[Galapac]

Suppose I wanted to build a Crack with a brass plate instead of the usual one. Is there an easy place to get my hands on a brass plate with the proper cutouts, or would I have to commission/make one myself?

You could probably get one made and use the plate that comes with it as a template but one of the main functions of the plate is to use it to ground your components and brass is not a great conductor of electricity for grounding.
That is why you do not see the plates painted underneath.

While the plate that it comes with is aluminum you can see brass drops a third in conductivity In the chart below.
It may be better to go with copper and you would get a nice patina over time.
Something to consider.

Material IACS (International Annealed Copper Standard)
Ranking	Metal	% Conductivity*
1	Silver (Pure)	105%
2	Copper	100%
3	Gold (Pure)	70%
4	Aluminum	61%
5	Brass	28%
6	Zinc	27%
7	Nickel	22%
8	Iron (Pure)	17%
9	Tin	15%
10	Phosphor Bronze	15%
11	Steel (Stainless included)	3-15%
12	Lead (Pure)	7%
13	Nickel Aluminum Bronze	7%

 

[bagwell359]

That’s interesting because I prefer the speedball upgrade as it appeared quieter overall where there was the lack of music, at least to me.
I enjoyed both versions, and for me, the speedball edged out.
I also own an Elekit TU-8200 and prefer that overall to all of my amps and is my workhorse amp but I did heavily modify it with all upgraded components including Lundahl transformers so there is that.

My music genres do you listen to the most and what headphones do you primarily use with the OG BHC?
That may be a factor why you prefer the the original as your whole chain works for you best.

That's not what I said. I like the sb better, and along with the other mods it's superb for what I like. Still want a 800 on it.

I listen to a lot of stuff - Norah Jones, Krall, Cowboy Junkies, Dead Can Dance, Prokofiev, Copeland, Miles Davis, King Crimson, Joni Mitchell, Neil Young, Durutti Column, Felt, Agnes Obel, etc...

 

[bagwell359]

Suppose I wanted to build a Crack with a brass plate instead of the usual one. Is there an easy place to get my hands on a brass plate with the proper cutouts, or would I have to commission/make one myself?

Paint it. I did. It's back in this thread.

 

[dstarr3]

one of the main functions of the plate is to use it to ground your components

Oh, I didn't realize that. Then yup, I'll just paint it or something. Thanks for the heads up!

 

[GPJ7]

You could probably get one made and use the plate that comes with it as a template but one of the main functions of the plate is to use it to ground your components and brass is not a great conductor of electricity for grounding.
That is why you do not see the plates painted underneath.

While the plate that it comes with is aluminum you can see brass drops a third in conductivity In the chart below.
It may be better to go with copper and you would get a nice patina over time.
Something to consider.

There is a guy who just built a mainline using a carbon fiber plate. Pics at BH forum.

A thing to remember with the Crack is there are only 2 locations where grounding occurs on the plate.

1. Terminal 3 (considered the "audio" ground)
2. IEC Ground (plate bolt next to IEC socket)

This is to minimize noise in the amplifier.

The IEC plastic socket, plastic on/off switch, RCA's, transformer terminal strips, and headphone jack are all mounted with isolation. The transformer bell is held on with poorly conducting steel bolts. Ultimately, one of those bolts is connected to IEC ground.

The volume pot body is in contact with the plate but all six lugs are isolated from the plate locally at the pot. The volume pot body can be considered as part of the plate with nothing electrically connected to it from the pot internally. The black wire from 2 pot lugs is routed to Terminal 3 (audio ground).

Same goes for the octal socket clamp. It is in contact with the plate but the socket pins are isolated from it. It attaches to Terminal 8 which has nothing connected to it.

The 9 pin socket clamp is in contact with the plate and is bolted to Terminal 3 and therefore part of the audio ground.

So in reality, Terminal 3 ground ultimately travels to the IEC grounding point through the plate. I am going to think a brass plate is going to be OK as long as everything is wired correctly. However, I am not the amp designer and it's best to contact BH for expert advice.

 

[Galapac]

That's not what I said. I like the sb better, and along with the other mods it's superb for what I like. Still want a 800 on it.

I listen to a lot of stuff - Norah Jones, Krall, Cowboy Junkies, Dead Can Dance, Prokofiev, Copeland, Miles Davis, King Crimson, Joni Mitchell, Neil Young, Durutti Column, Felt, Agnes Obel, etc...

Sorry @bagwell359, I quoted the wrong post, I meant to reply to @smodtactical in my reply.
Must have been confusing.

 

[Maxx134]

With the Speedball and upgraded output film caps, bypass caps, volume pot, cree diodes, power cable, etc... The bass and mids are not one but notably better and it doesn't dominate my attention as the stock does.

There is a reason for this I will try to explain.

I got a Crack with speedball in so I can directly A-B, my notes:

So far
OG wins
speedball is more clear and crisper
a bit more detailed
but it loses some of the midrange magic and the emotion
and the texture in the singers voice
OG is smoother, more liquid... i think more bassy
speedball reminds me of elekit a bit
ya OG wins hands down... it sounds bigger, more 3d, more holographic... its amazing
the way the mids come forward in such an incredible way... like the singer steps forward out of the music to sing to you personally... its hard to describe
to be fair not the same tubes in each amp so i will try to swap tubes and compare further

OG is just more engaging
speedball is flatter sounding like elekit
honestly im not even sure speedball is more detailed... id say its 'crisper' maybe
but OG is more natural and has much better flow... the music just pours and spills around you..... "Lot of people overlook Crack OG (without speedball)... its insane magic. This is one of the darkest head chains you can get but its still remains enthralling and detailed"...

I would like to clarify what is going on here, with the speedball implementation.
Traditionally, this is called a "CCS" circuit. "Constant Current Source"
Look it up. Yet, from a designer's point of view, the end main result will cause less harmonics, and so "clean up" the sound.
This equals less tube sound..a less thick or what amouts to less "euphoric" sound.
there are also other ways to have less tube (harmonics) sound. Elimination of a cathode cap is another.
The main strength of tube holography stays regardless of how "clean" it will sound.

So choosing option of "speedball", should really be an option of how much color, or richness in sound that you prefer...
From a designer's perspective, it should be viewed as a signature choice, rather than an "improvement".
I would say that the crack as an amp is as worthy as any amp to keep regardless of other expensive amps, if you prefer it's signature. Dont think just by buying a more expensive amp, you will be any more happier, if you already prefer the crack..

Yet resolution is another matter. If you want higher resolve, then you just have to focus on the most prominent places for sound upgrade. All amps can benefit similarly from upgrades...
So were? the coupling cap, and output cap areas are main areas that what you wanna upgrade for higher resolve.
Resolution is different from noise level, or added harmonics. There is a vague misconception that fixing all other things in an amp, will bring you higher resolve. It may change and add performance to the resolve, but it basically that's not raising it.
For instance, we can lower noise floor, and lessen harmonics to give a "cleaner" sound, but that's not increasing Resolution. We can add more dynamics with larger caps, but that's not increasing Resolution.
Those are separate added aspects.

So basically, if you prefer the stock non-speedball sound, then you would like thicker amps.
Beware the illusion of going up the "price" ladder with other amps would be any better.
You should try and listen to them first, because many top amps have even more bloom and thicker or euphoric sound.

As most sound observations are "subjective" my comments are only my opinion, and should be put in perspective, as your ear and experience is what matters in the end. If there's anything I would want you to know, is that you should not second guess your observations for others. Believe your ears

 

[JNKM]

There is a reason for this I will try to explain.







I would like to clarify what is going on here, with the speedball implementation.
Traditionally, this is called a "CCS" circuit. "Constant Current Source"
Look it up. Yet, from a designer's point of view, the end main result will cause less harmonics, and so "clean up" the sound.
This equals less tube sound..a less thick or what amouts to less "euphoric" sound.
there are also other ways to have less tube (harmonics) sound. Elimination of a cathode cap is another.
The main strength of tube holography stays regardless of how "clean" it will sound.

So choosing option of "speedball", should really be an option of how much color, or richness in sound that you prefer...
From a designer's perspective, it should be viewed as a signature choice, rather than an "improvement".
I would say that the crack as an amp is as worthy as any amp to keep regardless of other expensive amps, if you prefer it's signature. Dont think just by buying a more expensive amp, you will be any more happier, if you already prefer the crack..

Yet resolution is another matter. If you want higher resolve, then you just have to focus on the most prominent places for sound upgrade. All amps can benefit similarly from upgrades...
So were? the coupling cap, and output cap areas are main areas that what you wanna upgrade for higher resolve.
Resolution is different from noise level, or added harmonics. There is a vague misconception that fixing all other things in an amp, will bring you higher resolve. It may change and add performance to the resolve, but it basically that's not raising it.
For instance, we can lower noise floor, and lessen harmonics to give a "cleaner" sound, but that's not increasing Resolution. We can add more dynamics with larger caps, but that's not increasing Resolution.
Those are separate added aspects.

So basically, if you prefer the stock non-speedball sound, then you would like thicker amps.
Beware the illusion of going up the "price" ladder with other amps would be any better.
You should try and listen to them first, because many top amps have even more bloom and thicker or euphoric sound.

As most sound observations are "subjective" my comments are only my opinion, and should be put in perspective, as your ear and experience is what matters in the end. If there's anything I would want you to know, is that you should not second guess your observations for others. Believe your ears

Really appreciate accessible explanations like this — thanks! What are some examples of higher-tier amps that are even more thick and bloomy?

 

[L0rdGwyn]

This "thick" sound that is being heard without the Speedball upgrade is the sound of second harmonic distortion. Going from non-Speedball to Speedball changes the loading of both the 12AU7 input and 6AS7G output from a resistive load to a CCS load.

Functionally what this does is "flatten" the load line of the tubes as viewed on their characteristic curves. The end result of that is minimization of second harmonic distortion as well as increase PSRR (power supply rejection ratio). The increased PSRR means less of the power supply noise reaches the tube gain stage.

So if you like the sound of stock, that is the sound of second harmonic distortion.

 

[bagwell359]

There is a reason for this I will try to explain.







I would like to clarify what is going on here, with the speedball implementation.
Traditionally, this is called a "CCS" circuit. "Constant Current Source"
Look it up. Yet, from a designer's point of view, the end main result will cause less harmonics, and so "clean up" the sound.
This equals less tube sound..a less thick or what amouts to less "euphoric" sound.
there are also other ways to have less tube (harmonics) sound. Elimination of a cathode cap is another.
The main strength of tube holography stays regardless of how "clean" it will sound.

So choosing option of "speedball", should really be an option of how much color, or richness in sound that you prefer...
From a designer's perspective, it should be viewed as a signature choice, rather than an "improvement".
I would say that the crack as an amp is as worthy as any amp to keep regardless of other expensive amps, if you prefer it's signature. Dont think just by buying a more expensive amp, you will be any more happier, if you already prefer the crack..

Yet resolution is another matter. If you want higher resolve, then you just have to focus on the most prominent places for sound upgrade. All amps can benefit similarly from upgrades...
So were? the coupling cap, and output cap areas are main areas that what you wanna upgrade for higher resolve.
Resolution is different from noise level, or added harmonics. There is a vague misconception that fixing all other things in an amp, will bring you higher resolve. It may change and add performance to the resolve, but it basically that's not raising it.
For instance, we can lower noise floor, and lessen harmonics to give a "cleaner" sound, but that's not increasing Resolution. We can add more dynamics with larger caps, but that's not increasing Resolution.
Those are separate added aspects.

So basically, if you prefer the stock non-speedball sound, then you would like thicker amps.
Beware the illusion of going up the "price" ladder with other amps would be any better.
You should try and listen to them first, because many top amps have even more bloom and thicker or euphoric sound.

As most sound observations are "subjective" my comments are only my opinion, and should be put in perspective, as your ear and experience is what matters in the end. If there's anything I would want you to know, is that you should not second guess your observations for others. Believe your ears

Interesting. I agree harmonics are manipulated for popularity/sales. Music reproduction with none is like a desert. Too much and it's like carmel on everything. I like hybrid tubed electronics and Nelson Pass Class A amps - in the middle.

I think it's "euphonic" not "euphoric" BTW.

 

[Asterisk3095]

Hello, I am interested in getting the Bottlehead Crack as my first ever tube amp, and my foray into soldering electronics. However I have one question I can't seem to find an answer for. Whenever I see anything about the Crack, people say to get the Speedball upgrade because it makes noticeable improvements to the amp. However, I have not seen any answer to what those improvements are, and what the speedball upgrade actually does. If anybody here can elaborate on this, that'd be great!

 

[CaptainFantastic]

Hello, I am interested in getting the Bottlehead Crack as my first ever tube amp, and my foray into soldering electronics. However I have one question I can't seem to find an answer for. Whenever I see anything about the Crack, people say to get the Speedball upgrade because it makes noticeable improvements to the amp. However, I have not seen any answer to what those improvements are, and what the speedball upgrade actually does. If anybody here can elaborate on this, that'd be great!

Look precisely two posts above yours. Best succinct explanation I have seen.

 

[Asterisk3095]

Look precisely two posts above yours. Best succinct explanation I have seen.

ah... this is embarrassing. Anyways thanks for the help!

 

[DenverW]

ah... this is embarrassing. Anyways thanks for the help!

We’ve all been there!

 

[GPJ7]

I am actually buying a new Crack with no speedball to rediscover what I missed.. Admittedly, I immediately added speedball and output caps and recently did Crees and choke. All since initial build in 2014. End result is incredibly good but I want to find out what a bone stock (keep it unmodified out of box) Crack amp sounds like without all the changes. By the time I build it (hasn't shipped yet), I will have spent a great deal of time with the modified amp. So, it should be a really fun comparison. I think even better than doing it the other way. I will have the amps side by side for immediate comparison.

If I find it not to my liking I can always upgrade it cheap (or my brother gets a nice b-day present!)