- #41 [achow], 16-03-09 17:03
- #42 [4613], 16-03-18 12:02EML1605要用它有點頭痛.因輸出牛不好找.似乎訂造會是較理想.委託幫也造這對牛的朋友有這樣的看法,似手認為EML1605比300B(classic 300B tubes)更線性.
I checked the diagrams on their web site. I checked your operating conditions. This tube should be very linear and very good sounding. It seems to be much more linear than classic 300B tubes. Although 300B has more or less the same internal impedance, it requires much hogher load to perform in the most linear territories. However, this tube seems to be considerably more linear.
As a rule of thumb, I always try to follow the rule of 4x for loading any power tube and never stay below this factor. That means for a plate impedance of 860 Ohms, I would recommend a minimum load of 3.5kOhms. This would give something between 12 and 15 Watts of Class A1 power output to your speakers, it depends on the curves of this tube but cannot estimate with precision because I do not have the full curves. For sensitive speakers like your own ones, this power output capability is exceptionally good! If you would like to sacrifize some power output for increased sonic performance, we can go up to 5kOhms of impedance. You will lose a bit of power output for better handling of sound, as the output impedance of the power stage decreases and linearity of the loading conditions increases.
Minimum connection scheme is 4-8-16 ohms loading conditions and there are chances for even higher number of secondary options. This has to be studied after we decide the other parameters.
The specific core size will be able to handle up to 30 Watts of RMS power down to 20 Hz but you should not worry for this because this tube will not give this power output level. We can still accomodate lower power capabilities for even better sonics!!!
參考官方資料,EML1605與300B Plate Impedance很相近,然而我同意為初級取值為5k.5K比3.6K/3K/2.7K更好聲是有理據的!!
http://www.emissionlabs.com/datasheets/EML1605.htm
EML1605 factory data it:
Plate Impedance (Rp)
861Ohms
Manufacturer recommends:
Load Impedance (Ra)
2700-3600 Ohm
最後修改時間: 2016-03-18 12:03:00 - #43 [4613], 16-03-19 21:58EML1605 & EML AD1共用的佈局。
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- #44 [4613], 16-03-19 22:04一支現代胆,必需加入一些“毒素"才能满足聽慣了古董胆的耳朵。
那些霧氣是被熱加蒸化出來有毒的水銀氣。 - #45 [4613], 16-03-19 22:07這性感的蓝光隨着胆机的血管~電源,令整個係統充滿了毒。
- #46 [4613], 16-03-19 22:13計劃為這支胆的供電&推動級大致定案。
- #47 [michael@33], 16-03-21 10:41推動級選用德仔
- #48 [michael@33], 16-03-21 10:54Telefunken RE係列是靚到不得了的膽,是至今能找到放大線性最靚的膽.例如RE084是希特拉指定為他演說用麥克風放大器的指定配置.
可惜!
只有DIY才會享用.
推動級比功率級更重要!我不願意用6SN7這類失真高的管,更不會用12AX7,5687這些線性差的花生膽.
最後修改時間: 2016-03-21 10:57:38 - #49 [schmike], 16-03-21 11:04點睇到線性差同好呢michael兄
分享下 - #50 [michael@33], 16-03-21 11:51這Emission Lab官綱己有論述.更指出了DHT推DHT的神奇之處:
http://emissionlabs.com/datasheets/EML20B.htm
The 20A, 20B and 30A tubes are based on a very old principle, where high gain tubes have much wider plate distance. This is still the ultimate way to make a very linear DHT high gain tube. Miniaturization has always been the enemy of tube linearity, specially with DHT. The 20A/20B/30A will outdo any small size tube. We encourage you to check the tube curves of any miniature tube, like 6SN7, ECC88 or ECC82, and you will see this series presented here is much superior. However this results of larger dimension tubes is a higher working voltage. For this reason, tubes like this were not made any more after 1935, when miniaturization of tubes started to become more important. With the new production tubes we make today, miniaturization is no requirement. So for high gain tubes, we can now focus on lowest possible distortion. We build these tubes again the original way, with wide plates. Check plate picture here.
This tube is one of the lowest distortion tubes ever build. Total distortion for small signal has been measured below 0,08% at 10 Volt Eff output signal, 400V plate. The distortion will almost not increase at higher signal. (See Note5) . Interestingly, when one DHT triode is driving another, a part of the distortion of the second tube will be eliminated by the first tube. This even harmonics cancellation appears only with triodes, and they must be similar tubes, like drive a 300B with one of the tubes of this series. Since Triodes produce very low uneven harmonics, canceling the overall distortion this way, is an amazing application of the 20B or 30B tube. (See note 4) - #51 [michael@33], 16-03-21 11:55http://emissionlabs.com/datasheets/EML20B.htm#note4
在Note 4.更能啓發我選用DHT drive DHT的考慮.
Note 4) Theoretically, distortion of two tube stages in series, are eliminated provided both tubes produce only even harmonics, and produce the same percentage of even harmonics for each frequency at each signal level. This can be demonstrated indeed with two triodes of the same type, and the same electrical circuit, and the first stage has adjustable bias. You will find one specific bias point where the second harmonic is cancelled out almost completely, at one specific signal level. Since the third harmonic is of very low content with DHT triodes, what is left is a very small fraction of 4th harmonics, even so cancelled very much. The result will be zero 2nd harmonics, the normal level of 3rd harmonics, though very low with triodes anyway, much reduced 4th harmonics, whereas 5th harmonics and higher are not present e any more. In a practical set up, you can use the 20A or 30A for this, and choose the bias point of this tube for best results with the end stage tube chosen. Ultimate results will be achieved with 20A driving the 20B as output tube. This needs no further pre amp tube, so two tubes make the complete amplifier. However also with 20A combines with 300B or similar will make a perfect combination since 20A curves are exceptionally linear, with resemblance to 300B tubes. This method of distortion elimination method has first been described by Ratheiser, in the four-books tube manual. This is a "standard about tubes and circuits theory, only available in German language. Also this method is described in the book "Verstaerker in Roehrentechnik" by Rainer zur Linde ISBN nr: 3-928051-02-4, also only available in German. The Japanese designer SAKUMA has published a great variety of circuits, based on this principle, even driving 211 tubes with another 211. - #52 [michael@33], 16-03-21 12:24原本打算選用同是Telefunken的大花生管,因為它易於匹配手頭上己有的5K:5k insterge,傍熱6.3v燈絲又易搞.但全直熱三極是具更大魔力.終於令我放棄EC8020 5K:5K IST推動級方案.
最後修改時間: 2016-03-21 12:25:25 - #53 [michael@33], 16-03-25 12:36決定用佢d牛
- #54 [sp11], 16-03-26 00:12以色列牛?
- #55 [sp11], 16-03-26 00:38#51
看完報告後對20A mesh產生興趣⋯⋯但支膽似乎太大! - #56 [michael@33], 16-03-27 11:14以色列牛?
不是呀.是另一位.他曾在香港工作過.本地一些發燒友也識得佢.
5K:0/4/6/8/16 Output在製作中.
Hello Michael. Today I hope that I will have finished the 1st piece. Look at the paper fibers coming out between the pri turns. This is totally handmade thing :-) - #57 [michael@33], 16-03-27 11:39EML 20A Mesh係好正的推動管,推動級靚,功率多則不會出差的聲.
個人認為使用它,給它一組獨立供電較為好.因它需要20多ma流工作.我也曾考慮過用佢. - #58 [schmike], 16-03-27 13:15真夠發燒
本地試牛王非米高兄莫屬 - #59 [4613], 16-03-31 20:45之前用於300B,px25的牛牛因只能使用於90ma電流之內,需然很喜歡它的音效,但無理浪費1605支胆。
- #60 [4613], 16-03-31 20:47可能係發燒過度,傻左,将D大廠有名的牛牛出售套現,到頭來還是用土炮牛.
它造好了,等運到。
最後修改時間: 2016-03-31 20:51:43 - 下一頁 (3 of 8)
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