A new Crack addict

[soundfanz]

Hi all,

I joined up a week or so again, but this is my virgin post. I came to the Bottlehead Crack + Speedball via a purchase on a local hi fi forum I subscribe too. It replaced a Schitt Valhalla.
So all the hard work was done for me, and so far am really loving the amp, especially with my Sennheiser HD600 cans.
Tubes currently fitted are the Tung-Sol 5998 and a Siemens E80CC driver tube. I did have a Tung-Sol 12 AU7 fitted up until I received the Siemens today, and the Siemens is staying in, it's a great tube.

I'm primarily a vinyl user, it's long been my format of choice, but do seem to listen to more cd's when using head fi.

I've read some great press about 50's Valvo ECC82 tubes with the long plates and angled getter, so purchased one today, will be interesting to see how it sounds in a week or so when it arrives.
Any other users of this tube here?

Anyway, a few pics.

(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fi330.photobucket.com%2Falbums%2Fl425%2Fsoundfanz%2FHA1_zps9xtwv93e.png&hash=0b8ada3bbde1a6c6e600576d91c563b34e756233)

(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fi330.photobucket.com%2Falbums%2Fl425%2Fsoundfanz%2FHA2_zpsxaakxjuc.png&hash=8f4bb29656f59d15748a8771c5be5cb56e57237c)

(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fi330.photobucket.com%2Falbums%2Fl425%2Fsoundfanz%2FHA3_zpsm7tu5jnw.png&hash=153622f46a9dd9bbae6884a3e10168ee266be102)

[Strikkflypilot]

Hi! Welcome to the Board, couldn't see the Pictures.

The E80CC and 12AU7 are not operated under quite the same parameters. On the small Speedball Boards, 237Ohms on the R1 resistors is optimal for the 12AU7/ECC82, for the E80CC the R1 resistors should be 470 Ohms.

[soundfanz]

Hi! Welcome to the Board, couldn't see the Pictures.

The E80CC and 12AU7 are not operated under quite the same parameters. On the small Speedball Boards, 237Ohms on the R1 resistors is optimal for the 12AU7/ECC82, for the E80CC the R1 resistors should be 470 Ohms.

Oh. So can I use the E80CC without any modification? I have read of others using this tube on a speedballed Crack, haven't read of any changes needed.

[Strikkflypilot]

The standard tube is the 12AU7, so if Your Crack+Speedball is unmodified, it has the 237Ohms resistors in R1 on the two small PCBs.
If You take a Picture of the PCBs, we can tell You if it is Stock or optimized for E80CC.

On another note, You can run the E80CC Without modifying the Circuits but the tube would not run optimally.

[soundfanz]

The standard tube is the 12AU7, so if Your Crack+Speedball is unmodified, it has the 237Ohms resistors in R1 on the two small PCBs.
If You take a Picture of the PCBs, we can tell You if it is Stock or optimized for E80CC.

On another note, You can run the E80CC Without modifying the Circuits but the tube would not run optimally.

Thanks, I might just reinstall the Tung Sol 12AU7, and await the Valvo ECC82 tube. I'll have to contact last owner to see if he changed circuit at all to use the Siemens E80 CC.

[Strikkflypilot]

Just post a Picture from underneath Your amp where the small PCB Boards show, and some of us on this board might be able to tell You.

[Deluk]

From memory, someone here as added another pair of 237 (235) ohm resistors with a switch so you can use either valve.

[Strikkflypilot]

This is my rendition, single 470 Ohm for E80CC and two 470 Ohms in parallell (making for 235Ohms) for running 12AU7.

[Deluk]

Very neat. I'm sure you'll be asked about where you can get the switches so I might as well be first. 

[Deluk]

Yes, very neat but that was a lazy reply. They seem to generally available. Here in the UK RS-Spares have them.

[Strikkflypilot]

I got my DIP switches from Farnell, but as You say, they are readily available.

[soundfanz]

Just post a Picture from underneath Your amp where the small PCB Boards show, and some of us on this board might be able to tell You.

I have been informed that no modifications were made to allow optimal use of E80CC tube, so no need for photos.
 I might do mod at a future date, for the minute I have reinstalled a 12AU7.

[Strikkflypilot]

Well, my mod is straightforward.
All You do is remove the 235 Ohms. R1 resistor from each small PCB, replace with 470Ohm, add DIP Switch and additional 470Ohm, as shown,  they are connected via a thread on the rear side that is already in place, afterwards check resistance across either of the newly added resistors for 470 Ohms when switch is in Off, and 235 Ohms when in On, and You're done.

[Hornet900]

Hello 

If you go buying more tubes fanz try a  Mullard tube like the cv4003 for the HD600's  .. especially before modding the amp

I find the Mullard tubes  smooth out the brightness of hd600s
You see most people use the Hd650 with this amp and i find most tubes recommend sound bright with the hd600s..... so look for smooth sounding tubes 

I find most tubes sound quite similar but the mullards stand out ...  its smoother darker detailed sound and much better midrange

Have fun