Substitute 6E5 for 6U5? Posted: Jan Thu 15, am. I fired up my radio and found out the 6U5 tuning eye is dead. But, I happen to have a spare 6E5 that works. Same pinout and ratings except for sensitivity. The 6E5 is about 3 times more sensitive than the 6U5. I flooring installation warranty letter I can probably stick a big resistor in there somewhere to attenuate the signal, but I thought I'd ask if anyone else has done this before I start monkeying around.
If an eye closes all the way and overlaps you can reduce sensitivity by using a voltage divider on the AVC voltage. AVC goes to pin 3. Use high value resistors as not to load down the AVC line. Thanks Norm. There's no overlap, even on strong stations. That may change once the set is aligned, but it will do just fine for now. The typical AVC system of the day had a range of about 20 volts, from no signal to max signal.
But the 6U5 only had a dynamic range of about 5 volts. The 6E5 has a range of about 20 volts, to match the AVC system more accurately.
Free Tube Substitution Guide Manuals & Free Tube Data Sheet Manuals
I thought it was vice versa? The 6U5 needs from zero to about volts for its range and the 6E5 only needs about zero to -8 volts. The 6U5 is Came without tubes, and of course it needs a 6U5. Everything else I had in the tube box, so I can at least get it playing.
No wonder they're so blasted difficult to find. Posted: Jan Thu 15, pm. Sorry, guys. I screwed up. The 6E5 has the narrow control voltage range.
The 6U5 has the replacement with the wider control range.Ideally, every 12AX7 should yield the same gain when placed in the same circuit. However, in reality there are comparative gain differences among 12AX7s. Today, it is by far the most common preamp tube used for electric guitar amplification and there is an almost overwhelming supply of current production options to choose from. The purpose of this comparison is simply to provide guitar players with a frame of reference to help in finding the best current production 12AX7 for their needs.
The 12AX7 is a 9-pin miniature, high-mu, twin triode.
12AX7 Comparison of Current Made Tubes
What does that mean? The 9-pin miniature part tells us what kind of socket the tube plugs into. It has nine thin pins arranged along the circumference of a circle with a diameter of just under half of an inch.
There is a large gap between pins 1 and 9 to ensure that the tube can only be plugged in one way. This gives us a general category of amplification that the tube was designed for as compared to other preamp tube types like the "medium-mu" 12AU7.
The twin triode part tells us that there are two identical and independent triodes contained within the one tube. A triode is the most basic tube structure that allows for signal amplification and it has three electrodes: plate, grid and cathode. Each tube sample was tested in the same Fender black face style preamp circuit as shown in the schematic below with bass and treble set to their maximum.
A frequency generator was used to measure voltage gain and plot the frequency response from 10 Hz to 18, Hz.
From the frequency plot it could be seen that there are three extrema at about 50 Hz, Hz and 4, Hz. These three frequencies were then used to quickly measure the low, mid and high frequency voltage gain on the same number of samples for each tube in our comparison. The average from each tube's samples was then calculated and used for comparison.
The smallest average low frequency gain tube was used as the reference for a gain of "1" and the largest average low frequency gain tube was used as the reference for a gain of "10".
This gain reference method was then repeated for both the mid and high frequency averages. Each tube sample was again tested in the same preamp circuit and an oscilloscope was connected to the amplifier output to monitor the amplitude of the voltage spike produced by tapping on the tube's glass envelope.Emma Technology Company eama Circuit characteristics: the use of two-stage direct-coupled amplifier circuit, bile Sauvignon, extended at both ends of the deep, dynamic range!
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Thank you! Economy International Shipping. Standard International Shipping. Expedited International Shipping.It has many circuit diagrams, using these tubes and all the information, about these original vacuum tubes. Very handy for ordering tubes that are over priced or hard to get today.
The substitutes work the same. This manual provides substitutions for the first radio receiving tubes till This works for all radios made on or before Radio receiving tubes and swap tips for the new 7 pin and 9 pin miniature tube types. How to replace many Octal tube types with the new then miniature ones.
Hence problem with that tube or its soldered to tube pins circuit components. This manual tells what radio receiving tube will substitute for another and work as a replacement.
If no replacement is shown for a particular tube number, there is no replacement and you must use original tube number to replace a defective tube. You can use a European tube in a USA radio for example. This RCA BELOW manual gives full tube data on all the modern receiving tubes and others back to about mid 's,but good for future tube design work.
We find this incorrectly! So is for instance a 6DJ8 wich is made in the sixties by Philips in the Netherlands for an American colleague, exactly the same as their ECC88 sold on the European market. Only the imprint is different.
Also the Mu is almost te same, 35 instead of You can see that in the table below. With a large enough power transformer that shall be no problem, but it is something to care about. That is an important reason wherefore it can not replace in all times a 6DJ8 etc.You are reading the older HTML site. I love and appreciate tube based audio gear and own sixteen pieces of tube gear between my two reference systems. Without a thorough knowledge of tube types and their substitution possibilities, you may be over-paying for your new or NOS tubes you employ, or just pick the wrong ones.
This data is based on my experience, and input from my electrical engineering audiophile friends. Knowledge is power, and knowing an unusual substitute may be a true joy.
Small Signal Tubes:. The GE is a bargain basement musical giant! The Mullard CV is still fairly cheap, plentiful, and magnificent. The bargain priced PCC88, the 7 volt version of this tube, works nicely in the vast majority of 6 volt applications. Buy it used, but checked, if necessary.
A killer tube, but huge and requires lots of space bigger than a KT Other Dual Triode Tubes:. The available brands of these tubes are highly variable musically and microphonically. The Electro Harmonix is very good, too. Same comment as 6SN7 type. Output Tubes:. Am told the NOS Mullard prices are strong, but worth it. Lots to choose from. Usually your manufacturer tuned the gear to a certain brand of these. Be mindful of that before you spend tons of money on vintage NOS versions that end up not sounding as good.
At least try KT88s! Same comment as EL34 type. I would! If in doubt, check with your manufacturer before substituting. The above substitutions have been checked as carefully as possible.Posted: Nov Fri 30, am. I'm working on a RCA 9X It runs a 35Z5GT rectifier tube. These tubes seem to be expensive. Are there other tubes that would work just as well. Use 45Z5GT. They have a 10 volt higher filament but work well with today's line voltage.
If a radio doesn't use a pilot lamp 35Z4GT may work. RCA 9X uses two pilot lamps. If I were concerned about the pricing of a 35Z5, I would make a solid state replacement, very easy to do and can also provide for the dial lamp s.
Less than a dollar's worth of parts, two 1. Posted: Nov Fri 30, pm. The average consumer hasnt a clue about that tube. Posted: Dec Sat 01, am. With today's generally higher line voltages, it's a good idea to raise the sum voltage of the AA5 heater string by ten volts. It makes life easier on all the tubes in the string. About 8 months ago, I tested this rectifier swap on a breadboard. Wire up the filaments in series and put a fixed load on the power supply Then show the voltages across each filament and the output of the power supply--at various line voltages.
Posted: Dec Sat 01, pm. WOW, that's quite a chart, nice work In your case the signal tubes have more drop for their ratings than the audio and rectifer I've seen opposite with a 50L6 that was dropping 55v, and signal tubes were low Just goes to show the current ratings wasn't always in spec