[Wes S]

Now I remember seeing these tubes once. So basically you cut these flying leads short? If it is the case, are these remaining leads too soft to serve as 12AU7 pins?

They are definitely too soft. I believe that is why they have a base with pins, that the leads are fitted into and soldered. The plastic base does give you something to grab, when removing the tubes, so that is a plus.

 

[cddc]

They are definitely too soft. I believe that is why they have a base with pins, that the leads are fitted into and soldered. The plastic base does give you something to grab, when removing the tubes, so that is a plus.

Yep, having a base is definitely better. The pins of 12AU7 are soft anyway

 

[340519]

I just bought the gold lion 6922 for the CTH . Looking forward to it.

 

[Wes S]

You can measure the plate voltages using a digital multimeter - remember how to check voltages in Crack?

Check the voltage on pin 1 or pin 6.

How hard is this to test, if I have a multimeter? I don't have a clue what I am doing, but would really love to know, whats really going on with my "Top Tier" 12AU7's.

Edit - I see my man @ksorota is one it, so I will wait to see what he finds.

 

[ksorota]

What's the plate voltage loaded onto 12AU7 in LP?

I don't have an LP, but it seems LP is not designed for 12AU7. If the plate voltage is too high, it will reduce the lifespan of 12AU7.

I can check this out once I put the board back into the chassis. I am staring at the chassis ground location on the board, but since its not in the chassis, Im not sure I want to use it.

 

[Wes S]

I can check this out once I put the board back into the chassis. I am staring at the chassis ground location on the board, but since its not in the chassis, Im not sure I want to use it.

Awesome man! I look forward to your findings.

 

[cddc]

How hard is this to test, if I have a multimeter? I don't have a clue, what I am doing, but would really love to know, whats really going on with my "Top Tier" 12AU7's.

It's not difficult at all, you don't even have to open the chassis.

Just lift the 12AU7 tube a little bit until you can see part of the pins. Then attach the negative probe to the ground, and attach the positive probe to pin 1 or pin 6, and measure the voltage.

Attention though, extreme care must be taken when measuring the plate voltage, as the plate voltage can be very high and lethal.

 

[Wes S]

It's not difficult at all, you don't even have to open the chassis.

Just lift the 12AU7 tube a little bit until you can see part of the pins. Then attach the negative probe to the ground, and attach the positive probe to pin 1 or pin 6, and measure the voltage.

Attention though, extreme care must be taken when measuring the plate voltage, as the plate voltage can be very high and lethal.

Thanks for that! I am a complete novice, and the mention of the word "lethal", is enough for me to wait for a professional (@ksorota) to check it out.

 

[ksorota]

Thanks for that! I am a complete novice, and the mention of the word "lethal", is enough for me to wait for a professional (@ksorota) to check it out.

Come on...live a little!

I hope to have it all back together tonight and be able to test!

 

[Wes S]

Come on...live a little!

I hope to have it all back together tonight and be able to test!

LOL! I am enjoying life too much right now (listening with my cap modded LP), to take the risk.

 

[nwavesailor]

I will check tonight. I have some needle probes on my Fluke meter and will get the 12AU7 voltage reading.

I may not 'know tubes' but was an audio tech for 17 years and this is simple stuff!

 

[nwavesailor]

What's the plate voltage loaded onto 12AU7 in LP?

I don't have an LP, but it seems LP is not designed for 12AU7. If the plate voltage is too high, it will reduce the lifespan of 12AU7.

I measured the anode on 4, 12AU7's at: 99 -105 vdc (2 Tele, 2 Baldwin branded Raytheon)

Very close to the 105 vdc of the 6922 anode (Amperex PQ)

 

[Wes S]

Hey y'all! The next tube up for my LP tube rolling adventures with 12AU7's, is in the house and is a very special one folks. This tube is super rare for a reason, and completely blew my mind last night. This tube is in a class by itself, and my desire of tube hunting for 12AU7's ends with this tube, as it's that good. This tube has been described quite well a few pages back by my man @Guidostrunk, so I will just share some pics. I will say it is without a doubt, the best tube I have heard in the 12AU7 family. This tube puts you there with the musicians like no other, and is one of the best experiences I have had in the hobby so far. These puppies won't be leaving my amp anytime soon, if ever.

Raytheon 7730 Long Plate Bent Square Getters

Happy Rolling, Hunting, and Listening.

Wes

 

[DowdyPrime]

Hi all. Here's a tube question, particularly to those with some Lyr3 experience. I'm evaluating the LP vs. Lyr3 right now and am completely torn (and can't keep both!). I love the detail of the LP, but the Lyr3 has a smoothness in the upper range that I really like. To my ears, violin solos on the LP sound a bit too mosquito-y on the HD6xx. But I find the low end on the Lyr3 too pronounced. What tubes you would recommend -- on the cheap side! -- that may tame the LP's high-end a bit? (Right now, I'm listening on HD6xx and Oppo PM-3. I'm just starting out on headphone listening...)

 

[cddc]

I measured the anode on 4, 12AU7's at: 99 -105 vdc (2 Tele, 2 Baldwin branded Raytheon)

Very close to the 105 vdc of the 6922 anode (Amperex PQ)

100 VDC plate voltage is okay for 12AU7, it's within normal operating points. As long as it's not 200+ VDC, nothing to worry about with regard to life span.

FYI, the plate voltage in Crack is 90 VDC, where the circuit is designed for 12AU7.