Little Dot Tube Amps: Vacuum Tube Rolling Guide
Dec 20, 2020 at 7:39 PM Post #12,451 of 12,832

mordy

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Am i rich mordy ?1 SYLVANIA 6SN7WGT $45.00CA 28-05-2015 .JPG
If you are satisfied and happy with what you have, then you are rich....

The tube in the picture is a WGT and not the real BB. I have this tube, as well as the Sylvania 6SN7W (and some fake BBs), Tung Sol 6SN7 BGRP and the 7N7 "Frankie" but I could never get myself to really like any of them. (Am I allowed to say this?)
But give me a 6N7/6N7G or 6C5/6J5 variants and now we are talking!
 
Dec 20, 2020 at 8:18 PM Post #12,453 of 12,832

mordy

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Am i rich mordy ?1 SYLVANIA 6SN7WGT $45.00CA 28-05-2015 .JPG
Mikelap inspired me to check my 6SN7 box to see what's there - any buried riches?
Found six Sylvanias. One is from 1953 6SN7GT but it does not have all the signs of the real BB even though it looks similar with the three hole plate and green print; I think it is called a Chrome Dome. Then a pair of 1954 GTA and four GTBs from 1955-60.

Another box has a Sylvania 1955 GTW Mikelap clone and a couple of 1945 6SN7W rescued by lodkolv from the minefields of pops and explosions. They share the box with a quad of aircraft quality RCA 12SX7.

In the first box there is also a quad of Japanese NEC 6SN7GTB under the Channel Master label - these are good sounding tubes and can still be found inexpensive. And a bunch of others....
 
Dec 20, 2020 at 9:11 PM Post #12,454 of 12,832

gibosi

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you know.., the problem with all these bad-good-what?-boy is that there are too many different versions of the same tube code... year ... manufacturer... bla bla bla... a nightmare...

ok many very useful info are inside this thread and many others inside the 6SN7 thread... but both together are more than 1000 pages and billions of words... here inside there are two very useful chart collecting all the info, it would be very useful something similar where, over the time, people add pictures with descriptions so when a rookie need to double-check to avoid surprise a place to go exist

The following thread is very useful in identifying 6SN7GT

http://www.head-fi.org/t/209782/the-6sn7-identification-guide

And from that thread:

Sylvania 6SN7GT 1952 “Bad Boy”
Also JAN-CHS-6SN7GT
Made only from late 1951 (‘1-48’ examples seen) to 1952. Differs slightly in construction from ‘regular’ Sylvania rectangular top mica 6SN7GTs. Re-labeled bad boys are known to exist.

Base: black, green labels marked ‘2-XX’ (where XX is the week of the year)
Glass: clear
Plates: black, T-plate with 3 holes per plate
Getter: bottom, foil, flashing can extend up to 1/3 of way up tube
Top mica: rectangular with 3 spikes on each of the shorter edges
Other significant features: bottom mica is rectangular. When seen, date codes are vertically arranged (from top to bottom) ‘YWW’ with Y underlined. Y = last digit of year, WW = week number of year.

(I should note that I have seen some Bad Boys manufactured as late as 1953.)

2020-12-20 20.56.50.jpg

2020-12-20 20.56.31.jpg
 
Dec 20, 2020 at 9:53 PM Post #12,455 of 12,832

MIKELAP

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This was reach for the sky setup,complete with cloud lol900x900px-LL-31267b5f_SKY005.jpeg
 
Dec 21, 2020 at 7:43 AM Post #12,457 of 12,832

MIKELAP

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I remember the picture but not the tubes....
Where are the copper pipe adapters?
I think those adapters were the first ones I got not sure but tubes are 6AU6 I use to like those a lot still have all of them with new adapters not those Dont know if possible to use these with WA22 in 6SN7 slots with adapters ?
 
Dec 21, 2020 at 3:01 PM Post #12,459 of 12,832

triod750

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I have now listened to my Brimars without the external PSU. Yes, they did sound really good, but....laidback compared to when fed by Deyan's PSU. Serious comparison takes time and careful sound level matching and careful listening to different kinds of music and.....I won't go into that. I will most likely use external electrons now when I have them and then, some time in the future, revisit the internal transformer to check my reaction. Imagination is powerful - I can't promise that you would hear what I think I hear.
 
Dec 21, 2020 at 3:23 PM Post #12,461 of 12,832

triod750

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It's simple: Trust your ears! (Barring first time immediate impressions)

Yes, my ears are my only instrument. But if there is a difference it can take some time to find out all the aspects of it. Not all of them might be good. Some of them can be bad and eventually take over. I've been there before. What is out of focus in the beginning can develop to become quite annoying.

I received my adapter for 6N7 today...
 
Dec 22, 2020 at 8:39 AM Post #12,462 of 12,832

warp2600

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I have just received an order of 2pcs TUNG SOL 5654 tubes listed as NOS on ebay. The measurements were not listed in the description but the boxes they came in have them: one is 13.7/5.1 but the other one says 6.5/4.5 Annoyingly different. Does anyone around here know anything about test measurements and minimum values? Thanks.
 
Dec 22, 2020 at 8:54 AM Post #12,463 of 12,832

mordy

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I have just received an order of 2pcs TUNG SOL 5654 tubes listed as NOS on ebay. The measurements were not listed in the description but the boxes they came in have them: one is 13.7/5.1 but the other one says 6.5/4.5 Annoyingly different. Does anyone around here know anything about test measurements and minimum values? Thanks.
The problem is that every tester is different and the testers themselves are not showing accurate readings unless they have recently been calibrated professionally.
People who calibrate testers claim that almost every one they receive is inaccurate .
Each tester’s readings have to be compared to it’s own minimum or good readings.
Different manufacturers use different parameters.
You are left with the most sensitive instrument of all - your ears. If it sounds good, that’s it, and don’t worry!
 
Dec 22, 2020 at 9:15 AM Post #12,464 of 12,832

warp2600

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The problem is that every tester is different and the testers themselves are not showing accurate readings unless they have recently been calibrated professionally.
People who calibrate testers claim that almost every one they receive is inaccurate .
Each tester’s readings have to be compared to it’s own minimum or good readings.
Different manufacturers use different parameters.
You are left with the most sensitive instrument of all - your ears. If it sounds good, that’s it, and don’t worry!
Thanks, Mordy for this lightning fast reply. The seller also responded to my query. I've been concerned because the measurements were so "out of tune" (although they were not listed as a matched pair). He says he used an AVO vcm 163 tester and both tubes tested NOS and that book values for new tubes are 7.7/4.9
Tomorrow I will try them in the MK3
 
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Dec 22, 2020 at 7:28 PM Post #12,465 of 12,832

triod750

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Recently I was very disappointed when listening to a pair of Tung-Sol Chatham 6080. In the same lot a pair of 'ordinary' Tung-Sol 6080 were included. I am listening to them right now with CV4010 as input and they are clearly better, in fact not bad att all. Maybe the first pair is 'tired'. At least it's useless. This pair is quite listenable. That means that I can't write off the 6080 type tubes. Thougt it would be fair to report this. It took about an hour of warming up until they started to sound decent. Another hour had me warmed up to them.
 

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