constructive criticism on the crack's building process and manual

[harari]

Hi all,

I just received my crack kit a couple of days ago. I built it the same night it arrived, it took me about 4 hours and it's working flawlessly.
I also got the SpeedBall upgrade but I didn't install it yet. I want to try out the stock crack for a couple of weeks before I install it.

I want to share my thoughts of the building process and what I expected to get from it, but first, some background about me:
I'm a communication systems engineering student and this is not my first DIY project. I'm pretty familiar with soldering irons and electronic circuitry, but I haven't messed with analog audio circuits before. Most of my projects include digital circuits and microprocessors.
I play music and I've been into audio for a while now, the evolution of my speaker setup started long ago, but I discovered the magic of headphones a few years back.

A decent headphone setup was a dream of mine and now that I have the resources and time to invest in it, I decided to go for it. I bought a pair of HD650's and a crack with SB (I heard the 650-crack combination a few years ago at a headphones meetup in another forum and decided that when the time will come - this would be the setup I'll buy) and when they arrived I was so excited I dove right in.

Part of the reason I went for the crack is the DIY aspect of it. This would mean I could make it my own, with a different design and upgrade it as I wish to make it truly one of a kind. I figured going DIY would have some added value, I wanted to learn about analog audio amplification circuits and how vacuum tubes work specifically - and what better way is there to learn about something than to fiddle with its components and build it from scratch.

Before I go in, I want to make something clear - THIS AMP IS AWESOME! it sounds great, it looks great, it was super fun to build and i'm incredibly happy with it.
Now that we cleared that up, I kind of expected it to give me a more full experience, i'm not talking sound quality but the building experience was lacking, in my opinion.
I found the instructions WAY too specific and I understand why, this needs to be a kit that a completely inexperienced individual can build on their own, but this method makes the process tedious and boring for experienced builders.
As I mentioned, one of the goals was to learn about analog audio circuits, but the instructions were very dry and had absolutely no technical data on the circuit, not even what purpose the main components serve, apart form one schematic that isn't referenced once through the entire build.
The instructions were so simplified and specific that you cannot see the big picture. You're instructed wire-by-wire and terminal-by-terminal instead of component-by-component or even according to the flow of the circuit. Even the names of the pins and terminals are meaningless. Because of this, unless you know your way around audio circuits, you don't have any idea how the signal flows through the circuit and what happens to it along the way. I could reverse engineer the circuit and figure it out, but this was not the intention.
I understand this product is not supposed to be educational, but what value is there to solder wires without understanding what they do? this would just make troubleshooting a nightmare without professional help (luckily for me, I can follow instructions).
If the purpose of the components was pointed out, I think we would have seen much more interesting builds and upgrades because people would know which part is worth investing and how to make it better.

I don't think the current instructions should be changed, there are still people who need this kind of guidance. I think there should be an option with more technical instructions and less soldering instructions.

I intend to read, learn and upgrade my crack to the max. I saw some interesting upgrades from other people and I have some ideas of my own to make it look and sound one of a kind.

How was your experience of putting the crack together? Is it just me? What do you think? I'd love to get feedback from the community.

Pleasant listening for all.

[borism]

Hi Harari,

Welcome to the forum. Reading your post I have to agree with some parts. For me it was a first (actually second build - Stereomour was first) since I have very limited experience with any kind of electronics.

However, I also found that more information about the purpose of parts and connections in the circuit would have been interesting. So, as opposed to an "either - or" suggestion regarding very detailed building instructions vs. general circuit explanations, I agree with you that both are welcome. I understand that this does create more work for Bottlehead and may ultimately result in increased kit prices.

Interesting idea though.

[Doc B.]

Wow, four hours, that is awesome. Well done! The kit description does explain that it's for a first time builder who knows nothing about electronics, and the focus is on learning the manual skills necessary to construct electronics and getting the kit to work. It's not really intended to be part of an electronics design curriculum. That said, there are hundreds of posts about capacitor choices, tube changes, power supply mods, etc. on this forum. I'll suggest that you might look around a bit and see if some of the info you seek is in these threads.

In terms of troubleshooting we have found that, unless we can be sure the customer is already trained in electronics repair, it is easier to walk them through a repair by directing them to measure the circuit values and let them use our experience to narrow down where the issue may lie. Back in the old days there were actually books published that documented various "tough dog" repairs so that techs wouldn't have to figure it out on their own, so this is not really anything new. The majority of our customers don't want to have to take an electronics course to locate a miswire, they just want to hear the music.

We tube audio guys are kind of a weird breed in that we got into this pre-internet when it was becoming a lost art form (this lost art form thing is a bad habit of mine, which also led to the reel to reel tape comeback). So it comes naturally to us that one has to dig up ancient text books to study at a swap meet and chip away at gathering parts and tweaking a project until we get it to do what we hoped it would. Actually so much of that info is on the net now that it is much easier to dive in. It sounds to me like you are dedicated enough to this stuff that you are about ready to go out and find a schematic to try, chase down the parts and start your first scratch build. I think the info you seek will present itself pretty well in that process and I bet you will end up with some really cool results. One place to dig around is Pete Millet's archive. Pete went out and gathered scans of all the books we used to buy at antique radio swaps and library sales, and put them in one place  -

http://www.tubebooks.org/

[mcandmar]

Interesting comments.  My S.E.X. amp was the first tube based circuit i had ever seen and like yourself i was very interterested to know how it worked, why specific parts and values are used, and what job each component does in the circuit.

Since then i have learnt a lot about valve amps and scratch built dozens of them for fun and i'm still only scratching the surface in the knowledge department.   From what i know now, vs what i knew then i really dont know how you could include more into the manual.  There is just so much you could say about each individual component and choice of circuit design you would end up with a manual the size of a telephone directory which would completly bamboozle 90% of the builders who really couldnt care less.

What i found the most usefull was to read a few different books on amplifier design to get a basic grasp of the circuit topologies, then try and reverse engineer the Bottlehead designs.  You will never understand it all as these guys have been doing this for decades, but you will learn a lot from them. I know i certainly did, but i am sad enough to find this fun

[harari]

DocB,
Well, as I mentioned, I'm well aware of the purpose of the kit and who it's intended for. I just find it weird that someone wanting to learn how to solder would try his luck on a 400$ piece of equipment instead of a 5$ lamp-and-switch circuit.. but maybe that's just me.
My criticism is not towards the current way of things because I understand why it is the way it is and I support it, I just wonder what part of your clientele is actually novice and how many advanced users are out there that want to enjoy your products and learn something in the process.
Also, I'm not unfamiliar with lost arts, this is just another step towards the light of analog heaven. I'm currently restoring a Thorens td-145 turntable from the 70's and a Pioneer SX-750 receiver from the same time. (there's also a rumor that there's an AKAI tape deck hiding somewhere in my dad's office that might be next).

mcandmar,
I'm not saying this should turn you into a tube master, far from it. Of course I'm going to read a lot and learn what I can, but I thought this would give me a head start with some experience.
I know I'm a minority in this (well, this forum kind of shifts the scales), most people just want to hear the magic and maybe have some fun in the process, but I would still expect some amount of technical data - not all of it, something that would give this product some added value along with the soldering experience that you can get anywhere.

I'm not really new to the forum, I've been a passive reader for a long time before I bought my crack. I'm not an impulsive buyer, I do my research and I know what I want. The major reason I wanted a crack was for the modularity, there are lots ready-made tube amps that allow tube rolling, but that's about it. The crack comes in a big enough box and its circuit is not on a PCB, this means you have much more freedom in means of design changes and upgrades - that, along with an active community and a big knowledge base (and lots of positive feedback online), is what bought me.

[Paul Joppa]

I'll just note that a great deal of technical information is shared on the Forum, where it can be tailored to a specific issue, and the community has a chance to contribute.