Dynahi Build Resources in 2023?

[Satyrnine]

Hello, new to Head-case, but an experienced elec tech. After demoing a friend's, I'd like to build a balanced Dynahi, but am having troubles tracking down documentation and boards. Can anyone steer me in the right direction? Thanks!

[jamesmking]

4 hours ago, Satyrnine said:

Hello, new to Head-case, but an experienced elec tech. After demoing a friend's, I'd like to build a balanced Dynahi, but am having troubles tracking down documentation and boards. Can anyone steer me in the right direction? Thanks!

in general there are no build guides unless a forum member explicitly makes one. Here is the link to the forum thread for the amp. I strongly suggest reading through it all... the threads document the evolution, modification and problems builders have.

https://www.head-case.org/forums/topic/9768-kg-balanced-dynahi-build-discussion-thread/#comment-468974

schematics can be found at 

https://drive.google.com/drive/folders/0B7egryukiT7_TFlEQlBRejdVdDQ?resourcekey=0-nGWwBYQ_Uivj-ciBLYMeaA

and gerbers to have pcbs made:

https://drive.google.com/drive/folders/1r3g2TAtBUaBdiMorTWX7yYgeJ7maQbYW

Also consider that people post schematics, their own gerbers etc in the thread sometimes.

Also be aware that if you need transistors which are no longer manufactured and only available as new old stock, there are many many sellers on ebay etc selling FAKES, which are look alike transistors with the original markings removed and the markings of the NOS transistor silk screened or laser etched on to them. These fakes of course will fail on first switch on... So if you need NOS components consult the forum before buying from a seller. 

Sometimes there are more then one version of an amp, one using NOS and one using modern components, but the speed through hole transistors are being marked as obsolete or end of life by the manufacturers mean that its a constant struggle to have amp designs that only use modern available parts. 

There are some forum members with stocks of NOS components who are sometimes willing to sell to members, in general what they don't want to do is to sell to someone who will then just resell the components at higher prices on ebay etc, if they are going to supply they expect the components to go into a build or be held as spares for an existing build since the supply of many genuine NOS components is getting very very low and often there are no modern drop in substitutes. So sometimes you have to be in the forum for a while and post pictures of your builds so you can show you are a genuine DIYer and not a high price reseller scalper.

often builders get the bare pcbs made by Chinese companies like JLCPCB who have a minimum order quantity of 5, so sometimes people have spare pcbs, so its often worth asking in the forum if anyone has a spare. There are also on going parts shortages so sometimes its possible to do a parts swap with another DIYer is they have spare of what you need and you have something they need....

Good luck and welcome.

(P.S. the moderators do a very good job of keeping junk sellers, bots, scammers, advertisers, spammers etc out of the forum. There is a wide range of threads not all DIY related and its generally frowned upon to do politics etc in a build thread.). 

 

 

Edited February 16, 2023 by jamesmking

[Satyrnine]

12 hours ago, jamesmking said:

in general there are no build guides unless a forum member explicitly makes one. Here is the link to the forum thread for the amp. I strongly suggest reading through it all... the threads document the evolution, modification and problems builders have.

https://www.head-case.org/forums/topic/9768-kg-balanced-dynahi-build-discussion-thread/#comment-468974

schematics can be found at 

https://drive.google.com/drive/folders/0B7egryukiT7_TFlEQlBRejdVdDQ?resourcekey=0-nGWwBYQ_Uivj-ciBLYMeaA

and gerbers to have pcbs made:

https://drive.google.com/drive/folders/1r3g2TAtBUaBdiMorTWX7yYgeJ7maQbYW

Also consider that people post schematics, their own gerbers etc in the thread sometimes.

Also be aware that if you need transistors which are no longer manufactured and only available as new old stock, there are many many sellers on ebay etc selling FAKES, which are look alike transistors with the original markings removed and the markings of the NOS transistor silk screened or laser etched on to them. These fakes of course will fail on first switch on... So if you need NOS components consult the forum before buying from a seller. 

Sometimes there are more then one version of an amp, one using NOS and one using modern components, but the speed through hole transistors are being marked as obsolete or end of life by the manufacturers mean that its a constant struggle to have amp designs that only use modern available parts. 

There are some forum members with stocks of NOS components who are sometimes willing to sell to members, in general what they don't want to do is to sell to someone who will then just resell the components at higher prices on ebay etc, if they are going to supply they expect the components to go into a build or be held as spares for an existing build since the supply of many genuine NOS components is getting very very low and often there are no modern drop in substitutes. So sometimes you have to be in the forum for a while and post pictures of your builds so you can show you are a genuine DIYer and not a high price reseller scalper.

often builders get the bare pcbs made by Chinese companies like JLCPCB who have a minimum order quantity of 5, so sometimes people have spare pcbs, so its often worth asking in the forum if anyone has a spare. There are also on going parts shortages so sometimes its possible to do a parts swap with another DIYer is they have spare of what you need and you have something they need....

Good luck and welcome.

(P.S. the moderators do a very good job of keeping junk sellers, bots, scammers, advertisers, spammers etc out of the forum. There is a wide range of threads not all DIY related and its generally frowned upon to do politics etc in a build thread.). 

 

 

Wow! This is exactly what I'm looking for! Thank you! Those google drive links are a treasure trove! My friend suggested I look into the CFA3 as well. Is there a similar thread for the CFA3? I definitely did some searches for "Kevin Gilmore Dynahi" and didn't find that thread you linked, so I appreciate any guidance there. 

I'm definitely not a scalper or such, just a hobbyist. My main area of work is custom guitar/bass tube amps and effects pedals for musicians, but I dabble in hifi. I have a heavily modded Darkvoice 336se, Schiit Vali2, and some mid level Schiit Dacs, and LCD-2's. Some heavily modded Adcom power amps as well. As soon as I heard my friends Dynahi, I knew I had to upgrade. Planning on a balanced DAC as well. 

Finding someone with a set of known good boards seems ideal, but I've had good luck with Oshpark, a domestic board maker. I'd likely use them if I have to make my own, never had an issue with their work fortunately. I've designed a few pcb's as well, but for relatively simple stuff vs a dynahi.

Good to know there's good mods here. Really makes or breaks a community, and seems like this one is great! Thanks for the warm welcome!

[Satyrnine]

I should add I realize I don't NEED a Dynahi for LCD-2's low impedance, but my bud has said that it's a fantastic pairing regardless, and will let me try higher imp cans later on. My Darkvoice mods (usually ideal for 600ohm cans) were all about making it work for lower imp cans. 5998a output tube, higher B+, drastically increased output cap value, etc.

Attached are pics of the Dynahi I biased/balanced for my bud.

[Pars]

The thread for the CFA2 or 3 is here:

Depending upon what you want, you could do either 4 CFA2 boards for balanced only, or do the CFA3 for the ability to run SE or balanced. For the CFA3, Kevin also did some split boards which separate the front end stuff from the amp guts and allow more flexibility in chassis layout.

Personally, I have built Dynahi's and would recommend the CFA3 instead. I have only built a couple of CFA2 boards, but worked on one of Dukei's CFA3s for another HC user and really liked it. Something that was finally a bit better than my DynaFET. And done with currently available parts as well (other than Toshiba JFETs for the input).

Edited February 17, 2023 by Pars

[Satyrnine]

13 minutes ago, Pars said:

The thread for the CFA2 or 3 is here:

Depending upon what you want, you could do either 4 CFA2 boards for balanced only, or do the CFA3 for the ability to run SE or balanced. For the CFA3, Kevin also did some split boards which separate the front end stuff from the amp guts and allow more flexibility in chassis layout.

Personally, I have built Dynahi's and would recommend the CFA3 instead. I have only built a couple of CFA2 boards, but worked on one of Dukei's CFA3s for another HC user and really liked it. Something that was finally a bit better than my DynaFET. And done with currently available parts as well (other than Toshiba JFETs for the input).

Excellent! Thank you! The split boards sound interesting, maybe try a tube input. Hmm.... CFA3 sounds ideal, since not all sources/cans will always be balanced. When you say "Kevin did some boards" how would a guy go about getting gerbers or such for that? I found his Google Drive full of schems, but didn't see much for the cfa3, or the split boards. Just message him? Sorry, new here.  Thanks!!

[Pars]

I believe they are the cfp3smtsplit gerbers (Amp and Pre) on his site. If you read the thread, Kerry also did some spilt boards with more SMT on them (so probably smaller), but I don't think he released the Gerbers. Probably going to do a commercial product with his new company with those.

[Satyrnine]

2 hours ago, Pars said:

I believe they are the cfp3smtsplit gerbers (Amp and Pre) on his site. If you read the thread, Kerry also did some spilt boards with more SMT on them (so probably smaller), but I don't think he released the Gerbers. Probably going to do a commercial product with his new company with those.

Will do! Thanks!