no problem if aux load(s), powered from 5V line, are mild
example of not mild load - TFT screen I'm using for my things is sucking 200mA just for backlight LEDs
so, I resorted early on to external 5V reg, feeding everything
I bought 5V relays. I will test them out first before installing in the PCB. I also picked up a few of the darlington relays to test out. My arduino wants 7-12 V on power plug or 5V on the USB. I was going to try for 5V since I already have a 5V supply for the DAC.
That should work well, @wcwc. I like the idea of the using Darlington transistor arrays. ZM might frown upon getting 5V power for the relays from the DAC PSU, but if there is interference, it'll be easy to add a dedicated PSU for the relays.
For my own project, I'd prefer using higher voltage relays because their current draw will be lower (than 5V relays), but I think one should base that decision on whatever voltage PSU is available - like you've done. I'm now contemplating using 12V relays, because I'll have a 12V PSU right there in the enclosure - the one I'm using for the stepper motors of my attenuator. So, thank you for your post. It has swayed my mind in a new direction about the relay voltage.
For my own project, I'd prefer using higher voltage relays because their current draw will be lower (than 5V relays), but I think one should base that decision on whatever voltage PSU is available - like you've done. I'm now contemplating using 12V relays, because I'll have a 12V PSU right there in the enclosure - the one I'm using for the stepper motors of my attenuator. So, thank you for your post. It has swayed my mind in a new direction about the relay voltage.
The balanced Iron Pre is a back-burner project for me right now.
Arduino and logic programming are beyond my scope and I don’t have the time or patience for the learning curve at this point.
However, I was interested in a volume solution beyond a pot for my balanced Iron Pre.
I looked into Muses solutions and came across Frank Wilker’s webpage Audio Perfect (someone else already posted they bought his Muses volume control in the main Iron Pre thread).
I have no affiliation with his venture, only interest in his product.
Anyway, I discovered he was already working on a balanced preamp project that would provide input switching control along with his balanced Muses volume Potis features.
I believe at least one other member has reached out to him with similar interests to mine.
I figured I would mention this here for anyone else that might be looking for more of a “turn key” volume and switching solution for the Iron Pre.
Frank is a member here. He can chime in to answer questions.
Most recently he suggested combining all logic, relay functions and power supply on one microcontroller board.
The microcontroller would function at 5V and he would like it to control 5V relays.
He also mentioned he thinks it is possible to maintain the original negative common rail relay switching ZM designed.
This would make the solution more plug and play for end users of the current Iron Pre PCBs.
He mentioned he thinks there is a possibility of regulating the output signal of the Iron Pre.
I’m not sure if he meant varying gain or if this is just volume control?
The Muses chip he uses can handle an input signal of up to about 9V.
He inquired as to the maximum output voltage of the Iron Pre.
I did not know what to respond as I thought that was governed by a particular source’s voltage output level and the gain designed into the Iron Pre.
Any input, questions, suggestions or discussion that could help bring this project to fruition would be great and possibly helpful to other members looking for a similar solution.
Arduino and logic programming are beyond my scope and I don’t have the time or patience for the learning curve at this point.
However, I was interested in a volume solution beyond a pot for my balanced Iron Pre.
I looked into Muses solutions and came across Frank Wilker’s webpage Audio Perfect (someone else already posted they bought his Muses volume control in the main Iron Pre thread).
I have no affiliation with his venture, only interest in his product.
Anyway, I discovered he was already working on a balanced preamp project that would provide input switching control along with his balanced Muses volume Potis features.
I believe at least one other member has reached out to him with similar interests to mine.
I figured I would mention this here for anyone else that might be looking for more of a “turn key” volume and switching solution for the Iron Pre.
Frank is a member here. He can chime in to answer questions.
Most recently he suggested combining all logic, relay functions and power supply on one microcontroller board.
The microcontroller would function at 5V and he would like it to control 5V relays.
He also mentioned he thinks it is possible to maintain the original negative common rail relay switching ZM designed.
This would make the solution more plug and play for end users of the current Iron Pre PCBs.
He mentioned he thinks there is a possibility of regulating the output signal of the Iron Pre.
I’m not sure if he meant varying gain or if this is just volume control?
The Muses chip he uses can handle an input signal of up to about 9V.
He inquired as to the maximum output voltage of the Iron Pre.
I did not know what to respond as I thought that was governed by a particular source’s voltage output level and the gain designed into the Iron Pre.
Any input, questions, suggestions or discussion that could help bring this project to fruition would be great and possibly helpful to other members looking for a similar solution.
Hi, I´m Frank from Audio-perfect.de
For relay control:
If you use the ULN2803 (as I do), it is no problem to feed in a higher voltage than 5V in addition to the relay control.
@chromenuts: I´ll answer your mails in a few moments.
For relay control:
If you use the ULN2803 (as I do), it is no problem to feed in a higher voltage than 5V in addition to the relay control.
@chromenuts: I´ll answer your mails in a few moments.
change to existing pcb is trivial, making guy with logic tasks much easier life
besides, revised relays control (positive rail common) already sent to Guyz (IAIMH) for future batches
now, regarding other things - to avoid broken phones, if there is anything I need to specify - best if person developing it asks directly here
I just saw that the change to operate with a microcontroller has already been documented by Zen Mod (#14).
I also want to add a Muses chip-based volume control to my balanced Iron Pre. Certainly my final preamp thank you Zen Mod 
In the past I have used relays but I have never been able to solve the relay flipping problems in certain positions.
But my technical knowledge is very limited. So I hope someone more qualified than I can contribute a solution to the community. Hopping for a group buy!
Someone please!! (Fank!? Meldano!? ....)
In the past I have used relays but I have never been able to solve the relay flipping problems in certain positions.
But my technical knowledge is very limited. So I hope someone more qualified than I can contribute a solution to the community. Hopping for a group buy!
Someone please!! (Fank!? Meldano!? ....)
same as already mentioned for input relays - best to use make-before-break (Lorlin) switch to avoid clicks
so, for resistor matrix switched by relays, it's just matter of code to get MBB action - switch on relay group N - delay - switch Off relay group N-1
works as charm
so, for resistor matrix switched by relays, it's just matter of code to get MBB action - switch on relay group N - delay - switch Off relay group N-1
works as charm
I touched base with Frank last week.
He was busy, but said he would be on the forum.
I’m not sure how many things he may be juggling or how much interest he has had for an Iron Pre Muses solution. Just have to be patient and see.
I told him I was on board.
I added some 5V and 12V Takamisawa relays to my last Mouser order so I’m covered regardless of the direction things go.
He was busy, but said he would be on the forum.
I’m not sure how many things he may be juggling or how much interest he has had for an Iron Pre Muses solution. Just have to be patient and see.
I told him I was on board.
I added some 5V and 12V Takamisawa relays to my last Mouser order so I’m covered regardless of the direction things go.
Thanks Zen Mod , of course for input selector no problem with Lorin but for volume control I would like something better than an alps blue pot and the convenience of remote control and mute would be very welcome.
As for coding I'm out! far beyond my capabilities😢
, of course for input selector no problem with Lorin but for volume control I would like something better than an alps blue pot and the convenience of remote control and mute would be very welcome.As for coding I'm out! far beyond my capabilities😢
Thanks for the information chromenuts 🙂regarding the possibility of having some contribution from Frank, in my search for the Muses chip I found his work and I also sent him a message showing interest in a solution adjusted to Iron Pre Balanced
At the request of a forum member, I will adapt the existing version so that it can be used directly with the IronPre.
This forum has helped me a lot in the last few years. I also appreciate that the interaction here is very friendly and fair. For this reason, I have been offering DIY users a discount on my products for years.
Furthermore, I would also offer the above-mentioned customised module as a kit or single board.
This forum has helped me a lot in the last few years. I also appreciate that the interaction here is very friendly and fair. For this reason, I have been offering DIY users a discount on my products for years.
Furthermore, I would also offer the above-mentioned customised module as a kit or single board.
Hi ZM. I'm having a hard time finding the correct positions for connecting just one input on the SE board, bypassing the relays.
Would you please mark the input on the board for me? I have stuffed the board and would like to test tonight if possible. I want to connect one input directly. I'll worry about connecting the relays later. The PSU part is working and outputting +15V and -15V. (I checked that before stuffing the rest).
I'm also not sure what the other two trimpots in the B1 section are for.
Would you please mark the input on the board for me? I have stuffed the board and would like to test tonight if possible. I want to connect one input directly. I'll worry about connecting the relays later. The PSU part is working and outputting +15V and -15V. (I checked that before stuffing the rest).
I'm also not sure what the other two trimpots in the B1 section are for.
Since this is in the logic thread, I'll assume you're going to use logic later with the relays. I'll also assume you want to use a volume pot connected to the standard pads. I'll also assume you've already stuffed the parts for relay power...
What I'd do... is wire one input to the standard spots for input 1 and include one relay. Use a jumper in the 14 pin connection to keep that relay selected until you install the logic.
If you don't want to do that... you can wire directly to the relay pads, but then you'll have to desolder them when you want to put in the relay.
Notes for P3 and P4 in schematic.
ZM will likely have (even better) alternatives. 🙂
What I'd do... is wire one input to the standard spots for input 1 and include one relay. Use a jumper in the 14 pin connection to keep that relay selected until you install the logic.
If you don't want to do that... you can wire directly to the relay pads, but then you'll have to desolder them when you want to put in the relay.
Notes for P3 and P4 in schematic.
ZM will likely have (even better) alternatives. 🙂
Thank you IAIMH. Yes, I'll later use logic with the relays.
I want to wire directly to the relay pads and desolder later, but I'm not sure which pads to use.
Thank you!
I'll post back in a bit when I can get to a board and schematic unless ZM (or anyone else) answers first.
Should be under an hour.
Should be under an hour.
Put R and L grounds in marked spots per normal.
Put R and L signal one set of pads away from the normal pads onto the relay pads. Those pads (the relay pads) should run straight to the pot CW pads for the respective channels.
Double-check my work.
Put R and L signal one set of pads away from the normal pads onto the relay pads. Those pads (the relay pads) should run straight to the pot CW pads for the respective channels.
Double-check my work.