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I'm back from holiday. Shop is open.

Latest version of REDD EQ PCB in stock. Also had another delivery of DB25 PCBs and TwinLineAmp PCBs.

Cheers

Ian
 
hi ian

would you condsider using the redd eq for mastering job? , i was looking at getting some quad 8 312 eqs do you think the sound would be similar

thanks in advance

r yeah thanks for those pcbs they did the job.

8) skal1
 
skal1 said:
hi ian

would you condsider using the redd eq for mastering job? , i was looking at getting some quad 8 312 eqs do you think the sound would be similar

thanks in advance

r yeah thanks for those pcbs they did the job.

8) skal1


A lot depends on what you are mastering and what you expect from a mastering EQ. The Quad 8 312 has selectable HF and HF frequencies which the REDD does not so in that sense it is more flexible. On the other hand, the REDD does sound rather nice as you can hear from the demo recording I made of it.  Possibly the main advantage of the REDD EQ for mastering is that it is 100% stepped so repeatability is assured, something that's not really possible with regular pot controls.

As I have mentioned elsewhere, I get the impression the Helios EQ is an extension of the REDD EQ with more mid range frequencies and a selection of LF frequencies so if you replaced the regular pots in the Helios with stepped ones you would have the basis of a rather nice mastering EQ. I posted an outline schematic of this in the REDD EQ thread:

http://www.groupdiy.com/index.php?topic=51030.msg671466#msg671466

To build one you could use a pair of my regular Helios PCBs and simply replace the pots with stepped switches.

Hope that helps.

Cheers

Ian

 
Ian, you mailed me the ReddEQ and other associated boards last Friday, they arrived in Sydney today (wednesday), not sure how you managed to get them here so quick, but awesome job, they look great.
THANKS!!
 
Junction said:
Ian, you mailed me the ReddEQ and other associated boards last Friday, they arrived in Sydney today (wednesday), not sure how you managed to get them here so quick, but awesome job, they look great.
THANKS!!

Maybe is a Commonwealth thing???


Cheers

Ian
 
REDD EQ PCBs have sold out already!  I have another batch on order. Should be here in a couple of weeks.

Cheers

Ian
 
The second batch of REDD EQ PCBs arrived in the post this morning. I will be shipping outstanding orders over the next couple of dyas.

Cheers

Ian
 
REDD EQ PCB's arrived yesterday. Now that's really fast !
About to gather parts. Haven't done much diy lately, been very busy elswhere (work work kids work...)
so looking forward to this build  :)
Great thank's !
 
I have run out of stock of HT350 boards. I have some more on order. I am also down to the last Lorlin header board. I am not planning on ordering any more of this design because is was squeezed rather tight onto the PCB to get a pair of switches in and I find it hard to saw them into two separate boards. If there is enough demand I'll do an updated design that is more DIY friendly but the price will be a bit higher. I still have plenty of Grayhill header boards left.

Cheers

Ian
 
I just had a delivery of HT350 boards so there are plenty in stock. I'll update the main web page to reflect this.

Cheers

Ian
 
Hello,
I'm interested in your Helios 69 eq's. Could you answer a few questions about them when used as a stand-alone, line-input eq:
Are input and output transformers required?
What would the circuit require in order to use some of my existing mic preamps for make  up gain?
What basic topology of mic preamp would help them to come closest to the sound of the original Helios eq's?
If instead I were to incorporate make up gain into the units themselves, what options on the DIY market do you think would get me closest to a vintage Helios?

thanks a lot.
JS
 
skidmorebay said:
Hello,
I'm interested in your Helios 69 eq's. Could you answer a few questions about them when used as a stand-alone, line-input eq:
Are input and output transformers required?

The input and output of the EQ are unbalanced so if you want a balanced input you need to add either a `10K:10K input transformer or a semiconductor based balanced to unbalanced circuit.

What would the circuit require in order to use some of my existing mic preamps for make  up gain?

The EQ output  needs to be loaded with not less than 50K. To use a mic amp for gain make up you could a a DI transformer like the Carnhill VTB9072. This will cause an additional loss of about 22dB on top of the 18dB loss of the passive EQ so your mic mp would need to be set to approximately 40dB gain.

What basic topology of mic preamp would help them to come closest to the sound of the original Helios eq's?

My own tests indicate that 99% of the Helios EQ sound is in the EQ itself. The gain make up circuit contributes very little to the overall sound, I would go for transparency.

If instead I were to incorporate make up gain into the units themselves, what options on the DIY market do you think would get me closest to a vintage Helios?

thanks a lot.
JS

Once again, provided the gain make up amp has an input impedance in excess of 50K ohms and  is relatively transparent it should sound fine.

Several group members have made op amp based gain make up amps and I believe they have even offered them for sale. Check out the poor man's EQP1A thread for details. You can also use something like JLM Audio Dingo board. You just need to use the recommended FET op amp and change some resistor values to ensure the nake up amp input impedance is high enough. Or you could use my poor man;'s tube gain make up amp or my Twin Line amp if you want to go for a tube based solution.

Hope that helps.

Cheers

Ian
 
I recently received stock of both types of Helios 69 EQ boards. I will update the stock levels on the main web site.

Cheers

Ian
 
The new two module motherboard PCB is now available from the emporium (see first page for price information). Inspired by Holger's 2 module motherboard design for his 4 channel EZ Tube Mixer build, this new two module motherboard replaces the original 6 module motherboard. The XLR footprints and the simple pads for internal connections have all been replaced by rear mounted 3 and 2 way Molex KK connectors and there is space for a 6 way Molex connector to connect the mix buses together. Pads have been added to the HT and heater buses as test pads so you can check supply voltages.

Cheers

Ian
 
Good day Ian,

    I wanna say thanks, i got the motherboards and power supply prototype. Should we start a new thread for the power supply?

Regards,

Pierre
 
anjing said:
Good day Ian,

    I wanna say thanks, i got the motherboards and power supply prototype. Should we start a new thread for the power supply?

Regards,

Pierre

I think that might be a good idea. There are a few variations you can play with and there will no doubt be some questions on component and connector selection. Also, I have just started to build one for a client - but he wants a tube rectifier for the HT which has its own set of problems.

Which section do you think it should be in; the lab or mixers/monitors??

Cheers

Ian
 
Good day Ian,
 
    I'm not sure were to put the power supply thread....maybe in the ez-lunchbox thread? Maybe thats were it will be the most helpful...

Regards!

Pierre
 

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