[buke9]

Thank for your replays, I'm going with the ts 5998 nos from the 60s and mullard ECC82.
Hope it will last long enough.

The 5998 is a very good choice I hope you like it. Nothing last forever.

 

[NightPhotograph]

   
Another option you could try would be bypassing the Cracks 100uf output capacitors with some Russian 250v 1uf K75 10 capacitors they are only a couple of dollars each and should add bags of character, think full rich juicy mid centric sound with bags of texture plus you should get the roll off you are after. Cheep to try anyhow so thought I would throw the idea out there for consideration..
 
http://www.enjoythemusic.com/diy/0411/capacitor2.htm
 
http://www.ebay.co.uk/itm/1uF-250V-Hybrid-PIO-Capacitors-K75-10-Matched-Pair-2-x-0-947uF-/201719646854?hash=item2ef76d8a86:g:HykAAOSwiONYK-Tr

I have no prior experience in DIY projects. Can you please tell how you replace 100uf capacitor with 1uf one? Shouldn't the capacity be kept equal when capacitors are replaced?
 
Cheers

 

[daltonljj]

bypass not replace. its just to have it soldered parallel to the output caps. make sure its in the right direction if the caps you buy have polarity. 

 

[JamieMcC]

  I have no prior experience in DIY projects. Can you please tell how you replace 100uf capacitor with 1uf one? Shouldn't the capacity be kept equal when capacitors are replaced?
 
Cheers

The 1uf doesnt replace the 100uf capacitor its added by soldering the two leads of the 1uf  capacitor one lead to each of  the same terminals the 100uf is attached to so you have 101uf. As the K75 is a film capacitor doesnt have a +/- polarity like the 100uf electrolytic doesn't matter which way round the leads are connected.
 
A pic of some in my old Crack
 

 
Later some teflons bypasses were added to the mix as well

 

 

[NightPhotograph]

 
The 1uf doesnt replace the 100uf capacitor its added by soldering the two leads of the 1uf  capacitor one lead to each of  the same terminals the 100uf is attached to so you have 101uf. As the K75 is a film capacitor doesnt have a +/- polarity like the 100uf electrolytic doesn't matter which way round the leads are connected.
 
A pic of some in my old Crack
 

 
Later some teflons bypasses were added to the mix as well

 

Thank you very much for the information. Woaa! that's a giant Crack . Do the capacitors affect sound stage? Crack has somewhat narrow sound stage. Is it possible to improve it a little bit?

 

[JamieMcC]

Going down the standard Crack upgrade path can make a noticeable difference. However its still going to be a more intimate presentation compared to Bottleheads Sex and Mainline headamps.

 

[Tom-s]

 I thought to remember you once left SEX as is, because your maximally modded Crack was sounding as good or better?
 
And @NightPhotograph if you think that Crack is big. Jamie once used one with 100uf PIO cans attached to it externally.

 

[HOLLOWCOW]

Hi guys,
I found a tung sol 5998 clear top year 1967 from eBay. (bottom getter)
I understand the clear top are the best quality.
 
however I thought the clear top were made in the early 50's and not the 60's.
the tube have green letters writing in the bottom "tung-sol made in usa 3226731-3"
any thoughts?

 

[Tom-s]

The difference is marginal between those. I had both and kept the 50's version. 
Any 5998 will be a big step up over the standard 6080 you use now.

 

[HOLLOWCOW]

I can get a 50's version but not a clear top.  
(for the same price) 190$

 

[Tom-s]

The price is a bit steep for both.
I think a good Tung Sol 5998 can be had for way less. 
Theres a few for sale here on the forum. A topic was bumped last week selling 2.
Use the search.
 
 
My bad; only ships to US: http://www.head-fi.org/t/779391/great-tubes-for-crack

 

[HOLLOWCOW]

I look everywhere on tubes website and ebay and those are the prices.
Of course I will prefer to buy from a forum member.
 
The 5998 clear top from ebay test are:
T1 10,500 105% T2 10,500 105% No gas leak, No shorts, Low microphonics. Tested 4/2016 WE 539C tester calibrated in Q3 2015.

Min new is 10,000gm on this tester
 
is this any good?
will it last 5+ years?

 

[Allanmarcus]

There's a good discussion of various tubes for the Crack on another site. Sorry, I cannot link to it, but if you google
 
bottlehead crack tube overview driver tubes
 
and click on the first hit, you will see a good thread.

 

[HOLLOWCOW]

i just need to know if those test results are any good.
thanks

 

[buke9]

i just need to know if those test results are any good.
thanks

It is testing as new as far as lasting 5 years depends on use I would imagine have not had my amp but a few months so don't know.