Update. Just tried the Takatsuki 274B on my GG DAC over the weekend. The Elrog 300B and Takatsuki 274B tubes are match made in heaven in the GG. Expensive as hell for these tubes, but the best sound I've heard from the GG DAC by far. I've tried Psvane 101D, EML 45 mesh plate, and TJ Full Music 300B SE output tubes with Psvane 274B replica, Brimar 5Z4GY, Sophia Electric Princess Rigid Plate 274B, and EML 5U4 rectifiers with the GG.
The Takatsuki 274B is the best built and most immaculate rectifier tube I've ever seen. It exudes quality, as it should for a $800 tube. It looked like it came from a silicon wafer chip manufacturing facility. |
Dmarkov, I will keep posting. I have EML 45 and RU4, Psvane 101D and 274B replicas, TJ Full Music 300B SE, Elrog 300, and Brimar 5Z4ZY. I have the Takatsuki 273 on the way. |
Based on my experience with 2 different pairs of Elrog ER 300bs, break-in is fairly rapid. In my system they were indeed excellent brand new. I'd say 50 hours and they're pretty much burned in. Joe(Snowpro) yes, as excellent as the Takatsuki sounds, the Elrog is fuller and has superior harmonic and tonal richness. The preference could certainly vary I imagine in a different amplifier/system.
Charles, |
Dmarkov, I will keep posting. I have EML 45 and RU4, Psvane 101D and 274B replicas, TJ Full Music 300B SE, Elrog 300, and Brimar 5Z4ZY. I have the Takatsuki 273 on the way. |
Hi Dmarkov,
I have my Taks almost 2 years. They are well broken in and the Elrogs had less then 100 hrs.
They are both excellent tubes. The Elrogs give me a little more body to instruments, which I like. |
Dracule1, please keep us updated on Elrog in Lampizator Golden Gate! Did you have a junior model Lampi before?
My Lampi came with EML 45 Mesh.
I might try PSVANE WE 101D replica on it and Takatsuki but this will not be any time soon, need extensive burn in on them all to be meaningful.
I am also with you on passive preamps :) I used to have several, from resistor based attenuators which depended too much on impedance matching and cables to many transformer based volume controls which were so much better in sound and so much easier in matching. I now use either Coincident Line Stage with transformer volume control or Kondo active pre but I still have a current model of Django TVC with Silk Audio transformers. |
Snopro, how many hours did you have on both pair of tubes when you compared them?
The reason I am asking is that it's crucial.
Takatsuki requires 150 hours of burn in. 100 hours minimum from my own experience with many pairs of these tubes in various systems. Until 100 hours they could be a hit or miss. When they are fresh they can even sound like 200 dollar tubes, nothing special. I'd say 150 hours is a must for any critical listening or comparison to other tubes.
I've asked about Elrog's burn time previously but I don't have an answer at the moment. Several people reported they sound good right from the start. But from all my experience with various 300B tubes all of them require burn in. PSVANE T2 requires 300 hours before critical listening or comparison to other tubes, Takatsuki - 150 hours. Elrogs probably some time as well. TJ Full Music SE may sound nothing special until 60-70 hours but full break in is longer. I don't believe Elrog has 0 hours to be broken in. I would give it 150 hours to be fair.
Also, amps that have manual bias, like one of my amps, should be biased for any new tube installed otherwise sound comparison doesn't make sense.
|
I have addressed the over voltages and under voltages of my incoming power by using a PS Audio P-10 regenerator. I think it's a great thing. In my area, the power was measuring anywhere from 116v to 124v. I'm not associated with PS Audio in any way but the P-10 really works well. |
Thanks again, Jet. And kudos for the prudence and thoroughness that is evident in your approaches.
Best regards,
-- Al
|
Al - yes I installed a 100ohm resistor on one leg of the primary side of the filament transformer. And I did not change that value when changing from Eml to Sophia.
My vintage Stancor filament transformers are rated for 117v.
These trannies have a center tap so I can bias through it and avoid a bad sounding hum pot and still use a/c heat. I have no 60hz hum but if I put my ear to the speaker I hear what I believe to be a harmonic of 60hz which is 120hz. At least that is what I think I am hearing. The ELM tubes are so well balance a hum pot was not needed. But I was not so lucky with the Sophia which I could not use with out installing a hum pot.
When I removed those hum pots this amplifier came to life.
I would not feel comfortable running these tubes much above 1% which is 5.05v. |
P.S: A sharp-eyed reader may notice that at one point in my post just above I kind of juxtaposed EML's +/-5% tolerance with the 5.06 volt measurement Jet provided for the Sophia tube. I'm assuming that had Sophia provided a +/- tolerance on the 5 volt supply, the number would have been similar to EML's.
Best regards,
-- Al
|
Thanks very much for providing that info, Jet. I've done some fairly lengthy calculations based on it, the results of which are listed below. These results assume (as I would expect) that the dropping resistor you mentioned is on the primary side of the transformer, that its setting wasn't changed during these measurements, and that the tubes were reasonably warmed up for the measurements. The results of my calculations are as follows:
Filament winding impedance at 60 Hz (which I would expect to be not greatly different than its DC resistance): 0.33 ohms.
Open circuit output voltage of the filament winding (i.e., the voltage it would put out if zero current were drawn from it): 5.46 volts.
The 0.33 ohms is just a bit higher than the 0.25 ohm spec I had mentioned for one of the MIL spec transformers for which I found specs, that transformer being reasonably comparable in terms of its voltage and current ratings.
I note that in contrast to most manufacturers EML actually indicates a tolerance on the 5 volt filament specification of their 300B-XLS, that being +/- 5%. Kudos to EML for providing that. Although I still wouldn't count on prolonged use of the tube at or near the upper limit of that tolerance to not result in some degradation of MTBF (long-term reliability).
5.06/5.00 is an increase of about 1.2%, which seems very comfortable, at least in terms of reliability if not sonics. But I suspect that you have done a very wise thing in using a dropping resistor to correct for your relatively high (although certainly not uncommonly high) line voltage. Even if the transformer is designed for an input of 120 volts, as opposed to say 117 volts, 124/120 is a 3.3% increase all by itself. And the MIL specs I looked at generally indicated transformer tolerances of +/-2% or more. The sum of those two deviations, if not corrected for as you have done, would already exceed EML's 5% tolerance recommendation if the deviation in the transformer happens to be in the upper half of its +/-2% range.
Turning to rectifiers, for a 3 amp tube obviously a winding having a somewhat heftier rating than the 3 amp rating of the one you are using for the 300B would be used, so chances are its resistance would be a bit less than the 0.33 ohms. Let's say 0.25 ohms, the rating of one of the MIL spec transformers I looked at. Substituting a 2 amp tube would result in a voltage increase, relative to use of a 3 amp tube, of 0.25 ohms x 1 amp = 0.25 volts = 5%, which does not take into account line voltage variations, transformer turns ratio tolerances, and other factors that could further increase the voltage applied to the tube. Not an immediate disaster by any means, but certainly undesirable and a cause for significant concern over the long-term.
Thanks again. And I hope that some of those reading this thread will find this analysis to be helpful. Best regards,
-- Al
|
Al-
when I got home this evening I measured my Brooklyn line voltage with my fluke meter and got 124v which is more or less normal. My EML300b XLS filaments measured 4.97v and my Sophia mesh measured 5.06v. That's about a 2% increase. I am using 5v filament transformers that are over spec. They are rated at 3amps. |
Thanks very much, Jet. Could you give us a rough idea of the magnitude of these voltage changes that you see in your particular amp?
I did a few minutes of research trying to find specs on the resistances of filament windings of transformers that would be used in these kinds of applications, and came up pretty much empty. It is surprising that such specs aren't commonly provided, which makes it hard to pin down the issues being discussed in any kind of quantitative manner. Which opens the door to speculation and differences of opinion.
Not to mention that it seems highly unlikely that data would be available for the particular tubes being discussed, or most other tubes for that matter, which would quantitatively indicate how their MTBF (mean time between failure) varies as a function of filament current, among other application dependent variables.
In fact the only conceivably relevant data I was able to find was for some military grade 60 Hz filament transformers specified in MIL-PRF-27 and its associated documents. For transformers intended for applications that are roughly similar in terms of voltage and current those documents generally indicated filament resistances in the area of 0.1 to 0.25 ohms. Which seems reasonably small **IF** the transformer and its turns ratio are chosen by the designer based on a loading assumption that is at least roughly in the general ballpark of the actual load.
Best regards,
-- Al
|
I have measured this in my amp. Since my EML 300b XLS filaments draw 1.5 amps I have to adjust the dropping resistors so I still get 5 volts because voltage gets pulled below 5 volts. Other 300b tubes that draw 1.2 amps makes the voltage rise above 5 volts making me re adjust the dropping resistors. It's ohms law in practice. I heat my filaments with a/c. Jet |
It occurs to me that I should perhaps add some clarification to Matthias' statement I referred to just above, which I quoted in my first post of yesterday. That statement was: If an EML 300B XLS is the right choice we have 1.5A heater current at 5V. There is no voltage regulation. A transformer a rectifier bridge and a CLC only. May be the XLS is underheated (so I hope) ore all other (right) 300B are overheated, because they draw 1.2A (some russians and chinese 1.25A)only. This would result a heater voltage above 5V...not so good for any 300B and very bad for an Elrog 300B, because the use of thoriated tungsten for filaments. Higher heater voltage will result a (much) higher anode current and a much lower lifetime... What he is saying is that if the power transformer's filament winding is designed to provide exactly 5 volts to a 300B which draws 1.5 amps, if a different 300B which draws 1.2 amps is substituted the voltage applied to that 300B will be higher than 5 volts, to a degree that might be harmful over time. The reason for that increase in voltage is that the reduced current draw will result in a reduction in the voltage that is dropped across the resistance of the filament winding. Note also that he is referring to a difference in current draw of only 0.3 amps. In principle similar considerations may come into play when a rectifier rated at 2 amps is substituted for one rated at 3 amps. However I suspect that the sensitivity to filament voltage increases of the rectifiers being discussed is considerably less than the corresponding sensitivity of a 300B. Best regards, -- Al |
Thanks, George. I don't doubt that what you are saying is correct in most and perhaps nearly all cases. But without knowing the DC resistance or low frequency impedance of the filament winding of the particular transformer (which would enable calculation of the voltage that is dropped across it for a given current draw), and perhaps also the +/- tolerance on the transformer's turns ratio, I'm not certain we can say that for sure. Although I will state that I don't have a particular feel for what those numbers are likely to be for the kinds of power transformers that are used in audio components such as these. Again, see the statement by Matthias of Elrog that I quoted in my first post dated yesterday (10-28-15). 10-28-15: Dracule1
So as far as Elrog 300B in Lampizator Golden Gate DAC is concerned, a rectifier that draws 2A/5V is fine (assuming GG DAC has a separate 3A winding for rectifier tube)?
10-29-15: Dracule1
Based on what George just said, I suppose the answer to my question is a yes. Yes, certainly as far as the 300B is concerned, given George's point about the separate filament windings. And most likely as far as the rectifier is concerned, although per my comments above I for one am not sure we can say that with certainty. FWIW, IMO, etc. Best regards, -- Al |
Based on what George just said, I suppose the answer to my question is a yes. |
Al,
If you have 200 amp service in your home, do you use all of the current that your electrical service box offers? Of course not. It's there to insure capacity. Also, many 5 volt filament transformers for output tubes provide in excess of the 1 1/4 amps that a traditional 300b tube will draw.
Right now I happen to be looking at a Hashimoto power transformer that has a 5 volt/3 amp winding for each channel of a 300b amplifier. The tube doesn't need that amount of current, but will function just fine connected to it. The output tube draws what it needs from the current reservoir. The same goes for a rectifier tube. With rectifier tubes, you control the amount of B+ you have in your circuit by deciding on your choice of rectifier tubes.
Many people talk about how one rectifier tube sounds over another, but the real reason for this is the amount of B+ that has been added(or reduced)into the equation. This causes the output tube to work at a higher or lower anode voltage and that of course will influence the sound of what is being heard. Hope this helps.
Best,
George |
Yes, thanks for chiming in, George. After thinking about your comment I agree -- the 5 volt winding for the directly heated 300B and the 5 volt winding for the rectifier must be separate, or the circuits wouldn't work properly. Thanks for pointing that out.
I'm still a bit uncertain, though, that it would necessarily/always be appropriate, with respect to long-term reliability, to use a 2 amp rectifier on a winding that is designed with the expectation that it would be used with a 3 amp rectifier. My concern, as I mentioned earlier, being that the filament voltage provided to the rectifier would increase to some unknown degree compared to the voltage that would be provided to a 3 amp tube, due to the lighter loading on the winding.
Thanks again. Best regards,
-- Al
|
Hi George thanks for chiming in. So as far as Elrog 300B in Lampizator Golden Gate DAC is concerned, a rectifier that draws 2A/5V is fine (assuming GG DAC has a separate 3A winding for rectifier tube)? |
|
Hello Al,
A directly heated triode requires it's own dedicated filament winding unlike an indirectly heated triode. If you look at the bottom of a power transformer(not a plate transformer mind you)you will see individual windings for the output, signal & rectifier tubes. Indirectly heated driver tubes such as the 6sn7,6sl7 etc can share a 6,3v/2 amp winding. Of course the rectifier tube has it's own winding as well. It's typically 5v/3a.
You can use a 5v/2a tube on a 3 amp winding, but you can't use a 5u4g on a 5v/2a winding. Since this thread is largely about the "Franks", lets try to keep in mind that these two circuits are completely different from one another, and that we don't have a "one size fits all" situation here. Hope this sheds some light up here.
Best,
George |
Hi Bill,
The upshot of my previous post is that if no one participating here has already done so I suggest that one of the Lampi users ask Lampi if each of the various rectifiers that have been discussed is suitable for use in the Big 7 and the GG. And that Lampi also be asked if the filaments of the output tubes and the rectifier tube in those DACs are supplied by the SAME 5 volt output winding of the power transformer. As opposed to the filaments of those tubes being supplied by separate 5 volt windings in the power transformer.
If the answer to the latter question is "yes" I would recommend against using a rectifier tube having less than a 2.4 amp filament current at the same time as an Elrog 300B is being used. If the answer to the latter question cannot be obtained, I would suggest that there is a non-zero risk in doing so.
Best regards,
-- Al
|
Sorry Al, That was a CV378. It is a British Military 5U4. Thanks for the info and the assurance on my rectifiers. Someday, I'm going to have to go a little deeper than Ohms law. As for your response to Dracule, it is a little like trying to read German. I understand about half of what you wrote. |
10-27-15: Dracule1
Thanks Al. I got the distinct impression from George at TubesUSA to stay away from rectifier tubes that draws more than 2 amps. The list of rectifiers recommended by George for the Elrog 300Bs I think draw no more than around 2 amps (5R4, 5R4GY, GZ34 and GZ37). I'm afraid to try my EML 5U4 (3 amps) with my Elrogs. The 5R4 tubes and the GZ34 are approximately 2 amps, although the GZ37 is about 2.8 amps. I’d question whether George really meant to indicate that you should stay away from tubes drawing significantly more than 2 amps, given that all of the tube choices Lampi supplies with the Big 7 are around 3 amps, and the choices provided with the GG are 2.4 and 3 amps. And if he did really mean that, I would want to know what his reasoning is. The 2 amp draw of the Takatsuki you are using will result in some increase in the voltage supplied to the filament of that tube, relative to the voltage that would be supplied if the tube were drawing a higher current, due to the lighter loading of the 5 volt winding of the power transformer. Matthias of Elrog made exactly that point, although in connection with a 300B used in a power amp rather than a rectifier used in a DAC, in a post in this thread dated 6-19-15 when he said: If an EML 300B XLS is the right choice we have 1.5A heater current at 5V. There is no voltage regulation. A transformer a rectifier bridge and a CLC only. May be the XLS is underheated (so I hope) ore all other (right) 300B are overheated, because they draw 1.2A (some russians and chinese 1.25A)only. This would result a heater voltage above 5V...not so good for any 300B and very bad for an Elrog 300B, because the use of thoriated tungsten for filaments. Higher heater voltage will result a (much) higher anode current and a much lower lifetime... Now that increase in filament voltage in this case might be small enough to not matter, or it may not be. We have no way of knowing, and I’m not sure that George does either, with respect to the specific design of the Lampi. And given that a 300B and these rectifiers both have 5 volt filaments, perhaps the design even utilizes the same transformer winding to power both, which would result in the 300B seeing more than the 5 volts it is designed for. That suspicion is heightened by the indication you provided that the Lampi applies AC to the filament of the 300B. So regarding your statement that "I'm afraid to try my EML 5U4 (3 amps) with my Elrogs," it seems very conceivable to me that using a rectifier having a 2 amp filament current draw might be more stressful to the Elrog than one having a 3 amp draw. Especially given the very high 600 volt plate rating of the Elrog tube, which together with Matthias' statement quoted above would seem to indicate that it is more vulnerable to a filament voltage increase than to a B+ voltage increase that might result from a rectifier change. There are undoubtedly other significant differences in the electrical parameters of these various tubes, which I haven’t taken the time to study and which don’t seem to be available in all cases. But I would certainly expect that between those differences and differences in the value of the filament voltage resulting from differing current draws there would be significant differences in the DC voltages supplied by the rectifier circuit to the rest of the DAC, including the output tube. Which can certainly be expected to result in sonic differences, for better or worse, even apart from differences in the intrinsic sonic characters of the tubes. But not having knowledge of the specific designs we have no way of knowing what the long-term effects on reliability might be. As I said earlier, changing a rectifier to one that draws significantly different filament current than the one the unit is supplied with amounts to incorporating a design change into the unit. As an electronic circuit designer (not for audio), it goes against my grain to implement a design change without having either a means of understanding its ramifications, or an ok from the designer or some other source having specific knowledge of the design. Bill (Brownsfan), it looks like the CV387 is a small pentode, so you may have mis-typed that number. Otherwise, though, given that I see on Brent Jessee’s site that the VU-71 is equivalent to the 5U4GB, and given the rest of the facts stated in your post, including operation at a lowish line voltage, I don’t see that you have any issues. Enjoy! Best regards, --Al |
Dracule and Al Here we go again! I pasted in below a comment from page 6 of this thread from Matthias regarding AC voltage and Elrog life. Now, I am hearing that there is another issue, i.e. filament current. The 5U4, 5U4GB, CV387 tubes recommended for the Frankensteins, in addition to my beloved VU-71s, all have a filament current of 3A. The communication from Matthias below indicates that what is required is selecting Elrogs that are appropriate for the operating requirements of a given amp. I have such a pair. In addition, I am regulating the incoming voltage at 115 V using a PS audio P10. I have detected no erosion of sound quality vs regulating at 120 V. I assumed that given all of this, I should be in good shape with my Elrogs. Comments?
07-07-15: Mk_
Hello,
Thanks to snopro for his efforts on this topic...I received the results a day earlier ;-)
By my oppinion a variac is not needed. As can be seen all the measured tubes are having a little bit different operating conditions. All they are 300B fitting the WE300B datasheet (more or less) wthin the tolerances...The Takasuki's running a little "hotter" and the Psvanes a little "cooler". This is the effect of the deviations of real tube data...(against the design center values/plate curves in datasheet)
So the task is very simple. We have to select the "right" pairs of ER300B fitting to the operating conditions of the Franks (or any other amp whose conditions are known) in all cases(+10% or -10% main voltage) with a small safty margin.
A smart dealer like Gorge should be able to affairs which.
No variac is needed nor any changes in the amp...We only need to know the type of amplifier, so we can deliver the fitting tubes. (This way will improve the sound quality too.)
Regards, Matthias
Mk_ (Answers | This Thread) |
Thanks Al. I got the distinct impression from George at TubesUSA to stay away from rectifier tubes that draws more than 2 amps. The list of rectifiers recommended by George for the Elrog 300Bs I think draw no more than around 2 amps (5R4, 5R4GY, GZ34 and GZ37). I'm afraid to try my EML 5U4 (3 amps) with my Elrogs. |
Charles1dad, for awhile I thought I had a bad set. I've gone direct to amp before with mixed results, but mostly positive. The Elrogs seem to be very sensitive tubes on many levels. But Elrogs in the GG DAC seem to have one of the most dramatic change in sound going direct to amp. |
Wyan, thanks for reminding me. I forgot it was you in the other forum. |
As a point of information, the Big 7 is indicated at the Lampi site as being supplied with one of the following rectifiers. I've determined the filament currents listed for each tube from datasheets that can be found elsewhere on the web:
5C3S (filament current 3 amps +/- 10%)
Shuguang 274B (filament current 3 amps)
(Optional) EML 5U4G (filament current 3 amps)
Other tubes mentioned in Wyan's post just above:
5Z4 (filament current 2 amps)
Cossor 53KU (filament current apparently 2.8 to 3 amps)
WE 422a (filament current 3 amps)
WE 274A/B (filament current 2 amps)
Takatsuki 274B (filament current 2 amps)
Hope that helps. Regards,
-- Al
|
Dracule1,
I'm glad that you are able to finally appreciate the excellence of these Elrog tubes. |
Hi, Dracule1, we pm'ed about rectifier at another forum (I was not able to registered for the same user name). Anyhow, 5z4gy -> Cossor 53KU / WE422a -> WE274A/B & Takatsuki 274B. I am now using Takatsuki 274B and like it. No chance to compare it with WE's though. |
Thanks Wyan. BTW, what rectifier tube did you use in the Lampi with the Elrogs? |
Hi, Dracule1,
I am glad it works out for you. I totally understand your absence. :p
Elrogs produce the lowest sound floor on Lampi compared to other tubes. And thus the details and transparency. Like I said, you don't even have to a/b to hear the difference from 101D. Go out for a long trip, come back and plug in 101D instead and you immediately realize. I don't have golden ears but it was just so obvious.
I really really hope that they will give you a long long period of musical enjoyment. |
Hi Wyan, sorry for the delay. I was listening to my music through the Elrogs. I connected the GG DAC directly to my amp, bypassing my LDR passive preamp. When I did this, there was dramatic improvement in sound. I start hearing all the accolades this tube was known for. The highs were extended, clear, and dynamic. I am hearing fine detail that was absent before. The midrange is much clearer with more emotion. I can hear subtle inflections in voice and instruments that was not apparent before. It is the most transparent tube I have now. The bass now has speed and impact. However, it is not as exended as with the LDR preamp in place. Overall, 90% of the sound was markedly improved. Just goes to show you how impedance mismatch can affect the sound. Interestingly, the Psvane 101D and TJ FM 300B SE sound fine with the LDR preamp. They have none of the issues I experienced with the Elrogs. But I haven't tried them without the LDR preamp yet. |
Correction. Apparently George at TubeUSA misheard me when I asked him about the 5AR4. He thought I said 5AU4, which draws 4 amps. As Al has pointed out, the 5AR4 draws 2 amps. |
10-27-15: Dracule1
Thanks Al, for the detailed explanation. Can you point out where on the lampizator site it states the rectifier filament current needs to between 2.4 to 3.0 amps? I'm currently using the Psvane 274B replica tube. Does this tube have filament current in the correct specified range? You're welcome, Dracule. But I didn't say that the site specifies 2.4 to 3 amps. What I said is that the site indicates that the GG is supplied with either the EML 5U4 or the EML 274B. And I said that since those tubes have filament current ratings of 3 amps and 2.4 amps respectively, as can be seen at the emissionlabs.com site, without an ok from Lampi I would be hesitant to substitute a tube having a filament current rating significantly outside of that range. As I see it, doing so would amount to incorporating a design change into the DAC, without any means of knowing what its ramifications may be, in terms of long-term reliability as well as sonics. I couldn't find a datasheet on the Psvane 274B. FWIW, though, the original Western Electric tube that it is intended to emulate was rated at 2.0 amps, although I wouldn't necessarily assume that the Psvane version is the same. Regards, -- Al |
Hello, Dracule1, have you solved the issue? What is your impression of the sound?
I am eager to know, since I hope that they don't alter the tube too much for longer use, at the cost of sound. Like I said, I really miss them on my Lampi. :) |
Thanks Al, for the detailed explanation. Can you point out where on the lampizator site it states the rectifier filament current needs to between 2.4 to 3.0 amps? I'm currently using the Psvane 274B replica tube. Does this tube have filament current in the correct specified range? |
I'm so happy! I found the problem. |
While I'm hesitant to question George's recommendations, FWIW I don't understand some of them. According to my documentation and my understanding, the 5AR4 (which he advises against) is two-way interchangeable with, and therefore very similar to, the GZ34 and the GZ37 (which he suggests trying). Also, the filament current drawn by the 5AR4, at least in its vintage incarnations, is 1.9 amps, not 4 amps as stated. 1.9 amps being substantially LESS than the draw of the EML versions of the 5U4 and 274B that are supplied by Lampi according to its website, as well as the filament draw of the vintage versions of those tubes. It is also slightly less than the 2.0 amp filament draw of the 5Z4 and 5R4.
Although if the filament current drawn by the tube is too low, as well as too high, problems can result. If it is significantly too low relative to what was anticipated in the design it could conceivably result in the filament voltage that is applied to the tube being high enough to shorten its life.
If it were me, without an ok from Lampi, either directly or via some indication on its website, I would be hesitant to use a rectifier whose filament current is significantly outside of the range of 2.4 to 3.0 amps, those being the ratings of the EML tubes the Lampi site indicates they supply. Are 1.9 and 2.0 amps "significantly outside" of that range? Not having knowledge of the specifics of the design, I don't know.
Good luck. Regards,
-- Al
|
My amp has input impedance of 100 kOms and has built in stepped attenuator. I'm going to try hooking my GG DAC directly into the amp bypassing my passive preamp. In some situations, this can dramatically improve the sound. I also spoke toe George a TubesUSA. He recommended trying different types of rectifier tubes including 5R4, 5R4GY, GZ34 and GZ37. He told me to stay away from 5AR4 which draws 4 amps and is too much. I'm currently using the Psvane 274B replica. I also have the EML 5UG that came with DAC which I haven't tried with the Elrogs. I also have a Brimar 5Z4GY coming soon. It was recommended by a fellow Audiogoner who used it in the Lampizator. |
Stefan,
So far my replacement Elrogs are working fine(few months) in my amplifier. More time is needed to make any declarations regarding longevity/reliability. I'm hopeful. |
first time poster here....
I own a Lite7 since a few months. I had the 101d WE and more recently the Elroy 300b. the elrogs were my preference ... much fuller sound!
two weeks ago one of the elrogs failed ... I sent them back and now the dealer is hesitant to send me a replacement pair as long as he doesn't know what's going on. he would prefer to give me the money back ...
so here are a few questions for those of you who experienced failures with elrog tubes:
were there any problems with replacement tubes?
any replacements died?
any known causes that lead to failure?
date of production of the replacement tubes?
any information welcome
cheers!
stefan |
10-25-15: Charles1dad
Hi Al,
Good point, but interestingly Wyan001 and Germanboxers use the same DAC with superb results. Thanks for pointing that out, Charles. In looking at the Lampi site, though, I see that Dracule's GG is described as having a choke (i.e., an inductor) as the plate/anode load for the output tube, while the Big 7 which the other two gentlemen have been using is described as using a resistor. I don't know if that might account for any difference in how the Elrog performs in the two designs, but it suggests that it could conceivably be a possibility. 10-26-15: Dracule1
System synergy is a possibility. I use a Tortuga Audio passive LDR preamp. May there's an impedance mismatch? Tortuga has a new software upgrade so you can vary the impedance of the preamp, which I don't have. May its time to upgrade and see if this will improve the sound. There isn't enough information at the Lampi site to be able to say for sure, such as an output impedance spec, but I'd be surprised if there was an impedance compatibility issue here. It appears that all of the currently produced Tortuga passive preamps have input impedances of around 20K or more, regardless of the attenuation setting, which, given that it uses LDRs, figures to be essentially constant as a function of frequency. I'd be surprised if the Lampi's performance would be compromised by such a load. And while the input impedance of your amplifier will reduce the 20K somewhat, depending on the attenuation setting, since you are using a passive preamp I assume the input impedance of the amp is high and will therefore not have a large effect on the impedance seen "looking into" the preamp. On the other hand, though, it appears that the 300B or other output tube that may be used in the GG & Big 7 is used in an anode follower/plate follower configuration, which leaves me a little bit less certain about impedance compatibility than I would be if it were a cathode follower that would undoubtedly have low output impedance. Best regards, -- Al |
Dracule, This is odd. Your findings are so different from Wyan, who also had the opportunity to evaluate both the Elrogs and the Psvane 101D WE replicas. He had a strong preference for the Elrogs in his Lampi. I know the Psvanes from using them in my Coincident CSL, and they are very good tubes. Highly resolving with excellent tonality. It is possible you just like their sound better, or they do match your system better. I will say this, when my first set of Elrogs began to go bad, their sound was nothing special to say the least. I can't rule out that you have a couple tubes that are not up to snuff. |
System synergy is a possibility. I use a Tortuga Audio passive LDR preamp. May there's an impedance mismatch? Tortuga has a new software upgrade so you can vary the impedance of the preamp, which I don't have. May its time to upgrade and see if this will improve the sound.
I don't doubt the Elrog owners who heard improvements with this tube. |
Dracule1,
Sorry for the bad news. Elrogs are supposed to be great even without breaking in. And their sound signature doesn't change much during burnt-in process.
I am not sure if Elrog change the formula a little bit and cause the difference.
WYAN |
Hi Al,
Good point, but interestingly Wyan001 and Germanboxers use the same DAC with superb results. Could system synergy partially explain it? |
