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Author Topic: Modifications to run e80cc/12bh7a/5687 for Crack+Speedball  (Read 50798 times)

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Offline kscwuzhere

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Modifications to run e80cc/12bh7a/5687 for Crack+Speedball
« on: March 29, 2014, 09:48:59 AM »
Hey so I currently have a crack with speedball driving my Hd650s. My current output tube is the Chatham/Tung-sol 5998 and the driver tube is the Tungsram e80cc. I read somewhere that there are some possible circuit changes you can make to run these two tubes optimally and I was just wondering what these changes were? Do I need to replace or add any additional resistors? Thank you bottlehead community!
« Last Edit: May 20, 2014, 10:10:39 AM by kscwuzhere »

Online Paul Birkeland

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Re: Modifications to run e80cc + 5998 for Crack+Speedball
« Reply #1 on: March 29, 2014, 10:07:38 AM »
What voltages do you get at T1 and T5 with the E80CC?
Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man

Offline kscwuzhere

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Re: Modifications to run e80cc + 5998 for Crack+Speedball
« Reply #2 on: March 29, 2014, 12:50:54 PM »
Terminal 1: 130V
Terminal 5: 121V

Online Paul Birkeland

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Re: Modifications to run e80cc + 5998 for Crack+Speedball
« Reply #3 on: March 29, 2014, 04:00:59 PM »
Yeah, that's not really so great. 

Try replacing the 237 R1 resistors with 470 Ohm resistors to see if the voltage bumps down between 55 and 85V.

-PB
Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man

Offline xcoolhandx

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Re: Modifications to run e80cc + 5998 for Crack+Speedball
« Reply #4 on: March 29, 2014, 04:28:08 PM »
Yeah, that's not really so great. 

Try replacing the 237 R1 resistors with 470 Ohm resistors to see if the voltage bumps down between 55 and 85V.

-PB

wouldn't this be a permanent change and how would this affect the other tube rolling ?

Offline kscwuzhere

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Re: Modifications to run e80cc + 5998 for Crack+Speedball
« Reply #5 on: March 29, 2014, 05:50:16 PM »
So I went ahead and ordered a bunch of 470 ohm resistors, hopefully that'll do the trick!


Online Paul Birkeland

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Re: Modifications to run e80cc + 5998 for Crack+Speedball
« Reply #6 on: March 30, 2014, 06:26:16 AM »

wouldn't this be a permanent change and how would this affect the other tube rolling ?

Yes, it would be a permanent change.  Yes, it won't be ideal for other tubes.
Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man

Offline JamieMcC

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Re: Modifications to run e80cc + 5998 for Crack+Speedball
« Reply #7 on: March 30, 2014, 06:55:28 AM »
So I went ahead and ordered a bunch of 470 ohm resistors, hopefully that'll do the trick!

Please post some feed back here on how you get on with the resistor swap, I tend to favour the E80cc also and am very tempted to go down the same path.

Cheers
Shoot for the moon if you miss you will still be amongst the stars!

Offline xcoolhandx

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Re: Modifications to run e80cc + 5998 for Crack+Speedball
« Reply #8 on: March 30, 2014, 07:22:44 AM »

wouldn't this be a permanent change and how would this affect the other tube rolling ?

Yes, it would be a permanent change.  Yes, it won't be ideal for other tubes.

what could happen if I won't change resistors....would I need one of this attached to Crack 

Online Paul Birkeland

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Re: Modifications to run e80cc + 5998 for Crack+Speedball
« Reply #9 on: March 30, 2014, 07:43:49 AM »

what could happen if I won't change resistors....would I need one of this attached to Crack

You'll throw off the operation of the 6080.  The results won't be great (IMO) with both the Speedball and the stock kit.
Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man

Offline xcoolhandx

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Re: Modifications to run e80cc + 5998 for Crack+Speedball
« Reply #10 on: March 30, 2014, 08:16:42 AM »
Thanks Caucasian

Offline kscwuzhere

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Re: Modifications to run e80cc + 5998 for Crack+Speedball
« Reply #11 on: March 30, 2014, 10:34:02 AM »


Please post some feed back here on how you get on with the resistor swap, I tend to favour the E80cc also and am very tempted to go down the same path.

Cheers

I'll make sure to update this thread with the voltage changes after I swap the resistors.

By switching the resistors and running the tubes optimally, what audible differences would result?

edit: Also, I ended up getting the 1/4W 470ohm 1% metal film resistor, would this suffice for the swap?
« Last Edit: March 30, 2014, 11:31:39 AM by kscwuzhere »


Offline kscwuzhere

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Re: Modifications to run e80cc + 5998 for Crack+Speedball
« Reply #13 on: March 31, 2014, 11:40:41 AM »
So I ordered the wrong resistor? Are 1/4W 470 ohm resistors fine or should I order something else?

Online Paul Birkeland

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Re: Modifications to run e80cc + 5998 for Crack+Speedball
« Reply #14 on: March 31, 2014, 12:23:48 PM »
1/4 Watt will work fine, they will just be physically kind of large.
Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man