Jeb's Build

[Strikkflypilot]

That's great to hear.
You have built a real good looking set, there.
How did You get the acrylic done?

[Jeb Jeb]

Thanks! - the sound is amazing.  One of the best compliments I can give it right now is I was so lost in the music after an hour I didn't realise how much of a headache I was getting from the clamping force of the new HD650s! I'm sure that gets better with use!?

The acrylic for the desktop platform I just bought a piece online cut to the same size as the piece of birch ply I got.  I was able to drill the holes for the screws for the feet and the 10mm holes for the spike feet with a very sharp forstner bit.  My first idea was to use glass but it wasn't really feasible to drill at home.  But the plastic cutters were able to polish the edges so it seems quite glass-like in the flesh.

The clear base for the amp I downloaded a trial of adobe illustrator and drew up a quick design for the exact size with some vents and sent off for it to be cut by an online laser-cut place where you can just upload your design and then they send it to you in a few days.  I thought I may as well get the "bottlehead" name too   It was pretty inexpensive for a small piece of acrylic with a simple cut pattern like that - around £10 or 12 if I remember correctly.

obviously if my wiring had turned into too much of a horror-show I might have just used a piece of wood with vents instead 

[adydula]

Great job!!!

Nice looking build, now you can relax and listen and enjoy!!

I just took mine apart to get ready to speedball it!!

Look forward to a more detailed review on how it sounds over the next week or so....

A simple amp that does very, very well with high impeadance cans!!

Alex

[mcandmar]

The base looks lovely, you can tell you spent some time sanding and prepping it

[JamieMcC]

Super job Jeb congratulations on being up and running. I really like the acrylic base you had made. Any chance you can forward on the link to the supplier and adobe file I fancy getting one made for my Crack.

Ps the HD650 clamping pressure eases up with use, if you wanted to speed up the wearing in you could leave them lightly clamped to a few books when not in use.

Enjoy your Crack

Cheers
Jamie

[Chris65]

Excellent work Jeb, the base & bottom cover are really nicely done. Now on to some tube rolling & of course, Speedball!

[Jeb Jeb]

adydula thanks - all your help was invaluable.  I'll really look forward to your thoughts on the speedball installation and effect.  I'm already thinking about it too so i'll be interested to hear how easy it is to get popped in.  I did have a quick look at a few pics and I wondered about fitting one of the stand-offs since where it goes looks like a real nest of wires on mine!

mcandmar - also thank you.  Yes I was pleased with the base - alder isn't something I've seen very often at all here and I really liked the look of it so I wanted to keep it natural looking as possible.  Doc said they used to use a Satin water based and had gotten good results.  I did spend far too long sanding it ...obsessively.  I spent a long time on the case - partly because I was nervous about beginning the build

Chris - thanks - speedball seems inevitable doesn't it?! Crack is a gateway amp!


Jamie - glad to hear that about the 650s i think I will try and stretch them out a little over-night - they've come alive on the Crack.   

The online laser-cut people are called razorLAB.   I actually did the case-work a long time ago (procrastinated about doing the wiring...) so my adobe trial is long expired but I do have the final razorlab template I uploaded for cutting - It's not a file-type I can attach here (an .eps )  But if you would like it please shoot me a PM and I can email it to you.  I measured it for my crack base and it's 142mm x 245mm.

 I  checked my invoice and the standard Acrylic piece they sold (384 x 384mm) was £5, out of that I got two bases cut (in case I then messed up drilling the holes for the spike feet...which I did)- cutting cost for that was £8.  The annoyance is delivery - £10.  & + VAT on top so I guess it does all add up in the end.

One cheaper alternative I thought about was just getting a piece of acrylic from any of the online "cut-to-size" companies, then drilling lots of holes for vents in an nice arrangement.   I used 3mm acrylic - and while it's not really flimsy, you wouldn't want to press on it too hard when picking up the amp for example.  If your Crack case/feet can accommodate 5mm thick base then I think that would be quite a bit stronger and also look cooler!

Jeb.

[adydula]

Jeb,

I got the speedball in the mail yesterday and was out of town. I got up early this am and it took 3 hours of populating the three small pc boards and all the parts. Its installed and all the voltages are fine and I have played some music but cant really listen carefully...we have a hardwood floor installer here and its really LOUD!! LOL. But it worked the first time.

The mechanical plastic standoffs to which the boards attach and mount to need some careful moving of some wires a small amount to get them screwed to the existing screws....have to be careful, some as most of the wires seem to be a bit longer than really needed and they are pretty "stiff" and if you move them with pliers etc to get them away from the screw needed for the plastic standoffs you can move some of the tube socket terminals and may short out something. Just take a look on what might need re-positioning and be careful not to short anything.

The teflon wire is a smaller gauge and quite "slippery" to handle,,,,lol....it works fine but its a pain to me to work with.

IF you have never worked with transistors, these are small and when soldering I am careful  not to solder all three leads (EBC) at the same time. I solder one lead and go around and solder others and come back and do the second lead etc...it prevents too much heat being applied to a small silicon based device..just a precaution I have always used over the years.

Its a real simple build, some of the labels on the small pc boards are a little hard to read, but the speedball manual is great as usual and easy to figure out...

As soon as the floor pounding is done in a few hours I will let you know how I feel it sounds etc...

Congrats again on your build!!!

Alex

[adydula]

Jeb,

Finally quiet.....one word its "superb".....

I am a pretty objective guy...with my T90's and this upgrade I cant honestly see how it can get any better...

Listening to all my stuff again and its indeed still magic +.

The upgrade to me cant hurt what the crack is, its just better....soundstage etc...all those superlatives etc..

I got in on the $20 deal here and for that price its a real no-brainer....

Best $20 I have spent in this hobby in a long time!

Alex

[Jeb Jeb]

Nicely done Alex - you didn't hang about did you!

Very pleased to hear you feel it brings positives with no downsides.  I'm thoroughly enjoying the Crack - being really objective about this amp is pretty difficult because I found it so much about the experience as much as the sound.. but i'm always open to sonic improvements and superlatives...so I'm keen on the Speedball. I think i'll place an order.

I've taken on-board your tips and experience fitting it - i'll definitely need to do a bit of re-arranging for the stand-offs by the looks of it.  Obviously i've never done soldering to a board like that so perhaps while waiting I could pick up some cheap components and a board and practice a little to minimise risk of me frying anything.

I looked at the pics - do the capacitors near the 6080 socket just get bent out of the way ? i'm wondering if I left the leads long enough.

Congrats on your new new amp:  Speedball fitted & new hardwood floors - life is good   

[adydula]

Yes the caps will bend right over so the board can mount on the standoffs, they touch the bottom of the board somewhat but no issues there.

I had my crack running for a few weeks before I decided to do the speedball, the price was right and hey soldering is always fun to me! LOL.

I think the low bass notes, kick drums, bass and tympani are just so superb now....who knows....the idea behind a constant current source has its benefits, sonically oeprating in the linear range and power supply isolation should be a better all around technical scenario...it sure doesnt hurt the crack in anyway IMO. I dont think anything has gone negative at all.

Cosmetically it starts to get crowded inside...more stuff and wires!!

Enjoy your crack for awhile and then you will have a good comparison to the sound quality etc.

oh...no we stayed and watched the floor guys OMG it was noisy!! Its done!!

Alex

[Jeb Jeb]

Excellent!

I am awaiting a speedball kit & will enjoy the stock Crack in the meantime.  Pretty excited.  Excited about the bottlehead baseball cap I ordered too.   I heard it improves the soundstage - but that's unconfirmed 

Have fun with your new kit.

Jeb.

[adydula]

Thanks!

I have been swapping tubes in and out and having some fun with that, the tubes I got are really good to me, but I found several fairly inexpensive tubes to play within my budget...and most of them sound just as good!!

Let us know when your ready to Speedball!!

Alex

[Jeb Jeb]

Will do - I think it may be a little while before I receive my kit.  I totally agree about tubes - I've done a bit of rolling in other amps (12AU7s mainly) and although some of the *best* (whatever that means) tubes can command quite high prices,  inexpensive tubes that really deliver and offer great bang for buck have always given me the most satisfaction.   

One thing I'm finding with the Crack is how little I need to turn the volume knob to get to my ideal listening level - if 0 is at about 7 O'clock, I only need to go to just between 8 O'clock and 9 O'clock.  I'm using a player on my computer that fixes the volume sent to the DAC  (Rega DAC) and it seems to do this at max or near max (80%) - It was my understanding that this was the "correct" thing to do.  Are there any benefits/disadvantages to changing things so I can reduce the computer volume and so have the volume pot on the Crack in a more open position?   To be clear, despite not really having anything to play with with the volume pot - I don't have a problem with the sound I'm getting - i'm not hearing any imbalance and everything seems dead-quiet, but then I don't know any different at this point. 

I see in the Crack FAQ it suggest adding some 75K resistors for both the red and white wires where they enter the volume pot, and a 33K resistor between each of the outer lugs - but I just wondered what the benefits were to a more open volume position and if i'd just be trying to solve something that isn't a problem anyway.  I also see lots of people upgrade their volume pots.  I'm open to doing that but probably somewhat nervous to go "off-piste" from the manual at this point!


Jeb.

[adydula]

Ha...funny I just posted a new thread on this topic.

I had the same experience and added the voltage divider network of the two 75K/33K resisitors etc and it works well to allow more adjustment on the volume control...

With speedball I am back to noticing the volume is now at a lower mechanical postion 9 o'clock or there abouts..

So I think the gain with the speedball might have increased, I think that PB or Doc will respond with a change in the resistor values...I would be afraid to add these etc....no real issue that I can see..maybe some "johnson noise" added etc...

I agree on the price of tubes, some are absolutely out of this world....its more important to me to know the circuitry and what effect it has on the audio signal and circuits have more of a pronounced affect of things than changing tubes to me.

I have 7 power tubes and they all work well, spend too much time rolling to find that thing that eludes us!!! LOL. I have my wife change tubes on me and not tell me whats installed and I have tried to pick one over the other!!! I could not!!!

Time for more coffee and just enjoy the music!!

Alex