Plate amps

[JPJ]

So having managed to buy back my old SWR Marcus Miller preamp I’m back thinking of building a 2x12 version of the Basschat 1x12 project cab, but adding a plate amp to make it a powered self contained rig with the SWR pre. 
As I seem unable to find a supplier of a reasonably priced 500W into 4 ohm plate amp, I’ve been considering buying something like the replacement amp module from an EV ZLX PA cab. We run two of those for FoH duties and despite running quite hot, have been reliable for the last  3 years (would be 4 but for lockdowns).

Am I mad for even considering this or is there a better plate amp option?

[Phil Starr]

We've been looking into a powered version with John @Chienmortbb doing all the work on amps, I'm sure he'll be along soon. 

One option I've been trying is using a Behringer PA amp with the DSP as a crossover. that saves you the cost of the crossover too and you can tailor the response with HPF on the bass driver and dynamic limiting for speaker protection. I've toyed with the idea of building the amp straight into the cab.

In any case the zlx amp is split between a class D bass amp and a smaller powered class AB for the tweeter with a crossover built in. It won't work with the passive crossover in the BC design. The Inconvenient Truth about your Electro-Voice ZLX-12P & ZLX15P amplifier - YouTube

[JPJ]

Thanks Phil, interesting stuff. All I know about our ZLX’s is the make a nice sound. I’ll be watching closely the development of the basschat plate amp option.

[Dan Dare]

I've wondered about doing that, too. I've only been able to find plate amps for subs. The idea of using a powered PA speaker amp module sounds interesting. I found a company called KJF Audio in Warwickshire that sells Hypex plate amps, but they seem to be aimed more at the hi-fi market. They're at Full range drivers, DIY speaker kits and DIY audio components (kjfaudio.com).

[Phil Starr]

@Chienmortbb knows much more than I do, I'm a bit analogue  class D and switch mode supplies scare the hell out of me.The problem with a lot of this stuff is price. That EV plate amp is £200 and the ICE Power amps are around that just for the board. There are a limited number of chipsets that are widely used and you can buy Chinese made boards for peanuts, but by and large the ancillary components aren't up to spec and they won't be reliable. the suspicion is also there that if they are using substandard components that there will be little or no quality control. John is currently looking for some of the longer established Chinese companies products.

The Behringer NX3000 uses the same amp module as the Bugera Veyron as far as I can tell, though the Veyron uses it in bridge mode for more power. I'm using the predecessor iNuke for speaker development at the moment  but I've never had a problem with the Behringer PA amps. Pulling apart Behringer stuff it is quite nicely made, very nice considering the price. I 've been wondering about seeing how easy it would be to just rip out the innards of one and install it into a cab. Or looking for a Behringer with blown speakers but a working plate amp.

[EBS_freak]

8 hours ago, Phil Starr said:

@Chienmortbb knows much more than I do, I'm a bit analogue  class D and switch mode supplies scare the hell out of me.The problem with a lot of this stuff is price. That EV plate amp is £200 and the ICE Power amps are around that just for the board. There are a limited number of chipsets that are widely used and you can buy Chinese made boards for peanuts, but by and large the ancillary components aren't up to spec and they won't be reliable. the suspicion is also there that if they are using substandard components that there will be little or no quality control. John is currently looking for some of the longer established Chinese companies products.

The Behringer NX3000 uses the same amp module as the Bugera Veyron as far as I can tell, though the Veyron uses it in bridge mode for more power. I'm using the predecessor iNuke for speaker development at the moment  but I've never had a problem with the Behringer PA amps. Pulling apart Behringer stuff it is quite nicely made, very nice considering the price. I 've been wondering about seeing how easy it would be to just rip out the innards of one and install it into a cab. Or looking for a Behringer with blown speakers but a working plate amp.

Be wary of the noise of Behringer amps (although you probably have already clocked this) - they are perfectly good (a little optimistic with their ratings but the DSP onboard is very good) but the fans are incredibly loud. I switched the fans out for some Arctic quiet ones that seem to be good and keep the amp cool enough - but I couldn't any proper specs for the fans (admittedly this was a while back) that enable me to be confident with a like for like change. I'll see if I can find what fans I bought by looking through my emails. 

Edited March 15, 2021 by EBS_freak

[EBS_freak]

I used Arctic F8 - I started with an Arctic F8 silent but the air flow was noticeably lower than the stock fan. The F8 is a very quiet fan anyway, certainly quieter than those found in some bass amps!

Edited March 15, 2021 by EBS_freak

[Phil Starr]

I can't hear the sound of the Behringers fans over the sound of those in the Peavey Minimax

Mind you I can't hear much of anything once our drummer starts shed building.

[Chienmortbb]

Warning long reply.

@Phil Starr the blown module from his Behringer active monitor some weeks ago and I have to say it was well put together and extremely well engineered. I have salvaged the Switch Mode power supply for use on another project. All these active speakers from te low/mid priced systems seem to use the same  basic systems, chip based class D amp(usu ally from the TDA89XX series) to drive the Woofer and a class A/B chip amp to drive the tweeter (either TDA7493/7494 or LM3876/3886 series). This is true of Behringer, Mackie (Thump range) and EV to my knowlledge and I have seen the LM 3886 in cheapo Gemini type active speakers.

Despite things like the Mackie and EV speakers being claimed 1000W speakers, the reality is that the most you can get from those chip amps (TDA8954) is 320-340W bridged into an 8 ohm load. Add 80watts from the treble amps and the reality is that these speakers will struggle to get to 500 watts (at 1% THD plus noise) , unless superb cooling systems are deployed.

So can you use these for "activating" the BC112 MK3? Yes and No. There are few good implementations of these chips available to buy that will allow them to used at anywhere near 300W. The Ebay/AliExpress/Banggood ones costing betqeen £15-£30 are 5H1T. Some will blow at well belpw the rated voltage (so you cannot get the power out) and others will overheat due to the lack of cooling if they don't blow sooner. 

Are there any good implementatiosn of these chips available? Yes, Connex Electronics do both an amplifier and a complete unit with power supply included. Funnily enoough they say it can output 360w at 8 ohms at 1%. That would drive a single BC112 Mk3 nicely. However you will still need to add improved cooling. Connex say " For proper operation the board must be installed on a heatsink or an aluminium baseplate which will serve as heatsink." https://connexelectronic.com/product/tda8954smps/

 

Plate Amps

On to plate amps. As mentioned most prebuilt amps are for subwoofers only and useless for us bassists. The frequencies they ampilfy are the very ones we need to tame usually. the exception to this are the Hypex plate amps. These are exteremely well engineered  and the Fusion Model 252 would do very well in this application, except that the power into 4R is reduced to 400W when bridged. It will give 2 x 250W into 8R or 1 x 500W into 8R so would suit but then the price (£462 excluding postage from Wilmslow Audio https://www.wilmslowaudio.co.uk/hypex-fusion-fa252-2824-p.asp ) makes it an expensive option. These do include a limited form of DSP to allow digital crossovers to be tailored.

The other option is MiniDSP's PWR-ICE units that include ICEPower modules alongside extensive DSP. these will do 450W* into 4R. These will also set you back close to £400 including duty and shipping. https://www.audiophonics.fr/en/amplifier-boards/minidsp-pwr-ice125-asx2-amplifier-module-450w-4-ohms-dsp-p-9530.html?search_query=PWR&fast_search=fs

Both these options have built in power supplies though unlike the cheaper Chinese amps.

*As with many amplifiers,  manufacturers quote their power ratings in a favourable light. Firtly many will quote assuming that normal listening is at 1/8 or even 1/10 full power. Another "trick" is to quote at a high distortion figure. Some will quote at 10% distortion.

Both these options have built in power supplies though unlike the cheaper Chinese amps.

Of course you could buy an ICEPower 125ASX2 module BUT the distributor prices are high, approx £240 inc VAT and delivery from Profusion https://www.profusionplc.com/parts/icepower125asx2,  You will need to add about £15 for the cables and you will have to supply your own metalwork. you will also need a bridging converter and regulator board as the 125ASX2 is a stereo amp and you need to bridge it to get the full 450 watts into 4 ohms.

The 125ASX2 are available on Ebay from China and all indications are that these are genuine models however some on here have had problems with EBAY boards.  See the comments to the contrary below from @agedhorse

So what is the best solution. Not for me to decide but I have been trying out the Connex IRS500SMPS. 500 watts into 4 ohms and 300 watts into 8 ohms. It has a connector to wire in a volume control and does not need any other circuitry. However, as with the other modules mentioned, it will need extra heatsinking. More later.

 

 

 

 

 

Edited March 18, 2021 by Chienmortbb

[agedhorse]

Virtually all ICEPower 125ASX modules available on ebay that are shipped out of China and Hong Kong are counterfeit. 

[Chienmortbb]

14 hours ago, agedhorse said:

Virtually all ICEPower 125ASX modules available on ebay that are shipped out of China and Hong Kong are counterfeit. 

 I should add that I respect @agedhorse's knowledge here. I used to think that they were all probably fake but was persuaded otherwise. However I suspect that there are few people on the planet that have more experience/knowledge  with class D modules that @agedhorse so if he says those sourced from the Far East are fake, I trust him.

Edited March 17, 2021 by Chienmortbb
clarification

[JPJ]

8 hours ago, Chienmortbb said:

Warning long reply.

@Phil Starr the blown module from his Behringer active monitor some weeks ago and I have to say it was well put together and extremely well engineered. I have salvaged the Switch Mode power supply for use on another project. All these active speakers from te low/mid priced systems seem to use the same  basic systems, chip based class D amp(usu ally from the TDA89XX series) to drive the Woofer and a class A/B chip amp to drive the tweeter (either TDA7493/7494 or LM3876/3886 series). This is true of Behringer, Mackie (Thump range) and EV to my knowlledge and I have seen the LM 3886 in cheapo Gemini type active speakers.

Despite things like the Mackie and EV speakers being claimed 1000W speakers, the reality is that the most you can get from those chip amps (TDA8954) is 320-340W bridged into an 8 ohm load. Add 80watts from the treble amps and the reality is that these speakers will struggle to get to 500 watts (at 1% THD plus noise) , unless superb cooling systems are deployed.

So can you use these for "activating" the BC112 MK3? Yes and No. There are few good implementations of these chips available to buy that will allow them to used at anywhere near 300W. The Ebay/AliExpress/Banggood ones costing betqeen £15-£30 are 5H1T. Some will blow at well belpw the rated voltage (so you cannot get the power out) and others will overheat due to the lack of cooling if they don't blow sooner. 

Are there any good implementatiosn of these chips available? Yes, Connex Electronics do both an amplifier and a complete unit with power supply included. Funnily enoough they say it can output 360w at 8 ohms at 1%. That would drive a single BC112 Mk3 nicely. However you will still need to add improved cooling. Connex say " For proper operation the board must be installed on a heatsink or an aluminium baseplate which will serve as heatsink." https://connexelectronic.com/product/tda8954smps/

 

Plate Amps

On to plate amps. As mentioned most prebuilt amps are for subwoofers only and useless for us bassists. The frequencies they ampilfy are the very ones we need to tame usually. the exception to this are the Hypex plate amps. These are exteremely well engineered  and the Fusion Model 252 would do very well in this application, except that the power into 4R is reduced to 400W when bridged. It will give 2 x 250W into 8R or 1 x 500W into 8R so would suit but then the price (£462 excluding postage from Wilmslow Audio https://www.wilmslowaudio.co.uk/hypex-fusion-fa252-2824-p.asp ) makes it an expensive option. These do include a limited form of DSP to allow digital crossovers to be tailored.

The other option is MiniDSP's PWR-ICE units that include ICEPower modules alongside extensive DSP. these will do 450W* into 4R. These will also set you back close to £400 including duty and shipping. https://www.audiophonics.fr/en/amplifier-boards/minidsp-pwr-ice125-asx2-amplifier-module-450w-4-ohms-dsp-p-9530.html?search_query=PWR&fast_search=fs

Both these options have built in power supplies though unlike the cheaper Chinese amps.

*As with many amplifiers,  manufacturers quote their power ratings in a favourable light. Firtly many will quote assuming that normal listening is at 1/8 or even 1/10 full power. Another "trick" is to quote at a high distortion figure. Some will quote at 10% distortion.

Both these options have built in power supplies though unlike the cheaper Chinese amps.

Of course you could buy an ICEPower 125ASX2 module BUT the distributor prices are high, approx £240 inc VAT and delivery from Profusion https://www.profusionplc.com/parts/icepower125asx2,  You will need to add about £15 for the cables and you will have to supply your own metalwork. you will also need a bridging converter and regulator board as the 125ASX2 is a stereo amp and you need to bridge it to get the full 450 watts into 4 ohms.

The 125ASX2 are available on Ebay from China and all indications are that these are genuine models however some on here have had problems with EBAY boards.

So what is the best solution. Not for me to decide but I have been trying out the Connex IRS500SMPS. 500 watts into 4 ohms and 300 watts into 8 ohms. It has a connector to wire in a volume control and does not need any other circuitry. However, as with the other modules mentioned, it will need extra heatsinking. More later.

 

 

 

 

 

Great answer, thank you for taking the time to share this. I’ll be interested to hear your further thoughts on the Connex option. 500W in to 4R would work for me. I plan on building a 2x12 version of the Basschat 1x12, and I’m much handier with wood and metal than electronics so I’m confident I could  rustle up a reasonable heat sink. 

[agedhorse]

20 hours ago, Chienmortbb said:

 I should add that I respect @agedhorse's knowledge here. I used to think that they were all probably fake but was persuaded otherwise. However I suspect that there are few people on the planet that have more experience/knowledge  with class D modules that @agedhorse so if he says those sourced from the Far East are fake, I trust him.

It is unfortunate. As a long time (as in almost the beginning of IcePower when they were financed and partially owned by B&O) designer of products using IcePower parts, I have access to much more information than most do. The backstory is complicated and confidential, but it was basically outright theft of their IP. Unfortunately it's hard (read as virtually impossible) to enforce anything in China, and there were some amp manufacturers that used of IcePower product that were tempted by the lower price of the counterfeits (most didn't realize they were counterfeits as they were marketed as surplus from a large Chinese contract manufacturer who got stick with thousands of these parts) only to learn that they were counterfeits and the reliability was nowhere near the same.

Counterfeiting is a very real problem. I got burned once (about 20 years ago) when I ordered a National Semiconductor part from a reputable authorized National Semiconductor distributor. The parts didn't work the same, but they looked identical in every way. Sent them to the manufacturer for x-ray analysis and it turned out to be a different die inside the package with different characteristics. It turned out that a customer ordered many thousands of these parts and then returned counterfeit parts in counterfeit sealed packaging to the distributor (common practice) several thousand of the parts for credit. They were an expensive enough part that it was worth the hassle apparently. 

[EBS_freak]

24 minutes ago, agedhorse said:

It is unfortunate. As a long time (as in almost the beginning of IcePower when they were financed and partially owned by B&O) designer of products using IcePower parts, I have access to much more information than most do. The backstory is complicated and confidential, but it was basically outright theft of their IP. Unfortunately it's hard (read as virtually impossible) to enforce anything in China, and there were some amp manufacturers that used of IcePower product that were tempted by the lower price of the counterfeits (most didn't realize they were counterfeits as they were marketed as surplus from a large Chinese contract manufacturer who got stick with thousands of these parts) only to learn that they were counterfeits and the reliability was nowhere near the same.

Oh man. Sounds similar to the EHX vs Mooer case!

[Chienmortbb]

3 hours ago, agedhorse said:

It is unfortunate. As a long time (as in almost the beginning of IcePower when they were financed and partially owned by B&O) designer of products using IcePower parts, I have access to much more information than most do. The backstory is complicated and confidential, but it was basically outright theft of their IP. Unfortunately it's hard (read as virtually impossible) to enforce anything in China, and there were some amp manufacturers that used of IcePower product that were tempted by the lower price of the counterfeits (most didn't realize they were counterfeits as they were marketed as surplus from a large Chinese contract manufacturer who got stick with thousands of these parts) only to learn that they were counterfeits and the reliability was nowhere near the same.

Counterfeiting is a very real problem. I got burned once (about 20 years ago) when I ordered a National Semiconductor part from a reputable authorized National Semiconductor distributor. The parts didn't work the same, but they looked identical in every way. Sent them to the manufacturer for x-ray analysis and it turned out to be a different die inside the package with different characteristics. It turned out that a customer ordered many thousands of these parts and then returned counterfeit parts in counterfeit sealed packaging to the distributor (common practice) several thousand of the parts for credit. They were an expensive enough part that it was worth the hassle apparently. 

I have been lucky, I bought an 125ASX2 from someone in the UK from a half completed project. It has been running for 3-4 years and is fine. I also bought three 50ASX2s and those were also from a UK seller. The only problem with this was my hamfistedness when I blew the fuses in the aux supplies of one of the 50ASX2s. It is the 50ASX2 that "reminded" me of the high DC voltages. 

[nilebodgers]

You would think Icepower would do a 2 pronged attack of a PR campaign highlighting the quality of the genuine parts (and the likelyhood of the counterfeit parts leaving a smoking crater) alongside making the 125asx2 much more available at a reasonable cost. The counterfeit parts are only attractive because the genuine part is very expensive and also hard to get. There is obviously a demand for the product and they'd probably sell a lot more.

[agedhorse]

The genuine parts are more expensive to build, the test process is very comprehensive, the factory’s are more expensive to operate because they are under NRTL (nationally recognized test lab) inspections, and the products include international safety and EMC compliance which is also costly to maintain.

All OEM’s who currently use this part are aware of the situation now, but the damage is done. Most quality OEMs buy directly from ICEPower so there is no issue with us receiving counterfeit parts as the tracking is quite thorough and serial numbered.

[Chienmortbb]

2 hours ago, agedhorse said:

The genuine parts are more expensive to build, the test process is very comprehensive, the factory’s are more expensive to operate because they are under NRTL (nationally recognized test lab) inspections, and the products include international safety and EMC compliance which is also costly to maintain.

All OEM’s who currently use this part are aware of the situation now, but the damage is done. Most quality OEMs buy directly from ICEPower so there is no issue with us receiving counterfeit parts as the tracking is quite thorough and serial numbered.

@nilebodgers does have a point. No one would suggest that the few distributors of ICEPower products do not have a have a right to mark up a reasonable amount but for example Profusion's one off price o

£190.39 excluding VAT (sales  tax) and shipping ends up close to £250  ($340 approx) for a single piece of 125ASX2. Without the knowledge you have shared with us, you can understand why people buy ONCE from EBAY.

 

[nilebodgers]

45 minutes ago, Chienmortbb said:

@nilebodgers does have a point. No one would suggest that the few distributors of ICEPower products do not have a have a right to mark up a reasonable amount but for example Profusion's one off price o

£190.39 excluding VAT (sales  tax) and shipping ends up close to £250  ($340 approx) for a single piece of 125ASX2. Without the knowledge you have shared with us, you can understand why people buy ONCE from EBAY.

 

Yes, for (very) old legacy products like the 125asx2 all the r&d has been recouped, the production is routine as is the testing. Taking a commercial view and then doing them at (say) £125-150 would kill a large amount of the fake sales without impacting on the more premium product sales that no-one can fake (yet).

Mind you, keeping them expensive does filter out a lot of clueless users that would be pestering for applications help and electrocuting themselves when they went poking about where they shouldn't. It's going to be a lot less trouble for a manufacturer that only wants to deal with OEMs.

[agedhorse]

ICEPower only sells OEM, that represents 99.9% of their business. That’s likely why it’s not worth the effort or the cost on an older product. 

Those who buy a product like this on eBay from China, outside of the authorized distribution network, are getting what they pay for in the sense that eBay is well known as a marketplace for counterfeit goods. 

Profusion is an authorized distributor for some ICEPower models, but yes they are more expensive.

 

[Jack]

On 16/03/2021 at 20:52, JPJ said:

Great answer, thank you for taking the time to share this. I’ll be interested to hear your further thoughts on the Connex option. 500W in to 4R would work for me. I plan on building a 2x12 version of the Basschat 1x12, and I’m much handier with wood and metal than electronics so I’m confident I could  rustle up a reasonable heat sink. 

Is the solution not just a simple 2u airhead? A used pro pa amp would be peanuts on ebay (I sold my PLX1602 for £160) and that would run rings around the plate amps being discussed here. The execution wouldn't be as neat though, heavier too...

[Phil Starr]

On 16/03/2021 at 11:37, Chienmortbb said:

Warning long reply.

 All these active speakers from the low/mid priced systems seem to use the same  basic systems, chip based class D amp(usu ally from the TDA89XX series) to drive the Woofer and a class A/B chip amp to drive the tweeter (either TDA7493/7494 or LM3876/3886 series). This is true of Behringer, Mackie (Thump range) and EV to my knowlledge and I have seen the LM 3886 in cheapo Gemini type active speakers.

Despite things like the Mackie and EV speakers being claimed 1000W speakers, the reality is that the most you can get from those chip amps (TDA8954) is 320-340W bridged into an 8 ohm load. Add 80watts from the treble amps and the reality is that these speakers will struggle to get to 500 watts (at 1% THD plus noise) , unless superb cooling systems are deployed.

So can you use these for "activating" the BC112 MK3? Yes and No. There are few good implementations of these chips available to buy that will allow them to used at anywhere near 300W. The Ebay/AliExpress/Banggood ones costing betqeen £15-£30 are 5H1T. Some will blow at well below the rated voltage (so you cannot get the power out) and others will overheat due to the lack of cooling if they don't blow sooner. 

 

I think this shows all the signs of an immature market. The chipsets are pretty standard but the boards are either populated with substandard components or fiercely expensive. Meanwhile mid price manufacturers are increasingly producing perfectly acceptable amps at good prices with the chipsets available. Behringer/Bugera/Sampson/Wharfedale/ TC and all the badged OEM stuff from Thomann and the like. Unfortunately nobody seems to be making the mid priced reliable boards you'd expect with serviceable but well priced components. @Chienmortbb and I have been talking about the Wharfedale Wharfedale PSX112 350W Active PA Speaker - Andertons Music Co.  it's rated as 250W and 100W for the tweeter (within the sort of parameters of the TDA chips John referred to above). The interesting thing is the the price; £114 for an active speaker! The whole package is cheaper than just a plate amp or even just the bare boards we are talking about. Have no doubts, Wharfedale are huge, not the Yorkshire company of old but a Hong Kong/Chinese owner of a whole load of older brands including Quad and Audiolab. Nonetheless if i could get a 250W plate amp or even a bare board for £114 with a power supply I'd take your arm off, the fact that is has a pre amp and all the connectors makes it an extraordinary bargain. I have a Wharfedale Titan here which seems to be a predecessor of this speaker. I think i might have to dissect it.

[JPJ]

3 hours ago, Jack said:Is the solution not just a simple 2u airhead? A used pro pa amp would be peanuts on ebay (I sold my PLX1602 for £160) and that would run rings around the plate amps being discussed here. The execution wouldn't be as neat though, heavier too...

I used to run a PLX with the Marcus Miller but the combination was almost as heavy as my SM1500. I may however have solved my own problem as I’ve just scored a SWR amplite which is a lightweight 400W into 4R single channel power amp.

[Owen]

There is the answer, right there.

[Chienmortbb]

23 hours ago, nilebodgers said:

Yes, for (very) old legacy products like the 125asx2 all the r&d has been recouped, the production is routine as is the testing. Taking a commercial view and then doing them at (say) £125-150 would kill a large amount of the fake sales without impacting on the more premium product sales that no-one can fake (yet).

Mind you, keeping them expensive does filter out a lot of clueless users that would be pestering for applications help and electrocuting themselves when they went poking about where they shouldn't. It's going to be a lot less trouble for a manufacturer that only wants to deal with OEMs.

Very True.To be honest the ASX range is very long in the tooth and is largely superseded by the AS range. To me the ideal module for the diyer is the 700AS1 from ICEPower 350W 8ohm, 700W 4 ohm and all the functions needed to make a modern amp easier to build. I believe that this amp is used in many of the "800 watt" amps of the last 3-4 amps. ICEPower seem to have controlled distribution of this model better than the lower power ASX modules. I suspect @agedhorse knows this module well but it is unfair to ask him about it.