Hi Tom,
Because Modulus-686 is a bridged amp come to speculate if it can run from a single supply and virtual ground as Sansui used lot back in eighties, wearing my audiophile glasses 😀 (get your audio off the ground) have always thought about below single supply block diagram that it looks very clean and beautiful, no common modes and no cold dirty speaker returns anywhere, cost of higher voltage capacitors for linear supply will take a hit but if performance numbers also increase a little bit some will probably like that.
Because Modulus-686 is a bridged amp come to speculate if it can run from a single supply and virtual ground as Sansui used lot back in eighties, wearing my audiophile glasses 😀 (get your audio off the ground) have always thought about below single supply block diagram that it looks very clean and beautiful, no common modes and no cold dirty speaker returns anywhere, cost of higher voltage capacitors for linear supply will take a hit but if performance numbers also increase a little bit some will probably like that.
Attachments
Last edited:
Agree in effect its absolute same but as is guess PSU have a null buzz common highway bonded we get lifted out, that said you know much better than me 🙂.
The high currents flow through the supply caps and those connections are as short as can be.
Tom
Tom
The Intelligent Soft Start is now ready for prime time. Boards are in stock! Images attached. Description here: ISS: Intelligent Soft Start
I've learned quite a bit building that circuit and discovered some failings of the commonly used resistor-based soft starts. I'll need to gather my thoughts and start a separate thread on that topic.
Starting said thread was pushed firmly to the back burner a couple of hours ago when my mom let me know that my dad has had a major stroke. So I'm headed out of town ASAP to be with family. I'll fill orders until my flight leaves.
Tom
I've learned quite a bit building that circuit and discovered some failings of the commonly used resistor-based soft starts. I'll need to gather my thoughts and start a separate thread on that topic.
Starting said thread was pushed firmly to the back burner a couple of hours ago when my mom let me know that my dad has had a major stroke. So I'm headed out of town ASAP to be with family. I'll fill orders until my flight leaves.
Tom
Attachments
Tom,
The Intelligent Soft Start looks good. Tell us more about it vs other solutions when you get time.
Sorry to hear about your Dad's stroke - wishing him recovery and wish you safe travels. Take care.
The Intelligent Soft Start looks good. Tell us more about it vs other solutions when you get time.
Sorry to hear about your Dad's stroke - wishing him recovery and wish you safe travels. Take care.
Tom,
So sorry to hear about tour dad’s health situation.
All the best and hoping for a good recovery!
Daan
So sorry to hear about tour dad’s health situation.
All the best and hoping for a good recovery!
Daan
Well, I seem to find myself with about three hours before my next flight boards...
You'll get the highlights of the ISS vs other solutions by following the link to its page on my website that I linked to in Post #505. Also note that the description page has a link to an old HP Journal, which details the HP 14570A power controller. The ISS can be viewed as one channel of a 14570A power controller and the HP Journal is a good read.
In addition, considerable effort went into the selection of the NTC resistor used in the soft start. I optimized the circuit to ensure a fast startup while also limiting the inrush current.
Part of my design process was to compare the NTC-based solution with the more common (in DIY circles anyway) power resistor-based solution. I found the solution based on power resistors to be inefficient at limiting the inrush current as the current limiting resistor is usually way too large. While this does limit the initial inrush, the second inrush, which occurs when the relay closes and shorts out the resistor, is almost as large as the inrush current without any limiter. Basically: The power resistor-based inrush limiters are inferior to the NTC-based limiters, even when optimized.
I'll post data to support this once my situation gets back to normal.
From the latest report it doesn't sound like there'll be any recovery. Thanks for your thoughts, though.
Tom
Does anyone have a good recommendation for a shielded cable for the XLR connectors?
Also, I'm contemplating if I can use the same cable that connects my speakers within the Amp. A Kimber 8TC, might be a pain though to get the 9AWG cable connected to the molex connectors.
Would anyone see advantages or disadvantages of using such cable within the Amp chassis?
And finally another question: would there be pro's or con's in using a filtered IEC inlet?
Also, I'm contemplating if I can use the same cable that connects my speakers within the Amp. A Kimber 8TC, might be a pain though to get the 9AWG cable connected to the molex connectors.
Would anyone see advantages or disadvantages of using such cable within the Amp chassis?
And finally another question: would there be pro's or con's in using a filtered IEC inlet?
I like Canare L4E6S or L2T2S cable for balanced XLR runs... Yes, I've tried Mogami etc etc. There are probably other good cables too (eg Belden), the Canare has the best shield I've seen and excellent construction.
I am using mogami xlt interconnects. Are you also using canare (or something similar) inside the amp’s chassis?
Van Damme starquad core in and out here.
Seems to have less capacitance than Canare starquad. Van Damme - Specifications - Tour Grade Classic XKE Starquad microphone cable
Some silver plated strands thrown in too.
Seems to have less capacitance than Canare starquad. Van Damme - Specifications - Tour Grade Classic XKE Starquad microphone cable
Some silver plated strands thrown in too.
Last edited:
Yes. What can I say Tom. All the best and my condolences to you and your family.
Best regards
SH
Best regards
SH
Condolences
Wanted to express condolences to you after your father's passing. May he rest in peace.
Wanted to express condolences to you after your father's passing. May he rest in peace.
Thank you for all of your condolences. I really appreciate it.
I'm getting back to something that resembles normal.
Tom
I'm getting back to something that resembles normal.
Tom
Tom,
I'm about to start populating the ISS board, but I cannot find the detailed component mapping in the ISS docs.
The Mouser project lists all the components but does not list where to mount them (R7, R7, etc..)
Am I missing something?
Thanks,
Daan
I'm about to start populating the ISS board, but I cannot find the detailed component mapping in the ISS docs.
The Mouser project lists all the components but does not list where to mount them (R7, R7, etc..)
Am I missing something?
Thanks,
Daan
Another question is regarding the connection from the ISS to my 4 meanwell RPS-400-36 PSU's..
The ISS documentation states to either configure for 115v or 230v.
I am assuming this configuration has to do with connecting the ISS to transformers as they typically need the primary wired in series
If I omit the wire bridge for 230v, am I correct in assuming that the output of the ISS will have two 230 VAC outputs (J8 --> AC | 0 | 0 | AC)?
Or do I also need the bridge for 230VAC above J8 when using the Meanwell SMPS's?
The ISS documentation states to either configure for 115v or 230v.
I am assuming this configuration has to do with connecting the ISS to transformers as they typically need the primary wired in series
If I omit the wire bridge for 230v, am I correct in assuming that the output of the ISS will have two 230 VAC outputs (J8 --> AC | 0 | 0 | AC)?
Or do I also need the bridge for 230VAC above J8 when using the Meanwell SMPS's?
Argh!! It looks like I forgot to include the BOM in the design doc. I'll fix that when I get home. I travel on July 3rd, so expect the doc to have been fixed by July 4th or 5th. Sorry for the omission.
Yes. The BOM... 🙂
Configure the board for your local mains voltage. Then hook the Mean Well supplies to the two AC terminals (terminal 1 and 4). I forget which is the live and which is neutral. You can easily trace the neutral on the board. If I recall correctly, terminal 4 (oval pad) is the Neutral and terminal 1 (rectangular pad) is the Live.
I should add that to the doc as well.
Tom