[breizheau]

Hi there,

after searching on various threads, forums, etc.... i haven't found files or pictures to make the Dynalo PCB. I and a friend of mine woulf like to do this headphones amp. We have the famous 2sk389 and 2sj109, BL grade, and the other stuff are not so difficult to buy.

What resistors do you use ? I remind that people use Dale resistors. Can you confirm ?

Cheers,
Olivier

 

[liltehood]

if u have the schematic why dont u do the layout urself?

hood

 

[tomb]

http://djgardner.com/headphone/gilmore/

 

[Pars]

As Tomb pointed out, Dan Gardner still has PCBs for both Dynalo and Dynahi. He travels a lot, so you will need to be patient.

As for resistors, most people in the US have used Dales (it will fit RN60Ds), but any 1/4W or so metal film would be sufficient. I used Roderstein Resistas in a couple of them that I built, filling in with PRPs where the Resistas were no longer available.

 

[breizheau]

Thanks. I have a "doubt" : i have a Sennheiser 600, Z=300. Do i have to build Dynalo or Dynahi ?

 

[MASantos]

Quote:

Originally Posted by breizheau /img/forum/go_quote.gif Thanks. I have a "doubt" : i have a Sennheiser 600, Z=300. Do i have to build Dynalo or Dynahi ?

Both will do a fine job at powering the HD600's. The dynahi is a more powerful amplifier and it will be much more expensive. Go over to headwize and you'll find the original projects history and quite a few threads.

 

[breizheau]

I have decided to go for the Dynalo with the help of Dan (djgardner). And the good news is that he still has PCB for this !!!!
Now i will read the "howto" for this amp.
Thx to all of you.
Olivier

 

[Ozymand]

Good luck with the build!

Looking back at the build instructions, I noticed that the Toshiba SA1015 and SC1815 parts (along with the all-important SK109 and SK389) don't exist anymore. Are the Fairchild equivalents for the SA1015 and SC1815 acceptable for this application? Comparing the spec sheets they seem identical... but then spec sheets don't necessarily tell the whole story.

 

[NelsonVandal]

Good news! How much is a board?

Regarding JFETs, you can buy matched quads of SK170/SJ74 from amb. I doubt you'll find the original dual JFETs.

About those bjts, I've never heard them, but Toshiba clones from Fairchild has a good reputation amongst DIY'ers.

 

[breizheau]

For the SA1015 and SC1815, i will buy them at Futurlec and match them myself. It seems that it's Toshiba. I am lucky because i have already the jfets 2sk389 and 2sj109 BL. I used some for my preamp and amp.

I am waiting for the PSU BOM to finish my shopping.

Do you know what is te value for the volume pot ?

Maybe i will do a ladder attenuator.....

One more question : where to buy RN60 resistors without paying a crazy amount...

i don't live in US and shipping fees are 75 USD. It's amazing.

 

[Pars]

The 2SA1015 and 2SC1815 are readily available in the US (Toshiba) thru BDent and probably MCM Electronics as well. You won't find any 2SJ109s and 2SK389s and if you do, I would check them very carefully. As noted. the 2SJ74 and 2SK170s are the single versions and are still available, though these are discontinued as well, so will be drying up.

As for resistors, use what you can get that is good (1% metal film; 1/4, 0.4 or 0.6W). I used Rodersteins and PRPs in mine (from Michael Percy audio).

 

[Ozymand]

Quote:

Originally Posted by breizheau /img/forum/go_quote.gif Do you know what is te value for the volume pot ? Maybe i will do a ladder attenuator.....

AMB has some Alps pots in stock and would make for a fine volume control.

Quote:

Originally Posted by breizheau /img/forum/go_quote.gif One more question : where to buy RN60 resistors without paying a crazy amount... i don't live in US and shipping fees are 75 USD. It's amazing.

When I bought the parts (oh.. back in 2005.. sad that it's only now I'm starting to build it), I bought some Yaego 1% 1/4W resistors for the kit. Don't remember if they were on the original BOM or not, but I think they were acceptable for the application. The RN55's would be acceptable as well, and probably a tad bit cheaper than the RN60's.

 

[dgardner]

Quote:

Originally Posted by tomb /img/forum/go_quote.gif DIY RESOURCES - Kevin Gilmore DYNAMIC HEADPHONE AMPLIFIERS and POWER SUPPLIES

Yes, there are still boards left over from the past group buys.
-Dan

 

[breizheau]

Pars, i have my 2SK389 and 2SJ109 BL from a previous GB with a french forum homecinema-fr.com • Page d’index and they are not fake. We were lucky to still find them..... I remind that on diyaudio, there was a GB of 389 and 109 but after checkings they were fake !!!
I used them to do preamp + amp pass-like. Sounds great believe me !!!!!!

For the PSU, i will try different models. The creator of the UGS + UP (preamp + amp) is somebody amazing and for the preamp he did a quite nice PSU. i still have boards, HS, caps and all the stuff to do them. How is the current consumption of the Dynalo ? I need this valu to define my resistors and pot.

For the casing i think to use 1U slimline casing from Hifi2000 and put everythnig inside. the HS will be the sides of the casing.

Do you think it will fit inside or do i have to look for a 2 U ?

I can't wait to receive all the stuff to build it .

 

[Pars]

Quote:

Originally Posted by breizheau /img/forum/go_quote.gif Pars, i have my 2SK389 and 2SJ109 BL from a previous GB with a french forum homecinema-fr.com • Page d’index and they are not fake. We were lucky to still find them..... I remind that on diyaudio, there was a GB of 389 and 109 but after checkings they were fake !!! I used them to do preamp + amp pass-like. Sounds great believe me !!!!!! For the PSU, i will try different models. The creator of the UGS + UP (preamp + amp) is somebody amazing and for the preamp he did a quite nice PSU. i still have boards, HS, caps and all the stuff to do them. How is the current consumption of the Dynalo ? I need this valu to define my resistors and pot. For the casing i think to use 1U slimline casing from Hifi2000 and put everythnig inside. the HS will be the sides of the casing. Do you think it will fit inside or do i have to look for a 2 U ? I can't wait to receive all the stuff to build it .

Yes, I was aware of the GB on diyaudio. I still have a few genuine (from 3-4 years ago), so I did not get in on this GB.

Current consumption for the Dynalo if I remember right is around 100mA per channel. I would plan on perhaps 200mA per. You will not need to heatsink the output transistors on the Dynalo (they are TO92 case). They will get a bit warm but nothing to worry about (mine I can easily leave my finger on after its been running an hour).

As for fit in a 1U enclosure? The Dynalo board would definitely fit; this is more up to the PSU, etc. as to whether a 1U or 2U would be better.