Official 33609 builder's tread. See 1st page for updates.

[Igor]

Definately, yes.

 

[RedNoise]

Sorry for the redundant question , thanks .

 

[danjpiscina]

Hi guys. I almost have all the parts and I'm planning on starting this build soon. I've built an 1176 and a bunch of 1290 mic pres. This project is definitely a step up though! I've been reading through some posts and got some info, but I was wondering if anyone can tell me a little about their experiences and problems. I'd like to avoid trouble! Are there any mistakes that are easy to make? Any "errata" on the boards? etc. Any help would be much appreciated. Thanks!

Dan P.

 

[ultra-alex]

hi dan, the best advice i can give is, read this thread entirely and carefully. if you´re done, read it again. this is a nearly "complete" support thread. when you start building and get in doubt you will most likely find every question already answered...
take your time and measure/check twice every component before soldering in. the only real trouble i had was using some wrong resistor values cause i blindly trusted farnell. 
alex

 

[promixe]

ulta-alex, Nice unit! Congrats! How does it sound? =)

Update on my LF distortion saga:

I finally got a minute to plug in the second set of the boards (I was building two 33609s at the same time) into the first unit chassis (all switches+PSU remained from the first unit, just the channel boards are the new ones). After calibrating one of them I ran the same music test through it as I did with the original problematic boards - this one behaved in EXACTLY the same way, i.e. had the same character LF distortion at the same settings etc. So, the conclusion is - all four channels that I built act identically and all have the distortion issue.

RuudNL, have you been successful with your LF distortion mod overtime? Have you compared it to the original 33609 units in terms of how it sounds and how similar its response is? I'm thinking this is my last resort is to implement your mod on all four boards that I have.

Igor, since I have four boards that all have the "mystery LF distortion" problem, that at least 4 more people beside me on this thread have experienced, would you be interested in checking one of my boards if I send it to you?

Thanks for the support! =)

 

[rrs]

HI

I am just putting together this project and have realised theat the BOM states the SPDT farnell code as a on-off-on switch . It this correct or should it be on - on

 

[Rob Flinn]

on on is the correct part

 

[rrs]

Damn that's $80 down the drain.
Can someone fix the BOM. 

Can a (on-off-on) be used anyway and just avoid the middle position ?

 

[RuudNL]

Yes! (In the middle position no contact is made.)

 

[rrs]

Thanks I'll do that.

 

[maxheadroom]

Igor, since I have four boards that all have the "mystery LF distortion" problem, that at least 4 more people beside me on this thread have experienced, would you be interested in checking one of my boards if I send it to you?

Thanks for the support! =)

i welcome your idea!
you know i have the same problem, so when i can help you somehow please tell me.

 

[Igor]

OK, promixe will send me one channel set and I'll try to see what is possible to do.

 

[danjpiscina]

Does anyone else find it REALLY difficult to avoid solder bridges when installing the resistors on the elma PCB's? Maybe I just need to get a really really fine solder tip. Any suggestions? Higher temperature?

 

[Igor]

Use 63/37 alloy and good brand iron. I used to Weller WSD80. However, Hakko or other brands have good stuff as well.

 

[tommypiper]

Promixe, (and previously RuudNL), I'm sorry to hear your LF distortion is continuing without a cure...  I've been waiting to build mine, wondering if this mystery issue will be solved.  Thanks for sharing the problem and for everyone's sake I hope you find the solution.

A friend of mine here has built his 33609, but he is not impressed with the sound -- so I think he may have some distortion too but has not had time to measure or diagnose it.  There may be other people with this problem who do not know it.

Your theory was originally that the distortion could be in the diode bridge, rectifier in the sidechain?  Do I have that right?  Was that ever looked into?

If the problem is not on the channel boards, Igor's test will not find it...  (Thanks to Igor for the support!)

 

[promixe]

Promixe, (and previously RuudNL), I'm sorry to hear your LF distortion is continuing without a cure...  I've been waiting to build mine, wondering if this mystery issue will be solved.  Thanks for sharing the problem and for everyone's sake I hope you find the solution.

A friend of mine here has built his 33609, but he is not impressed with the sound -- so I think he may have some distortion too but has not had time to measure or diagnose it.  There may be other people with this problem who do not know it.

Your theory was originally that the distortion could be in the diode bridge, rectifier in the sidechain?  Do I have that right?  Was that ever looked into?

If the problem is not on the channel boards, Igor's test will not find it...  (Thanks to Igor for the support!)

I'll send a set of boards to Igor: that is the main channel board, the limiter panel board and the compressor panel board, all assembled. So if the problem is on one of the panel boards it will reveal itself when Igor hooks it up and tests it. =)

RuudNL has concluded that the reason the distortion occurs is because the release timing capacitor in the limiter chain can't keep the charge between two consecutive LF cycles. It discharges and then recharges thus introducing CV distortion superimposed on the audio signal. If you listen to my MP3s on page 20 of this thread (post #384) you will hear the nature of the distortion in the examples C & D - it increases with the increase of LF content in the material. I think RuudNL and I also agree that the worst sounding distortion occurs when the limiter is just barely touching the signal, and decreases (by a small amount) as you slam the limiter more. I urge the people who have built their units to download my original test MP3 in post #384 and run it through their 33609s with the setting described in the same post. Then post it here so we can evaluate the sonics of their units, because it could be quite possible that some people will simply not perceive the issue we're talking about here.

I have swapped most of the components in the limiter sidechain on one of the boards and it didn't get rid of the issue, so it must be something else. I'll try to arrange the shipping to Igor sometime next week. I am very very curious what his findings will be. =)

 

[rrs]

Re: Diode matching D3-6.

I have a function on my Digital Multimeter that measures forward voltage of diode.
Is this sufficient?

 

[rob_gould]

Hey Dave,

I've been trying to PM you but your inbox is full. 

Rob

 

[rrs]

Cleared Mail box !

 

[Rob Flinn]

Re: Diode matching D3-6.

I have a function on my Digital Multimeter that measures forward voltage of diode.
Is this sufficient?

That is what I used.  I use some sticking tape, to stick the diodes to a sheet of paper in a column.  Then go down with the meter checking forward voltgae drop.  Then write the value next to the diode being measured, until I find 4 of equal value.  It is important not to touch the diodes whilst measuring because their voltage drop will change due to heat from your fingers !!