2359glenn | studio
Apr 12, 2023 at 3:41 PM Post #39,797 of 40,062
Do the Elrogs have a lower recommended operating point? I noticed you're running them with 10mA lower plate current vs. the Taks.
I'm playing on the safe side until I can find out the recommended operating point. I contacted Elrog but they said "consult your amp manual"... I could try Glenn but he's AWOL.
 
Last edited:
Apr 12, 2023 at 3:59 PM Post #39,798 of 40,062
I'm playing on the safe side until I can find out the recommended operating point. I contacted Elrog but they said "consult your amp manual"... I could try Glenn buts he's AWOL.

Both the Elrogs and the Taks have a 40W max plate dissipation, original Western Electrics were rated for 36W. I don't see any reason you should have to run the Elrogs cooler. If you wanted to know for sure, you'd have to measure the plate voltage Glenn used to calculate the plate dissipation (plate voltage x bias current in amps). Hard max of 40W, but it's common to bias tubes around 80% of maximum for longevity.
 
Apr 12, 2023 at 4:07 PM Post #39,799 of 40,062
Both the Elrogs and the Taks have a 40W max plate dissipation, original Western Electrics were rated for 36W. I don't see any reason you should have to run the Elrogs cooler. If you wanted to know for sure, you'd have to measure the plate voltage Glenn used to calculate the plate dissipation (plate voltage x bias current in amps). Hard max of 40W, but it's common to bias tubes around 80% of maximum for longevity.
Tom just said exactly the same to me! I'll try again this evening :)
 
Apr 12, 2023 at 4:48 PM Post #39,800 of 40,062
Usually Glenn would tell you at some point what plate voltage he was targeting for the output stage, it might be mentioned in old messages between the two of you during the build. For manual bias amps like ours it's actually kind of rough not knowing that piece of info.
 
Jun 28, 2023 at 5:58 PM Post #39,801 of 40,062
This thread has been pretty quiet as late so thought I would post a picture. :)

The GOTL with a pair of Chatham 6520, a Voskhod 6N23P and a Philips 1701 rectifier. Of course, it sounds great! :)

2023-06-28 17.45.00.jpg

The 1701 is a gas rectifier, about 1930, and the gas is argon, with a 1.8V heater.

2023-06-28 17.53.42.jpg



2023-06-28 17.53.26.jpg
 
Jun 28, 2023 at 7:07 PM Post #39,802 of 40,062
This thread has been pretty quiet as late so thought I would post a picture. :)

The GOTL with a pair of Chatham 6520, a Voskhod 6N23P and a Philips 1701 rectifier. Of course, it sounds great! :)

2023-06-28 17.45.00.jpg

The 1701 is a gas rectifier, about 1930, and the gas is argon, with a 1.8V heater.

2023-06-28 17.53.42.jpg


2023-06-28 17.53.26.jpg
raccoon-clap.gif


Ooooh, shiny.
 
Jun 28, 2023 at 7:07 PM Post #39,803 of 40,062
This thread has been pretty quiet as late so thought I would post a picture. :)

The GOTL with a pair of Chatham 6520, a Voskhod 6N23P and a Philips 1701 rectifier. Of course, it sounds great! :)

2023-06-28 17.45.00.jpg

The 1701 is a gas rectifier, about 1930, and the gas is argon, with a 1.8V heater.

2023-06-28 17.53.42.jpg


2023-06-28 17.53.26.jpg
I always wondered about the 6520 - is it just another 6AS7G? Maybe with different specs? Complicating it is that some 6520 tubes have domino plates like the 5998 - are those 6520 tubes the same as 5998?
It seems from the picture that these 6520 tubes have regular plates. These are labelled Chatham but I have seen other rebranded names as well.
And while we are at it, Here is a picture of my GOTL (in daily use) with a pair of 6S2S (6J5GT) and a sextet of 6N12S.
1687993492556.png

IMHO the 6S2S (6C2C) is a very good sounding tube but probably too cheap to be taken seriously - please don't tell anybody so the prices stay low!
 
Jun 28, 2023 at 7:31 PM Post #39,804 of 40,062
I always wondered about the 6520 - is it just another 6AS7G? Maybe with different specs? Complicating it is that some 6520 tubes have domino plates like the 5998 - are those 6520 tubes the same as 5998?
It seems from the picture that these 6520 tubes have regular plates. These are labelled Chatham but I have seen other rebranded names as well.
And while we are at it, Here is a picture of my GOTL (in daily use) with a pair of 6S2S (6J5GT) and a sextet of 6N12S.
1687993492556.png
IMHO the 6S2S (6C2C) is a very good sounding tube but probably too cheap to be taken seriously - please don't tell anybody so the prices stay low!

The fine print on the datasheet reveals that the Chatham 6520 is simply a tweaked Chatham 6AS7G. Those that look like 5998 are in fact 5998. Why Chatham/Tung Sol deliberately mislabeled them as 6520 is not known.

http://frank.yueksel.org/sheets/127/6/6520.pdf
 
Jun 28, 2023 at 7:43 PM Post #39,805 of 40,062
The fine print on the datasheet reveals that the Chatham 6520 is simply a tweaked Chatham 6AS7G. Those that look like 5998 are in fact 5998. Why Chatham/Tung Sol deliberately mislabeled them as 6520 is not known.

http://frank.yueksel.org/sheets/127/6/6520.pdf
I have a Tung Sol labeled 6520. Sounds pretty much the same to me as my Chatham 6AS7G's. Got it about a year ago for the starting bid of $4.95 'cause the seller mistyped it as a 6250 in the Ebay listing. 🤣


6520 Tung Sol.jpg
 
Jun 29, 2023 at 8:22 AM Post #39,807 of 40,062
This thread has been pretty quiet as late so thought I would post a picture. :)

The GOTL with a pair of Chatham 6520, a Voskhod 6N23P and a Philips 1701 rectifier. Of course, it sounds great! :)

2023-06-28 17.45.00.jpg

The 1701 is a gas rectifier, about 1930, and the gas is argon, with a 1.8V heater.

2023-06-28 17.53.42.jpg


2023-06-28 17.53.26.jpg

I have not bought any tubes for a long time, mainly because I feel I have more than I could ever use, but those Chatham 6520 are something I do not own and I love my Chatham 6AS7G's. I have a few pair's. I guess since they sound pretty much the same, I will pass on looking for some.
Sounding like the Chatham 6AS7G is a good thing though, as those are some great sounding tubes that pair great with many driver tubes.
I have some in my GOTL now.

IMG_2906.JPG
 
Jun 29, 2023 at 8:27 AM Post #39,808 of 40,062
I have not bought any tubes for a long time, mainly because I feel I have more than I could ever use, but those Chatham 6520 are something I do not own and I love my Chatham 6AS7G's. I have a few pair's. I guess since they sound pretty much the same, I will pass on looking for some.
Sounding like the Chatham 6AS7G is a good thing though, as those are some great sounding tubes that pair great with many driver tubes.
I have some in my GOTL now.

I had Chatham 6520 and Chatham 6as7 but I have released them all. Onto different tube types now. Enjoy Joe, that's an iconic amp with lovely tubes.
 

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