or Connect
AVS › AVS Forum › Audio › DIY Speakers and Subs › Yung Plate Amp - Initial Impressions
New Posts  All Forums:Forum Nav:

Yung Plate Amp - Initial Impressions - Page 3

post #61 of 120
Javygonx, I have a Yung 300 watt plate amp that I purchased from Parts Express back lin September. I am getting ready to sell it because I just purchased a Behringer EP-4000. My Yung amp has a custom built cabinet that is really good looking. If you are interested in this amp, please feel free to hit me up. I will sell it for way less than what I paid for it. smile.gif
post #62 of 120
Thread Starter 
Marty, is that the non-boost version? If so, any chance you can measure a couple of resistors for us? Look over this thread, it has pics to guide if you are able.
post #63 of 120
Marty, I PM you. And Garcia I can measure the resistors (well; if Marty sells it to me).... I work for HP and on the assembly lines they have all tools needed to measure boards.
Edited by javygonx - 12/6/12 at 2:08pm
post #64 of 120
It'll be great to know where the actual filter is on the non-boost versions.
post #65 of 120
Quote:
Originally Posted by Martycool007 View Post

Javygonx, I have a Yung 300 watt plate amp that I purchased from Parts Express back lin September. I am getting ready to sell it because I just purchased a Behringer EP-4000. My Yung amp has a custom built cabinet that is really good looking. If you are interested in this amp, please feel free to hit me up. I will sell it for way less than what I paid for it. smile.gif

I'm waiting.....! biggrin.gif
post #66 of 120
Thread Starter 
Quote:
Originally Posted by javygonx View Post

Marty, I PM you. And Garcia I can measure the resistors. I work for HP and on the assembly lines they have all tools nedded to measure boards.

Sounds good. I noticed PE still has the 300W for a good price, and I'm tempted. But with two extra 500W BASH's, a Yung 200W-6, a 300W BASH, and a CSS 500W Yung, do I really need another plate amp? Plus I have a PE SA-1000 waiting to be used too! And that's not counting the old Keiga sitting in an enclosure that I can always use if needed. Sounds like I need more woofers, not amps! smile.gif
post #67 of 120
Quote:
Originally Posted by garciab View Post

Sounds good. I noticed PE still has the 300W for a good price, and I'm tempted. But with two extra 500W BASH's, a Yung 200W-6, a 300W BASH, and a CSS 500W Yung, do I really need another plate amp? Plus I have a PE SA-1000 waiting to be used too! And that's not counting the old Keiga sitting in an enclosure that I can always use if needed. Sounds like I need more woofers, not amps! smile.gif

Which Keiga? Any comments on their amps?
post #68 of 120
Thread Starter 
The old style 280W? that Madisound sells. It's been solid, and very well built. Mine induced a bad hum in my system, due to a protection filter of sorts on the preamp inputs (filtering to earth gnd). I didn't see any other amp doing this, so I removed the filter and now it's dead quiet. May have just been caps going bad, but I removed it to isolate the audio circuitry completely from earth ground.
post #69 of 120
Quote:
Originally Posted by javygonx View Post

I'm waiting.....! biggrin.gif

I will reply to your PM in just a few minutes!
post #70 of 120
Thread Starter 
Well, I got a little ambitious and ran some plots.

Here are two graphs showing the FR of a Yung 200-6 plate amp. One with and one without modification to the hpf. Notice there is still a boost even when the hpf is modified. The hpf was modified to have an Fc of about 13Hz, and a Q of .6. There should be NO boost at all, and FR should actually sag down low. There is some recovery in the frequencies below 30Hz, but not what I'd expect. Educational for me, as I now suspect I will have to learn about active boost filters. When I reassembled my 200-6, I did note another pair of matching caps, and they were configured in a way I haven't seen in any other plate amp schematic. I'm suspecting that is the stage providing the boost, in addition to the stock hpf.


post #71 of 120
Thread Starter 
I just noticed someone had plotted the fr of their 500-6 (borrowed from a gent on the PE forum). It does have the bass boost as spec'd, and achieves this in spite of having the 30Hz HPF as noted here. So there appears to be a seperate boost circuit in the signal chain. I will trace the fr along the way, and see if I can find a way to mod/defeat the bass boost.

post #72 of 120
Quote:
Originally Posted by garciab View Post

I just noticed someone had plotted the fr of their 500-6 (borrowed from a gent on the PE forum). It does have the bass boost as spec'd, and achieves this in spite of having the 30Hz HPF as noted here. So there appears to be a seperate boost circuit in the signal chain. I will trace the fr along the way, and see if I can find a way to mod/defeat the bass boost.

That's good to see!
post #73 of 120
Im still waiting for Marty so he can ship the Yung 300 amp to me to check the resistors.... cant wait!! smile.gif
post #74 of 120
Parts Express is sold out of the Yung 300 watt amps... Won't be back in stock until end of March...
post #75 of 120
Its pretty sad. I had the opportunity to buy it when onstock but bought and used one from marty and came faulty. It does not turn on. Now im waiting for him to renfund the money or check with parts express for warranty.
post #76 of 120
Thread Starter 
Do you at least get the red power led when you plug it in? If so, do you hear a slight click when you feed it an audio signal? Have you checked to see if the fuse is blown?
post #77 of 120
No red led. I have to check the fuse!!

See this video

http://www.youtube.com/watch?v=elEqplEOfgg
post #78 of 120
Looks like a blown fuse. Will let you know as soon as I replace it. Is this common on this amp to blow fuse frequently?
post #79 of 120
Thread Starter 
Not enough experience with these yet to see if there are common problems with any of these models. I did order a 300W model after all, so I hope they don't suffer from some design defect. Keep us posted.
post #80 of 120
Installed a 2.5amp / 250v fuse and blows it instantly. The fuse i removed from yung is a 5amp / 250v

I installed a 2.5 amp because I cant find a 5amp / 250 volts fuse. The fuse size is small. I was able to find it but bigger size which does not fit.

Now im wondering what is the exact type of fuse needed for the yung 300 amp?
Can someone do me a favor and check it out for me?
Thanks.
post #81 of 120
The fuse that use the Yung 300 is a 5 amp - 250v Slow Blow. I bought 4 of them and .... Blows it instantly. Thats for sure something is really wrong with the amp.
post #82 of 120
Thread Starter 
Yes, something is definitely wrong. Give the amp a good visual inspection to make sure there is nothing touching that shouldn't be, like a couple of components leads shorted, or something touching the metal plate. It's about all you can do. Hope it's something as simple as that.
post #83 of 120
Ok. Keep you posted. May I measure the resistors you were looking in that condition? Or the amp needs to be power on?
post #84 of 120
Thread Starter 
Yes, measure the resistors if you can. Make sure the amp is completely unplugged before you do to avoid accidentally shocking yourself. No power necessary to measure them. Thanks.
post #85 of 120
Thread Starter 
So here is a wrap up regarding the frequency response of this line of amps. We know that all the boost models share the same HPF (subsonic, rumble filter, etc), and it is set at 30Hz with a little boost above that. We also know that there is a seperate bass boost circuit to give the boost that is spec'd for each model. The HPF and boost are summed (combined) to give the overall frequency response (plus the phase and low-pass adjustments of course). So for those still interested in these, and having the desire to modify/customize the response, here are a couple of pics to help. Best thing to do is to defeat the boost circuit altogether, then tweak the HPF as desired, and as is common with other plate amps.

This pic points to the two resistors that need to be changed to tweak the HPF. They are located close enough to the edge of the pcd (near the led) that it shouldn't be too difficult.



This next pic is the back of the preamp pcb, and shows the two jumpers needed to defeat the bass boost circuit.



Here is the frequency response of my 200-6, after defeating the bass boost circuit, and modifying the HPF to an Fc of 13Hz, Q = 0.6.



We haven't had any user feedback about the non-boost models, but my suspicion is that they share the 30Hz HPF, but their boost circuit is configured for no boost. I will try to confirm this when my backordered 300W model arrives.
post #86 of 120
What value are the capacitors in the 2nd order HPF? I think from the picture they're C4 / C5.
post #87 of 120
Thread Starter 
They are .22uF.
post #88 of 120
Capacitors? It looks like 2 resistors and 2 jumpers. Can you clarify garciab?
post #89 of 120
Thread Starter 
The two resistors are for modifying the HPF.

The jumpers bypass (short across) the capacitors that are on the SEPERATE bass boost circuit, to defeat the boost. Placing the jumpers on the back side is easier than having to remove the caps and install jumpers in their place. Also, one may actually like the bass boost, in which case they can simply remove the jumpers to re-enable the boost. The major drawback to this boost circuit is that it really hurts the low-end frequency response of these amps, especially if one is looking for output below 20Hz.

These amps actually have a little boost configured into the HPF and also have a seperate circuit that provides the bass boost that is spec'd for each model. The outputs of these two circuits is summed together (combined) right before the signal hits the 'phase adjustment' circuit, then on to the 'low-pass adjustment' circuit. So I identified the components for tweaking the HPF, and also identified a way to defeat completely the bass boost. It would be nice to find a way to modify the bass boost circuit, but its components are located such that it would require removing the board, which is quite a pain and not worth the trouble. Better to just defeat it completely, and incorporate any desired boost at the HPF stage.
post #90 of 120
So, does the supposedly boost free version still need C13 and C14 of the boost circuit shorted in order to get a flat response controlled only by R8 and R23?
New Posts  All Forums:Forum Nav:
  Return Home
  Back to Forum: DIY Speakers and Subs
AVS › AVS Forum › Audio › DIY Speakers and Subs › Yung Plate Amp - Initial Impressions