The Unnamable Limiter... a troubleshooting long shot...

I just bought a clone of a well known Limiter whos name I suspect is not to mention here at GDIY...

But unfortunately, this build, or all of them?, do have issues with the metering being way of when it is supposed to show the first 3.5dB of limiting. In other words the last four leds showing 1 dB peak reduction, seems to show the right amount of reduction, but the blue leds that is supposed to show half steps of the first 3.5 dB of limiting is totaly unusable (for example, the step between -3.5 and -3dB is actually 8dB, and is showing the signal about 5 db below the limiting threshold... and so on... So the blue leds are not doing what they are supposed to do, but instead showing the signal way below threshold, which is kind of useless).

All the components seems to be in the right places with corect values according to BOM and one doc showing component placement on PCB. I got no schematic or anything else that could be of help doing troubleshoting.

Anyone here familiar with this build?

Please PM me if you do have any info to share!
  / Mattias


.... I attached a pic showing the section that I suspect is faulty in some way... all the compoments in the metering sectiont seems to have the right value and in the right places, so without a schematic I'm trying to get my head around this using logic reasoning and studying led meters using the LM339 circuit...

I cannot think of any limiter we would not mention here.

Cheers

Ian

Ok, I dont know if this will help me in some way but its a clone of the P*nd*l*m PL-2.

tonedude said:

Ok, I dont know if this will help me in some way but its a clone of the P*nd*l*m PL-2.

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Oh yeah.....I saw that one mentioned on the BM a while ago.......

Good Luck!

Not easy without schematics or info...

There are some trimmers in the GR section ?

scott2000 said:

Oh yeah.....I saw that one mentioned on the BM a while ago.......

Good Luck!

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Thanx!

Cardinen said:

Not easy without schematics or info...

There are some trimmers in the GR section ?

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Yes, there is one trimmer for each channel that effects limit threshold, range of ceiling knob, behaviour of ceiling knob, etc...

http://www.bristolwatch.com/ele2/comparator.htm

This is probably the circuit [LM399]. Check the voltage divider resistors?  You could put a trimmer in for the problem LED to set when it turns on?

mrclunk said:

http://www.bristolwatch.com/ele2/comparator.htm

This is probably the circuit [LM399]. Check the voltage divider resistors?  You could put a trimmer in for the problem LED to set when it turns on?

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Yes I tried that but the result was not predictable, I could change it with a trimmer but just by a small amount, but I'll try some more.

Voltage divider resistors have a total value of 104k, and I guess I have to keep the total value not to change the now functional "top range" of the meter?

Sure you're looking at the correct resistors? Don't think it's the ones in the picture.
You don't want the current limiting resistors attached to the leds btw but the ones across the LM399 pins.
I would draw out the LED driver section.
sorry if u know all this... 

Thanx! 

But yes, I'm sure, I have double checked it.

The meter section on the PCB is quite "large" consisting of a total of nine IC's per channel. I'll post a picture of the whole thang later... the current limiting resistors are are on another part of the board, closer to the contacts to the leds on the front.

mrclunk said:

Sure you're looking at the correct resistors? Don't think it's the ones in the picture.
You don't want the current limiting resistors attached to the leds btw but the ones across the LM399 pins.
I would draw out the LED driver section.
sorry if u know all this... 

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Guys,

Just so everyone is on the same page here Tonedude is talking about a clone of the Pendulum PL2 Limiter.  It was also mentioned by member Hugo in this thread with a picture -

https://groupdiy.com/index.php?topic=66924.0

You'll notice that he has deleted his post and pic presumably in response to my comment.

The clone was an exact copy of an in production product including the Pendulum name on the faceplate.  It reeks of the kind of B.S. that Purusha was up to back in the day.

I own a Pendulum OCL2 that I bought directly from Greg, he runs a small boutique operation and does not deserve to be defrauded like this.  These rip-offs will find their way into the used market and eventually be passed off as original to someone who does not know better.

I know this is a tricky area for the community but I don't think we should support such blatant rip-offs.  Many of us either have small businesses or work with small audio businesses and would not like to see others profit from our designs and work like this.

ruairioflaherty said:

These rip-offs will find their way into the used market and eventually be passed off as original to someone who does not know better...

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No, this one will not...

... but it seems as the picture of a PL-2 on reverb.com, if you do a search for it there, is a clone...

ruairioflaherty said:

The clone was an exact copy of an in production product including the Pendulum name on the faceplate.  It reeks of the kind of B.S. that Purusha was up to back in the day.

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Amongst other things...
I had no idea this was one of that cunts rip offs.

I fully understand your concerns about this and I have no intention spreading knowledge about this circuit.

So, if someone have knowledge about this "issue" with the meters being of on this clone, please PM me.

And... its obviously a very fine piece of equipment and it sounds great. My workaround is using the 5 dB point as a reference and then back of with the ceiling control to lower the amount of peak limiting to my liking.

Since I dont find any components being wrong on the PCB my guess is that this reverse engenering wasn't fully successful...

tonedude said:

the blue leds that is supposed to show half steps of the first 3.5 dB of limiting is totaly unusable

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This seems to indicate there is something very wrong with the reference ladder. Does it do it on both channels?

mrclunk said:

Amongst other things...
I had no idea this was one of that ****s rip offs.

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Mrclunk,

Just to be clear I wasn't saying that this was a Purusha product, I don't know that.  My point was it was the kind of I.P./Brand/Trademark infringement that he was involved in that was shunned by this community (deliberately producing knock off cases with Purple Audio logos for example).

abbey road d enfer said:

This seems to indicate there is something very wrong with the reference ladder. Does it do it on both channels?

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Yes its the same on both channels.

I'll have a thorough look at it when I have time.

tonedude said:

I fully understand your concerns about this and I have no intention spreading knowledge about this circuit.

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You may understand my concerns but you obviously don't share them if you were prepared to buy the unit.

Let me ask this another way - how would we collectively feel if Tonedude was asking for help with an exact knock off of a Gyraf product, or one of Mike's Hairball products?

Someone profited from the sale of this knock off, but they are not available to help?

(Again, echoes of Purusha with his laughable errors in clones).

Voltage divider / reference ladder resistors have a total value of 104k, I guess I have to keep that total value not to change the now functional "top range" of the meter? Somebody know about this?