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Dilema QSC vs T Amp

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Old Croc
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Post Options Post Options   Thanks (0) Thanks(0)   Quote login4 Quote  Post ReplyReply Direct Link To This Post Posted: 15 March 2007 at 4:37pm
the internals look the same on the dap vision 3500, darq pa18 and the bst 3600 but they must be a difference because the dap audio amp is rated at less power, could it be that there just being honest ..

im looking to buy one of the three but i just cant decide which one, and were to get them from...
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Post Options Post Options   Thanks (0) Thanks(0)   Quote JD01 Quote  Post ReplyReply Direct Link To This Post Posted: 15 March 2007 at 10:58pm
@ levyte: Yes, I had two of them. Only reason I sold them is because they were much too heavy for me. They don't say anything about 2 ohms stereo/4 ohms bridge  operation, but it works well (but I never tested the limiters in 2 ohms). In fact they even play below 2 ohms stereo. I don't know why they don't say anything about 2 ohms at all.
 
@ ArthurG: I have to tell you that you should check the specs and data first before calling someone misinformed!
 
1. ALL these ratings are EIA ratings, which aren't done with sinus signals, but a shaped signal that should equal typical music. While their MAY be minimal differences in power output at other crest factors than the one the EIA test offers, 1300W or 1400W isn't that big of a difference. The reason the CA12 can play better on bass than say TA2400 or C-Mark is simple. It can drive more complex loads (as bass speakers in many cases are compared to tops) much better. The Crest CA12 to CA18 are well designed amps. Nobody said anything else.
 
2. Believe what you want, I know from a test in a German magazine that  the PL6.0II is from China (since it is the II model) and STILL carry the 'made in USA' sign (to say it again, there is no law forbidding that). Besides, the old PL6.0 and PL9.0 weren't made in the USA either, they came from Canada (from a company called Bombardier or something similar in name).
 
4. Strange then that the first DAP Visions in Germany even had the same printings on the PCB as the CA18, including something like 'designed by Crest USA' or similar (I have to see if I still got the pictures). They were even presented that way on the ProLight&Sound, but only until Crest noticed it and sent lawyers to the fair to have them remove the amps. Crest doesn't produce ANY AMP in USA anymore. (Maybe you noticed that even EAW is manufacturing their boxes in Asia now, it's nothing special)
 
5. ANY chinese license manufacturer has very high failure rates on SOME series. The simple point is that the amps produces for renowed USA and Europe companies get a way better QC (which is paid for). If you get a DAP Vision 3500 and it will work for half an hour, it will work forever (until the capacitors dry out, which isn't that hard to fix, still you paid quarter the price of the original). If it burns up within the first half hour, the company (DAP or BST) will replace it with a new one.
The DAP and BST have a electronic fuse. There is nothing to blow. The amp is started and stopped by pushing a button for a few seconds. No real switch conducts the power.
A CA18 has different transistors on the high rail than on the low rail. The ones on the low rail can handle more power. The DAP Vision 3500 has the SAME transistors on all rails: The BIG kind Crest has only on the low rail. And to top that, they even put in MORE transistors of that kind than Crest does (or let's say 'than Crest orders').
 
@ login4: I don't know for the darq (or whatever), but the BST Liker 3600 and the DAP Vison 3500 are completely the same but for the outside color. DAP is even a bit conservative on the power rating. This amp really drives bass very very well.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote norty303 Quote  Post ReplyReply Direct Link To This Post Posted: 16 March 2007 at 4:57am
Are German magazines are reliable source of info?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Tekasis Quote  Post ReplyReply Direct Link To This Post Posted: 16 March 2007 at 5:20am
This is great interesting stuff but well confusing for the Newbies.
 
Info on Darq Amps.
 
 
 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote login4 Quote  Post ReplyReply Direct Link To This Post Posted: 16 March 2007 at 5:30am
ok cheers JD01, i did find the dap vision 3500 for 499 squid a while back but i cant find it again,

does anyone know of a good place to get one?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote ArthurG Quote  Post ReplyReply Direct Link To This Post Posted: 16 March 2007 at 5:58am
Originally posted by JD01 JD01 wrote:

@ ArthurG: I have to tell you that you should check the specs and data first before calling someone misinformed!
 
1. ALL these ratings are EIA ratings, which aren't done with sinus signals, but a shaped signal that should equal typical music. While their MAY be minimal differences in power output at other crest factors than the one the EIA test offers, 1300W or 1400W isn't that big of a difference. The reason the CA12 can play better on bass than say TA2400 or C-Mark is simple. It can drive more complex loads (as bass speakers in many cases are compared to tops) much better. The Crest CA12 to CA18 are well designed amps. Nobody said anything else.
 
2. Believe what you want, I know from a test in a German magazine that  the PL6.0II is from China (since it is the II model) and STILL carry the 'made in USA' sign (to say it again, there is no law forbidding that). Besides, the old PL6.0 and PL9.0 weren't made in the USA either, they came from Canada (from a company called Bombardier or something similar in name).
 
4. Strange then that the first DAP Visions in Germany even had the same printings on the PCB as the CA18, including something like 'designed by Crest USA' or similar (I have to see if I still got the pictures). They were even presented that way on the ProLight&Sound, but only until Crest noticed it and sent lawyers to the fair to have them remove the amps. Crest doesn't produce ANY AMP in USA anymore. (Maybe you noticed that even EAW is manufacturing their boxes in Asia now, it's nothing special)
 
5. ANY chinese license manufacturer has very high failure rates on SOME series. The simple point is that the amps produces for renowed USA and Europe companies get a way better QC (which is paid for). If you get a DAP Vision 3500 and it will work for half an hour, it will work forever (until the capacitors dry out, which isn't that hard to fix, still you paid quarter the price of the original). If it burns up within the first half hour, the company (DAP or BST) will replace it with a new one.
The DAP and BST have a electronic fuse. There is nothing to blow. The amp is started and stopped by pushing a button for a few seconds. No real switch conducts the power.
A CA18 has different transistors on the high rail than on the low rail. The ones on the low rail can handle more power. The DAP Vision 3500 has the SAME transistors on all rails: The BIG kind Crest has only on the low rail. And to top that, they even put in MORE transistors of that kind than Crest does (or let's say 'than Crest orders').
 
@ login4: I don't know for the darq (or whatever), but the BST Liker 3600 and the DAP Vison 3500 are completely the same but for the outside color. DAP is even a bit conservative on the power rating. This amp really drives bass very very well.




hmmm you are false again...

1. EIA rating is with dummy 100% pure resistive load, far from what is a real complex load. so my point is still valid and you admit it telling how Crest CA drive easily complex loads ;)

2. So you trust a german journalist working on his desk all the day and going to Frankfurt PLS Fair one time per year and you don't trust me who I leave in China, dealing everyday with Chinese suppliers and who have visited more than 100 factories during the last 4 years ? comon this journalist knows nothing from China and probably has never visited a chinese factory.  I know Soundking factory and some of their engineers and they have no serious QC nor technical support to work with a company like QSC. Go with me to their plant, it's just 1 hour drive from my office and you will see it by yourself...
And by the way, Crest still produce many amps in US, only entry level stuff is made in China


3. It's not "strange", it's called "copy". You can go to dozen of Chinese amps manufacturer websites and see everywhere the trademarked Crest technologies like ACL, IGM, TourClass or AutoRamp. If I follow you idea, it means Crest has dozen of Chinese factories producing CA series  wake up dude,  You cannot imagine how much Chineses could be vicious in business...



4. please don't give credit to this crappy delayed Power ON feature of BST/DAP thing. This is one of the most stupid design I saw in pro Audio. This design is so "smart" that  implementation cost is high compared to a good breaker switch (because it uses small transformer and relay for idle current) and it's impossible to use the amp in a fixed install with sequencing power ON/OFF controller
Regarding the transistors, it's not a problem at all to use different models in same design. in Class H topology, rail voltages are difference so why not use the right solution for each rail ? and the number of transistors tells you little about output power. rail voltage is also very important.
Finally regarding amp failures, I see that you have never worked for a repair service. If only caps are subjet to failure why service centers have thousand different parts in their stock ?... The fact is on BST/DAP thing only sub parts are used and failure rate is more important than an amp with good components. One example, a switch is rated by number of push/slide cycles before failure. A typical chinese switch is rated at 5000 cycles where same famous brand part can sustain easily more than 100.000 cycles. Another example, DAP/BST use inrush current limiter from NANJING (chinese factory around Ningbo city). Problem is that this component has so low manufacturing tolerance that rising time varies a lot (and I don't talk about reliability which sux ). So SAE china must use 5 pcs of it  in the biggest DAP/BST model with unpredictable performance where a good EPCOS model needs only 2 pcs for the same job with higher reliabily and consistent rising times !
and finally, all this Chinese factories has no consistency in component sourcing. The only rule in their purchase department is "buy at the cheapest price". So components change from batch to batch and it's nearly impossible to get good support when an amp fails because the engineer doesn't know which exact brand/model was used during production
And I can continue pages and pages about how "good" are 95% of  chinese amp factories. They are no secret in this industry, cheap price means cheap components and/or bad QC process. My old mum always told me to make a good soup you need good vegetables. for amps is the same, and good things are not cheap. period


Edited by ArthurG - 16 March 2007 at 6:34am
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Post Options Post Options   Thanks (0) Thanks(0)   Quote hikk Quote  Post ReplyReply Direct Link To This Post Posted: 16 March 2007 at 9:25am
Originally posted by ArthurG ArthurG wrote:





hmmm you are false again...

1. EIA rating is with dummy 100% pure resistive load, far from what is a real complex load. so my point is still valid and you admit it telling how Crest CA drive easily complex loads ;)

2. So you trust a german journalist working on his desk all the day and going to Frankfurt PLS Fair one time per year and you don't trust me who I leave in China, dealing everyday with Chinese suppliers and who have visited more than 100 factories during the last 4 years ? comon this journalist knows nothing from China and probably has never visited a chinese factory.  I know Soundking factory and some of their engineers and they have no serious QC nor technical support to work with a company like QSC. Go with me to their plant, it's just 1 hour drive from my office and you will see it by yourself...
And by the way, Crest still produce many amps in US, only entry level stuff is made in China


3. It's not "strange", it's called "copy". You can go to dozen of Chinese amps manufacturer websites and see everywhere the trademarked Crest technologies like ACL, IGM, TourClass or AutoRamp. If I follow you idea, it means Crest has dozen of Chinese factories producing CA series  wake up dude,  You cannot imagine how much Chineses could be vicious in business...



4. please don't give credit to this crappy delayed Power ON feature of BST/DAP thing. This is one of the most stupid design I saw in pro Audio. This design is so "smart" that  implementation cost is high compared to a good breaker switch (because it uses small transformer and relay for idle current) and it's impossible to use the amp in a fixed install with sequencing power ON/OFF controller
Regarding the transistors, it's not a problem at all to use different models in same design. in Class H topology, rail voltages are difference so why not use the right solution for each rail ? and the number of transistors tells you little about output power. rail voltage is also very important.
Finally regarding amp failures, I see that you have never worked for a repair service. If only caps are subjet to failure why service centers have thousand different parts in their stock ?... The fact is on BST/DAP thing only sub parts are used and failure rate is more important than an amp with good components. One example, a switch is rated by number of push/slide cycles before failure. A typical chinese switch is rated at 5000 cycles where same famous brand part can sustain easily more than 100.000 cycles. Another example, DAP/BST use inrush current limiter from NANJING (chinese factory around Ningbo city). Problem is that this component has so low manufacturing tolerance that rising time varies a lot (and I don't talk about reliability which sux ). So SAE china must use 5 pcs of it  in the biggest DAP/BST model with unpredictable performance where a good EPCOS model needs only 2 pcs for the same job with higher reliabily and consistent rising times !
and finally, all this Chinese factories has no consistency in component sourcing. The only rule in their purchase department is "buy at the cheapest price". So components change from batch to batch and it's nearly impossible to get good support when an amp fails because the engineer doesn't know which exact brand/model was used during production
And I can continue pages and pages about how "good" are 95% of  chinese amp factories. They are no secret in this industry, cheap price means cheap components and/or bad QC process. My old mum always told me to make a good soup you need good vegetables. for amps is the same, and good things are not cheap. period




So arther if you had to buy a cheap amp WHICH ONE WOULD YOU GO FOR? Name some semi reliable  cheap amps...........Where would you put your money in a have to buy situation?

And my mom also said the same thing to me but we always drove an escort and not a rolls.......... if get what i mean with THE UPMOST respct


Edited by hikk - 16 March 2007 at 9:26am
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Post Options Post Options   Thanks (0) Thanks(0)   Quote ArthurG Quote  Post ReplyReply Direct Link To This Post Posted: 16 March 2007 at 9:54am
Helllo hikk

Regarding my previous messages, I must add that not all Chinese amp factories are bad. Mostly of them are but not all. Some are descent and a very few are (very) good. Of course when QSC or Peavey decide to manufacture a series in China, it's not in a low grade small factory like the ones producting now for many european distributors. it's under strict quality control with in site QC staff from QSC or PV.

To reply to your answerm, I can tell you that Unika factory in Taiwan does good job ( http://www.unika.com.tw ) and for example, immediately coming to my mind : American Audio V plus series and Yorkville AP series are good value and are manufactured by Unika.

hope it helps
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Heathrow_B_line Quote  Post ReplyReply Direct Link To This Post Posted: 16 March 2007 at 11:32am
bass ive got 2 new p7000s's today, if you want i'll bring them over and im sure you will be impressed.  plus they only weight 10kg....
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Post Options Post Options   Thanks (0) Thanks(0)   Quote JD01 Quote  Post ReplyReply Direct Link To This Post Posted: 16 March 2007 at 6:02pm
@ ArthurG:
1. In no way did I say that they're using speakers to determine power output. I just said they DON'T use sine signals but instead a signal shaped like 'typical' music in crest and spectral energy distribution.
 
2. So you trust your knowledge of maybe half the chinese manufacturing plants (not to mention there are 'a few more' in other asian countries) over the word of an PA amp industry insider? I will stick with the things he tells me or writes in the magazine. He was 99% right in the past, so why should I doubt him?
 
3. Yes, maybe the chinese people are liars. They told me that these are exactly THE PCBs used on the Crests, as they manufacture for them. Their word doesn't mean more to me than yours, if you say you know what's going on in China.
 
4. I DON'T give credit for the crappy turn-on method. In fact I dislike it (still the amp is cheap and works solid), but it's NOT the way you described it in the first post where you accused me of being misinformed.
Also I did not say that there would be any problems with using different sets of transistors per rail. I just said, that the BST/DAP only has the big type, which would give more thermal headroom.
About the other parts in sub-standard quality: You were talking about caps, so I was talking about caps. The thing is that most of these parts are easily replaceable and pretty cheap. And the parts taking the real hard work are ok. It's like I said: Either they burn within the first 30 minutes or they'll work for a long time. I know dozens of people having the DAP Vision 3500. They all have the same experience as me and none of them regretted buying that amp.
 
You seem to know very little about how big European and US companies work. They HAVE to sell a product for multiples of the price they manufactured, because they have to pay their secretaries, shippers etc. as well as they pay the chinese secretaries, shippers etc. by paying the manufacturer. Also they expect bigger profit (and achieve it) AND they have a known name. The chinese manufacturer COULD INDEED sell EXACTLY the same product for about one third to half of the price.
 
By the way: I'm distributor of a brand of amps. I'm doing service for them in house.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote ArthurG Quote  Post ReplyReply Direct Link To This Post Posted: 17 March 2007 at 8:00pm
JD01,

1. fair but still, you cannot say 2 amps are the same because they put same power on the specsheet.

2. I think you missed my point. I don't trust my knowledge. I trust what I have seen with my own eyes. I visited Soundking factory (more than one time), I talked to engineers and management, I evaluate their methodology and their QC workflow process, all in one I was there. Can your so called "industry insider" tells the same about soundking ? Did he visited the factory plant ? Did he saw with his eyes QSC PL II maufactured there ? or (like I think) did he got the information from whatever rep talking in the name of this factory to glorify it ?

3. trust whatever you want, no problem.

4. heppay you don't like the Power ON method regarding reliability, unfortunately you don't want to listen to my arguments. So I cannot say nothing more now and let's see if in 3 years these amps will run fine as today...

and finally, for your information, DAP Vision 3500 BOM cost is 1800RMB (=180 EUR). On the other side, if you want to manufacture a 100% exact copy of Crest CA18 in China, the BOM cost is 5500RMB (=550EUR). Moreover, Labour cost in China for this kind of amp with correct QC is around 60RMB (=6EUR).  In US/EU it's something around 60EUR. Now apply same coeficient between BOM price of DAP made in China and Crest made in US compared to street price an you will see that the Crest is not so expensive
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Post Options Post Options   Thanks (0) Thanks(0)   Quote JD01 Quote  Post ReplyReply Direct Link To This Post Posted: 17 March 2007 at 9:27pm
1. I didn't say they are the same. I said that the power won't differ that much that one could say that the 1300W from the RMX are driving the PDs fully, while the 1350W from the ProLine won't.
 
2. Soundking is know for 'not so good' QC, that's nothing new and I didn't state anything like this. But I don't know why there shouldn't be a seperate QC for the 'big deal' amps. A lot of companies do it that way.
The journalist said it was info from inside QSC, not the new manufacturer.
Anyways, it's no secret that the PL6.0II isn't even near as good as the old PL6.0 was.
 
4. Some of them are already running for nearly three years now.
 
I don't want to talk about prices only a few of us can get. Only that much: If I can get 4 DAPs (and that is the quota everyone can get) with flaws I can easily fix myself (IF they ever occur) for the price of ONE CA18, it's not that much to think. The circuitry is the same, rail voltages are very similar, no advantage by lower weight of the 'high class product',  more transistors....
I somehow get the feeling that you bought a lot of expensive amps, now you're looking for a way to justify this or you have to gain something else from saying 'USA amps are worth their money'. I had a lot of people really knowing about amps interiors (more than I, known in Germany for their knowledge about amps) look into them and noone found a real issue not to buy them. In fact some of them are using them now for budget apps.
 
I guess this whole discussion has no point anymore. You won't change your standpoint, I won't change my point of view....


Edited by JD01 - 17 March 2007 at 9:29pm
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