Barry Porter "Net EQ"

[prescott]

And can I simply use them in the same time without changing the gain structure?

 

[Harpo]

Yepp. The loading on the filter driving stage (U2-A) is still the same. For adding more filter bands for whatever reason, some unity gain buffers in front of the filter inputs might be needed.

 

[prescott]

Ok, its very good!

But how can I adjust the volume of the shelv and peak to differect positions at the same time?
Where can I connect another rotary to?

 

[Harpo]

But how can I adjust the volume of the shelv and peak to differect positions at the same time?
Where can I connect another rotary to?

Instead of FI relay K3, switching between the peaking and shelfing low band, you have an additional center tapped pot or rotary switch substitution in parallel to the other level pots with wiper connecting thru a 2K2 to the decoupled filter output (junction C45/R50). Leave out K3,D3,Q3,C37,R34,R36,R103,S2,LED2 and jumper K3-pin2 with pin3 at pcb.
Same for the high peak/shelf band with corresponding parts.
Consider you might run out of frontpanel real estate at some point or fingers are not small enough to comfortably fit between knobs ...

 

[prescott]

Thanks again Harpo!

Its time to understand, but I will save this comment

 

[petermontg]

My knobs arrived.......

 

[skidmorebay]

Hi,
Anyone care to share how much they spent to finish this project?
thanks,
JS

 

[petermontg]

Anywhere, from 1-2.5k, depending what rotary switches you choose and of course less man hours.....

 

[Gustav]

My build looks like it will land around 7-800 euros in parts. Certainly less than 1k...

But its a lot of hours in work.

Gustav

 

[skidmorebay]

Thanks!
Harpo, or anybody, could you post a new link to the spreadsheet of resistor values? When I click on the link labeled "Hop" in the earlier posts I just get a screen full of random characters....
JS

 

[Harpo]

JS, no link broken. Maybe use right-click / save_as for a workaround (some program might have occupied the standard file extension .XLS for a different -no more related to MS-Excel or OpenOffice calc sheet- purpose).

 

[druu]

Another complete! Just need to go through the calibration but so far it all checks out fine.

Huge thanks to Harpo, ppa and the usual guys I hassle over PM.

For anyone thinking to add +/-6dB Input Gain control, see here. Works perfectly (Thanks ppa)

 

[petermontg]

I have a small problem with mine.
The 10r in R18 which is on the -18v line keeps blowing out,  have checked my PS and everything is fine there.

Any ideas?

 

[Gold]

I haven't looked at the schematic but it sounds like those 10R in series with the rail. If this is correct the 10r are essentially fuses. If it keeps blowing something down the line is shorting out.

 

[petermontg]

Thanks Paul.

Checked the following Cap with the MM and it's polarity is labelled wrong.

Must of been an ebay purchase I will check it later tonight.

Edit: Some bad ceramics....

 

[MrBlomski]

Another complete! Just need to go through the calibration but so far it all checks out fine.

Huge thanks to Harpo, ppa and the usual guys I hassle over PM.

For anyone thinking to add +/-6dB Input Gain control, see here. Works perfectly (Thanks ppa)

Do I see a DR-MQ5 eq?

 

[druu]

No, that EQ below the BP is built using Igor's GML/Massenburg 'MEP250' boards with MS/Bypass, before the DR-MQ5 copies came out.

 

[Gustav]

1.The PCB has a 6 pin footprint for the switches, and the schematic has a DPDT switch drawn up for the bypass switches, but is there any reason why I couldn't just use a single pole on/off switch and tap into the two "relevant" points on the board for each of the four switches?

2. Frame = chassis on the 10 pin connector?

If you are using Harpo's excellent excel sheets, this should be a correct list of the resistor changes on the board.

Cut (freq)

R114, R115
R111 R112
R108 R109
R105 R106


Short (freq)

R87 R61
R83 R58
R79 R55
R74 R51

Short (shelving)

R78
R91

Replace values (Q)

R99 R100 R101 R102 = 10K
R95 R96 R97 R98 = 5K1

Short (Q)
R104 R107 R110 R113

Replace values (Gain)

R13 R14 = 5K1
R77 R82 R86 R90 = 6K49

Short (HPF)

R93 R 94

 

[druu]

Single pole is all that's required. The extra pole would be there to add rigidity if mounted to the board.

 

[petermontg]

You can place the last resistor on the chain into the short positions save having them hanging off the rotary.