[m17xr2b]

My crack is almost complete, still can't find a matching volume knob.

Custom Sowter 50W transformer
Custom laser cut and chromed top plate and wood chassis.
Duelund 20 and 26AWG OCC copper with cotton wiring.
Dual choke UK made.
2x220uF Jensen caps and 3x50uF oil output caps with Duelund bypass
100uF Mundorf Evo Oil output caps with VCap TFTF 0.15uF bypass
TKD 2511 pot
NiMh battery bias instead of led.
Cree diodes
About 40 hours of work.


I still have a few things to do and overall I'm very happy with how it sounds. I rotate the output tube between GEC 6AS7G and 6080, Bendix solid and slotted and Sylvania 6080GB. I do have the 5998 but it's pretty much unused.

 

[JamieMcC]

My crack is almost complete, still can't find a matching volume knob.

Custom Sowter 50W transformer
Custom laser cut and chromed top plate and wood chassis.
Duelund 20 and 26AWG OCC copper with cotton wiring.
Dual choke UK made.
2x220uF Jensen caps and 3x50uF oil output caps with Duelund bypass
100uF Mundorf Evo Oil output caps with VCap TFTF 0.15uF bypass
TKD 2511 pot
NiMh battery bias instead of led.
Cree diodes

I still have a few things to do and overall I'm very happy with how it sounds. I rotate the output tube between GEC 6AS7G and 6080, Bendix solid and slotted and Sylvania 6080GB. I do have the 5998 but it's pretty much unused.

Sure looks like you have had a blast building your Franken Crack. There used to be a real fun thread on the bhf with these sorts of builds in might have been capacitor porn or something along those lines, it was a blast to follow some of the crazy builds.

I'm off to google NiMh battery bias

 

[L0rdGwyn]

My crack is almost complete, still can't find a matching volume knob.

Custom Sowter 50W transformer
Custom laser cut and chromed top plate and wood chassis.
Duelund 20 and 26AWG OCC copper with cotton wiring.
Dual choke UK made.
2x220uF Jensen caps and 3x50uF oil output caps with Duelund bypass
100uF Mundorf Evo Oil output caps with VCap TFTF 0.15uF bypass
TKD 2511 pot
NiMh battery bias instead of led.
Cree diodes
About 40 hours of work.


I still have a few things to do and overall I'm very happy with how it sounds. I rotate the output tube between GEC 6AS7G and 6080, Bendix solid and slotted and Sylvania 6080GB. I do have the 5998 but it's pretty much unused.

https://www.partsconnexion.com/ANKNOB-81888.html
https://www.partsconnexion.com/ANKNOB-81897.html

 

[Tom-s]

Tonight i've had a first few hours with a Telefunken 6080WA output tube. A tube i previously thought off as non-existent with only fakes on the market.
Bought it by chance, as is. Tested it >100% NOS, lucky me!
Telefunken only produced +- 27.000 6080's and 9.000 6080WA's (i have a 1965 6080WA).
For comparison, the rare and wanted ECC803s almost 150.000 pcs. The 6080WA is as rare as the EC8020.
The cheap ones found on ebay and other websites are mostly Telefunken faked GE / RCA / Thomson (France) tubes (the last ones sound good aswel!).
Read about the fakes here https://jacmusic.com/nos/images/Fakes/

Never read about these on this forum nor found a review. So it was a gamble for me.
How does it sound? Clear, open, detailed. It's just turning up the typical Telefunken sound another notch.
It's a tube to look out for! Definitely! And you can easily identify them by build (see Jac).
The tubes.rs ones are the real ones.

 

[cddc]

My crack is almost complete, still can't find a matching volume knob.

Custom Sowter 50W transformer
Custom laser cut and chromed top plate and wood chassis.
Duelund 20 and 26AWG OCC copper with cotton wiring.
Dual choke UK made.
2x220uF Jensen caps and 3x50uF oil output caps with Duelund bypass
100uF Mundorf Evo Oil output caps with VCap TFTF 0.15uF bypass
TKD 2511 pot
NiMh battery bias instead of led.
Cree diodes
About 40 hours of work.

I still have a few things to do and overall I'm very happy with how it sounds. I rotate the output tube between GEC 6AS7G and 6080, Bendix solid and slotted and Sylvania 6080GB. I do have the 5998 but it's pretty much unused.

Very nice mod!

It's the first time I saw dual choke on BHC...used to see only single choke before.

Must be very good at electronics to figure out all these fancy mods!

 

[cddc]

Why the fu*k Amperex gives a flash when powering on?

I almost had a stroke this afternoon seeing the flash...thought it's arcing, so immediately unplugged my HD800 and put on a pair of crappy testing cans.

But it turned out to be OK, and I realized it could be something like the famous "Mullard flash", am I right?

 

[Tom-s]

Why the fu*k Amperex gives a flash when powering on?

I almost had a stroke this afternoon seeing the flash...thought it's arcing, so immediately unplugged my HD800 and put on a pair of crappy testing cans.

But it turned out to be OK, and I realized it could be something like the famous "Mullard flash", am I right?

You are correct. This is a normal phenomenom with tubes, mostly seen in European or Philips tubes. Wether they are branded Amperex, Mullard, Valvo, Siemens, Philips, Adzam etc. It also happens on GEC's i.m.e. Most American brands and the European counterparts (Brimar for instance) use a controlled heater warmup, which eliminates the flash and supposedly prolongues valve life. Telefunken also uses controlled heater warmup for its valves.

A word on the Telefunken 6080WA. After a few evenings of listening i can't get it to sound optimal. It has the typical Telefunken sound but lacks in lower end (extension).
This makes it an awesome tube, but only for those wanting to make their system as detailed as possible. I prefer the Bendix/GEC type 6080 sound.
A picture on the night stand, with a Heerlen E80CC to fatten up the sound without losing quality (also comes with "Mullard flash" ).

 

[JamieMcC]

E80cc is a superb tube there is a very simple and inexpensive mod on the bhf which allows you to run this tube in its sweet spot voltage wise well worth doing if using this tube.

From what I understand the E80cc was only manufactured by two companies Tungsram (Hungary) and Philips/Siemens (Holland). Any E80cc with other branding are more than likely to have been manufactured in Philips Heerlen plant who were suppliers to many other brands such as Amperex, Miniwatt, Valvo, Mullard, La Radiotechnique RTC, Siemens Adzam

 

[cddc]

You are correct. This is a normal phenomenom with tubes, mostly seen in European or Philips tubes. Wether they are branded Amperex, Mullard, Valvo, Siemens, Philips, Adzam etc. It also happens on GEC's i.m.e. Most American brands and the European counterparts (Brimar for instance) use a controlled heater warmup, which eliminates the flash and supposedly prolongues valve life. Telefunken also uses controlled heater warmup for its valves.

A word on the Telefunken 6080WA. After a few evenings of listening i can't get it to sound optimal. It has the typical Telefunken sound but lacks in lower end (extension).
This makes it an awesome tube, but only for those wanting to make their system as detailed as possible. I prefer the Bendix/GEC type 6080 sound.
A picture on the night stand, with a Heerlen E80CC to fatten up the sound without losing quality (also comes with "Mullard flash" ).

Cool...so there are indeed Amperex flash, Mullard flash, Valvo flash...all kinds of flashes.

I'm normally on U.S. tubes, the only European 12AU7 that I have is a Telefunken, but it does not give start-up flashes. So was terrified yesterday to see the "Mullard flash"

 

[cddc]

A question regarding how to identify 12A?7 tubes:

Say, sometimes you messed up with a bunch of 12AU7 / 12AT7 / 12AX7 tubes, and most of the print on tubes are gone, how can you tell a tube is a 12AU7 or 12AT7 or 12AX7?

They all look the same to me.

 

[Tom-s]

Just look up the tube you think they are and compare internals with pictures. That usually works. With US tubes there's normally an etched engraving that gives away the type.
For Philips tubes there's a code on the lower part of the tube, or on the bottom.
If this all not works, test it on a tester and see how it does.

Best is to keep your ECC's organised. I use Sunware brand Q-line 22Liter boxes. These use an insert that is perfect fit for ECC's. About 200 pcs fit the top insert, with convenient separations.
Here's an example with ECC81's. The bottom of these boxes hold the new in box ones. And these boxes are easily stackable. Saving space.
https://ep1.pinkbike.org/p5pb17835015/p5pb17835015.jpg

But, i have confess, many tubes end up on piles. For this, i use old shoe boxes (because, also stackable)... and they are not so organised.
Below an example with 6189's or close lookalikes (mostly 12AX7's from GE), so yes, these get messed up..
https://ep1.pinkbike.org/p5pb17835008/p5pb17835008.jpg

Edit: Removed pics, only links, as they are not very relevant for the topic.

 

[cddc]

Good idea, I should begin to label tubes and get a storage box for them, as the number is ever increasing

Do you think if the etched code "12AU7" or "6SN7" can be erased by alcohol?

I often use alcohol to clean tubes, and I find some print / stencil on tubes can easily be removed by alcohol, especially on these miniature glass bottle tubes.

 

[audiowize]

Say, sometimes you messed up with a bunch of 12AU7 / 12AT7 / 12AX7 tubes, and most of the print on tubes are gone, how can you tell a tube is a 12AU7 or 12AT7 or 12AX7?

They all look the same to me.

In a Crack with no Speedball, you can run it with no 6080 and plug these tubes in. The 12AU7 will produce the expected plate voltage that's around 75V or so.

A 12AX7 is going to show very, very high plate voltage. With or without the Speedball, it's going to be up close to whatever your B+ is, so 180V DC or so.

A 12AT7 with a Speedballed Crack will show about 130V on the plates, and it looks like without the Speedball it will be fairly close to that.

You do not, under any circumstances, want to run the Crack with a 12AT7 or 12AX7 if it has a 6080 plugged into the octal socket. I can't predict what would break first, there are too many choices!

 

[cddc]

Thanks very much for the practical method to ID 12A?7 family tubes without a tester. A very smart approach!

I won't risk my Crack with any of the 12AX7 or 12AT7 tubes for sure . I read your detailed explanation where I asked the question some pages earlier...and it etched onto my memory already

Ideally the etched code like "12AU7"or "6SN7" should stay there after alcohol cleaning. But after cleaning one of my 6SN7 tubes with alcohol, I found the etched "6SN7" code on top of the bottle faded away...or maybe the golden paint on the etched code faded away...sadly I couldn't recognize the "6SN7" after cleaning

So I'm concerned about the etched codes. If it is gone after cleaning, it would be very difficult to identify 12AU7 from 12AT7/12AX7 visually as all of them look the same.

PS: I grabbed a bunch of 12A?7 tubes with a pack deal some time ago, most of them are 12AU7, but 2 of them happened to be 12AT7 and 1 12AX7.

 

[DenverW]

So about two months ago I traded another headfier my amp for his bottlehead crack (w/speedball) and absolutely fell in love with it. Too much love, as I’ve showered it with affection in the form of output and driver tube rolling. I have to say that I’ve really enjoyed listening and experimenting with it.

So far I’ve tried:
RCA 6as7g (came with it, along with a stock 6080 I don’t recall)
Tung sol 6080
Tung sol 5998
Tung sol 7236

Driver tubes:
Jj/Tesla 12au7
Mullard 4003
Phillips e80cc
Tungsram e80cc
Tung sol 12bh7a
RCA 12bh7a
Ken rad vt231
Tung sol 6sn7gt mouse ears

I also have a Raytheon 6f8g I haven’t been able to test yet but I’m looking forward to trying.

I plan on building a second crack on my own for fun once a good enough sale pops up, which should help me learn the ins and outs of the amp. Important because when it stops working, like it is right now, I won’t need outside help to get it running again.

Until then I’ll just keep having fun reading about tubes and impressions!