I was going to do this with Jung's modification of his original design for shunt operation.
Hello,
I'm going to build this amplifier soon. Mr. Marsh did amazing job here and I'm really impressed with this relatively simple circuit. Currently I'm at state of gathering parts but I have few doubts here.
What offset and DC transients should be expected during powering off and on? I wonder if something like this or this is required. The second thing is choice of capacitors. Any particular recommendations? I've seen a few people using Elna Silmic II 220uF 35V. As far I understand correctly low ESR caps like Panasonic FM should be avoided? Is it good idea to upgrade them to 470uF? What about bypassing them with 100nF X7R ceramics?
Rest of things looks straightforward - I'm going to order PCB and matched transistors from tech-diy. The power supply would be probably mravlca's TPS7A4700 running at +/- 15V. 10K Alps RK27 or maybe stepped attenuator. Everything fitted in some nice enclosure.
Regards,
Miłosz
I'm going to build this amplifier soon. Mr. Marsh did amazing job here and I'm really impressed with this relatively simple circuit. Currently I'm at state of gathering parts but I have few doubts here.
What offset and DC transients should be expected during powering off and on? I wonder if something like this or this is required. The second thing is choice of capacitors. Any particular recommendations? I've seen a few people using Elna Silmic II 220uF 35V. As far I understand correctly low ESR caps like Panasonic FM should be avoided? Is it good idea to upgrade them to 470uF? What about bypassing them with 100nF X7R ceramics?
Rest of things looks straightforward - I'm going to order PCB and matched transistors from tech-diy. The power supply would be probably mravlca's TPS7A4700 running at +/- 15V. 10K Alps RK27 or maybe stepped attenuator. Everything fitted in some nice enclosure.
Regards,
Miłosz
Richard:
my current supply is a very low noise borbely-sulzer doing +/- 17V.
i'm working on building a shunt reg to try with the amp since everybody talks them up so much
)), but haven't finished it yet.
I'll comment when I do.
But I'm not a reviewer.
It will be +/- 25v (apprx).
Do you have any recommendations? I'm leaning towards something similar to the front end shunt from Mihai's RMI-FC-100 amp .
mlloyd1
my current supply is a very low noise borbely-sulzer doing +/- 17V.
i'm working on building a shunt reg to try with the amp since everybody talks them up so much
)), but haven't finished it yet.I'll comment when I do.
But I'm not a reviewer.
It will be +/- 25v (apprx).
Do you have any recommendations? I'm leaning towards something similar to the front end shunt from Mihai's RMI-FC-100 amp .
mlloyd1
Richard:
my current supply is a very low noise borbely-sulzer doing +/- 17V.
i'm working on building a shunt reg to try with the amp since everybody talks them up so much
I'll comment when I do.
But I'm not a reviewer.
It will be +/- 25v (apprx).
Do you have any recommendations? I'm leaning towards something similar to the front end shunt from Mihai's RMI-FC-100 amp .
mlloyd1
How does it sound with the present volt reg and then later you can tell us about the comparison with a shunt.
THx-RM
Gnerally, I always use polar caps rated for 105C and I like low esr/esl types myself.
There has been no turn on-off transients. DC offset is also minimised by placing a large value cap across the PS lines... + to -. This tends to keep the two supplies at same voltage during power up and power down so no offset on amp output. Or a master-slave arrangement so both supplies are always at same voltage.... they move together. A shunt would be self balancing during turn on or off.
Good to see the higher voltages being used also.
THx-RNMarsh
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I guess Walt terminated the site. Here's the schematic for the one I have simulated. You have to allow enough current to flow through the D-MOSFETs to accommodate the overhead of the 45H11 op amp etc.
Attachments
Probably doesn't like the deep linking. The article is available by navigating from the top: Walt Jung
Hi Richard:
As I've said before, I think your HPA sounds fabulous with the series regulator.
This series regulator was designed to power a pretty good MC phono preamp so is VERY low noise. My suspicion is whatever I can quickly pull together as a shunt reg won't be able to technically compete - different design objectives. It would probably be more fair to modify one of my Jung Super Regs series with the DN2450 CCS to be a shunt reg as Walt cleverly showed in one of his write-ups earlier.
But I don't think I'll have time for that right now, unfortunately.
At any rate, I promise I'll comment when I'm done.
mlloyd1
As I've said before, I think your HPA sounds fabulous with the series regulator.
This series regulator was designed to power a pretty good MC phono preamp so is VERY low noise. My suspicion is whatever I can quickly pull together as a shunt reg won't be able to technically compete - different design objectives. It would probably be more fair to modify one of my Jung Super Regs series with the DN2450 CCS to be a shunt reg as Walt cleverly showed in one of his write-ups earlier.
But I don't think I'll have time for that right now, unfortunately.
At any rate, I promise I'll comment when I'm done.
mlloyd1
It appears that Walt is shutting down his Blog, and all of the documents will eventually be available as archived PDF's. At this point though, the permissions seem to be wrong(and/or non existant) for the archived files on the "Site Pages".
Anyone interested might want to get what they can from his original blog here before its too late: Walt's Blog 2014 | Walt Jung's 2014 Blog and Info Archive
I use Erno's shunts for my Borbely preamp, dac, and phono stage. it's a big board, all discrete jfet and fet, It takes a lot of chassis space to do a fully balanced version of the Dac, Phono., and line amp with separate shunts for each phase. I recently updated the Borbely shunt's LM 329 voltage references to 4 green LEDs in series based on Walt's latest design and Crister's earlier work on LED noise as voltage references.
Walt had hinted a new regulator or update was in the works when he introduced his new LED voltage reference, but closing his website is not a good sign.
Walt had hinted a new regulator or update was in the works when he introduced his new LED voltage reference, but closing his website is not a good sign.
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Tickenpop,
You are right about board space, I have been working on a balanced preamp and the regulators take up more space than the gain section. Christers work was great and I use 12v zeners a led's for voltage references and for some reason the sound better than devices like the LM 329.
You are right about board space, I have been working on a balanced preamp and the regulators take up more space than the gain section. Christers work was great and I use 12v zeners a led's for voltage references and for some reason the sound better than devices like the LM 329.
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