anthony vinyl Posted December 8, 2021 Share Posted December 8, 2021 Hey is there anything specific to look out for in the awv tubes or are they all consistently good through the years? Thanks anthony Link to comment Share on other sites More sharing options...
xlr8or Posted December 8, 2021 Share Posted December 8, 2021 (edited) You don't need to spend mega bucks to get really good sounding tubes. The older the vintage, the better sounding the tube. You may be asking why this is. Well with technology change, tubes were specified to be constructed with the objective of meeting more stringent noise characteristics. Aircraft got faster and manoeuvring became more rapid. Tubes constructed in WW2 were simply too noisy for use during the cold war and later periods of warfare. With generational change, tubes were manufactured with the main aim of exhibiting the lowest noise floor. No vibration of internal elements was the key. Although a tube made in the 1970's may have the lowest noise floor it also sounds restricted for audio use. In contrast, a tube made in the 1940's may well 'ring', but hell when it sings it really sings, like a microphone. Edit: Just adding that long anode plate construction, black charcoal welded plate construction, inverted cup getter construction, glass envelope pinching, fewer mica plates etc. are all features of older type tubes. Edited December 8, 2021 by xlr8or 3 1 1 Link to comment Share on other sites More sharing options...
xlr8or Posted December 8, 2021 Share Posted December 8, 2021 (edited) 2 hours ago, El Tel said: So I've been lurking... My McIntosh has 2 x 12AT7 (ECC81) and 2 x 12AX7 (ECC83) slots in the pre-amp stage. I rolled the stock tubes for 2 matched pairs of modern manufactured Mullards. The difference was initially subtle, but fuller and richer after about 60hours or so. I'm now intrigued enough to investigate some NOS matched pair options. Should I swap out all 4 in one hit, or change each pair and see what effect it has? Any suggestions, observations, alternates (12AU7?) or guidance? Cheers Tel Changing the first stage input tube will have the most significant impact on sound signature. It would be best to start there and incrementally assess a change in vintage tube type for that position and then follow the same approach at a much later date for swapping vintage tubes for the other stages that follow. So is it the 12AX7 that first receives the signal from the source? Edited December 8, 2021 by xlr8or 3 Link to comment Share on other sites More sharing options...
muon* Posted December 8, 2021 Share Posted December 8, 2021 (edited) 2 hours ago, El Tel said: So I've been lurking... My McIntosh has 2 x 12AT7 (ECC81) and 2 x 12AX7 (ECC83) slots in the pre-amp stage. I rolled the stock tubes for 2 matched pairs of modern manufactured Mullards. The difference was initially subtle, but fuller and richer after about 60hours or so. I'm now intrigued enough to investigate some NOS matched pair options. Should I swap out all 4 in one hit, or change each pair and see what effect it has? Any suggestions, observations, alternates (12AU7?) or guidance? Cheers Tel You can swap out both pairs for their respective tube types, or one pair at a time to see what each change makes. 12AU7 is not a substitute for either the 12AT7 or the 12AX7, all three types have different amplification factors to each other. Swap 12AT7 types for 12AT7 types, 12AX7 types for 12AX7 types. Edited December 8, 2021 by muon* typo 2 Link to comment Share on other sites More sharing options...
xlr8or Posted December 8, 2021 Share Posted December 8, 2021 Here is my pick for the 12AX7 pair: https://www.ebay.com.au/itm/1-40s-GE-Ken-Rad-long-Charcoal-pewter-plate-12ax7-Dimple-D-foil-getter-Tube-/284553162356 2 1 Link to comment Share on other sites More sharing options...
Volunteer El Tel Posted December 8, 2021 Volunteer Share Posted December 8, 2021 31 minutes ago, xlr8or said: Changing the first stage input tube will have the most significant impact on sound signature. It would be best to start there and incrementally assess a change in vintage tube type for that position and then follow the same approach at a much later stage for swapping vintage tubes for the other stages that follow. So is it the 12AX7 that first receives the signal from the source? Trying to find the order for my MA352 - can't find reference to what order the signal passes through in the manual. The sockets are labelled v1 thru v4. v1 (12ax7a) and v3 (12at7) on the left and v2 (12ax7a) and v4 (12at7) on the right. Link to comment Share on other sites More sharing options...
xlr8or Posted December 8, 2021 Share Posted December 8, 2021 9 minutes ago, El Tel said: Trying to find the order for my MA352 - can't find reference to what order the signal passes through in the manual. The sockets are labelled v1 thru v4. v1 (12ax7a) and v3 (12at7) on the left and v2 (12ax7a) and v4 (12at7) on the right. V1 and V2 positions are the first stage. One 12AX7 on the left and one 12AX7 on the right. 1 Link to comment Share on other sites More sharing options...
xlr8or Posted December 8, 2021 Share Posted December 8, 2021 Here is my pick for the 12AT7 pair: https://www.ebay.com.au/itm/2x-Mullard-ECC81-Valves-Tubes-1552-J3-I3-1953-Eq-12AT7-B309-CV4024-A2900-M8136-/294610296871 1 1 Link to comment Share on other sites More sharing options...
Volunteer El Tel Posted December 8, 2021 Volunteer Share Posted December 8, 2021 (edited) 6 minutes ago, xlr8or said: Here is my pick for the 12AT7 pair: https://www.ebay.com.au/itm/2x-Mullard-ECC81-Valves-Tubes-1552-J3-I3-1953-Eq-12AT7-B309-CV4024-A2900-M8136-/294610296871 Is there any concern with the differences in their testing values? Or am I being too fussy? Edit - actually, similar question for the 12ax7 too (the guy is offering upto 4 tubes but no test values). Edited December 8, 2021 by El Tel Link to comment Share on other sites More sharing options...
xlr8or Posted December 8, 2021 Share Posted December 8, 2021 2 hours ago, El Tel said: Is there any concern with the differences in their testing values? Or am I being too fussy? Edit - actually, similar question for the 12ax7 too (the guy is offering upto 4 tubes but no test values). It's becoming increasingly difficult to find NOS vintage tubes. Even if UOS they are still difficult to come by. You should be fine though in purchasing UOS for many years to come. 9-pin minis keep working and working. They often outlast their owners, even if they test low, which in this specific case the 12AX7 and 12AT7 links I shared are far from. 1 1 1 Link to comment Share on other sites More sharing options...
Volunteer El Tel Posted December 8, 2021 Volunteer Share Posted December 8, 2021 (edited) 6 hours ago, xlr8or said: It's becoming increasingly difficult to find NOS vintage tubes. Even if UOS they are still difficult to come by. You should be fine though in purchasing UOS for many years to come. 9-pin minis keep working and working. They often outlast their owners, even if they test low, which in this specific case the 12AX7 and 12AT7 links I shared are far from. Thanks for the advice, Kirk. I'm spinning the wheel. Ordered a pair of each of the 12ax7 and 12at7 tubes from those links. Now we wait.... Cheers Terry Edited December 8, 2021 by El Tel 2 1 Link to comment Share on other sites More sharing options...
Jehuty Posted December 9, 2021 Share Posted December 9, 2021 15 hours ago, xlr8or said: Here is my pick for the 12AX7 pair: https://www.ebay.com.au/itm/1-40s-GE-Ken-Rad-long-Charcoal-pewter-plate-12ax7-Dimple-D-foil-getter-Tube-/284553162356 How do you rate these Kirk? Say as compared to MC1... Link to comment Share on other sites More sharing options...
xlr8or Posted December 9, 2021 Share Posted December 9, 2021 (edited) 8 hours ago, Jehuty said: How do you rate these Kirk? Say as compared to MC1... More spread, warmth, body and dynamics to the music. It's a different sound compared to the mC1 Blackburn beauties. Both are excellent tubes. I suspect like so many of the other tube recommendations that have been given out we won't hear back. Edited December 9, 2021 by xlr8or 2 Link to comment Share on other sites More sharing options...
xlr8or Posted December 15, 2021 Share Posted December 15, 2021 Group buy alert! Happy to contribute cash to any Melbourne or Geelong members' willingness to grab these for local pick up. https://www.ebay.com.au/itm/radio-valves-tubes-/363657286279 1 1 1 Link to comment Share on other sites More sharing options...
Jehuty Posted December 15, 2021 Share Posted December 15, 2021 Far out Kirk, that's a bargain! 1 1 Link to comment Share on other sites More sharing options...
xlr8or Posted December 15, 2021 Share Posted December 15, 2021 1 minute ago, Jehuty said: Far out Kirk, that's a bargain! Yes, Will. I reckon there are some hidden treasures in there probably worth at least 10 times the BIN price. 2 1 Link to comment Share on other sites More sharing options...
xlr8or Posted December 15, 2021 Share Posted December 15, 2021 GEC Hammersmith October 1955 production U709 EZ81 substitute rectifier: https://www.ebay.com.au/itm/VERY-RARE-MARCONI-U709-EZ81-BLACK-PLATES-SQUARE-GETTER-1955-/203747137230 1 1 Link to comment Share on other sites More sharing options...
Jehuty Posted December 15, 2021 Share Posted December 15, 2021 1 minute ago, xlr8or said: GEC Hammersmith October 1955 production U709 EZ81 substitute rectifier: https://www.ebay.com.au/itm/VERY-RARE-MARCONI-U709-EZ81-BLACK-PLATES-SQUARE-GETTER-1955-/203747137230 I got my eyes on this...and I put a lot of money on my bid! 1 Link to comment Share on other sites More sharing options...
xlr8or Posted December 15, 2021 Share Posted December 15, 2021 GEC Hammersmith September 1955 production U709 rectifier available in this lot: https://www.ebay.com.au/itm/3x-Old-Stock-Rectifier-Valves-EZ81-U709-by-Mullard-GEC-Equiv-6CA4-M333-/203739566747 2 Link to comment Share on other sites More sharing options...
Volunteer El Tel Posted December 15, 2021 Volunteer Share Posted December 15, 2021 1 hour ago, xlr8or said: Group buy alert! Happy to contribute cash to any Melbourne or Geelong members' willingness to grab these for local pick up. https://www.ebay.com.au/itm/radio-valves-tubes-/363657286279 If I had a dollar for every pixel in those photos, I'd have $3.27... I tried zooming in to see if I could ID any 12AT7/12AX7 labels, but to no avail. It's the better part of 3hr30 return trip and probably half a tank of fuel. I'm wondering if it is worth chancing it. Great find, Kirk. Link to comment Share on other sites More sharing options...
Volunteer El Tel Posted December 16, 2021 Volunteer Share Posted December 16, 2021 So at 8am this morning, that job lot of tubes in Geelong was no longer listed with a BIN price, and when I just checked again, the listing has been removed. Urgh. Link to comment Share on other sites More sharing options...
Artnet Posted December 16, 2021 Share Posted December 16, 2021 6 minutes ago, El Tel said: So at 8am this morning, that job lot of tubes in Geelong Yep GOne, thought about this and put it on a watch list 13 hours ago, Jehuty said: I got my eyes on this...and I put a lot of money on my bid! Mmm, I am after one of these also. I might be beaten off by Santa's more needy helpers. I will look another time Link to comment Share on other sites More sharing options...
Thelastjedi Posted December 19, 2021 Share Posted December 19, 2021 Any recommendations for 6922 tubes? Need a quad set. Link to comment Share on other sites More sharing options...
Jehuty Posted December 20, 2021 Share Posted December 20, 2021 E88CC gold pins is direct substitute of 6922. I love my old stock Philips Heerlen ones. 2 Link to comment Share on other sites More sharing options...
Gryffles Posted December 20, 2021 Share Posted December 20, 2021 Ok so not the usual Hifi tubes but who’s got some Type 37 vacuum tubes floating around? I need a pair asap! Link to comment Share on other sites More sharing options...
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