[Wes S]

My Chatham 6as7g arrived and I have a question for you. Compared to my RCA JAN 6as7g I had to open the volume by 30% to reach the same volume that I had with the RCA. This is normal?

30% difference seems quite high to me, and especially since they are both 6AS7G. Makes me think the Chatham might be a weak testing tube. My volume on the Bottlehead Crack stays the exact same or very close (within 5%), when using different brands of the same tube type. I am sure others will chime in, but that sure seems odd to me.

 

[Ripper2860]

+1 -- That definitely sounds like a low measuring tube.

 

[SHIMACM]

Another different thing that I'm noticing at Chatham is when it starts to heat up it starts to make little crackles. The other 6as7g tubes I have do not crack when heating. Is this also normal in this tube?

 

[bcowen]

Another different thing that I'm noticing at Chatham is when it starts to heat up it starts to make little crackles. The other 6as7g tubes I have do not crack when heating. Is this also normal in this tube?

Are you talking crackling or more like a 'tinking' sound (like you're lightly tapping the glass with a piece of metal)? The latter is not unusual and not necessarily any indication of a problem. Crackling? I guess it all depends on exactly what it sounds like and how loud it is.

However, as @Wes S and @Ripper2860 have noted a 6AS7G is a 6AS7G and should have (with perhaps some slight variation) the same amount of gain regardless of the brand or manufacturer. Sounds to me like you got a badly worn (or worn out) tube. Did the seller provide any test data and relevant info about the tester's minimum or standard NOS value for that tube?

 

[cddc]

I agree, the 'tinking' sound is normal. The components inside a tube will expand when being heated by tube heater, some will make 'tinking' sound some will not. But it's all normal phenomena. Likewise, you will hear the same sound when turning off your amp.

 

[LoryWiv]

Another different thing that I'm noticing at Chatham is when it starts to heat up it starts to make little crackles. The other 6as7g tubes I have do not crack when heating. Is this also normal in this tube?

My Tung-sol 7236 crackle sometimes when warming up but the key is it's gone by 1 or2 minutes, rarely recurs, so I don't worry about it.

 

[adeadcrab]

One of my Bendix 6080WB did a mini-arc/pop once while warming up the first time I plugged it in, I don't think they are NOS but they're rated to last for basically forever.. after that I cleaned the tube pins with deoxit red, wiped all the gunk off so the pins were clean and coated with deoxit gold, those tubes were in use many times after for several years. Waiting on new amp but will test them again.

 

[SHIMACM]

The noises are really tinkling, which happen when I turn the amplifier on and off. Good to know that it is not a problem. Now, regarding the volume, after resting my hearing and doing new tests at night, I realized that the difference in volume opening was below 10%. I think that in the afternoon, my hearing was fatigued, as I had listened to music at high volume for more than an hour on my solid state amplifier (Arcam rHead), and I did not compare Chatham with RCA at the same time (as in Darkvoice I always listen to music at 9 o'clock, I didn't feel the need to take RCA and listen to it immediately after Chatham). It relieves me a lot. Thanks for the quick responses from the community.

 

[SHIMACM]

Are you talking crackling or more like a 'tinking' sound (like you're lightly tapping the glass with a piece of metal)? The latter is not unusual and not necessarily any indication of a problem. Crackling? I guess it all depends on exactly what it sounds like and how loud it is.

However, as @Wes S and @Ripper2860 have noted a 6AS7G is a 6AS7G and should have (with perhaps some slight variation) the same amount of gain regardless of the brand or manufacturer. Sounds to me like you got a badly worn (or worn out) tube. Did the seller provide any test data and relevant info about the tester's minimum or standard NOS value for that tube?

In his ad, he just gave the information he tested hard. As he has 19,000 qualifications and all positive, I trusted him.

 

[bcowen]

The noises are really tinkling, which happen when I turn the amplifier on and off. Good to know that it is not a problem. Now, regarding the volume, after resting my hearing and doing new tests at night, I realized that the difference in volume opening was below 10%. I think that in the afternoon, my hearing was fatigued, as I had listened to music at high volume for more than an hour on my solid state amplifier (Arcam rHead), and I did not compare Chatham with RCA at the same time (as in Darkvoice I always listen to music at 9 o'clock, I didn't feel the need to take RCA and listen to it immediately after Chatham). It relieves me a lot. Thanks for the quick responses from the community.

Well that explains it then: the solid state listening killed your ears. Fortunately they will recover, unlike a worn out tube.

 

[SHIMACM]

What do you think of the measurement of this TS5998?

https://www.ebay.com/itm/353113741375?ul_noapp=true

 

[Dogmatrix]

What do you think of the measurement of this TS5998?

https://www.ebay.com/itm/353113741375?ul_noapp=true

All you can take from that is the tube functions and the balance is ok
With 5998 and related tubes a good indicator is the presence or not of carbon in the lower section below the bottom mica , a tube that has led a hard life will display a noticeable grey black tint in that area . Many sellers photograph tubes on a black background to disguise this

 

[bcowen]

What do you think of the measurement of this TS5998?

https://www.ebay.com/itm/353113741375?ul_noapp=true

I would say those are great measurements if the seller is being honest. I don't have any 5998's, but many of the 6080's and 6AS7's I've tested on my Hickok give well above average NOS readings.

 

[JKDJedi]

Another different thing that I'm noticing at Chatham is when it starts to heat up it starts to make little crackles. The other 6as7g tubes I have do not crack when heating. Is this also normal in this tube?

Might be the tube is so new that it needs some burn in. Same thing happens to some of my tubes. And our amps aren't the best out there, the transformer is a 110v attached to an amp wired for 120v so things can get a little wonky while it's warming up. For me once warmed up all is good. Holy cow...I haven't been getting any notification on this thread . Grabbing another cup of coffee and catch up here

 

[JKDJedi]

Sure hope you're right on these, or you're going to have to go stand in the Pinnacle corner with @JKDJedi .

Couldn't resist for the price, although the same can be said for most tubes I hoard collect.

You grabbed them!! L O L.. wow impressions please!!! NICE!