[Igor]

Here is the support thread for He-69, Helios inspired EQ.

For now, I tested the PCB's for 500/51X version, they will be available at my store
within a hour from now; rack version PCB will be available very soon.
Rackit! can be used for testing/racking this (and many others) 500/51X projects:

http://www.groupdiy.com/index.php?topic=45678.0

500/51X:



Rack version (2 channels can fit in 1RU):



Front view:



Transformer version:



Transformerless version:



Please, download documentation and meditate to files at least 30 minutes

http://ij-audio.com/downloads/HE_69.rar

PCB set is as usual, high quality, Israeli made.

Kit contains: PCB set, black Aluminum anodized, machined/engraved front,  bracket, inductors, mounting hardware, DOA sockets.

Please note, we will be able to ship the kits after Sept 28th (we almost out of brackets and ordered new batch;
it should be ready at Sept 26th).

[Igor]

RESERVED

[Dubka]

Mate, where are these knobs from?

[Igor]

The knobs are ELMA.
In Israel, they are available from local distributor (MOQ = 100+); in small quantities,
these knobs, usually in black, are available from Farnell.
10mm wing knob, 10mm knob, grey, without line, + black skirt with line, + black cap with line; 3.15mm shaft.

The great advantage of these knobs is they are available in sizes 9...45mm for every possible shaft,
can be stacked for concentric pots, can be used with skirt/pointer, etc. Excellent quality BTW.

http://il.farnell.com/jsp/search/browse.jsp?N=2017+202401&Ntk=gensearch&Ntt=elma+knob&Ntx=mode+matchallpartial

[Grummy77]

Anyone build this yet? I'm thinking of pulling the trigger as I am in need of some hardawre eq. Doesn't look like it'd be too difficult of a build.

[Igor]

I built 8 of these EQ's at the moment. It is way more simple than 90% of my other projects.

[Grummy77]

I built 8 of these EQ's at the moment. It is way more simple than 90% of my other projects.

Care to share your thoughts on the plus and minuses of the transformer vs the transformerless versions? I noticed your store on diyrecordingequipment no longer is offering the partial kit anymore. Will you be selling partial kits for these again?

Cheers.
Aaron

[Igor]

The store is updated, kits are in stock. Thoughts...... Transformers = lows and low-mid saturation, some phase shift on highs;
generally, more iron is more 3rd harmonic (but it is shifted by 90 deg to sound in opposite to say PP circuits)....mmmm....dunno)
Last time I more and more tending to clean sound with bit of second harmonic. Too much distorting Iron is long time ago out of my style.
However, the combination which I liked very much sound-wise is LL1524 and balanced line receiver.

[Grummy77]

Thanks for the reply. I'll be getting a couple at some point, hopefully sooner rather than later. Glad to hear the kits are back.

Cheers.

[ruffrecords]

On the mid section front panel layout I think the switch should have PK above and TR below (for trough) - not TH.

Cheers

Ian

[Igor]

Thanks for the reply. I'll be getting a couple at some point, hopefully sooner rather than later. Glad to hear the kits are back.

Cheers.

Mm. Yep. Welcome

[Igor]

On the mid section front panel layout I think the switch should have PK above and TR below (for trough) - not TH.

Cheers

Ian

Thanx Ian! Will fix for the next batch.

[jandoste]

Hey Guys,
If you have any TBD link on mouser or Farnell link  I'll be very happy guy:)! sorry about my newbie question 
1   TBD   C10                                 
5   TBD   MF 1/4W 1%         R10, R12, R13, R14, R15

Thanks

[zayance]

Hey Guys,
If you have any TBD link on mouser or Farnell link  I'll be very happy guy:)! sorry about my newbie question 
1   TBD   C10                                 
5   TBD   MF 1/4W 1%         R10, R12, R13, R14, R15

Thanks

TBD: To Be Determined  :-)

Zobel network maybe? Don't have the schemo in front of me...

[jandoste]

Hey Guys,
If you have any TBD link on mouser or Farnell link  I'll be very happy guy:)! sorry about my newbie question 
1   TBD   C10                                 
5   TBD   MF 1/4W 1%         R10, R12, R13, R14, R15

Thanks

TBD: To Be Determined  :-)

Zobel network maybe? Don't have the schemo in front of me...

Thanks Zayance
TBD: To Be Determined  
cheers,

[jandoste]

Hey Igor,
Please can you tell me if 9048 is on right position?
Thanks

[jandoste]

Hey Guys,
I think Igor will back here in two months  so if you have any idea that can I use 608pF instead of 506pF? [ CH5 and CM1 ]
Thanks for any advance!
cheees,

[Igor]

Here. Took less than a year!!! Woa!!!!!

680/560 pf. Mmm.... I'd use 5% values for all, but there is another way, connect 2 capacitors in parallel....
Cay 560 pf is 220 || 330 pf.... (roughly)

Carenhills. On back side of PCB printed inductor values at each pin. I don't have schem at this comp.
If not found, drop a line, will check and post. However, don't give a fish, but teach fishing:
Inductor datasheet and schematic/pcb!!!

[jandoste]

Hey Igor,
I really can't understand that what I need to use for R12 and R15?

OUTPUT TRANSFORMER     T1   
1   LL1524(1517) 1:1 OR  1:2 CAN BE USED;
for 1:2 output transformer, r12/r15 should have relation 25/5.1, for example, r12=24k9/r15=5k1,
depending on which impedances your amp wants to see; for amp used with f76, i used 2k49 and 511r;
for 1:1 output transformer or transformerless,[/size] r12/r15=50:5.1 That what I used

and also you are saying here,

1   TBD   POLY/COG 22...330 PF 50...200V   C7   
DEPENDING ON FEEDBACK RESISTOR'S VALUES AND AMP; 22PF WITH R12=47K, 330PF WITH R12=2K5

next question is about R17! Can I use 51R ?



Thanks

Regards

[Igor]

Hey Igor,
I really can't understand that what I need to use for R12 and R15?

OUTPUT TRANSFORMER T1
1 LL1524(1517) 1:1 OR 1:2 CAN BE USED;
for 1:2 output transformer, r12/r15 should have relation 25/5.1, for example, r12=24k9/r15=5k1,
depending on which impedances your amp wants to see; for amp used with f76, i used 2k49 and 511r;
for 1:1 output transformer or transformerless,[/size] r12/r15=50:5.1 That what I used

and also you are saying here,

1 TBD POLY/COG 22...330 PF 50...200V C7
DEPENDING ON FEEDBACK RESISTOR'S VALUES AND AMP; 22PF WITH R12=47K, 330PF WITH R12=2K5

last question is about R17! Can I use 51R ?

Mm... OK!
Don't give a fish, but give a fishing tutorial
http://ij-audio.com/downloads/HE_69.rar
File:
SCHEM_PS_IO_RELAYS.png
r17 depends on relays coil resistance. Mine are 200R; yours can be different.
Take one relay, measure the coil resistance with ohmmeter, all calculations are shown on schemo/datasheet.
The voltage on each relay should be 5V, and voltage on r17 should be 1.25V. The rest is Ohm's law.

In case of use 1:1 output transformer, use 4k99, about 200pf (+/-30% is fine), and 511R.
What transformer and discrete op-amps are used?

50K low-boost resistor. See the picture. Tie 3 pins together. Connect free pins.

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