Getting Started in DIY

[ilikebananafudge]

Hey y'all,

 

I've lurked around here for a few years but now I'm planning on getting started building amps, and I could use a bit of assistance. I've never soldered anything and I've probably stripped a wire once, so I'm gonna need to ease into this. From what I've read here and on Innerfidelity the Bottlehead Crack or Torpedo would be good places to start, as they're simple builds and pair well with my HD650s. Any other suggestions?

 

I read this plan on getting the Hakko FX-888 as my solder 'gun' and 63-37 eutectic solder. According to tangentsoft I need small screwdrivers, small cutters and pliers, and a wire stripper. Are any other supplies needed?

 

After this build I'll probably want to build a dynalo/dynahi/dynamite or beta22, which requires casework apparently, are there other supplies I need to do that (I don't need to engrave anything, just drill holes I guess)?

 

Finally, I'm interested in learning the theory behind all the capacitors and various FETS that get jammed into headphone amps. I took introductory physics in undergrad, but I'm a chemist so circuits are pretty foreign to me. Is there a good place to learn the basics of headphone circuitry?

 

Apologies for the barrage of noob questions, but any help or suggestions would be appreciated. Snarky comments, banter, and insults are expected, as per usual.

[Pars]

The Art of Electronics, Horowitz and Hill is a good book. You might want to just grab the shit to make a Cmoy from ratshack for a bit of practice first before you start into anything. I probably have an extra panasonic pot laying around that you could have for that. Maybe an opamp as well. Besides that, you should be able to get everything there for cheap (metal film resistor assortment, board). Will give you some soldering practice, and doesn't sound too bad.

Edited December 22, 2013 by Pars

[n_maher]

http://www.innerfidelity.com/content/introduction-headphone-diy

 

http://www.innerfidelity.com/content/ultimate-headphone-guide-articles-introduction-headphone-diy

[spritzer]

I'd gradually build up to something like the Dynahi, not jump in.  The B22 is fragile so be prepared to to some error checking which is arguably the hardest part of DIY. 

[dsavitsk]

 From what I've read here and on Innerfidelity the Bottlehead Crack or Torpedo would be good places to start, as they're simple builds and pair well with my HD650s. Any other suggestions?

 

After this build I'll probably want to build a dynalo/dynahi/dynamite or beta22, which requires casework apparently, are there other supplies I need to do that (I don't need to engrave anything, just drill holes I guess)?

 

Finally, I'm interested in learning the theory behind all the capacitors and various FETS that get jammed into headphone amps. I took introductory physics in undergrad, but I'm a chemist so circuits are pretty foreign to me. Is there a good place to learn the basics of headphone circuitry?

 

 

The Torpedo and Crack will teach you wildly different soldering skills. If you see yourself building one-off tube amps using point to point techniques, the Bottlehead is a good starting point. If you want to do primarily PCB based projects, the Torpedo is better.

 

It is probably a good idea to get one project under your belt before jumping into future ones.

 

Different people learn differently -if you are a book learner, Art of Electronics is excellent. If you are a hands on learner, start soldering working on other people's projects, and trying to trace what's going on. It is how a lot of us got into this stuff.

[jvlgato]

Don't know squat about DIY, just wanted to say that I happen to know a chemistry guy who seems to know quite a bit about circuits!

[nikongod]

I would start with a Cmoy. Even if you get one of the RA-1 clone kits (with a PCB) off of ebay. 

Building a perf-board CMOY is also great, but a decent bit harder than the PCB cmoy. Maybe save this for project #2. 

 

It's not the Cmoy is great, it isn't. But who cares? The Cmoy is cheap and a known standard. 

If it breaks someone here or there has probably broken one just like you did before - so you can find help. 

It is also has relatively few parts which makes checking every single solder joint and operating voltage that much easier. 

If you really cant get it running, what did it cost? like $50? Cheap enough to say oops. 

Since it is more likely that you do get it running, give it away, or sell it for $50, or just put on the shelf as a pleasant memory. 

 

The hardest part of DIY (maybe its just me, but its not) is casework. The Cmoy does require some casework, but who cares if you destroy an Altoids tin? Get another for $3 (and the mints!) and try again. Great way to practice. 

[n_maher]

^^ I agree with everything this guy says (at least in this case ).  Start small, see if you really enjoy it before sinking hundreds/thousands into the parts and tools needed to build something like a beta22/dyna.  

 

I also share the sentiment that the beta²² has an unacceptably high failure rate.  I haven't built one in years and I know that Ti has changed some part values to make it more robust but I haven't stayed in touch enough with those building them enough to know how much of a difference it has made.  

[fishski13]

... The B22 is fragile so be prepared to to some error checking which is arguably the hardest part of DIY. 

 

 

not recommended for a first time DIY project, but i wouldn't call it "fragile".

Edited December 24, 2013 by fishski13

[nikongod]

not recommended for a first time DIY project, but i wouldn't call it "fragile".

 

There should be a better word for this in English. 

I wonder if there is an engineering term? 

 

Insanely strong and powerful, until a mouse farts the wrong way and it explodes. 

Its a lot like Prince Rupert's drops (Check out the high-speed camera footage, they are fascinating) 

 

In a similar vein: a perfect soda can can support body weight. Well, until you tap it with a pencil and it collapses. 

Edited December 24, 2013 by nikongod

[livewire]

Heh, could be talking about the KGSSHV. Many of those pop and drop!

Disclaimer: not recommended as a first project.

[spritzer]

There has to be a better word than fragile but basically if the B22 shorts at any time then it roasts half the output stage.  This makes TRS plugs almost impossible to use. 

 

KGSSHV, yeah the first ones were not user friendly but then again, nobody has ever made a mass DIY project at +/-500V so there were bound to be some issues.  Still the final version (v1.0) of the PSU is promising. 

[fishski13]

i've never had an issue with my B22 in 5 years, even with 0.47R Source resistors.  i think most builders are opting to increase the resistance to 1-2.2R to provide a larger margin of safety against shorts.  

[luvdunhill]

I think fragile is the proper term.

[n_maher]

It lacks a gentle failure mode.

[luvdunhill]

fishski13: for a long time the problem wasn't acknowledged. Since the site won't load on my phone I cannot check the BOM to verify another part has been recommended. If not, then "fragile" is the right term.

[fishski13]

Marc, copy and paste.

 

Notes about R34 and R35:

The default value for these resistors is 0.47Ω. If you have TRS headphone output jacks, the value may be increased to 1&Omega to 2.2Ω for added protection. This is because TRS plugs create momentary short circuits while being inserted or removed, and could potentially damage the output MOSFETs.

On 4-channel balanced configurations with only XLR output jacks, or if the amplifier is for speaker use only, it is not necessary to increase the value of these resistors.

The drawback of increasing these resistors' value is a small loss of maximum output voltage swing capability.

If you use the default 0.47Ω value with TRS jacks, it is recommended that you turn off the amplifier before inserting/removing the headphones plug. Or, at the very least, turn the volume to minimum and insert/remove the headphone plug very quickly.

Metal oxide resistors are the only recommended resistor type for R34 and R35. In particular, do not use wirewound types. Also, do not use resistors rated higher than 2W.

[luvdunhill]

Cool So I am down to only one beef with amb.org. Recommending SSRs. I am going to put a community service project out to remedy this soon.

[fishski13]

Cool So I am down to only one beef with amb.org. Recommending SSRs. I am going to put a community service project out to remedy this soon.

 

i'm not SSR savy - only seen one in a B3 DAC repair i performed.  what's your primary beef?  

Edited December 24, 2013 by fishski13

[luvdunhill]

SSRs don't like inductive loads. The results are transformers that buzz. There were a few threads somewhat acknowledging the issue but in the end, whether the relay is zero - crossing or rated to 50x the needed current, removing the SSR results in quieter transformers. Just use a normal relay, there are only drawbacks to SSRs and no benefits.

Edited December 24, 2013 by luvdunhill

[kevin gilmore]

We all know a person who built a T2 as his first project ever. Then built a second one.

Then built all sorts of stuff. And has not looked back since. But probably not a good

idea for the timid.

[fishski13]

thanks!  TXs are inductive:)  the Bulgin latching power switches i use are rated only for 3A.  i wire in a 10A mechanical relay to take the brunt of the inrush current.  the only SSRs i've seen are spendy too.

[ilikebananafudge]

Okay, thanks for all the helpful info. I'll start by grabbing all the requisite tools and then the parts for a CMOY. What everyone is saying makes a lot of sense in terms of getting my feet wet with a small initial investment. After a CMOY or two I'll probably build a Torpedo since most of the projects I've been eyeing are PCB based. Apparently I'll stick with the gilmore projects and not the B22. But maybe a balanced M3. Maybe I should've gone to Northwestern for grad school...

Edited December 25, 2013 by ilikebananafudge

[nikongod]

If its any help (or not) I really like the CKK-III as a project for further down the road. 

On many levels its a shame that it gets passed over for the b22 so often. 

[deepak]

If you ever plan to explore the tube side of things I like Morgan Jones Valve Amp book, and the 4th edition is available digitally. IMO it's more practical information for non-EE's.

 

free resources-

VALVE magazine: http://www.bottlehead.com/VALVEarchive/default.htm

Vacuum Tube Valley: http://www.vacuumtubevalley.com/Magazines/