supply available, or 230 Vac when there is.

In the briefcase,  PJ drops the mains down to 12 Vdc and feeds that, or the battery into a +/-X volt SMPS to power his class D amp. On 12 Vdc you have one voltage conversion, but on mains you have two in a row. It's inefficient having two conversions, but with mains power it is not that important.

Looking at what is readily available, you can use a pure sine inverter with a 230 Vac rig, but that is one voltage conversion on mains, and two on battery, so it is inefficient and it is using up your battery power. As an example, my Ashdown MyBass Mk1 is Class D and with an inverter, it draws about an amp at 12 Vdc while idling, which is about a third of the capacity of an easy carry 7AHr battery. You can also use an automotive booster amp with an SMPS feeding a class AB amp, which  has a lower quiescent current, but takes more on peaks. In summary, an automotive class D amp fed from a 12 Vdc SMPS would be the optimal solution. Unfortunately they don't do them in smaller power output units, and with a bigger unit you are back into the wasted power problem again.

David

David I will reply later via pm so as not to clutter the thread. 

[Chienmortbb]

This morning I looked at the chassis and I have got room to move the power board about 10mm. That will allow the Speakon to be put inside and will make a much neater job. 

I have also found some pcb built power regulators that I could use instead of the lash-up I built. It would look neater but it is more work as they are designed to take ac in and I would need to remove some components. I will think about that some more.  
 

To get a feel for the cabinet( I have heard the amp part through another speaker) I decided to connect it to my Bugera Veyron. Plugged my bass in and .,,,  chuff chuff chuff. There was a noise when I played most of the E String on my bass. Went to bed feeling grumpy ( put your own punch line here).

The picture above shows the top of the cabinet. This morning I was determined to find out what was causing the noise so hit the cab and amp put again and using a signal generator app on the iPad, fed various frequencies to the cab. The noise was worse at 42Hz, approx Low E. I remembered we had a similar problem on another cab that turned out to be the jack socket. 
 

A ported or tuned cab is designed to have a hole in it called the port. The port is not seen as a hole by the speaker, more like  spring and so at most frequencies the cabinet is effectively sealed. However even a small hole like a jack socket with no plug in. or the handle mounting holes ( look closely at the picture above) can ruin the seal and sound. Putting a thumb over each of those two holes got rid of a lot of the chuffing. Next step, install handle.
 

 However was still some noise and I am in the process of sealing around the port( it was just pushed in) and sealing the hole where the speaker cable goes through the back panel. I am waiting for those to dry now.  Then I will check that the speaker is seated on its foam gasket properly. 

[Chienmortbb]

On 10/07/2020 at 16:21, Passinwind said:

I wasn't calling you out in any way John, I think you're doing it just right. Rod is in a position of extreme responsibilty and potential liability, and he did offer a Class D module as part of one or more projects a few years ago, but apparently doesn't anymore. I've purposely kept a lot of details of my DIY builds a bit vague in forum posts, but as always I'm happy to share more in PMs.

I'm always surprised not to see more mention of Hypex. They make great sounding stuff and are happy to support DIY'ers fully. In the US the ICEpower rep is a great guy and has helped me a lot, but tech support comes from Denmark and  IME those guys are pretty much all business. They changed their presence at NAMM from a public booth to appointment-only in a private office this year and I can't say I blame them. My first module came from a gray market source (lightly used evaluation kit) and was pretty expensive, but the guy was very helpful and made me a nice cable set on his nickel. For the last three I called in favors, schmoozed the right people, and so on, and the price for 700ASCs was very reasonable.

I have looked at HYPEX before but found them just as hard to get information as ICEPower. I contatcted them and they pointed me to their DIY site.Sdaly that only has separate power amplifiers and the beuaty of the ICEPower and OEM Hypex modules is the intergrated mains and auxilliary power supplies.