Loving the crack, hesitant to Speedball it!

[axg20202]

I completed building the Crack today. I was managing my own expectations to be honest - it's a headphone amp after all - but it really blew me away. Sounds superb and not a hint of background noise in normal use. The things is, I have the Speedball kit sitting on my workbench. I want to live with the stock amp for a while, but I really don't know what to expect when I install the Speedball and whether I will like it. Will it become too clinical sounding? The stock amp sounds so sweet and I don't want to lose that. Can anyone advise?

Andy.

[ideal.hat]

Hello Andy.

First off I would like to tell you that I am currently installing the speedball and I have some beginners issues that I am about to overcome with the great help here on the forum.

But in order to give you my opinion, I would like to know which headphones you will be using with the Crack.

The speedball update should be beneficial for low impedance headphones 300ohm+ and expecially the HD650.

As I understand it, In case you have high impedance headphones, you should not install the speedball.


A lot of reviews state that speedball is a must if you have HD650 or other low impedance headphones.

Best Regards,
Guåmundur

[Doc B.]

First of all the HD650 is a 300ohm headphone. That is not a low impedance headphone! Secondly, the Speedball will be an improvement, plain and simple. It lowers the noise floor and makes the bass tighter, cleaner and more dynamic.

[axg20202]

  Thanks Doc. Not wishing to be completely uncharitable to elgringo81, but it did make me laugh that the first reply to my first post on the forum is from someone who has no personal experience with the sound of the Speedball and doesn't appear to know what it's for.

[ideal.hat]

No offance taken.

Doc you are right. I just thought I could help with my input.
Ill keep my mouth clammed untill I know more about the subject.

Have a good weekend.

[adeep42]

Doc is definitely right of course. I can vouch that the Speedball does all that he says. Was in the same position as you. Built the Crack and was totally blown away as is. Added the Speedball because every body talked about the improvement. Everybody was right!

[axg20202]

Thanks. Well, proving that I am not at all capable of delayed gratification, I just went ahead and installed the Speedball today - I had a reasonable measure of the stock amp so thought sod it and went ahead. First impression is that this is not a subtle change. I think the stock Crack was very easy on my ear because it is more 'loose' and, although not mushy, was bathing everything in tubey warmth in a good way. As soon as I fired up the Speedball, I was initially disappointed because it felt as though some of that warmth and character had gone. However, after an hour of listening to various material I can see that there is still warmth there but the initial perceived 'dryness' is actually just the amp being relatively faster and more accurate. Bass is significantly tighter, instruments have better separation/definition and the amp sounds generally more forward and clean. My ears needed to reset to essentially a totally different amp. I will need to put some hours in on it to decide what to do next. Maybe nothing, but possibly a tube upgrade is on the cards.

This sounds like a mixed review. It's definitely not! I've been building and modifying tube amps for years (guitar amps), but this is my first headphone amp. This thing is superb.

(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fi204.photobucket.com%2Falbums%2Fbb75%2Faxg20202%2FBottlehead%2520Crack%2520with%2520Speedball%2520upgrage_1.jpg&hash=ebef7cbdd2c289fb5e82b2bef208e70169f6a8da)

[crizq0]

Your bottlehead crack looks awesome. What kind of modifications did you do to it?

Not that you have a few more hours with the speedball do you prefer the crack with or without the speedball upgrade?

[axg20202]

Thanks. No major mods, but I installed nicer rca connectors and a genuine Alps blue volume pot when I did the build. Everything else in the circuit is stock plus Speedball. After spending some time with the Speedball upgrade, I'm loving it. Definitely worth doing. However, I've swapped out the supplied 12au7 with an NOS military spec British Mullard, which is known for its rich mids. This has done wonders to the tone of the amp. I've also ordered some replacement output tubes just for the hell of it, but the new input tube really brought back the warmth and lush tone of the stock Crack, but with the tighter control of the Speedball.

[cddc]

I completed building the Crack today. I was managing my own expectations to be honest - it's a headphone amp after all - but it really blew me away. Sounds superb and not a hint of background noise in normal use. The things is, I have the Speedball kit sitting on my workbench. I want to live with the stock amp for a while, but I really don't know what to expect when I install the Speedball and whether I will like it. Will it become too clinical sounding? The stock amp sounds so sweet and I don't want to lose that. Can anyone advise?

Andy.

I think you can de-sold the 4 resistors from the Crack circuit instead of cutting them off from the circuit (as per the manual). This way you can always remove the Speedball upgrade and sold back the 4 resistors to restore the original Crack setup. Am I right?   

[kritpoon]

Thanks. Well, proving that I am not at all capable of delayed gratification, I just went ahead and installed the Speedball today - I had a reasonable measure of the stock amp so thought sod it and went ahead. First impression is that this is not a subtle change. I think the stock Crack was very easy on my ear because it is more 'loose' and, although not mushy, was bathing everything in tubey warmth in a good way. As soon as I fired up the Speedball, I was initially disappointed because it felt as though some of that warmth and character had gone. However, after an hour of listening to various material I can see that there is still warmth there but the initial perceived 'dryness' is actually just the amp being relatively faster and more accurate. Bass is significantly tighter, instruments have better separation/definition and the amp sounds generally more forward and clean. My ears needed to reset to essentially a totally different amp. I will need to put some hours in on it to decide what to do next. Maybe nothing, but possibly a tube upgrade is on the cards.

This sounds like a mixed review. It's definitely not! I've been building and modifying tube amps for years (guitar amps), but this is my first headphone amp. This thing is superb.

(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fi204.photobucket.com%2Falbums%2Fbb75%2Faxg20202%2FBottlehead%2520Crack%2520with%2520Speedball%2520upgrage_1.jpg&hash=ebef7cbdd2c289fb5e82b2bef208e70169f6a8da)

Hi Andy,

Please, pardon my English, since it is my second language. I was in the same situation as you are. I just finished my Crack and I must say I love the lush warming relax sound of it and Oh the mid-range magic! (I mostly listen to female vocals i.e. Ella Fitzgerald, Billie Holiday and slow tempo jazz i.e. Stan Getz, Mile Davis and etc.) And with those genre the stock just excels and beat my SS Amp by far margin. Though when I switch to rock, fast pace, modern pop it seems the Crack sounds a bit lagging interm of bass and slight roll off on the top end.

After a while with the stock unit (2 weeks), I decided that I will install and try a different flavor. Well, after I installed the Speedball, the sound change quite dramatically, Its like I've gotten a new amp! The sound has more control of the instrument, the bass is tighter more control. Instrument separation is much better, the top end is clearer, overall there are more +'s than -'s. The only downside is you kind of loose those lushness and warm from the original crack.

But after about two weeks with the speedball, I guess the Crack has adjusted itself from the Speedball installation and the sound now much smoother than before with better control and command of the instrument. Better imaging and wider sound stage. But I am still missing the smooth lush sound of the original crack.

So, I have decide to do some tube rolling with Mullard 12AU7 and Chantham 6as7G replacing the stock tubes. Wallah!!! The Crack sounds warm and lush again, the Warm Mid magic is back!!!!. Maybe not as much as the original, but with the Speedball and upgraded tube, My Crack lushness and warm sits between the original and original+speedball. But you still get the full benefits of sound control from the Speedball.

So, if you still sought after the sound from original Crack, but have already install the Speedball, may I suggest tube rolling? Expecially with the Mullard 12AU7 + Chatham 6as7G (or RCA 6as7G - as I hear they are quite warm sounding tube too... I have them coming in in 2days and will try to report the sound), it bring the magic mid-range and warmth back to the Crack.

Cheers and Happy Listening,
Krit.

[axg20202]

Cheers Krit. That's exactly what I did (see more recent post above). An NOS military Mullard 12au7 really made a huge difference. Not cheap but was totally worth it, which is more than I can say for previous tube rolling I've tried on my guitar amps - mostly slight sonic changes that weren't worth the outlay. I was pleasantly surprised that it made so much of am improvement on the Crack. The difference here is that I had a very clear idea of what I wanted to achieve with the tube swap, and then selected a tube that had the right profile to do it.