Can anyone help me finish wiring my 33609

GroupDIY Audio Forum

Help Support GroupDIY Audio Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

danjpiscina

Well-known member
Joined
Aug 27, 2008
Messages
245
Hi there. I am about 95% ready to hook up my new 33609. It has been a long time in the making and I'm really anxious to hear it!

I am not very great with wiring. I have an Avel Lindberg 2x25V/1A [model Y236206] power transformer but I'm not quite sure how to hook it up to Igor's power supply. Has anyone done this before? I don't want to hurt myself!

I guess my question is this:

do I wire it as "dual isolated secondaries"?
  [see this document:http://web.archive.org/web/20090914070140/http://www.diyfactory.com/data/transformer_connections.gif  ]

if so, then where does "0V" go? I know these are ridiculously newbie questions, but I'm still a newbie!

On Igor's PSU [  http://i251.photobucket.com/albums/gg291/diy33609/POWER_SUPP_33609.gif  ] there are 2 points labeled "~28." and "~28.." what are these? I'm also confused about "+CV" and "-CV"

Thanks for listening! Any ideas will be much appreciated : ]

-Dan P.
 
it appears that igors ps want 28vac...you should parallel your secondaries though the voltage may be low and feed the ~28 pads.
 
Thanks for your reply. I finally figured the power supply out and powered up the 33609. everything is fine until I connect the compressor board cable to channel 1 [cannel 2 is fine]. When this is connected, R26  [47R] starts to cook!I still can't find anything wrong. Does anyone have an idea of what I should be looking for?
 
resistors burn because they cannot dissipate the heat generated by the current flow. Check our parts and solder connections.  maybe try a larger wattage resistor?
 
my only fear with adding a higher wattage resistor [it's already 1/2 watt and only calls for 1/4] is that I will fry other components without knowing it because the resistor wont fry!

should I replace all "replacement" BC214's [BC237B] and BC184's? with NOS original components?



 
danjpiscina said:
my only fear with adding a higher wattage resistor [it's already 1/2 watt and only calls for 1/4] is that I will fry other components without knowing it because the resistor wont fry!

should I replace all "replacement" BC214's [BC237B] and BC184's? with NOS original components?

o.k. if you have already gone up a 1/4 watt to a 1/2 watt and it is still frying then you have a larger problem and the resistor burning is one of the symptoms. Replacing transistors to NOS will most likely not solve your issue. This when having a variac is handy as you can get power to trace circuits without having to have it running at full 120VAC.  You most likely have a faulty component/s, a transistor/s perhaps, faulty solder joint.. Go over everything and compare between both channels as you said channel 2 was working without issue.
 
First, it is confusing for you to post in the 33609 build thread and start a new thread here, because people have to be reading both.

Now - a problem with R26 is pretty isolated. The schematic shows that TR5 (bc214) is conducting based on the bias of the diode string, R26, and the ratio switch. With the power off you can check that the ratio switch is giving the correct resistance. Switches are often the source of problems. You can switch the switch boards between channel A and B to see if the problem follows the main board or the switch board. You shouldn't have to increase the wattage of this part - it is a simple part of the circuit setting the ratio.  Having a diode wrong is also a possible mistake. Make sure the 2.7v zener is oriented the correct way, otherwise it won't provide the correct voltage drop. The fact that the resistor is blown would warrant checking all the other silicon parts around there since they could be fried too. TR5, D12, D3, D4,D5,D6...

schematic for ref:
http://i251.photobucket.com/albums/gg291/diy33609/33609_SCHEM_VOLT.jpg
 
dmp said:
Now - a problem with R26 is pretty isolated. The schematic shows that TR5 (bc214) is conducting based on the bias of the diode string, R26, and the ratio switch. With the power off you can check that the ratio switch is giving the correct resistance. Switches are often the source of problems. You can switch the switch boards between channel A and B to see if the problem follows the main board or the switch board. You shouldn't have to increase the wattage of this part - it is a simple part of the circuit setting the ratio.  Having a diode wrong is also a possible mistake. Make sure the 2.7v zener is oriented the correct way, otherwise it won't provide the correct voltage drop. The fact that the resistor is blown would warrant checking all the other silicon parts around there since they could be fried too. TR5, D12, D3, D4,D5,D6...

schematic for ref:
http://i251.photobucket.com/albums/gg291/diy33609/33609_SCHEM_VOLT.jpg

Thank you Pucho and dmp! The reason I posted in the original build thread and then started this one is because the old thread had not been posted on in over a year so I wasn't getting any replies…

I have already switched the boards around and there was no problem with the other channel [so I don't think this issue is related to the switch board]. I will check the diode orientation and other silicon components when I get home. Then I'll report back!

Thanks again for your time guys : ]  I tend to freak out when I spend so many hours on a project and it doesn't work!

Dan P.
 
The BC237B's seemed to be the issue. I removed them [including TR5] and installed actual BC214's that a friend gave me. I replaced 1N4148's [D3 thru D6] and the 2.7V zener [D12]. Now the resistor doesn't fry. However, it does act just like channel 2; it's not working. It passes audio [when powered on, and not powered] but switching from comp in/gain knob, threshold, etc. have no effect whatsoever. Also, I do hear the relays click. They appear to be working fine.

I have also done the basic calibration test [PSU is feeding 23.7V to the mother boards, measuring 3V between +CV -CV on PSU, measuring 250mv from BA340 between R44, etc.] 

Could this be a grounding issue? Should I grab ground from somewhere on the main PCB and attach it to chassis ground? This seems very odd!

Dan P. 
 
You could have a problem anywhere in the sidechain.
I wouldn't suspect a grounding issue on this.
Does the meter bounce when you are running music through it?
That would tell you most of the sidechain circuit is working.
The whole lower section of the schematic is the sidechain. Check voltages throughout.

I did find that connecting the power ground on the psu board to the chassis ground was more robust for ground loop noise in different use situations.
 
dmp said:
You could have a problem anywhere in the sidechain.
I wouldn't suspect a grounding issue on this.
Does the meter bounce when you are running music through it?
That would tell you most of the sidechain circuit is working.
The whole lower section of the schematic is the sidechain. Check voltages throughout.

I did find that connecting the power ground on the psu board to the chassis ground was more robust for ground loop noise in different use situations.

Thanks for your reply dmp.

No, the meter does not bounce when I run music through it. It only bumps up and down slightly when I engage the channels' compressor in switch [or when I place crocodile clips between link and +CV of course. And turning the trim pot on the power supply does bring down the needle]. But that's it.

I have already connected the PSU ground to chassis ground.

I borrowed mata_haze's reference voltage numbers [from reply #723], and here is what I got on Board 1:

TR3 Base 17V = 16.66

TR3 Collector 17.6 = 4.79-----------and TR3 Emitter is 17.3V! [This is a newly-replaced transistor and the pinout is correct. It somehow seems like the Collector and Emitter should be swapped!]
TPA 4V = 4.79

TR4 Base 17V = 16.67
TR4 Collector 4V = 3.54
TPD 11.6 = 11.5

TR2 Base 4.1V = This starts @ 2.5V, then drops quickly. This transistor is also close to the resistor that would fry [R26] but this resistor was replaced. Very odd
TR2 Emitter 4.7V = Starts @ 3.3V, then slowly climbs

TR2 collector 0.64V = 0.63V
TR15 collector 9.9V = 11V

TR8 Emitter (TP E) 0V = 0.57V

TR9 Base 0.6V = 0.54V

R2 23.8V = 23.2
R2 (TR9 collector) 23.3V = 23.2V

TR6 Emitter 20.4V = 20V

TR10 Base 7V =7.13V
TR10 Collector 17.4V = 16.97
TR10 Emitter 6.4V = 6.64V
TR11 Emitter 2.5V = 2.32V
TR7 Emitter 23.7V = 23.5
TR7 Collector 0V = 0V

TR12 0.6V = 0.6V
TR1 Collector 0V = 0.1

All voltages that are not in bold are roughly where they should be. I am not very advanced with electronics, and perhaps I am "in over my head" with this compressor build, but I feel like I'm so close! I have successfully built two 1176's and eight channels of EZ1290's so I really don't think this should baffle me as much as it does. But it does! Any ideas would be greatly appreciated. Thank you! 

edit: I just got the meters to work. I had wired the input/output connectors incorrectly [I thought 1 corresponded to Ground of XLR, and 2 hot, 3 cold, but it's not wired that way].

Now my problem is that when I switch bypass in [out of bypass] I lose my output signal. The meters show compession but I can't hear anything. When the unit is bypassed, I hear it [not compressed, of course]. How is it that I completely lose the signal when the compressor is in? And how would I go about tracing the signal?
 
So this is a lot of progress. If the meters are working (bouncing when you play music through) then the sidechain is creating a cv for the compression.
You already said the audio works with the compress and limit off - meaning the audio path is working unless the sidechain is on (not just in hard bypass?)
(To clarify there is both a hard bypass (relays on in/out) and a soft bypass, when the limit and comress are both off, but the signal is still going through the 33609 audio path)

The main elements of this type of compressor is the audio path, the sidechain, and the gain reduction element (diode bridge).
If both the sidechain and audio path are working then you should look at the diode bridge having a problem. Are the diodes the right type, oriented the right way?



 
dmp said:
So this is a lot of progress. If the meters are working (bouncing when you play music through) then the sidechain is creating a cv for the compression.
You already said the audio works with the compress and limit off - meaning the audio path is working unless the sidechain is on (not just in hard bypass?)
(To clarify there is both a hard bypass (relays on in/out) and a soft bypass, when the limit and comress are both off, but the signal is still going through the 33609 audio path)

The main elements of this type of compressor is the audio path, the sidechain, and the gain reduction element (diode bridge).
If both the sidechain and audio path are working then you should look at the diode bridge having a problem. Are the diodes the right type, oriented the right way?

Thanks dmp this has been very helpful. I haven't had time to look at the compressor yet, but I know that that I replaced the 1N4148's [D3. D4, D5, D6] and the 2.7V [D12]. These are properly oriented.

I hear audio when the unit is hard bypassed. As soon as the relay bypass is out, I lose the signal; regardless of whether the compressor or limiter section are in. However, with those sections out, I don't see gain reduction which of course means those bypasses work fine as well.

I will check the diode bridge tonight. Thanks again!

Dan P.

P.S. : this is the 2.7V Zener that I am using. Is this correct?

http://www.mouser.com/ProductDetail/NXP/NZX2V7B133/?qs=%2fha2pyFadui9IEdkV%2fuBRFsCpJ8BpOIcLig%2f7FJe4jWx8o24qMCq7A%3d%3d
 
Checked the diode bridge. All components seem to be correctly oriented. No really sure what else to look for. I asked Igor about a capacitor I haven't installed yet [in the main build thread], and I will double-check output transformer wiring [I am using Sowter 8751's], but other than that, I am clueless!

Could this be a problem involving the BA340? I'm not really sure how to test it.

 
If you don't have a scope, you can make a test probe attached to headphones to listen for where the signal stops.
But I agree, you need to have a way to see where the problem is.
The BA340 is the make up gain amp so if it isn't working you won't pass signal.
 
buildafriend said:
what is the best bang for the buck 33609? my friend wants to build one, im trying to steer him strait as he has basically no DIY experience

apparently this one is pretty cool. and cheap. it's a simpler circuit and doesn't have any stepped stuff though:

http://www.vintageking.com/Black-Lion-Audio-AGB-Compressor

Thanks for the help guys. I will look into getting a probe working and report back!

One thing; I find the hot/cold/ground wiring strange. Looking at Igor's photos it looks like input 1,2,3 on the board corresponds to hot, ground, cold and output is the same. However, on the voltage schematic [ http://i251.photobucket.com/albums/gg291/diy33609/33609_SCHEM_VOLT.jpg ] 1,2,3 is hot, cold, ground. Very confusing! Wouldn't it make more sense if these numbers corresponded to the XLR numbers?
 
Back
Top