Elrog 300B vs Takatsuki 300B tubes
Hi Rob, You can use ER300B in the AN Kit-1 without problems... Because it's a kit I think You should have minimum skills at soldering and assambling. Thats why i suggest to add an additional resistor of 100Ohms(min 2W) between the paralled 1.5k Kathode resistors and the heater pin, so You get 850Ohms cathode resistor at all...resulting more gentle operating conditions. Best regards, Matthias |
Hi Robert (Rwanda), I could not find schematics of the Cary 300 SEI...But the description says 15W(!!!) watt per chanel (out of ONE 300B!). May be, they use class A2 conditions (driving the tubes to positive grid voltage) or they use the absolute maximum operating conditions (450V/80mA) to get this 15W... If this amps have a bias control and You can regulate the bias to 70-80mA, ER300B could be used successful. But I can not suggest this at the moment. Best regards, Matthias |
MK, Thank you so much for your input. You are a positive influence on the Agon, please keep coming back with your valuable input. We all welcome your knowledgable suggestions. We also all need to encourage folks like yourself and Elrog as a company to seek higher levels of advancement in audio. It is great that a modern tube can best NOS. all the best. Rob |
Hi Fla, I have read the article in 6moons and the description on the manufacturer's site. Very nice amp with a lot of effort in details (huge capacitors in HV supply, dedicated heater supplies for each output tube, smart solution for changing the gain, switchable output impedances from 2 to 16ohms). Very gentle operating conditions...30W dissipation per output tube only...So "Globe Mesh Type" 300B can be used. This tubes don't like stress also. This amp was build for ER300B ;-) For best results You should order a matched Quad. Best regards, Matthias |
This makes buying any amp and not just the franks super important that one knows the actual operating points of that amp so when it comes time to buy tubes one can do so with confidence. Also know the current draw of the tube one is buying and confer with the builder that all will be well when using that tube. High quality output tubes are so expensive this research is necessary and when both tube and amp manufacturer agree that a tube is safe to use one has mitigated one's risk. |
Ok, George from Tubes,USA came by Friday and took the measurements. He requested I hold off this information until he lets Elrog know his findings, which I will honor. I'll let everyone know sometime this week. First he tested all the tubes on his tube tester. They all came back testing excellent. These are the 300b we used in the Franks: Elrog EML XLS Takatsuki Psvane HI-FI series (stock tubes that came the amps) The cathode resistor measured value in my amp was 1.025k He tested for plate voltage and cathode voltages. I'll let you know the results once George talks with Elrog. Joe |
Ok, here is the information that George emailed me. Hi Joe, You can post this data. Be sure to mention that customers of these amplifiers test their AC line voltages(AC Voltmeter). Over 122V AC is a game changer for these or any other 300B tubes. Ideally, in their home they should be have voltages in the 114-122V range. If they have excessive voltage, they should purchase a "variac" as a means of protection for their equipment. Best, George Hello Joe, Here it is the recent data taken from Friday's testing...... Takatsuki 300B 474V plate 33 watt dissipation 84 V across cathode Elrog 300B 484V plate 32 watt dissipation 79V across cathode EML 300BXLS 486V plate 31 watt dissipation 75V across cathode Psvane 300B 484V plate 30 watt dissipation 74V across cathode Line voltage 119.4VAC Cathode resistor value 1.025K ohms Best, George I hope this helps, Joe |
Excellent info, Joe (& George). That all seems very comfortable relative to the specified "limiting operating conditions for safe operation" of the Elrog tube. (79V/1.025K = 77 ma). And the plate dissipation which can be calculated from those numbers is actually closer to 31 watts rather than 32. Enjoy! Best regards, -- Al |
Hi Al, In your opinion given the values that George measured, do you feel these represent a high stress level on the 300b tube or more of a moderate level? The heat dissipation levels measured by George are higher than the 26 watts that Israel cited for the amplifier. Although 31 W seems well off the maximum of 39 or 40 W dissipation for the 300b. Is the plate voltage similar to your VAC Renaisance? Thanks, Charles, |
Hi Charles, My only knowledge of the 300B operating parameters in my VAC Renaissance 70/70MkIII consists of the values Raquel provided in the thread I quoted from earlier. In which he said that the plate-to-cathode voltage is approximately 430 volts (compared with 484-79 = 405 for the Elrog in this case), with an idle current of approximately 85 to 90 ma (compared with 77 ma for the Elrog in this case). Also, based on those numbers for my amp, 90 ma x 430 volts = 38.7 watts plate dissipation. The numbers George measured for the Elrog seem to me to be moderate. Best regards, -- Al |
Al and Joe, Thanks much! These measurement findings do suggest that the Elrog tube should be fine in the Frankenstein amplifier. Al your selected 300b tubes must be vefy rugged to tolerate the parameters in your amplifier and provide the durability and longevity they do I need to measure my wall outlet AC voltage to be sure that it is not excessive. Charles, |
All, my AC measures 122.1 V. I got the same number last week as I did last November, so I am a little concerned regarding tube longevity in my Frankensteins. I did check to verify I have no red dots on the cathodes. My power company will not address the issue unless the voltage is outside of 120 V plus or minus 5%. I guess there is a silver lining to not having much listening time for the last couple months. Until if figure something out, I can reinsert my Psvane T's so that the Elrogs aren't compromised. I have followed the thread since its inception, and am most grateful to all those doing the heavy lifting on sorting through this. However, I am uncomfortable allowing the 122. 1 V situation to stand "unrectified." Were I to utilize a variac, I would probably require two due to my AC wiring configuration. Any recommendations on a relatively inexpensive variac? How about using one of the PS audio power plants with the Franks, which would require some limited room rewiring? |
07-07-15: BrownsfanThat is the standard in the USA for household AC, as measured at the service entrance. The upper limit of that range corresponds to 126 volts. With due respect to George, I must admit to some skepticism about the requirement of 122V max. I would expect that the designs of the power supplies in equipment marketed in the USA would in most cases be targeted to supply optimal DC voltages to the tubes and circuits for an AC input of exactly 120V. And I find it hard to believe that an increase of 1.67% from that figure would be the upper limit of acceptability. Also, I don't see how a statement as specific as "over 122V AC is a game changer for these or any other 300B tubes" can be defined in such a universal manner, apparently with applicability to all 300B-based designs, given that I would expect significant variation among different designs in the +/- tolerances of the transformers and other components in their power supplies. Not to mention in how hard the tubes are driven. Best regards, -- Al |
Thanks Al! I'm going to leave this discussion to you guys who actually know something. I will allow you and George to dialogue until a meeting of the informed minds occurs, at which point, I will act accordingly. I just don't want to start burning through 300Bs. Once again, you are a priceless AG resource Al! |
I use a PS Audio, P-10 power regenerator for exactly the same reason. The power in my area can range from 117v to 123v depending on the time of day. The P-10 shows you the voltage coming in and the regenerated voltage going to your equipment. It took me a long time to figure out why my system sounded so much different during particular times of day but once I did, it was a game changer. It's great to know that the Elrogs will be okay in my Franks. Thanks guys!! |
Bill (Brownsfan), thanks very much for the nice words. Charles, I suppose it would be reasonable to try that experimentally with an inexpensive variac, perhaps purchased used at eBay, but it wouldn't surprise me if the result was degraded sound quality. Due to both the effects on the amp's sonics of the lower voltage and the effects of the variac itself. Best regards, -- Al |
Al, I had exactly the same concern regarding variacs. I spent $1K having dedicated lines run to the room, and who knows how much on PCs. Now I'm supposed to run everything through a cheap variac? I'm also concerned about limiting current. Don't really want to throttle down the juice! On the other hand, one of the PS audio regenerators used might be a reasonable investment. I just know that not everyone likes these, especially for power amps. So even that is an expensive experimental question. I much prefer the do nothing option, but I won't be happy if I am buying new 300Bs 6 times a year. With respect to my nice words, my parents raised me right. Sometimes the children need to remain silent while the adults converse. Its been too long since my college physics course. Electrons are important to organic chemists too, but we are interested in pushing them from one nucleus to another, not pushing them through a bunch of wires and circuits. |
Today, over a six hour period, I measured voltages ranging from a low of 122.1 to a high of 123.3 on the dedicated lines in my listening room. My most current measurement was 123.2. I have a total of 5 dedicated duplex outlets feeding my listening room and the voltage measurements have been identical at each outlet. I also measured for stray voltage on ground and that tested at zero for each outlet. My utility company will not do anything to help me because my voltage is within 5% of 120 volts. I own the Frankensteins and Takatsuki, Elrog, Sophia Royal Princess and Black Treasure 300B tubes. I don't pretend to have the technical knowledge to participate in this conversation, but am I correct that I should not be using my Takatsuki tubes in the Frankensteins given my high voltage readings? |
Joe, thanks for clarifying. It could be a complete coincidence, but I had two different electricians read 122.1 V six months apart. I should probably begin taking my own readings at various times of the day to get a better feel for the range. Markus, thanks for your comment. I will give this some more thought. Snopro, i've heard the same things several times about Purepower. I don't patronize businesses that don't support their products, no matter how good they may be. |
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 |
Joe, My initial experience with George was three years ago when he sold me my pair of EML tubes. I was very impressed with his responsiveness and good attitude and I knew that customer service was very important to him. Well, he's done it again with his handling of the situation concerning the Elrog tube and various amplifiers, I give him a grade of A+! Charles, |
Although it may not be analogous and although I am not sure that I understand the principles involved, I had a similar experience with my Ancient Audio 300b SET. It was built with a protective circuit that proved rather touchy. As I learned through trial and error (and with the help of the folks at Sophia Electric and AmtransJapan, the distributor of Takatsuki), individual pairs of 300b tubes were less likely to trip the circuit if they had a low measured plate current. There is a range of specs for all tubes that fall within the high and low acceptable limits. The manufacturers helped to cull out pairs that were the most compatible with my amplifier. |
