Strikkflypilot
New member
Strikkflypilot said:
With parallell and 12AU7 I get 72v on terminal and 76 on term 5
In off position with E80CC I get 105v and 107 v (470ohm 0,125 w)
Is this acceptable? Or even understandable?
Modifications to run e80cc/12bh7a/5687 for Crack+Speedball
- Thread starter kscwuzhere
- Start date
With parallell and 12AU7 I get 72v on terminal and 76 on term 5
In off position with E80CC I get 105v and 107 v (470ohm 0,125 w)
Is this acceptable? Or even understandable?
kscwuzhere
New member
Strikkflypilot said:
So your values for the 12AU7 are fine but the e80cc ones are on the high side. Try messing around with different resistors (I bought a pack of resistors ranging from 10ohm - 900ohm) using alligator clips and test the voltage at T1 and T5. Not every tube performs exactly the same for example my buddy's Sylvania 12bh7a needed 91ohms to run at 75V and my RCA 12bh7a needed 140ohm to run at 75V; same tube variety, different resistance requirement. I'd say anything from 60-85V is on the safe side!
OK, finally here we are 8)
After hours of surgical operations, dealing with really tiny crowded spaces where binocular vision is sometime impossible, making desoldering or soldering a challenge, broken short stock 22AWG PTFE wires, everything is now in place and my crack has achieved its ultimate mutation on the input section :
- half-DPDT with a 330R in parallel of the stock 237R still in place to achieve the 138R needed for my 12BH7A (82V). I don't have E80CC, so no need for another resistor combination. Chances are good I won't have to change anything for the 7119 as it happened for kscwuzhere.
- 2 x DPDT switches for the Standard / 7119 configuration. The wiring with the leds (HLMP-6000 / HLMP-CB1A-XY0DD) is made according the drawing I posted a few posts upward. I finally kept the central pin of the socket wired to the ground and restarted from there to the switch. I modified the drawing accordingly.
- 2 x MJE5731A to replace the MJE350. These parts are incredibly hard to find right now, nowhere in stock in the major companies with months of wait, don't know why. I finally ordered on ebay to someone having motorola parts with short pins (new ?). Whatever, they work as intended (reverse from MJE350 !)
- In front on the right, the Valab 23 stepped attenuator 100k. Behind are the capacitors I'll describe in the capacitor porn thread http://bottlehead.com/smf/index.php/topic,4744.90.html.
Modifying the crack during the initial assembly would have been so much easier ! I've replaced the wires I needed to change with 20 or 22AWG PTFE, for a neater result, the overall diameter being smaller than with PVC. Everything eventually at risk has been isolated with shrink tube.
I now just have to wait for my 7119 PQ in transit…
After hours of surgical operations, dealing with really tiny crowded spaces where binocular vision is sometime impossible, making desoldering or soldering a challenge, broken short stock 22AWG PTFE wires, everything is now in place and my crack has achieved its ultimate mutation on the input section :
- half-DPDT with a 330R in parallel of the stock 237R still in place to achieve the 138R needed for my 12BH7A (82V). I don't have E80CC, so no need for another resistor combination. Chances are good I won't have to change anything for the 7119 as it happened for kscwuzhere.
- 2 x DPDT switches for the Standard / 7119 configuration. The wiring with the leds (HLMP-6000 / HLMP-CB1A-XY0DD) is made according the drawing I posted a few posts upward. I finally kept the central pin of the socket wired to the ground and restarted from there to the switch. I modified the drawing accordingly.
- 2 x MJE5731A to replace the MJE350. These parts are incredibly hard to find right now, nowhere in stock in the major companies with months of wait, don't know why. I finally ordered on ebay to someone having motorola parts with short pins (new ?). Whatever, they work as intended (reverse from MJE350 !)
- In front on the right, the Valab 23 stepped attenuator 100k. Behind are the capacitors I'll describe in the capacitor porn thread http://bottlehead.com/smf/index.php/topic,4744.90.html.
Modifying the crack during the initial assembly would have been so much easier ! I've replaced the wires I needed to change with 20 or 22AWG PTFE, for a neater result, the overall diameter being smaller than with PVC. Everything eventually at risk has been isolated with shrink tube.
I now just have to wait for my 7119 PQ in transit…
kscwuzhere
New member
Snarii said:OK, finally here we are 8)
After hours of surgical operations, dealing with really tiny crowded spaces where binocular vision is sometime impossible, making desoldering or soldering a challenge, broken short stock 22AWG PTFE wires, everything is now in place and my crack has achieved its ultimate mutation on the input section :
- half-DPDT with a 330R in parallel of the stock 237R still in place to achieve the 138R needed for my 12BH7A (82V). I don't have E80CC, so no need for another resistor combination. Chances are good I won't have to change anything for the 7119 as it happened for kscwuzhere.
- 2 x DPDT switches for the Standard / 7119 configuration. The wiring with the leds (HLMP-6000 / HLMP-CB1A-XY0DD) is made according the drawing I posted a few posts upward. I finally kept the central pin of the socket wired to the ground and restarted from there to the switch. I modified the drawing accordingly.
- 2 x MJE5731A to replace the MJE350. These parts are incredibly hard to find right now, nowhere in stock in the major companies with months of wait, don't know why. I finally ordered on ebay to someone having motorola parts with short pins (new ?). Whatever, they work as intended (reverse from MJE350 !)
- In front on the right, the Valab 23 stepped attenuator 100k. Behind are the capacitors I'll describe in the capacitor porn thread http://bottlehead.com/smf/index.php/topic,4744.90.html.
Modifying the crack during the initial assembly would have been so much easier ! I've replaced the wires I needed to change with 20 or 22AWG PTFE, for a neater result, the overall diameter being smaller than with PVC. Everything eventually at risk has been isolated with shrink tube.
I now just have to wait for my 7119 PQ in transit…
Absolutely beautiful implementation Snarii! Now just for those 7119's.......
Strikkflypilot
New member
kscwuzhere said:
Thank You and it is a good point. I only did this mod because it made sense. 470 in parallell makes 235 ohms and the switch would be easy and small. I am sure I will find something.
kscwuzhere
New member
Strikkflypilot said:
It's all about trial and error. Try using a 500, 550, or a 600ohm resistors for the e80cc position!
Strikkflypilot
New member
Or how about installing a self bias circuit?
Hi all,
my two 7119 PQ (yes, I like to always keep some spare) arrived this morning. Very good shape, like new indeed. They were made in Heerlen in 1966. One last visual wiring check, we're never too sure, and power. A few seconds then the 2 two blue leds light up, then the small speedbal cards, OK !
Time to check the plates. As expected, the 138ohm (= 237 // 330) 12BH7A resistor mod worked for the 7119, as I get 77.3V on the plate of the 2 triodes. Now let's get the tube the time to cool down, then put a 6H13C on its slot, and lets play some jazz….
Woww !! Stunning !
Absolutely no regrets spending some time integrating the 5687/7119 mod !
We are really one step beyond every progresses I've made so far installing all these gears. Transparency, liveliness of the music, improved soundstage, presence and focus of placement of the instruments, sensation of space, … what to say more, this 7119 tube is killer and pairs beautifully with the HD650. The 12BH7A was my favorite, but it never went this far, even properly driven by a good plate voltage.
3 months after my complete DIY beginning on the crack, I think my tuning journey has now ended, thanks to all at Bottlehead for this wonderfull amp, and those of you on the forum making me try something else, now time to enjoy the music !
my two 7119 PQ (yes, I like to always keep some spare) arrived this morning. Very good shape, like new indeed. They were made in Heerlen in 1966. One last visual wiring check, we're never too sure, and power. A few seconds then the 2 two blue leds light up, then the small speedbal cards, OK !
Time to check the plates. As expected, the 138ohm (= 237 // 330) 12BH7A resistor mod worked for the 7119, as I get 77.3V on the plate of the 2 triodes. Now let's get the tube the time to cool down, then put a 6H13C on its slot, and lets play some jazz….
Woww !! Stunning !
Absolutely no regrets spending some time integrating the 5687/7119 mod !
We are really one step beyond every progresses I've made so far installing all these gears. Transparency, liveliness of the music, improved soundstage, presence and focus of placement of the instruments, sensation of space, … what to say more, this 7119 tube is killer and pairs beautifully with the HD650. The 12BH7A was my favorite, but it never went this far, even properly driven by a good plate voltage.
3 months after my complete DIY beginning on the crack, I think my tuning journey has now ended, thanks to all at Bottlehead for this wonderfull amp, and those of you on the forum making me try something else, now time to enjoy the music !
kscwuzhere
New member
Snarii said:Hi all,
my two 7119 PQ (yes, I like to always keep some spare) arrived this morning. Very good shape, like new indeed. They were made in Heerlen in 1966. One last visual wiring check, we're never too sure, and power. A few seconds then the 2 two blue leds light up, then the small speedbal cards, OK !
Time to check the plates. As expected, the 138ohm (= 237 // 330) 12BH7A resistor mod worked for the 7119, as I get 77.3V on the plate of the 2 triodes. Now let's get the tube the time to cool down, then put a 6H13C on its slot, and lets play some jazz….
Woww !! Stunning !
Absolutely no regrets spending some time integrating the 5687/7119 mod !
We are really one step beyond every progresses I've made so far installing all these gears. Transparency, liveliness of the music, improved soundstage, presence and focus of placement of the instruments, sensation of space, … what to say more, this 7119 tube is killer and pairs beautifully with the HD650. The 12BH7A was my favorite, but it never went this far, even properly driven by a good plate voltage.
3 months after my complete DIY beginning on the crack, I think my tuning journey has now ended, thanks to all at Bottlehead for this wonderfull amp, and those of you on the forum making me try something else, now time to enjoy the music !
Absolutely beautiful build! After I installed the 7119 for my hd650s I felt the same way! I felt like I maxed out the hd650s potential and that's why I decided to upgrade to the hd800s haha! My journey has begun all over again.
Strikkflypilot
New member
kscwuzhere said:
So its not just something wrong with my E80CC?
kscwuzhere
New member
Strikkflypilot said:
Definitely not, no tubes are identical. Your e80cc can run at 108V or whatever value you were getting and your crack will sound wonderful but for a couple of bucks worth of experimentation I thought it was worth it to find the correct resistance to run the e80cc tube at the correct plate voltage.
Strikkflypilot
New member
I will certainly look into it. Maybe some resistor sockets of sorts for easier interchangability.
Strikkflypilot said:
If you have unusually high voltages with the same resistor that is working for the rest of the crowd, you may have a tired E80CC.
Strikkflypilot
New member
My thoughts exactly. Was supposed to be a NOS and everything.Caucasian Blackplate said:
By the way, I have read the 12AU7 datasheets :
http://free-hosting.infodiv.com/audiotube/small_signal_triode/small_signal_triode0018/small_signal_triode0018-01.html
To me, it seems a plate voltage of 100v should be a usual operating voltage, not 75v.
Again, there must be something I do not understand.
Strikkflypilot said:
There are literally an infinite number of operating points for any tube. The plate curves for a tube will reflect this. (They are usually a few pages into the datasheet).
The number on page 1 are maximum ratings. The 100V rating is an insulation rating.
Paul Joppa
Moderator
There is a listed operating point at 100v; it's just another example. The example operating points are just that - not recommendations, just examples of the infinite possibilities. In this case, the 100v example is also at zero bias, a point that will have significant nonlinear grid current and is unsuitable for audio. It might reflect use as a vertical deflection amplifier in B&W televisions.
Strikkflypilot
New member
Thank You both very much. I feel privileged to learn so much in so brief time!
onelivewire
New member
Just dropping in to give some updates on my 5687 experience. Recently I've become fond of kscwuzhere's Amperex 7119, which certainly became less sibilant after burn-in. However, just a couple days ago I received a Sylvania Gold Brand 5687 (Gold Pin variety). With the t1s, this tube is incredible. Easily takes the cake as my favorite tube for t1s. Soft, yet articulate, this tube truly takes away just about all the harsh glare that I find in bad recordings, while sacrificing nearly no articulation. I highly recommend this tube to any t1 owners running this mod.
Strikkflypilot
New member
Caucasian Blackplate said:
Some feedback.
Decided another attempt at ordering an E80CC instead of changing my resistors.
Received an unmarked Tungsram where the plate voltages are 78ish and 81ish with 470ohms
On my now heavily hotrodded crack with GEC brown based 6080, I am convinced the soundstage widened, upper mids and treble much clearer and stronger but no annoying sibilance. I use HD580s and am a very happy camper.
kscwuzhere
New member
I just received an RCA bronze plate 5687 as research eluded to it's warmth, which was something I was looking for my hd800s. After letting the NOS tube warm up for a couple of hours it has become my new favorite with the hd800s! Sonically, mid bass to mids have become much more lush and sound more whole-bodied and less airy than the 7119. Treble seems to be rolled off a little more than the amperex but is slightly more sibilant (won't surprise me if this goes with more burn in). The amperex 7119 bass is tighter and has an overall quicker presentation than the rca.
For more rock/metal orientated as well as poorer recorded music I find myself preferring the warmer RCA 5687s. Whereas for jazz, electronic and more "tamed" music, I find that the Amperex is my go to tube (particularly enjoy the speed the hd800's provide with these genres).
For more rock/metal orientated as well as poorer recorded music I find myself preferring the warmer RCA 5687s. Whereas for jazz, electronic and more "tamed" music, I find that the Amperex is my go to tube (particularly enjoy the speed the hd800's provide with these genres).
