That is unusual. I don't see anything on the boards. Can you check the actual resistance, please from just the GNDOUT to the Out+ and Out-. Also, just quickly check OUT+ to OUT-.
Unrelated, and you likely know, but don't forget to short your - to GND at the input for your SE inputs 1-3.
Unrelated, and you likely know, but don't forget to short your - to GND at the input for your SE inputs 1-3.
Hi Patrick,
Ugh, I was hoping you weren’t going to say that. Here’s what I measure:
GNDOUT to OUT+ is 54 ohms
GNDOUT to OUT- is 53.5 ohms
OUT+ to OUT- is 107.2 ohms
The other board had similar results.
Thanks for the help!
Ugh, I was hoping you weren’t going to say that. Here’s what I measure:
GNDOUT to OUT+ is 54 ohms
GNDOUT to OUT- is 53.5 ohms
OUT+ to OUT- is 107.2 ohms
The other board had similar results.
Thanks for the help!
Hey now ZM, Pippy would not approve of you picking on the schematically challenged!
Thanks for confirming my measurements. I will proceed with the program!
-Glen
Please, fire that thing up…otherwise you could be measuring for the next few months. You didn’t buy a QA403 did you🤪
Analysis paralysis! 
That QuantAsylum unit is on my wish list, but I will continue to suffer with my humble Focusrite Solo and REW.
I am getting back to work on the IP!
-Glen
That QuantAsylum unit is on my wish list, but I will continue to suffer with my humble Focusrite Solo and REW.
I am getting back to work on the IP!
-Glen
Thanks Patrick! I did consult those diagrams before I posted, but I just wasn’t 100% certain of what my measurements were showing. Another bit of knowledge gained here in DIYAudio U!
Happy Holidays!
-Glen
Happy Holidays!
-Glen
^ All good! 🙂
Glen clearly has it under control, but for those that may wonder...
The diagram showing the Cinemag transformer is a bit more clear, IMO. It is showing that:
With a fresh Cinemag CMOQ-4HPC...
Pin 2 to Pin 4 - 27RX
Pin 3 to Pin 5 - 27RX
Pin 8 to Pin 10 - 27RX
Pin 9 to Pin 11 - 27RX
Pins (2 and 4); (3 and 5); (8 and 10); (9 and 11) are the 8 ends of the 4 windings.
So, if we short pins 3 and 4 and measure from 2 to 5 => ~55R
Similarly, if we short pins 9 and 10 and measure from 8 to 11 => ~55R
Pin 5/8 to Pin 2
Pin 11 to Pin 2
🙂
Glen clearly has it under control, but for those that may wonder...
The diagram showing the Cinemag transformer is a bit more clear, IMO. It is showing that:
- Out+ In+ and GND are all in series with each other.
- Out- In- and GND are all in series with each other.
- Since GND is common... they're all in series with each other.
With a fresh Cinemag CMOQ-4HPC...
Pin 2 to Pin 4 - 27RX
Pin 3 to Pin 5 - 27RX
Pin 8 to Pin 10 - 27RX
Pin 9 to Pin 11 - 27RX
Pins (2 and 4); (3 and 5); (8 and 10); (9 and 11) are the 8 ends of the 4 windings.
So, if we short pins 3 and 4 and measure from 2 to 5 => ~55R
Similarly, if we short pins 9 and 10 and measure from 8 to 11 => ~55R
Pin 5/8 to Pin 11
Pin 5/8 to Pin 2
Pin 11 to Pin 2
🙂
It's alive! I soldered one SE input for testing and both BAL and SE outputs. Connected the IP to my amp via SE out. Everything seems to work.
Mine is the latest version of Balanced Iron Pre purchased from the diyAudio Store. In addition I opted for Franks Muses volume control built specifically for the balanced Iron Pre.
A couple of observations:
- Muses (default anyway) lowest volume setting is -50dB. Still, I have too much gain on the lowest setting. SE in SE out. The volume level is what I'd describe as lowish normal listening level. Any higher and my wife would raise her eyebrows as a sign to turn it down a notch. Does anyone know if there's a way to mend this either on the IP boards or with the MUSES?
- The sound is fine but not spectacular. Admittedly my expectations are high after a long building period and after reading this whole thread. The IP replaced a DIY passive preamp built with super high quality components. A stepped attenuator and a high quality input switch. No electronics. Still I've long had a feeling the passive pre is the bottleneck in my current system and I did not think the IP would have any problems bettering it. Maybe too early to make comparisons but as for now the IP sounds about on par with the passive pre.
My system is a Magna Hifi modified Sonos connect Ultimo feeding a heavily modded Aqvox DAC which is connected to Iron pre SE in and SE out to a Neurochrome 686 amp. Speakers are Troels Gravesens Faital 3WC-10 .
It's still my first listening hour so the IP might open up. I've experienced this many times with new gear. I also have yet to try both balanced in and balanced out to and from the IP. Now that I know it works I will connect the other inputs and put the lid on.
/Karl
Mine is the latest version of Balanced Iron Pre purchased from the diyAudio Store. In addition I opted for Franks Muses volume control built specifically for the balanced Iron Pre.
A couple of observations:
- Muses (default anyway) lowest volume setting is -50dB. Still, I have too much gain on the lowest setting. SE in SE out. The volume level is what I'd describe as lowish normal listening level. Any higher and my wife would raise her eyebrows as a sign to turn it down a notch. Does anyone know if there's a way to mend this either on the IP boards or with the MUSES?
- The sound is fine but not spectacular. Admittedly my expectations are high after a long building period and after reading this whole thread. The IP replaced a DIY passive preamp built with super high quality components. A stepped attenuator and a high quality input switch. No electronics. Still I've long had a feeling the passive pre is the bottleneck in my current system and I did not think the IP would have any problems bettering it. Maybe too early to make comparisons but as for now the IP sounds about on par with the passive pre.
My system is a Magna Hifi modified Sonos connect Ultimo feeding a heavily modded Aqvox DAC which is connected to Iron pre SE in and SE out to a Neurochrome 686 amp. Speakers are Troels Gravesens Faital 3WC-10 .
It's still my first listening hour so the IP might open up. I've experienced this many times with new gear. I also have yet to try both balanced in and balanced out to and from the IP. Now that I know it works I will connect the other inputs and put the lid on.
/Karl
Ok, I really should have RTFM before asking about the volume setting. The lowest volume level is easily adjustable all the way down to -110dB.
Leaving this on playing overnight to see if some burn in time will open up the sound.
Leaving this on playing overnight to see if some burn in time will open up the sound.
well, anything involving remote control - expect convenience as main virtue
and , when splittin' da hair, of all remote solutions (more or less) readily available, best ones are those made as discrete resistor matrix switched by relays
anyhow, if you want to squeeze max possible from your IPre, increase Rin resistor to max practical value
even 1Meg, why not
and yeah - it needs some time, if nothing else, wire in Cinemagz is welcoming some massage, and then happy ending
and , when splittin' da hair, of all remote solutions (more or less) readily available, best ones are those made as discrete resistor matrix switched by relays
anyhow, if you want to squeeze max possible from your IPre, increase Rin resistor to max practical value
even 1Meg, why not
and yeah - it needs some time, if nothing else, wire in Cinemagz is welcoming some massage, and then happy ending
I have read nothing but praise for the muses volume controller until now. It's supposed to be superior to any conductive plastic pot and easily on par with quality stepped attenuators, which is why I chose it. To me, remote control conveniences are welcome but not at the expense of sq.
I'll take a chill pill and finish the build. Will post pictures when done.
I'll take a chill pill and finish the build. Will post pictures when done.
I also doubt that the Muses is the culprit. The IP is easily the best preamp I've heard and I'm also using Muses attenuation.
If you're not blown away by the the musicality of the sound, I suspect there's something wrong with your build. No burn in will fix that.
If you're not blown away by the the musicality of the sound, I suspect there's something wrong with your build. No burn in will fix that.
That's reassuring to hear. I have been very careful with the build and had no problems setting PSU voltages, DC offset and current through jfets.
I'll give it some time. Will report back.
I'll give it some time. Will report back.