DIY-Racked DR-609 build...

[dmp]

The BA340 is used as an op-amp to drive the output. It is on a 24v power rail. If you fit / solder in a 990 it should work. You just need a DOA that is meant for 24v and has good drive capability.

FYI - you want heatsinks on the at least one of the BA340 transistors if your using that card (forgot which one). If you have it powered up, see which ones get really hot

 

[Rob Flinn]

If you fit / solder in a 990 it should work. You just need a DOA that is meant for 24v and has good drive capability.

All the 24v DOA's I know of need a bipolar +&-24v PSU & the 33609 only uses +24v

 

[dmp]

Good point.
If you search this thread there were additional components needed.
Would have to do some work to figure out how to get it to work

Hi Alex, 990 option is to use 990 style discrete op-amp instead of ba340.
There's components marked Cj, Rj, etc, at bottom silkscreen. Don't install them with 340.
They go only with 990 style opamp, to bias input to halfsupply and support feedback path.
IIRC nobody wanted to use 990 option, and it died on my proto, but tested.

 

[Rob Flinn]

Good point.
If you search this thread there were additional components needed.
Would have to do some work to figure out how to get it to work

Igors version pcb had provision for DOA's but it split the 24v supply rail so they were running on effectively +&-12v. Looking at this pcb as far as I can tell it doesn't appear to have been designed for a DOA option, but maybe I'm wrong.

 

[phelar]

I'd also be interested in other BA340/440 pcb's out there.

@phelar - Maybe try Tat on Facebook, he's quite responsive there

Yes, no answere im affraid....
@Jase_Sanderson maybe you can help me with the messures on the amp340 pcb. The board dimensions and the pitch between the connecting pins?
It would be very helpful.

 

[Rob Flinn]

Yes, no answere im affraid....
@Jase_Sanderson maybe you can help me with the messures on the amp340 pcb. The board dimensions and the pitch between the connecting pins?
It would be very helpful.
View attachment 101208

If it's to the original Neve dimensions I believe pitch is 0.1" because I seem to remember making a test jig using veroboard.

 

[phelar]

If it's to the original Neve dimensions I believe pitch is 0.1" because I seem to remember making a test jig using veroboard.

Thanks! Yes, you are right

 

[Jase_Sanderson]

Yes, no answere im affraid....
@Jase_Sanderson maybe you can help me with the messures on the amp340 pcb. The board dimensions and the pitch between the connecting pins?
It would be very helpful.
View attachment 101208

sorry only just seen this, I will take some measurements if still needed

 

[phelar]

sorry only just seen this, I will take some measurements if still needed

No problem I found some measures on the web.

 

[ateshk]

I am building a RD-609 V1. I have everything built, installed and connected except output transformers. I power it up without the output transformers and there was no smoke or anything. But, I am having problem with the dB compression meters, can someone confirm that the connections are reversed? On the PCB pin1 is ground that should be connected to - lead on the meter and pin 2 should be connected to the + lead on the meter? Even if I make the connection like this, there is +15V on pin2 and the meter goes all the way up immediately when I turn it on. What could be the problem here?
Are there any other issued about V1? please let me know.

 

[chefducuisine]

I built Igor's Version a couple of years ago and it does the same: During switch-on both VU-Meters hit the right end stops for a few milliseconds and drop back to the left. (The meter going up during switch on is perfectly normal on a 33609 as far as I know.)
Can you check this behavior on your unit? To avoid damage to the VU please disconnect the meters and verify by connecting a DMM instead. Measure if voltage is present during switch-on and falls back to near zero if correctly calibrated. (I cannot remember if the VU circuit requires calibration though).

Second question would be what VU-Meters you are using? (a Sifam AL19 is used in the original)

 

[ateshk]

I built Igor's Version a couple of years ago and it does the same: During switch-on both VU-Meters hit the right end stops for a few milliseconds and drop back to the left. (The meter going up during switch on is perfectly normal on a 33609 as far as I know.)
Can you check this behavior on your unit? To avoid damage to the VU please disconnect the meters and verify by connecting a DMM instead. Measure if voltage is present during switch-on and falls back to near zero if correctly calibrated. (I cannot remember if the VU circuit requires calibration though).

Second question would be what VU-Meters you are using? (a Sifam AL19 is used in the original)

thanks for the reply. Voltage does not drop. It stays at 15V.
I use S-500 dB compression. I get them from Don audio.

 

[chefducuisine]

Is the unit calibrated?

 

[abbey road d enfer]

Can you check this behavior on your unit? To avoid damage to the VU please disconnect the meters and verify by connecting a DMM instead. Measure if voltage is present during switch-on and falls back to near zero if correctly calibrated. (I cannot remember if the VU circuit requires calibration though).

Using a DMM is not a good indicator because it does not provide significant discharge path for current. It is better using it in DC milliAmmeter mode.

 

[fabius]

I am building a RD-609 V1. I have everything built, installed and connected except output transformers. I power it up without the output transformers and there was no smoke or anything. But, I am having problem with the dB compression meters, can someone confirm that the connections are reversed? On the PCB pin1 is ground that should be connected to - lead on the meter and pin 2 should be connected to the + lead on the meter? Even if I make the connection like this, there is +15V on pin2 and the meter goes all the way up immediately when I turn it on. What could be the problem here?
Are there any other issued about V1? please let me know.

Hi Ateshk

I have built two months ago a MB2 SSL Compressor from DIY Racked. And had the issue, that the vu meter was going straight full to the right! So, my friend has also done a MB2. Also with S-500 dB vu meter from Don Audio. As far as i can say, it seem's, that the PLUS and MINUS of the VU Meter are interchanged. As soon i have put the + Signal to the - of the vu meter and viceversa with the - to the + on the vu meter, everything was fine!

Be careful! I am not shure if it behaves the same on your unit. But on our MB2 we had to make it like that and it worked!

Best, Fab

PS: Also when we give power on the compressor, the needle goes under 0db and comes back to zero. On both units. But works perfectly!

 

[ateshk]

The unit is not fully calibrated. Because of the meter issue and not having output transformers, I didnt run a signal trough the unit.
when I invert the polarity on meter connections it goes below 0 dB and stays there. Its the same on both channels/PCBs. There is a mistake on the PCB and there is a fix for C20. Could this be related to the meters? Maybe the fix I made is not correct.

Could there be PSU issue? I have used a different regulator PCB but still it can supply very steady +/-24V. Its a big board that I have designed for an amplifier and it can handle current draw up to 5 amps. I have made a mistake on the original PSU board and ruined it while trying to fix it.

 

[fabius]

Atehsk

Contact Tat Parusha over Facebook and get a new PSU Board.... Stay on the original path...

Best, Fab

 

[HerbertR]

The unit is not fully calibrated. Because of the meter issue and not having output transformers, I didnt run a signal trough the unit.
when I invert the polarity on meter connections it goes below 0 dB and stays there. Its the same on both channels/PCBs. There is a mistake on the PCB and there is a fix for C20. Could this be related to the meters? Maybe the fix I made is not correct.

Could there be PSU issue? I have used a different regulator PCB but still it can supply very steady +/-24V. Its a big board that I have designed for an amplifier and it can handle current draw up to 5 amps. I have made a mistake on the original PSU board and ruined it while trying to fix it.

Hi, as Fabius said, I would suggest to stay on the original path. It is a more complex build. Try to get the output TX. Or it will not make sense to do any calibrations.
About the PSU - symetrical 24V and you should be okay, if measured properly. For the connection of the meter you can look at my detailed pictures with the colored arrows / wires. I hope my old detailed pictures will help.
But my boards are V1.1 and they have no issue. BR

 

[ateshk]

Thanks for all the help.
Finally I got the output transformers and finished building it.
I start calibrating. 1st few steps went ok and calibrated RV6 to 3V but RV2 does not seem to change anything. I keep reading 0.265V AC on the output of the unit. No sound on the output. keep reading around +15V on the + lead on the meter.

 

[ateshk]

I can measure AC in and out of the input transformer. After the the resistors and diodes, on test point F and H there is no AC but there is 650mV DC. On the input pins of the interstage transformer there is 3.6V DC. there is nothing on the output pins of interstage transformer. Are these measurements normal/correct? These measurements are taken with the setting written in the 1st step of calibration with 1 khz sine wave connected to input.