Chienmortbb Posted November 15, 2021 Share Posted November 15, 2021 (edited) I started a thread in the Amps and Cabs forum discussing the shortage of amps. I wanted a new power amp for my PA as I sold my heavy amps and it was as I was looking that I found there was a shortage of amps. Here is the other thread: So I decided I had enough modules and other parts around to build one myself. I had a number of power amp modules plus an enclosure and a DSP module that I wanted to use. I wanted a reasonably high power amp that was versatile, powerful and reasonably easy to repair. However I soon realised that the mish mash of modules I had would not fit the "easy to repair" requirement. I soon narrowed it down to two modules, both powered. These were the ICEPower 125ASX2 and a Connex IRS500SMPS. The Icepower unit can reach close to 500 watts into 4 ohms and the Connex can exceed 500 watts into 4 ohms. I decided on the Connex as the basis of my two channel power amp. I have had each of these units for some time and although sonically and in terms of power, there really is little to chose between them, the ICEPower unit seems to be affected by the worldwide shortage of components whereas the Connex was qouted as 10 days to shipment. In addition the Connex unit was more economical. A;though 125ASX2 is available from China for approc £120, most of theses are counterfiet and again would fall foul of the "easy to repair" clause. The Connex modules came out at about £120 per unit including shipping and Ihave had good support from Connex. I bought 2 and will then have three once the other two arrive (they were shipped 12th November). Edited November 15, 2021 by Chienmortbb 4 Quote Link to comment Share on other sites More sharing options...
Jus Lukin Posted November 15, 2021 Share Posted November 15, 2021 (edited) - Edited March 15, 2022 by Jus Lukin Quote Link to comment Share on other sites More sharing options...
Chienmortbb Posted November 15, 2021 Author Share Posted November 15, 2021 As I mentioned I wanted to use parts I had as much as possible and I already had the enclosure, https://modushop.biz/site/index.php?route=product/product&path=25_290&product_id=429 I also have the 3e Audio DSP module based on Analog Devices ADAU1701 chip. This is a basic DSP with 2 analogue inputs and four analogue outputs making it ideal for use as an active stereo crossover. http://www.3e-audio.com/dsp/adau1701-2in4out/ Quote Link to comment Share on other sites More sharing options...
Chienmortbb Posted November 15, 2021 Author Share Posted November 15, 2021 Just now, Jus Lukin said: Sounds exciting! Well beyond my capabilities, but I'm keen to see the results of your build! It is a steep learning curve for me. One thing I should mention is it is not a low cost option. I would have bought a ready rolled unit if I could. Quote Link to comment Share on other sites More sharing options...
Chienmortbb Posted November 15, 2021 Author Share Posted November 15, 2021 (edited) I chose powered amps as it means that the failure of one amp/power supply will not affect the other amp. The main use would be of a single channel feeding both the subs and the top PA speakers. There would also be line outputs for the second channel. This would be the line outputs for a second channel of subs and tops, just by adding another two channel amp. While thinking about the project it became clear that with simple switching the amp could be used as a standard two channel amp or a single channel (bridged amp) outputting well over 1000 watts. Here is a mock up of the rear panel: Edited November 15, 2021 by Chienmortbb 2 Quote Link to comment Share on other sites More sharing options...
Chienmortbb Posted November 16, 2021 Author Share Posted November 16, 2021 The case was originally intended for a new bass amp but that is on hold. The good thing about it is that the sides are chunky aluminium extrusions. As you can see from the picture this maes a nice 230 X 80 mm heatsink. Ideally the fins would be vertical but you can't have everything. AS the font and back panel are also aluminium (3mm thick) this is a fair amount of passive heatsinking for class D amps. I have a nice 80mm fan that I can install if needed. The weight is 1.9Kg, not lightweight but solid. Incidently I have not designed the front panel yet. The rear panel was designed in Quickpanel (www.quickpanel.sk) and has been ordered. I know from experience that DIY panel look homemade so I bit the bullet. 2 Quote Link to comment Share on other sites More sharing options...
Passinwind Posted November 16, 2021 Share Posted November 16, 2021 22 minutes ago, Chienmortbb said: The case was originally intended for a new bass amp but that is on hold. The good thing about it is that the sides are chunky aluminium extrusions. As you can see from the picture this maes a nice 230 X 80 mm heatsink. Ideally the fins would be vertical but you can't have everything. AS the font and back panel are also aluminium (3mm thick) this is a fair amount of passive heatsinking for class D amps. I have a nice 80mm fan that I can install if needed. The weight is 1.9Kg, not lightweight but solid. Incidently I have not designed the front panel yet. The rear panel was designed in Quickpanel (www.quickpanel.sk) and has been ordered. I know from experience that DIY panel look homemade so I bit the bullet. I've used several of the very nice Modu enclosures, shipping cost to the US is the biggest drawback and some of the bigger sizes tended to require additional bracing that I had to fabricate myself, although in retrospect I'll bet I could have paid them to do it for me. Good call on the panel IMO, it usually seems that buy once, cry once really applies here. Quote Link to comment Share on other sites More sharing options...
Jus Lukin Posted November 16, 2021 Share Posted November 16, 2021 (edited) - Edited March 15, 2022 by Jus Lukin Quote Link to comment Share on other sites More sharing options...
nekomatic Posted November 17, 2021 Share Posted November 17, 2021 Ooh, those cases are nice aren’t they? Has anyone bought one post B****t? Similarly, what’s the pricing and delivery like from quickpanel? Quote Link to comment Share on other sites More sharing options...
Chienmortbb Posted November 18, 2021 Author Share Posted November 18, 2021 Yes I bought my case about 6 months ago from Modushop. The panel shown above has been orderd from Quickpanel. I have not yet had an ETA but don't expect a really fast turnaround as they re-anodise the panel after machining. Of course the power amp modules are still in China so there is no rush. The cost for that panel including shipping is just over £36. To use anyone else that I have found would have cost over £60. Hifi2000/Modushop now offer a similar service and may be faster however the advantage of Quickpanel and a few others is that they have the software. 1 Quote Link to comment Share on other sites More sharing options...
Passinwind Posted November 18, 2021 Share Posted November 18, 2021 4 hours ago, Chienmortbb said: Yes I bought my case about 6 months ago from Modushop. The panel shown above has been orderd from Quickpanel. I have not yet had an ETA but don't expect a really fast turnaround as they re-anodise the panel after machining. Of course the power amp modules are still in China so there is no rush. The cost for that panel including shipping is just over £36. To use anyone else that I have found would have cost over £60. Hifi2000/Modushop now offer a similar service and may be faster however the advantage of Quickpanel and a few others is that they have the software. You can export to DXF from the Front Panel Express software, or so I've heard...😉 1 Quote Link to comment Share on other sites More sharing options...
Chienmortbb Posted November 18, 2021 Author Share Posted November 18, 2021 1 hour ago, Passinwind said: You can export to DXF from the Front Panel Express software, or so I've heard...😉 Yes that would make it easier to get panels made at HiFi2000/Modushop and I might try them for the front panel. 1 Quote Link to comment Share on other sites More sharing options...
Chienmortbb Posted November 19, 2021 Author Share Posted November 19, 2021 Just had a delivery from Thomann, new bass plus all the XLR and SpeakOn connectors. Decision time. Do I do a rough up of the back panel using the existing back panel so I can start on the wiring or wait for the delivery from Quick Panel? 3 Quote Link to comment Share on other sites More sharing options...
nekomatic Posted November 19, 2021 Share Posted November 19, 2021 Seems a shame to start making holes in (what I assume is) a nicely finished piece of aluminium - if it's strictly for mockup purposes can you use a spare bit of wood or something? On 18/11/2021 at 15:44, Passinwind said: You can export to DXF from the Front Panel Express software, or so I've heard...😉 I checked their T&C's and you're not supposed to use the DXF for getting the panel made elsewhere. I'm not sure how they'd know though… 1 Quote Link to comment Share on other sites More sharing options...
Passinwind Posted November 19, 2021 Share Posted November 19, 2021 12 minutes ago, nekomatic said: I checked their T&C's and you're not supposed to use the DXF for getting the panel made elsewhere. I'm not sure how they'd know though… A different and much more modest enclosure vendor mentioned it to me and added that they didn't recommend it, but would have no way of knowing if I'd done it, wink wink nudge nudge. I've bought a whole lot of stuff from Front Panel Express as they are nearly local to me, do great work very quickly, and customer service often comes right from the CEO, who really knows her shizz. They are a bit on the expensive side though, for sure. But if sticker shock appeals look at Protocase, who I used once because no one else was able to offer what they claimed to. That worked out fine eventually but there were a few too many twists and turns along the way for my liking. Interestingly enough, Protocase give you a DXF and a 3-D model as part of what you pay for and seem to assume you'll be using them the next time for production with some other vendor...wonder why? 😉 Quote Link to comment Share on other sites More sharing options...
Passinwind Posted November 19, 2021 Share Posted November 19, 2021 6 hours ago, Chienmortbb said: Just had a delivery from Thomann, new bass plus all the XLR and SpeakOn connectors. Decision time. Do I do a rough up of the back panel using the existing back panel so I can start on the wiring or wait for the delivery from Quick Panel? Never mind that, how's the bass John? Quote Link to comment Share on other sites More sharing options...
Chienmortbb Posted November 19, 2021 Author Share Posted November 19, 2021 2 hours ago, Passinwind said: Never mind that, how's the bass John? Great Charlie, as you would expect the action is too high and the passive tone control has hardly any effect. However, the rolled edge on the fingerboard is superb and the active pre is pretty good. I will post a review in a few days. 1 Quote Link to comment Share on other sites More sharing options...
Chienmortbb Posted November 21, 2021 Author Share Posted November 21, 2021 The worst bit about waiting for parts is that it allows you time to think and change your mind. One of the ideas from the start was to make the amp serviceable. This is from the module level and as far as posible at component level too, While the amps are made with many surface mount devices, I have had good support from Connex with regards to the technical performance of another module. Reeplies are usually within 48 houre by email and the command of English is excellent. Despite this the supply issues at the moment mean that I have ordered two modules to add to the one I already have. So if one goes wrong, I can slot in another in 5 minutes. One of the options in the design is whether to use powered amps or separate amplifiers and power supplies. The benefit of using powered amplifiers, where the amplifier and powersupply are integrated is that whether an amp or power suppliy fails, only one channel will be affected and there is a considerable space saving. 3 Quote Link to comment Share on other sites More sharing options...
nekomatic Posted November 22, 2021 Share Posted November 22, 2021 I always find the smaller and less consequential the design decision, the more time and analysis it takes to make. 2 Quote Link to comment Share on other sites More sharing options...
Chienmortbb Posted December 9, 2021 Author Share Posted December 9, 2021 The saying's go "no news is good news" and "good things come to those who wait" Well both or neither could be true here. I was told it would be 4-5 weeks for the rear panel and accepted that, Sadly the Class D modules seem to be lost somewhere in Chine. I am wondering if the decisions I took were correct. Ironically the "VU" meter had arrived and I will investigate that more later. So the next decision is when to cut my losses and raise a PayPal dispute? I notice that many power amps on Thomann are now showing short lead times and I keep saying to myself that the build was really an excuse to learn about DSP.... More shortly. Quote Link to comment Share on other sites More sharing options...
Chienmortbb Posted December 20, 2021 Author Share Posted December 20, 2021 (edited) I checked the tracking on the amp modules early last week, they were still in China after 4 weeks. The back panel had been delivered...to my old addressand to top it all, The amps I was looking at befpre were all now in stock.....Gr. So on Thursday I had to take SWMBO (is that sexist?) to the hospital. On the way back we called into my old house and collected the front panel. Phew! Arrived home and voila, a small but very visible from the road, parcel containing two power amps. Two power amps that were still in China according to the tracking website. So after convincing myself that the satisfaction of building you own was more than getting a mass produced item, I started sneezing and have had a heavy cold ever since,🤧😁 Yes blame me for the shortage of Lateral Flow Tests. The back panel and one power amp is below. The screws on the sockets are silver and I was considering buting some black ones but the small slide switches need M2.5 screws and those are harder to get than M3 or above. The amplifier modules from Connex come with all the cables so wiring is reletively easy. I have to get over this cold however to carry on but I will keep you posted. Edited December 20, 2021 by Chienmortbb 5 Quote Link to comment Share on other sites More sharing options...
Chienmortbb Posted January 2, 2022 Author Share Posted January 2, 2022 I have been quite poorly fo tge last two weeks and just about coming out of the other side. Not COVID although a nasty virus and it really knocked me sideways. When I ordered the back panel I calculated that each threaded hole cost 11p more than a clearance hole. My original thought was that I had enough machine screws, nuts and washers. Just to assuage my curiosity, I had the holes for the mains connector tapped and it was a mistake. I did not have as many fixings as I thought so the £2 odd saving I made was more than wiped out by the cost of buying more machine screws, nuts and washers. The next thought is whether to mount the connectors from the inside or outside, It is tidier from the inside as seen above but in such a tight space it makes sense to mount from the outside of the panel. It adds internal volume and also removes a number of surfaces from the inside that could restrict the airflow. As most of the connectors use faston connectors, it would not be difficult to revert to internal mounting. Of course this would not be possible if all the holes were treaded as this would mandate mounting the connectors on the outside. Off to start assembly. Quote Link to comment Share on other sites More sharing options...
Chienmortbb Posted January 3, 2022 Author Share Posted January 3, 2022 Here is the assembled back panel. I will be mounting amp modules on the chassis next. 5 Quote Link to comment Share on other sites More sharing options...
Richard R Posted January 3, 2022 Share Posted January 3, 2022 This is fascinating! Really enjoying following this, and glad to hear you're feeling better. Happy New Year! Quote Link to comment Share on other sites More sharing options...
Chienmortbb Posted January 3, 2022 Author Share Posted January 3, 2022 (edited) On 03/01/2022 at 19:48, Richard R said: This is fascinating! Really enjoying following this, and glad to hear you're feeling better. Happy New Year! Thanks for the support. It is staring to feel like a real project now. I put the sockets on the outside as I decided that it would give more space inside the case and aid cooling. It does not look quite as good as when they are mounted from the inside but there is a gain of about 2 cubic centimetre of air per connector. That gives between 10-12 cubic centimetres in total and might be important if the heat management is marginal. I believe there is enough heat sinking to keep the unit cool in most circumstances but it has to be remembered that even the best Class D Amps with a Switch Mode Power Supply is around 85% efficient. That means 15% of all power used produces heat. That means over 17 watts of heat per 100 watts delivered to the speakers or close to 200 watts at full power for this amp. Edited January 4, 2022 by Chienmortbb 1 Quote Link to comment Share on other sites More sharing options...
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