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Post by Mr Trev on Dec 28, 2017 4:04:36 GMT
I was reading through a tube rolling thread for the Vali 2 and somebody mentioned using an adapter (https://www.ebay.co.uk/itm/1pc-Gold-plated-12AU7-12AT7-ECC82-TO-ECC88-6922-6DJ8-Tube-converter-adapter/192035120609) to run 12au7. Had me wondering… is this even a good idea?
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solderdude
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Post by solderdude on Dec 28, 2017 8:19:03 GMT
The 12V - 6V switch in G1217 basically is the same as using a 12V tube in a 6V socket via an adapter. On Bravo designs this might even work as well.
The difference between 6V and 12V tubes with the same type number behind it is only the heater winding arrangement. 12V noval tubes simply consist of 2x 6V heaters that can be used in series (12V) or 6V (in parallel). The adapter merely changes the series configuration (between pin 4 and 5) to a parrallel configuration between pin 4 and 5.
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Post by Mr Trev on Dec 28, 2017 17:02:43 GMT
Thanks, good to know. Thinking about buying an used Vali2 (sorry, I know that's probably sacrilege round here - please don't ban me ) and the one sticking point was losing the 12v tube option
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solderdude
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Post by solderdude on Dec 28, 2017 22:33:26 GMT
Everyone is free to buy and recommend anything they like on this forum.
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Post by Mr Trev on Dec 28, 2017 22:36:25 GMT
I know, I just forgot to use the joking smiley face
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Post by lobalwarming on Dec 29, 2017 22:55:35 GMT
I know, I just forgot to use the joking smiley face Although... you can be banned for not using the correct emoji at the correct moment. Good thing Ian is away filming the famous winter emoji migration in the south of Britain.
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Post by Mr Trev on Dec 31, 2017 20:50:29 GMT
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solderdude
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Post by solderdude on Dec 31, 2017 21:35:22 GMT
Might work ... no guarantees though.
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Post by Mr Trev on Dec 31, 2017 23:07:24 GMT
In theory would it work?
The 12au7 6.3v is the part throwing me off. Let's say the adapters haven't been filled with epoxy - the last one I bought wasn't - I'd assume it would be relatively easy to "correct" the wiring?
Or would I just be better off getting a 6sn7 to 6dj8 adapter in the first place
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solderdude
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Post by solderdude on Jan 1, 2018 1:06:56 GMT
the only difference between 6V and 12V is the heater arrangement. Both 6V and 12V tubes work on 6V. In 12V tubes there are 2 x 6V heaters in series. In 6V tubes there are 2 x 6V heaters in parallel.
The Vali2 ONLY accepts 6V heaters thus having 6V between pin 4 and 5
The 12AU7 is 6V when pin 4 and 5 are connected together and the other part of the heater is connected to pin 9.
The converter simply re-wires 12V tubes. '12V' heaters thus are now '6V'.
The 6SN7 tube converts to 12AU7. When that one is inserted into 12AU7 to 6922 the 6SN7 is converted to a 6922.
The same as a 6SN7 to 6DJ8/6922 converter but a lot higher as 2 adapters are needed.
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Post by Mr Trev on Jan 1, 2018 3:02:33 GMT
I think I'm following you, I wasn't entirely sure if the 6sn7 adapter was doing the rewiring or not (as well as the 12au7 adapter) - I guess a person really can't say for sure unless you open the adapters up
Judging by the pics I've seen, I'll need 2 adapters regardless. The socket is recessed inside the Vali2 and I'd need a way to extend it to use the 6sn7 (or make the hole in the case a lot bigger)
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Post by lobalwarming on Jan 1, 2018 4:01:12 GMT
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Post by ronzo56 on Jan 1, 2018 7:44:08 GMT
Or you could email Schiit support and ask them. They are usually very good answering questions.
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Post by Mr Trev on Jan 1, 2018 17:45:53 GMT
Indeed. That was the route I was originally going down. Then I realized that if I was going to get a 12au7 adapter anyways, that could double as a socket saver for me. The seller I was dealing with sent a link to a 6sn7 to 6de7 adapter. Does the 6de7 have the same pinout as a 6dj8 (damn alphabet soup names). Regarding the links you posted, I messaged that Xuling guy a week ago about combined shipping they they still haven't gotten back to me. Reading the feedback doesn't exactly make me want to deal with them anyways "buyer blindman! buy DC instead AC! Banned for life!" - bloody adapter nazi I've seen some pics of that twin adapter in the Vali2, but I'll have to repeat a question that was asked in that thread… does 2 tubes really sound better than 1? Of course I really should stop talking about buying adapters until I actually buy and get the amp
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Post by lobalwarming on Jan 1, 2018 21:49:37 GMT
Indeed. That was the route I was originally going down. Then I realized that if I was going to get a 12au7 adapter anyways, that could double as a socket saver for me. The seller I was dealing with sent a link to a 6sn7 to 6de7 adapter. Does the 6de7 have the same pinout as a 6dj8 (damn alphabet soup names). Regarding the links you posted, I messaged that Xuling guy a week ago about combined shipping they they still haven't gotten back to me. Reading the feedback doesn't exactly make me want to deal with them anyways "buyer blindman! buy DC instead AC! Banned for life!" - bloody adapter nazi I've seen some pics of that twin adapter in the Vali2, but I'll have to repeat a question that was asked in that thread… does 2 tubes really sound better than 1? Of course I really should stop talking about buying adapters until I actually buy and get the amp No, the 6DE7 doesn't have the same pinout as 6DJ8 - No soup for you! Never had a problem with Xuling - also never got a deal on shipping - but did get the adapters I wanted. To answer the 2 better than 1 question...the answer is...it depends. While technically the 6SN7 is two 6J5 plates in one bottle, it's difficult to find NOS stock with identical plates in both a 6J5 & 6SN7. So it depends on which exact pair of twins you compare to which exact 6SN7. I've found differences between the same make & model of 6SN7 with different batches. Which is how we roll. And why. In my small sample size, with my small mind and ears, a pair of 6P5 round plates impart a slightly larger, wider, more open soundstage than almost all 6SN7s ladder plates. Only the round plate 6SN7s offer similar breadth. In my rolls of vintage glass have found the 6SN7 tubes from the 40s to have a more open presentation compared to the versions from the 50s and later. The 6J5/6P5/12J5 from the 40s exhibit this phenomena as well. At a much lower cost than the 40s 6SN7s, like TS RP, Syl 6SN7W, VT-231. In the context of tube rolling, context is everything. Have a pair of JAN Raytheon 6J5s from the 50s that are really good compared to 6SN7s from the 50s, but not quite as captivating as good 6SN7s from the 40s. In terms of tonality, balance and other attributes, the comparison is like any other tube comparo - some aspects better with one (or two) than another. The 6P5 was the last evolution of 6J5, but most samples used the old round plate design from the Type 76 - the most linear audio tube of all time according to tubophile measurements. If you can find a good deal on a pair of NOS round plate 6P5s, you will have an excellent benchmark for other tubes in the 6SN7 family. It's a large and diverse family that loves to be adopted. The only consideration with running a pair of RFI antennas is there are two. In my RFI polluted environ, have to use a copper mesh RFI modesty screen around the twin towers of sonic glory. Which can diminish their visual glory a little. Or increase it in a grungy steam punk style.
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