Help me choose a DIY amplifier project.

[Thomasr]

Hi all. I'm relatively new to the hobby, and am looking for my next project to keep things fun and interesting.

My current chain is the SMSL DO200mk2 DAC and HO200 amp (so, clean and transparent signature) and my modest collection of headphones span a range of impedance/sensitivity values. Down the road, I might add an R2R DAC and more headphones (in particular I've been looking at the Hifiman Arya Organic or HE1000 Stealth).

The BH Crack looks interesting, but I'm pretty sure I'd prefer something that can work well with lower impedance headphones. The BH Mainline looks really sweet, but hasn't been in stock for ages. Maybe Doc will gear up for one last hurrah or maybe he won't.

In terms of handyman skills, I'm pretty good with woodworking (I have a well-equipped shop that even includes a small 3018 CNC router) so I could build my own chassis if necessary. My soldering and electronics skills are a little more modest: I have all the necessary gear and am game to tackle any kit with through-hole soldering, but I'd rather avoid SMD work honestly.

Since my HO200 is widely regarded as being accurate and uncoloured, I want to build an amp that brings some kind of "special sauce" to the stack - whether that's holography, euphony, warmth, or something else. I've been reading about a range of kits and options from Bottlehead, Elekit, Korg, etc. I think I'm leaning towards tubes but I'm open to SS suggestions. I strongly prefer a "complete kit" approach that includes all parts along with detailed instructions. Walk before run and all that ...

 

[conductor609]

what kind of budget are you looking at? as far as stuff you didn't list already you could consider the whammy, available as a complete kit with a guide on the diy audio store and should be different enough to be interesting.

https://diyaudiostore.com/pages/project-whammy

 

[Thomasr]

what kind of budget are you looking at?

BH Mainline territory... maybe a shade more for something that intrigues me sufficiently

 

[LobalWarming]

BH Mainline territory... maybe a shade more for something that intrigues me sufficiently

The obvious choice would be the Lord's Aegis : https://www.head-fi.org/threads/aegis-diy-tube-headphone-amplifier.965530/

Beautiful amp. Cost of the Lundahl heavy iron is a bit of an obstacle for me.

I'm very impressed with Mr. Lion's (@g0ldl10n) project: https://www.head-fi.org/threads/mr-lions-diy-thread.974855/ - appeals to my cheapskate DIY ethos.

Some... maybe only me, have encouraged him to release as a semi-documented DIY build. Could be worth a look at his thread.

 

[Thomasr]

The obvious choice would be the Lord's Aegis

Why is the Aegis more obvious than ... say ... an Elekit TU8400?

 

[LobalWarming]

Why is the Aegis more obvious than ... say ... an Elekit TU8400?

Because this is Head-Fi.

Also the Aegis is designed specifically as a headphone amp. The Elekit TU8400 is both a speaker amp and headphone amp. It uses 12AX7 drivers vs a pair of 6SL7 in the Aegis. I'm not a fan of the 12AX7 outside guitar amps.

That said, expect the 8400 with Lundahls will be a good sounding amp - with a GEC A2900/Brimar 6060T/Tele ECC81 instead of a head-banging 12AX7.

 

[martelanc24]

A less known option with a price point closer to the Bottlehead Crack would be SE/84 Brachycera tube amp kit from Uraltone from Finland. It is a speaker and headphone amp and can power low impedance planar headphones to high impedance dynamic headphones. I only use it for headphones. Not a dead quiet amp for headphones, as you can hear some hum and noise, not a lot, but if it bothers you it may not be for you. But then again, many tube amps are not dead quiet. I had it for 3 years now, I run it 8-10h per day sometimes, and it has over 5000 hours of use all together.

Build instructions are here for checking out, just use a translate feature: https://uraltone.com/blog/putkivahvistinrakennusohje-se-84-karpanen/

I also have a DIY Aegis amplifier, and it is dead quiet, even with IEMs up to ~80% volume, no hum whatsoever at any volume. This is also an area where your money goes to, in addition to sound quality, if we are talking specifically about the Aegis.

 

[dunring]

Ive had that stack and before building one I'd recommend trying the color and filter settings on the DO200 MKII first. The 3 tube settings with a fast rolloff filter that has pre and post ringing might be just the sound your looking for without any work

 

[Thomasr]

Ive had that stack and before building one I'd recommend trying the color and filter settings on the DO200 MKII first. The 3 tube settings with a fast rolloff filter that has pre and post ringing might be just the sound your looking for without any work

Just so I'm clear, you're saying my options are:

1. Build something like the BH Mainline, then start upgrading the caps, transformers, etc in an ongoing quest for the ideal sound signature
2. Adjust some settings on the DO200 I already own

 

[Thomasr]

The BH Mainline looks really sweet, but hasn't been in stock for ages. Maybe Doc will gear up for one last hurrah or maybe he won't.

So I figured the easiest way to resolve this particular riddle was to just phone Bottlehead and ask. Which I did, and apparently they're just weeks away from getting the Mainline back in stock.

 

[AudioCats]

maybe an Elekit TU8900?
But it is not really a DIY, more of a AIY (assemble it yourself). The magic of that kit seems to come from the power/filament management modules (the two red PCBA's with all the SMD components fully populated). I don't see any schematic or even technical info for these modules in the included documents.

The actual tube amp circuitry is not that special, similar to the one used in a BoyuuRange A50.

 

[DenverW]

I've built all of the bottlehead headphone amps, as well as the Aegis. They're all fun builds and have great documentation.

For overall sound quality there is no comparison to the Aegis. You have to take extra steps in sourcing the parts, but the payoff is sonically worth it. For higher impedance dynamic headphones I saw an email from bottlehead that they had some remaining crackatwoa amps in stock recently; a nice upgrade from the crack.

 

[Thomasr]

At this point it looks like I'm going to build a SS amp by heavily customizing an Aliexpress PCB/kit. This definitely isn't a direction I anticipated for this project, but sometimes you just have to follow your random compulsions...

Should be quite a learning experience, and I'll do my best to document things as a go, with an eye toward maybe doing some kind of writeup when all is done.

Wish me luck!

 

[Somek]

At this point it looks like I'm going to build a SS amp by heavily customizing an Aliexpress PCB/kit. This definitely isn't a direction I anticipated for this project, but sometimes you just have to follow your random compulsions...

Should be quite a learning experience, and I'll do my best to document things as a go, with an eye toward maybe doing some kind of writeup when all is done.

Wish me luck!

Fingers crossed! Any updates?

 

[Thomasr]

Fingers crossed! Any updates?

Sort of...

As I've been learning more about amplifier design (via books, ChatGPT, and the occasional helpful forum member) I've come to realize there really isn't a ton of scope to customize the Kumisa III. I've also learned the hard way that Aliexpress is rife with counterfeit components, so I'm having to spend time testing and validating some of the stuff I bought.

And then there's my ideas for a chassis, which have gone back and forth a few times as I've pondered the materials and layout I'll use.

Long story short, I'm taking things slow, and may actually build a basic Kumisa III kit with no upgrades as a starting point. I've thought about creating a placeholder build thread here, but with the recent changes in double-posting enforcement here on HeadFi the idea has become much less appealing. We'll see.