The Multi Amp aka Dynalo Mk2

[astro]

@gepardcv cspirou has already answered the question. Check the upper-left corner  of the last pic where covered by yellow Kapton tape.

@cspirou I draw the cad myself and place a custom order from taobao. The temp I mentioned is inside the enclosure and there are holes underneath for sure. Without the case, the temp will drop 6~8C.

[ang728]

Congrates!

 

--

看起來也是住台灣的Diyer阿ww

--

[cspirou]

Damn, i wish I knew chinese.

I see you made the TKD version @astro, would you mind posting the front panel layout?

Edited November 25, 2017 by cspirou

[mypasswordis]

你們都在大臺北地區嗎？

[joehpj]

What? Is mypasswordis also taiwanness?

Edited November 26, 2017 by joehpj

[chinsettawong]

我常去台灣.

[mypasswordis]

I'm Taiwanese American, my parents are Taiwanese. Anyone interested in a meetup? I'll be there very soon.  

[joehpj]

I am at Taipei while ang is at the other side of Taiwan.

[mwl168]

I came to the states in 1985. Visit family in Taiwan from time to time. Always spend days and hours in 光華商場.

Used to walk the isles of 中華商場 in the old days.

[astro]

@cspirou It's based on the @johnwmclean's layout. I just tried to post, but the server only allow me upload the file size below 20KB. Maybe send to your via email?

Wow! Seems there are so many Taiwanese on this forum! 

[joehpj]

10 hours ago, mypasswordis said:

I'm Taiwanese American, my parents are Taiwanese. Anyone interested in a meetup? I'll be there very soon.  

When will you come to Taiwan? A HC Taiwan meet sounds interesting. 

[mypasswordis]

高鐵 isn't so bad  I will be there Dec 5 - 15 but don't know when I will be available. I'll PM you soon.

[ang728]

18 minutes ago, mypasswordis said:

高鐵 isn't so bad  I will be there Dec 5 - 15 but don't know when I will be available. I'll PM you soon.

too bad,the county I live (台東) has no THSR . May be you can have a quick meet with joehpj or others

[chinsettawong]

If you guys in Taiwan are interested in DIY electrostatic headphones, I can bring mine for you to try the next time I'm in Taiwan.  可能在明年四到五月.

[jose]

On ‎31‎/‎01‎/‎2015 at 2:03 AM, mwl168 said:

Sharing my findings with attempts to raise output BJT current as promised.

 

I am running +/- 16V rails.

 

Using 255R in R38 and R39, I got around 186mv voltage drop on the output resistors (20R) when the amp is fully warmed up (160mV at cold start). That's around 9mA current. I could barely feel a temprature on the output transistors at this operating condition.

 

I finally settled on 301R in R38 and R39 which results in 250mV across the output resistors at cold start, rising to and stablize at 320mV after a few minutes. The output BJTs are quite warm to the touch but not hot. I am really liking the sound of the amp at this condition.

 

For what it's worth, here is a few other values of R38 and R39 I tried and the resulting voltage drop across the output resistors:

 

R38/R39 = 287R, 230mV cold start, 273mV warmed up

 

R38/R39 = 317R, 300mV cold start, 360mV warmed up

 

R38/R39 = 402R, 500mV cold start, did not wait for it to warm up.

 

This amp really sounds great on both my Senn. HD650 and LCD2. Subjectively the best among the headphone amps I own and heard.

 

Many thanks Kevin for your ingenuity and help!

My Dynalo SS lives too.

My amp runs with 20Vdc rails and 255R Bias resistor and like Pars, I use Jfet (2SK170GR/2SJ74GR) instead That340 (I learned the lessond with my Dynahi). 

I measured 160mV at cold start and after 20 minutes my amp is stable to 0,205mVolt (around 10mA) with an offset of 0~4 mVolt. Transistors temperature is 35º and 40º.  I read all thread and on speciality this answer. I´m going to change R255 for other value around R280.

 

Edited November 27, 2017 by jose

[MASantos]

Hello guys, long time since I posted around here, hope everyone is doing well.  I am looking into the dynalo mk2 for a new headphone amp. I've read around the thread and still have a few doubts.

1- I've seen some references to a BOM for the Kerry dynalo mini board and also for the"normal" SMD version but couldn't find them anywhere. Could someone point me out where to find them? 

2- The GRLV seems to be the go to choice for the standard build. It does have some choices regarding output voltage and configuration, but I couldn't find it in the grvl thread.

3- Has anyone compared the bjt input IC  with matched jfet quad input? I have plenty jfets to use, any parts changes needed to use them instead of the THAT340?

4- I really like the small for factor of the mini board with all the components in one board. I'll will be driving sennheiser hd650 (6xx actually), would the extra output capability of the "regular" board be an advantage here? I've seen some references of running very warm, should this pose a problem in the long run?

5- I'll try to ask in the FS forum if anyone has spare boards for sale, if I don't have luck which gerbers should I use to order boards? There are many versions of the GRLV and dynalo mk2.

Sorry for all the questions I haven't been around much and didn't follow the development closely.

[ti5002000]

2 hours ago, MASantos said:

Hello guys, long time since I posted around here, hope everyone is doing well.  I am looking into the dynalo mk2 for a new headphone amp. I've read around the thread and still have a few doubts.

1- I've seen some references to a BOM for the Kerry dynalo mini board and also for the"normal" SMD version but couldn't find them anywhere. Could someone point me out where to find them? 

2- The GRLV seems to be the go to choice for the standard build. It does have some choices regarding output voltage and configuration, but I couldn't find it in the grvl thread.

3- Has anyone compared the bjt input IC  with matched jfet quad input? I have plenty jfets to use, any parts changes needed to use them instead of the THAT340?

4- I really like the small for factor of the mini board with all the components in one board. I'll will be driving sennheiser hd650 (6xx actually), would the extra output capability of the "regular" board be an advantage here? I've seen some references of running very warm, should this pose a problem in the long run?

5- I'll try to ask in the FS forum if anyone has spare boards for sale, if I don't have luck which gerbers should I use to order boards? There are many versions of the GRLV and dynalo mk2.

Sorry for all the questions I haven't been around much and didn't follow the development closely.

Hi

I have a BOM for ssdynalo smd version here that i can get you.

I also have ssdynalo boards here if you want ,but is the through hole version, but also i have here some through hole mpsw56 and mpsw06 that i can spare if you are interested.

About the grlv you have the formula to change the output voltage here :

I also have the schematic and the gerbers if you need it .

[Pars]

Hello guys, long time since I posted around here, hope everyone is doing well.  I am looking into the dynalo mk2 for a new headphone amp. I've read around the thread and still have a few doubts.
1- I've seen some references to a BOM for the Kerry dynalo mini board and also for the"normal" SMD version but couldn't find them anywhere. Could someone point me out where to find them? 
2- The GRLV seems to be the go to choice for the standard build. It does have some choices regarding output voltage and configuration, but I couldn't find it in the grvl thread.
3- Has anyone compared the bjt input IC  with matched jfet quad input? I have plenty jfets to use, any parts changes needed to use them instead of the THAT340?
4- I really like the small for factor of the mini board with all the components in one board. I'll will be driving sennheiser hd650 (6xx actually), would the extra output capability of the "regular" board be an advantage here? I've seen some references of running very warm, should this pose a problem in the long run?
5- I'll try to ask in the FS forum if anyone has spare boards for sale, if I don't have luck which gerbers should I use to order boards? There are many versions of the GRLV and dynalo mk2.
Sorry for all the questions I haven't been around much and didn't follow the development closely.

1. I have BOMs for both and the GRLV as well at home and can post or send tonight
2. Covered. My BOM has a “calculator” for this built in
3. Yes, you can use J74/K170 or equivalents. C-> D, B -> G, E -> S. Will plug right into the dip14 socket if you wish.
4. Maybe regarding the full vs. the mini. The mini uses the same devices, but the PSU is done using Meanwell AC/DC bricks
5. I am thinking about selling the mini boards and pots that I have (2). As for versions, the last GB earlier this year run by sbeylo would give you a handle on board versions. The MPSW06/56 thru hole devices are discontinued and not generally available so SMT with the PZTA devices would be the way to go. Both are setup to use the THAT340 for input.


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[MASantos]

ti5002000 thank you for your offer, but i prefer to build the smd version with available parts. Building with obsolete parts is risky.

 

Chris, YGPM.

[ti5002000]

1 hour ago, MASantos said:

ti5002000 thank you for your offer, but i prefer to build the smd version with available parts. Building with obsolete parts is risky.

 

Chris, YGPM.

No problem. It's not risky if you know the right source.. Justin just bought a pile of new old stock of jfets. Anyway, if you could sell me jfets to replace the that 340 I will be a buyer. If the price is right. But anything pm me. Thanks

[MASantos]

18 minutes ago, ti5002000 said:

No problem. It's not risky if you know the right source.. Justin just bought a pile of new old stock of jfets. Anyway, if you could sell me jfets to replace the that 340 I will be a buyer. If the price is right. But anything pm me. Thanks

Sorry, I have enough jfets for me, but not enough for selling!  You can buy them on diyaudio.com for about 50 $. 

Edited December 1, 2017 by MASantos

[Pars]

No problem. It's not risky if you know the right source.. Justin just bought a pile of new old stock of jfets. Anyway, if you could sell me jfets to replace the that 340 I will be a buyer. If the price is right. But anything pm me. Thanks

Those were dual BJTs, not JFETs, that Justin bought. They are the dual version of the 2SA970/2SC2240.


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[jose]

if you can uses Jfet  

. 

[ti5002000]

15 hours ago, Pars said:

Those were dual BJTs, not JFETs, that Justin bought. They are the dual version of the 2SA970/2SC2240.


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You´re right.For some reason in my mind i was with the idea that that was jfets...

19 hours ago, MASantos said:

Sorry, I have enough jfets for me, but not enough for selling!  You can buy them on diyaudio.com for about 50 $. 

yes,but 50$ for that low amount of jfets is what i call expensive ....I know they have to be matched and etc...but still..But i guess that is the price these days.

Obrigado

Tiago

[MASantos]

On 25/11/2017 at 4:32 PM, astro said:

 

 

Those heatsinks have very narrow fin spacing, better suited for forced cooling. Natural convection heatsinks have wider spaced fins to allow air to move.

 

This said, any possibility that you could order more of those cases for those interested? I might be interested in 2 cases depending on price.

 

Edited December 2, 2017 by MASantos