REDD EQ, Helios 69 and Dick Swettenham

I totally missed the poor man's makeup. Yeah, if that can be rewired to be similar / same as in the REDD, I'm a happy camper

Marc Duchesne said:

Cool, I can then manage to fit it in a 51X, do you happen to know if anybody designed a 500 front panel already...
Thanks Ian

-marc

Click to expand...

As far as I know there are no front panel designs at all right now.

Cheers

Ian

So discrete inductors will be the way to go for the small values?

Not a cheap build and not seeing myself able to save any time soon as I need tons of iron for current ongoing projects.

Hey Ian take your time on this one "slow makes perfect" and all that

Couple of Q if you can spare the time:
Any special considerations if planning on interfacing the O/p with a BA283?
Wouldn't the input have to be balanced? you said you were going to do 10k bridging just want to understand if this would be just something setting the impedance or dealing with the balanced in as well? (hope I'm making sense).

Cheers!

Ian, which inductors did you decide to use? I can't find any small value parts on Edcor's site.

I'll be in for a pair of boards.

Dylan

Dylan W said:

Ian, which inductors did you decide to use? I can't find any small value parts on Edcor's site.

I'll be in for a pair of boards.

Dylan

Click to expand...

My apologies, I must have had well known inductor manufacturers on the brain. The small value inductors are made by EPCOS. - the EPCOS - B82145A Series RF Chokes.

http://tinyurl.com/bz9dbct Edit: fixed URL

Cheers

Ian

jplebre said:

So discrete inductors will be the way to go for the small values?

Click to expand...

From the few tests I have done so far they seem to work fine. I was feeding levels of +10dBu or more into the test circuit so I could get a 0dBu output so they were getting realistic levels. With +15dBu fed in and maximum cut at 2.7KHz the 1KHz distortion at this level was 0.01%

Couple of Q if you can spare the time:
Any special considerations if planning on interfacing the O/p with a BA283?
Wouldn't the input have to be balanced? you said you were going to do 10k bridging just want to understand if this would be just something setting the impedance or dealing with the balanced in as well? (hope I'm making sense).

Click to expand...

Should be OK - I assume you are talking about the output section of the BA283. Its input impedance should be high enough hot to load the EQ.

The EQ as a whole is unbalanced just like the Helios EQ on which is is based. The input can be run balanced or unbalanced. You can use it unbalanced just like the Helios EQ in the EZTubeMixer or you can balance its input with a 10K:10K bridging transformer or an op amp circuit.

Cheers

Ian

baadc0de said:

I totally missed the poor man's makeup. Yeah, if that can be rewired to be similar / same as in the REDD, I'm a happy camper

Click to expand...

I have worked out how to modify the poor man's tube gain make up PCB so as to build the REDD 47 E88CC output stage on it. it is not pretty but it's not messy either. Attached pdf document describes how to do it. let me know if you think it is practical or not.

Cheers

Ian

Perfectly serviceable. Thanks! Put me down for two PCBs of each

ruffrecords said:

baadc0de said:

I totally missed the poor man's makeup. Yeah, if that can be rewired to be similar / same as in the REDD, I'm a happy camper

Click to expand...

I have worked out how to modify the poor man's tube gain make up PCB so as to build the REDD 47 E88CC output stage on it. it is not pretty but it's not messy either. Attached pdf document describes how to do it. let me know if you think it is practical or not.

Cheers

Ian

Click to expand...

Ian, do you think this buffer board could be supplied with something like the G9 (51X format) high voltage converter like Gemini86 built.

Marc Duchesne said:

Ian, do you think this buffer board could be supplied with something like the G9 (51X format) high voltage converter like Gemini86 built.

Click to expand...

I think it could. It only consumes about 5mA from the HT supply so it should be fine.

Cheers

Ian

Hi Ian,
how is the progress of the circuit?
Cheers

Fablab said:

Hi Ian,
how is the progress of the circuit?
Cheers

Click to expand...

Nearly done. I have been busy with other things just lately. I just need to put the last minute touches to the PCB. Then it's just a matter of guaging the level of interest before ordering some PCBs.

Cheersian

Thank you Ian
have you already defined the size of the pcb?
Have a nice day
Fab

Fablab said:

Thank you Ian
have you already defined the size of the pcb?
Have a nice day
Fab

Click to expand...

Pretty much. I made it 100mm  high with 3U fixing holes so it can be used in the EZTubeMixer project and so it would also fit in a 500 series module. The PCB is currently 100mm by 100mm. Attached is a pic of the current layout.

Cheers

Ian

Thank you Ian!
I have read that the frequency select switch for the Brilliance control will be off board
Do you think it is possible to put all the controls in a API front panel keeping the other switches on board?
Eventually, do you have plans to realise a lorlin off board adapter?

Fablab said:

Thank you Ian!
I have read that the frequency select switch for the Brilliance control will be off board
Do you think it is possible to put all the controls in a API front panel keeping the other switches on board?
Eventually, do you have plans to realise a lorlin off board adapter?

Click to expand...

I have just done a modification to the PCB layout so the brilliance frequency selector uses the same header that we use on the Universal EQ to mate with the off board Grayhill switch PCB. As several people requested it I also did a pin compatible Lorlin board. Both are now available in the Universal EQ group buy:

http://www.groupdiy.com/index.php?topic=51131.msg649433#msg649433

Cheers

Ian

Here is the latest version of the OCB. I corrected some minor and one major error and tidied up all the competent idents. The only thing I need to think about now is whether to include a bypass switch - the original did not have one - you just set the switches to 0dB for a flat response.

Cheers

Ian

A bypass switch would be nice. Sometimes it is better to improve things.

Holger said:

A bypass switch would be nice. Sometimes it is better to improve things.

Click to expand...

I think what I will do is include the 'pad' I used in the Pultec EQ then people can use any off board switch they like.

Cheers

Ian

Do you think to realize a "pro" PCBs like your other projects or only the gerber files?