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NOTICE: Yung Subwoofer Plate Amplifers

68K views 118 replies 28 participants last post by  patrikPAT 
#1 ·
In one of our threads the issue came up about whether the Yung SD-200 plate amp has a subsonic filter. In the "Questions and Answers" section on the Parts Express website, someone posted the amp does not have a sub sonic filter.
I heard that it did, so to clarify the issue I went to the source, http://www.yung.com.tw/

I asked: Does the SD-200 has a sub sonic filter, and if so, at what frequency.

The reply was All of our SD-series amplifiers have a sub sonic filter. The working frequency is 30Hz.

I thought it was a mistake and replied: You must mean the sub sonic filter is 20hz, am I correct?

The reply was Our engineer advised that the subsonic filter is 30 hz on all SD-series amplifiers.

EDIT

A Rep from P.E. has stated that the amps are (supposedly) flat to 30 hz and 3 db down at 21 hz, but this needs to be verified.

http://www.parts-express.com/term/yung?srch=yung





 
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#3 ·
Ouch. That's just nuts, that high of an HPF isn't good for anything besides small box 8" drivers or maybe a wimpy 10". That's going to make the Yung amps impossible to recommend. That is unless they publish info on how to modify the HPF, if the amp design even allows for that. I'd suspect that it might be since there are the models with boost.

It's even laughable. A 500W amp with an HPF at 30Hz, not to mention a 200W or 500W amp with 6dB boost and HPF at 30Hz.
 
#7 · (Edited)
I'm the one who ordered the 200W model with 6dB bass boost from PE, and found that there is boost, and Fc does calculate to be about 30Hz. Only thing was that the boost calculated to be only about 2.5dB. I also own the 500W model from CSS, which should have no boost and it was assumed had subsonic down about 20Hz. I'll take it apart and check the resistors to see where Fc is set.

As I warned before, it is not easy modding these. The preamp board is glued pretty well to the steel plate, and must be removed for safe modding due to the use of surface-mount resistors. The BASH is much easier to mod, for sure.

It's interesting that my 200W model had "200-6" written on the pcb with a marker, which I thought was a sign that it was actually as advertised. To me that indicated that it was indeed different from the 'no boost' model, and , even different than the other models with boost. I'm confident that all models use the same preamp board, so now I'm curious to see if my 500W model does extend down to under 20Hz.
 
#11 ·
I'm the one who ordered the 200W model with 6dB bass boost from PE, and found that there is boost, and Fc does calculate to be about 30Hz. Only thing was that the boost calculated to be only about 2.5dB. I also own the 500W model from CSS, which should have no boost and it was assumed had subsonic down about 20Hz. I'll take it apart and check the resistors to see where Fc is set.
The boost should be at 35Hz for the 200W model...

Do you mean the Fc of the HPF is at 30Hz? Is the boost actually centered at 35Hz as advertised?
 
#10 · (Edited)
Note...

A rep from PE (Mike V.) had this to say about the Yung amps...

"Sorry I'm late to the party on this. The Yung SD Series plate amplifiers are flat to 30 Hz, -1.5 dB @ 22.5 Hz, and -3 dB @ 21 Hz. I have no information on modifying this filter and strongly discourage it as Yung has designed the amplifiers to perform to high standards with the filter in place as-is."
http://techtalk.parts-express.com/showthread.php?234409-Yung-or-Bash&p=1869703#post1869703

So if it's -3dB at 21Hz, it'd be more appropriate to call it a 21Hz HFP, right?
 
#18 · (Edited)
Well, my 500W from CSS (non-boost) is even more troubling. Once again we do get an Fc of 30Hz, but with much more boost. Here are the stats.

Fc = 30.595Hz, Q = 1.7
Gain at Fc = 4.8dB
Center Frequency Boost = 34Hz, Gain = 5.1dB

So this kind of jives with what Yung communicated. PE is going to have to check some of their amps to see what they really have. I don't know if they've actually measured the circuit response, or if they are going by what Yung told them (which seems to be different than what they told us).

I must point out: MY circuit analysis is only based on ONE clear active circuit that I could find. I traced the board right up to where the signal goes to the level, low-pass, and phase pots. I'm not an expert at circuit design, but I don't believe there is any more HPF type circuitry mixed in there. What I've traced so far looks very typical of what I've seen in other plate amp schematics, except these numbers aren't looking good. I've been tweaking these circuits since back in the early days of DIY plate amps, and seems to me all other circuits were pretty close to what was advertised.

For whatever it's worth, there you have it.
 
#21 ·
Yes, the resistors are changeable. Not easy to do without removing the preamp board, but it's possible. I have the preamp board removed for my 200W model; wasn't a walk in the park but obviously possible. The resistors are close to one edge of the pcb, so it may be do-able without removing it. It won't be military-grade soldering, but it would likely work just fine. I did have a bit of difficulty getting my dmm to read the resistance, so that should give one an idea of accessibility.

The other problem is the fact that these are small surface mount resistors. It would be difficult to custom tune with the same ability that leaded resistor give, say if you needed to put two in series for example. Which I've had to do on every amp I've modded so far, but I was working with only an older resistor kit from RS.
 
#23 · (Edited)
I'll throw in my two cents regarding the 3 db down in response.

I'll eat my hat if anyone can actually hear the difference between dead flat and down 3 db in actual real use. Our hearing acuity is not that keen in the low end. And at 20 hertz most of you gents are not moving enough air to actually hear a clean 20 hz tone in the first place.

Second point is that almost every conceivable room will offer reinforcement due to being in the near field in respect to the frequency wavelength of 20 hertz.

Third point is that almost every room will offer substantially more than 3 db of room gain at 20 hz.

The Yung amps are solid performers that and DIYer should be proud to own and use.

I have recommended them in my work a number of times with no problems.


 
#32 ·
So it appears that all of the boost models from PE have the same HPF. A 200W, 300W, and 500W model have all been reported to have the same components.

Having said that, my 500W CSS does have different components, which show to have a true 6dB boost (or much closer than the PE models). So maybe you can provide some insight into what exactly CSS has asked from Yung for their design. Do you know if CSS actually wants them with boost or with a flat response? I'm just curious, as I gather info about these amps.
 
#25 · (Edited)
Just a heads up for those interested in these amps...PE has an AWESOME sale on the 500W-6 model, only $129! Make sure you click there from here. :) Good pricing on others too, but this is the most outstanding deal by far.

Edit:
Yikes!!! I thought PE was a sponsor here....what happened? Or was I wrong about that? Anyway, sorry about that.
 
#28 ·
If it does actually have the stated boost, you could use it with a sealed design and not worry about the particulars. I'd expect a sealed sub to benefit from the boost. If you wanted to use it in a vented design, I'd guess you'd be ok as long a your tuning wasn't too far from the boost.
 
#31 ·
Hi to all. I just need bit help here. I want to buy the 500w Yung but not sure if getting the +6db version or the normal one. I made a 15" sealed sub around 3cF.. Driver is a Dayton 15"HF. Enclosure is very well braced and with driver weights around 80 pounds. I was using a inuke 3000dsp but the inuke was damaged and meanwhile im using a bash 250w plate from my BicPL200 and guess what? With the 250w bash plate sounds better than my inuke!! And yes, I tried different dsp setups on the inukes....

On description says thst is good the +6 version for sealed subs.

I can get even the 300W version for such cheap price of $99 or the 500w with +6 boost @ 30hz from $129.

Help please
 
#33 ·
I no longer do any work for CSS.

And I was not a part of the sub amplifier purchase.

If you have done some measurements and calculations then please share them.
 
#35 ·
i have the yung 500w +6db modle and got a chance to use it and compair it to a oem 200watt plate amp out of a 15 klh subwoofer i have.

just a quick break down, i used 2 12's sealed in 3.3ft3 wired at 4ohm final load. the 200watt amp i have produces much more output for lfe while watching movies. my avr crossover set at 50hz and i got alot more volume from the klh amp, turned crossover to 80 and i got alot more from the yung amp, but its not what i wanted for a ht sub. i didn't try music, but i'm sure the yung would do fine there.

i think this experience shows more about the hpf issues with this amp, i'd love for somebody with more knowladge than me find a way to remove this HPF to make the amp more usible.
 
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