Assembly Manual • Schematic • Parts List • Tubes and Applications • Design • Simulations
At the time this manual was written,
I have built and tested a few different amplifier configurations that all share the same basic design. It is recommended that you duplicate one of these designs if this is your first amplifier, or you want to copy a known good design. Even if you use one of the standard configurations you should expect some variation from my measured values because of tube and line voltage variation.
The Most Popular SSE Design
About 95% of the Tubelab SSE's ever built were made this way. It is a well tested and proven combination. If this is your first amp build, this is the best place to start. The amp runs with a B+ of around 450 volts using 5K ohm output transformers and can be run in triode or ultralinear mode. All of the popular output tubes can be used.
Power Transformer:
The primary winding should match the line (mains) voltage available at your location. A universal (multi winding or multi tapped winding) primary can be used if it supports your line voltage.
The high voltage secondary should be 700 to 750 VCT (350-0-350) to (375-0-375) it should be rated for at least 175 mA DC output. An 800 VCT (400-0-400) transformer will result in too much B+ voltage and should NOT be used. This winding MUST have a center tap.
The rectifier filament winding should be 5 VAC at at least 2 amps. If a 5U4 or 5R4 rectifier is used this winding must be at least 3 amps. A center tap on this winding is OK, but it will not be used.
The main filament winding should be 6.3 VAC at at least 5 amps. A center tap on this winding is OK, but it will not be used.
The transformer may have additional windings or a bias tap. These will not be used.
For builders in the USA, Canada, or other 120 volt 60HZ countries the following transformers have been used:
- Allied 6K7VG
- Hammond 274BX
- Edcor XPWR035.
Many builders outside the USA have used the Hammond 374BX. It is a universal primary design and can be used in the US or just about anywhere in the world. Many builders feel that Hammond's 300 series transformers exhibit higher build quality than the 200 series. There are likely other transformers available to builders in other countries that I don't know about. If it matches the requirements listed above, it should work. Edcor lists a clone of the Hammond 374BX called an XPWR059. 120/240 primary, 375-0-375 @ 175 ma, 50V @ 50 mA, 6.3V CT @ 6A, and 5V CT @ 3 A. I have not tried it though.
Output Transformers:
The OPT is the most critical component in any tube amplifier, and one that is not likely to be upgraded later. The ability of an OPT to reproduce low frequencies is directly related to its size. There are plenty of different types of output transformers available for tube amplifiers. The prices go from $15 USD each to well over $500 USD each. How do you choose? First let me state the requirements:
The Tubelab SSE is a single ended amplifier. The output transformer MUST be designed to work in a single ended amplifier. A push pull transformer will NOT work. Severe distortion will result. The ideal primary impedance for this design is 5K ohms. The secondary impedance should match your speaker impedance. The transformer should be rated to handle the power produced by this amplifier. This could be as low as 5 watts in triode mode, or as high as 15 watts in UL (Ultralinear) mode. The output transformer must have a UL mode tap if you intend to use UL.
The performance of an output transformer is generally related to its size and therefore cost. It will have the biggest effect on the sound quality in the amplifier. I usually recommend that you start with the best transformers that the budget allows even if it means using cheaper tubes. You will upgrade the tubes later, probably not the transformers. See this page for more info.
The small OPT's in the 1 to 2 pound (weight) range will generally exhibit distortion on heavy bass notes. They may be OK if your speakers do not reproduce these frequencies, OR you use an active subwoofer. The small Edcors sound fairly good on my Yamaha NS-10's since their 7 inch woofers can't do much below 70 Hz. Popular transformers in this range are the Edcor XSE15-8-5K and the Hammond 125CSE. I have used both of these, and they work well within their limitations. I prefer the Edcor and it is cheaper. The Edcor has a UL tap, but is available in a single output impedance only (either 4 or 8 ohms). The Hammond has multiple output taps, but NO UL tap (triode mode only).
Both Edcor and Hammond have larger versions of these transformers. The Hammond 125ESE and the Edcor GXSE series have been used by SSE builders who report good results, but I have not tried either of them.
There are several transformers in the 5 to 7 pound range. These are probably the best choice for most builders. A transformer of this size can deliver full solid bass through a big speaker, without compromising the high frequencies, IF it is properly designed AND built. I have used these with good results. The One Electron UBT2, a custom "10 watt" Electra - Print, and an older "Transcendar" I got from Ebay. The Transcendar transformers that I used are no longer made. They were surplus "left over from a production run" I bought a pair and liked them so well that I bought 10 more pairs. There are still Transcendars available on Ebay. Several SSE builders have used them with good results. Electra-Print still makes very good transformers, but they are considerably more expensive than when I got them. The One Electrons are available from Antique Electronics Supply. I have used a pair of "Eastern Audio " transformers that are also common on Ebay. The pair that I have are 600 ohm for another project. They are rated at "50 watts", this is a joke, they are 8 to 10 watt transformers. The build quality is slightly worse than any of the others that I mention, but might be OK if the price is cheap enough. There are dozens of transformers in this size range that I have not tried.
There are also larger transformers available. I have tried the Hammond 1628SEA and the Edcor CXSE25-8-5K. The Hammond is huge at 11 pounds. It will produce full powered bass down to 20 Hz. It will also roll off some of the high frequencies and cost about a watt of output power. It makes bass that can be heard INSIDE the house across the street when connected to my 15 inch OB speakers. This is unreal for a SE amp. The big Hammond does not do well when connected to super high efficiency speakers. The Edcor is smaller than the Hammond at 9 pounds. It gives up very little in the big bass department, but offers serious improvements in the efficiency and high frequency department. I liked the big Edcor so much that I stole it from my SSE for use in a 300B powered Tubelab SE. These are very good transformers and may be cheaper than some of the smaller units. Keep in mind that both of these are BIG and HEAVY, verify chassis fitment and strength!
Other Considerations:
Several users have had problems with the FRED diodes from IXYS. I have noticed that the old ones (3 years ago or older) will live forever, but the newer production diodes are prone to failure. This has to do with their "avalanche performance" which was not specified on the IXYS parts. I no longer recommend IXYS diodes. I have been using Fairchild Semiconductor ISL9R8120P2 without issue, but Fairchild may be eliminating this part. Mouser has 5000 of them in stock. Understand that these diodes are only required if you want the solid state diode option and may be omitted. Simply leave them out if you only want to use a tube rectifier.
I advise adding an inrush current limiter in series with the line (mains) power input to the amplifier. This small component acts like a 120 ohm resistor when it is cold (initial turn on) and gradually reduces to about 2 ohms as it warms up. This greatly reduces the surge that occurs when the amp is turned on. This makes life far easier on the tubes and capacitors. Some users also add another in series with the center tap on the high voltage winding on the power transformer (red - yellow wire). This reduces the surge experienced by the rectifier tube as it warms up. The SSE runs the 5AR4 close to the maximum surge rating, and many new production tubes (especially JJ) are not up to the task. I use the CL-90 from GE sensing. it is DigiKey number KC009L-ND
Computer Simulations
If you already have transformers from another project I have included these amplifier simulations done with TubeCad SEamp Cad to give you an idea of where to start. Choose an output tube, and find the appropriate table. Then find the B+ voltage and load impedance that most closely matches the transformers that you have. You can then choose a cathode resistor value for a given amount of tube dissipation. The power output, distortion and damping factor values are also given. Keep in mind that these are just computer simulations based on a typical vintage vacuum tube.
Tube Type | B+ voltage | Load Z | Vp | Vk | Rk | Ik | Diss (idle) | Pwr Out | Dist - 2nd | Dist 3rd | DF |
---|---|---|---|---|---|---|---|---|---|---|---|
EL34 | 500 | 5000 | 485 | 43 | 560 | 77 | 34 | 7.58 | 7.8 | 0.5 | 4.44 |
EL34 | 500 | 5000 | 486 | 44 | 620 | 71 | 32 | 7.67 | 8.3 | 0.5 | 4.3 |
EL34 | 500 | 5000 | 487 | 45 | 680 | 66 | 29 | 7.76 | 8.8 | 0.4 | 4.17 |
EL34 | 500 | 5000 | 488 | 45 | 750 | 61 | 27 | 7.81 | 9.5 | 0.3 | 4.04 |
EL34 | 500 | 5000 | 489 | 46 | 820 | 56 | 25 | 7.87 | 10.1 | 0.3 | 3.92 |
EL34 | 500 | 5000 | 490 | 47 | 910 | 52 | 23 | 7.49 | 10.7 | 0.1 | 3.79 |
EL34 | 500 | 3000 | 493 | 44 | 620 | 72 | 33 | 10.6 | 12.3 | 0 | 3.13 |
EL34 | 500 | 3000 | 494 | 45 | 680 | 67 | 31 | 10.6 | 13.3 | 0.1 | 3.04 |
EL34 | 500 | 3000 | 494 | 46 | 750 | 61 | 29 | 9.98 | 14.1 | 0.3 | 2.94 |
EL34 | 500 | 3000 | 495 | 47 | 820 | 57 | 27 | 9.89 | 15.4 | 0.5 | 2.86 |
EL34 | 500 | 3000 | 495 | 47 | 910 | 52 | 24 | 9.66 | 16.9 | 0.8 | 2.76 |
EL34 | 450 | 5000 | 435 | 37 | 470 | 79 | 32 | 6.29 | 7.1 | 0.5 | 4.59 |
EL34 | 450 | 5000 | 435 | 38 | 510 | 74 | 30 | 6.1 | 7.2 | 0.5 | 4.47 |
EL34 | 450 | 5000 | 436 | 38 | 560 | 69 | 28 | 6.23 | 7.7 | 0.4 | 4.35 |
EL34 | 450 | 5000 | 437 | 39 | 620 | 63 | 26 | 6.33 | 8.2 | 0.4 | 4.21 |
EL34 | 450 | 5000 | 438 | 40 | 680 | 59 | 24 | 6.44 | 8.8 | 0.4 | 4.09 |
EL34 | 450 | 5000 | 439 | 41 | 750 | 54 | 22 | 6.17 | 9.1 | 0.2 | 3.97 |
EL34 | 450 | 3000 | 442 | 38 | 470 | 81 | 33 | 8.57 | 9.7 | 0.3 | 3.35 |
EL34 | 450 | 3000 | 443 | 39 | 510 | 76 | 31 | 8.71 | 10.4 | 0.2 | 3.26 |
EL34 | 450 | 3000 | 443 | 39 | 560 | 70 | 29 | 8.78 | 11.3 | 0.1 | 3.17 |
EL34 | 450 | 3000 | 444 | 40 | 620 | 64 | 27 | 8.32 | 11.9 | 0.1 | 3.07 |
EL34 | 450 | 3000 | 444 | 41 | 680 | 60 | 25 | 8.32 | 13 | 0.2 | 2.98 |
EL34 | 450 | 3000 | 445 | 41 | 750 | 55 | 23 | 8.26 | 14.3 | 0.4 | 2.89 |
EL34 | 400 | 5000 | 382 | 30 | 330 | 92 | 33 | 4.62 | 5.7 | 0.5 | 4.96 |
EL34 | 400 | 5000 | 383 | 31 | 360 | 86 | 31 | 4.49 | 5.8 | 0.4 | 4.85 |
EL34 | 400 | 5000 | 384 | 32 | 390 | 81 | 29 | 4.68 | 6.1 | 0.5 | 4.74 |
EL34 | 400 | 5000 | 385 | 32 | 430 | 75 | 27 | 4.84 | 6.5 | 0.5 | 4.61 |
EL34 | 400 | 5000 | 386 | 33 | 470 | 70 | 25 | 4.69 | 6.6 | 0.4 | 4.49 |
EL34 | 400 | 5000 | 387 | 34 | 510 | 66 | 24 | 4.86 | 7 | 0.4 | 4.39 |
EL34 | 400 | 3000 | 391 | 31 | 330 | 94 | 35 | 6.96 | 7.8 | 0.4 | 3.63 |
EL34 | 400 | 3000 | 392 | 32 | 360 | 88 | 32 | 6.7 | 8 | 0.4 | 3.55 |
EL34 | 400 | 3000 | 392 | 32 | 390 | 83 | 30 | 6.93 | 8.6 | 0.4 | 3.47 |
EL34 | 400 | 3000 | 393 | 33 | 430 | 77 | 28 | 6.63 | 8.9 | 0.2 | 3.37 |
EL34 | 400 | 3000 | 393 | 34 | 470 | 71 | 26 | 6.79 | 9.6 | 0.2 | 3.28 |
EL34 | 400 | 3000 | 394 | 34 | 510 | 67 | 25 | 6.94 | 10.4 | 0.1 | 3.2 |
EL34 | 350 | 5000 | 329 | 24 | 220 | 107 | 33 | 3.03 | 4.5 | 0.4 | 5.37 |
EL34 | 350 | 5000 | 330 | 24 | 240 | 101 | 31 | 3.23 | 4.8 | 0.5 | 5.26 |
EL34 | 350 | 5000 | 332 | 25 | 270 | 93 | 29 | 3.4 | 5 | 0.5 | 5.11 |
EL34 | 350 | 5000 | 333 | 26 | 300 | 86 | 26.5 | 3.28 | 5.1 | 0.4 | 4.98 |
EL34 | 350 | 5000 | 334 | 26 | 330 | 80 | 25 | 3.46 | 5.4 | 0.4 | 4.86 |
EL34 | 350 | 5000 | 335 | 27 | 360 | 75 | 23 | 3.36 | 5.5 | 0.4 | 4.75 |
EL34 | 350 | 5000 | 336 | 28 | 390 | 71 | 22 | 3.54 | 5.8 | 0.4 | 4.65 |
EL34 | 350 | 5000 | 337 | 28 | 430 | 65 | 20 | 3.7 | 6.2 | 0.4 | 4.52 |
EL34 | 350 | 5000 | 338 | 29 | 470 | 61 | 19 | 3.58 | 6.3 | 0.3 | 4.41 |
EL34 | 350 | 3000 | 340 | 24 | 220 | 111 | 35 | 4.78 | 5.9 | 0.4 | 3.95 |
EL34 | 350 | 3000 | 340 | 25 | 240 | 104 | 33 | 5.04 | 6.3 | 0.5 | 3.86 |
EL34 | 350 | 3000 | 341 | 26 | 270 | 95 | 30 | 4.82 | 6.5 | 0.4 | 3.75 |
EL34 | 350 | 3000 | 342 | 27 | 300 | 88 | 28 | 5.02 | 7 | 0.4 | 3.65 |
EL34 | 350 | 3000 | 342 | 27 | 330 | 82 | 26 | 5.23 | 7.5 | 0.4 | 3.55 |
EL34 | 350 | 3000 | 343 | 27 | 360 | 77 | 25 | 5.04 | 7.7 | 0.3 | 3.47 |
EL34 | 350 | 3000 | 343 | 28 | 390 | 72 | 23 | 5.26 | 8.4 | 0.3 | 3.39 |
EL34 | 350 | 3000 | 344 | 29 | 430 | 68 | 21 | 5.03 | 8.7 | 0.2 | 3.3 |
EL34 | 350 | 3000 | 344 | 29 | 470 | 62 | 20 | 5.19 | 9.5 | 0.1 | 3.22 |
Tube Type | B+ voltage | Load Z | Vp | Vk | Rk | Ik | Diss (idle) | Pwr Out | Dist - 2nd | Dist 3rd | DF |
---|---|---|---|---|---|---|---|---|---|---|---|
6L6GC | 500 | 5000 | 486 | 41 | 560 | 73 | 33 | 5.23 | 7.5 | 0.5 | 3.24 |
6L6GC | 500 | 5000 | 487 | 42 | 620 | 68 | 31 | 5.24 | 7.9 | 0.5 | 3.16 |
6L6GC | 500 | 5000 | 488 | 43 | 680 | 64 | 29 | 5.28 | 8.4 | 0.5 | 3.08 |
6L6GC | 500 | 5000 | 488 | 44 | 750 | 59 | 27 | 5.28 | 8.9 | 0.4 | 3 |
6L6GC | 500 | 5000 | 489 | 45 | 820 | 55 | 25 | 5.29 | 9.4 | 0.4 | 2.94 |
6L6GC | 500 | 3000 | 493 | 42 | 560 | 74 | 35 | 6.52 | 10.2 | 0.4 | 2.39 |
6L6GC | 500 | 3000 | 494 | 43 | 620 | 69 | 32 | 6.47 | 10.9 | 0.4 | 2.34 |
6L6GC | 500 | 3000 | 494 | 44 | 680 | 64 | 30 | 6.45 | 11.6 | 0.4 | 2.29 |
6L6GC | 500 | 3000 | 494 | 45 | 750 | 60 | 28 | 6.39 | 12.3 | 0.3 | 2.23 |
6L6GC | 500 | 3000 | 495 | 46 | 820 | 56 | 26 | 6.35 | 13.1 | 0.3 | 2.19 |
6L6GC | 450 | 5000 | 434 | 34 | 430 | 79 | 32 | 3.69 | 6 | 0.5 | 3.42 |
6L6GC | 450 | 5000 | 435 | 35 | 470 | 74 | 30 | 3.78 | 6.4 | 0.5 | 3.35 |
6L6GC | 450 | 5000 | 436 | 36 | 510 | 70 | 29 | 3.88 | 6.7 | 0.5 | 3.28 |
6L6GC | 450 | 5000 | 437 | 37 | 560 | 66 | 27 | 3.95 | 7.1 | 0.4 | 3.21 |
6L6GC | 450 | 5000 | 438 | 38 | 620 | 61 | 25 | 3.99 | 7.5 | 0.4 | 3.13 |
6L6GC | 450 | 5000 | 439 | 39 | 680 | 57 | 23 | 4.04 | 8 | 0.4 | 3.06 |
6L6GC | 450 | 3000 | 442 | 35 | 430 | 80 | 34 | 5 | 8.4 | 0.5 | 2.52 |
6L6GC | 450 | 3000 | 443 | 35 | 470 | 76 | 32 | 5.41 | 9.2 | 0.5 | 2.47 |
6L6GC | 450 | 3000 | 443 | 36 | 510 | 71 | 30 | 5.16 | 9.4 | 0.4 | 2.42 |
6L6GC | 450 | 3000 | 444 | 37 | 560 | 67 | 28 | 5.19 | 10 | 0.4 | 2.37 |
6L6GC | 450 | 3000 | 444 | 38 | 620 | 62 | 26 | 5.2 | 10.7 | 0.4 | 2.32 |
6L6GC | 450 | 3000 | 445 | 39 | 680 | 58 | 24 | 5.21 | 11.4 | 0.4 | 2.27 |
6L6GC | 400 | 5000 | 381 | 25 | 270 | 94 | 34 | 2.46 | 4.6 | 0.5 | 3.73 |
6L6GC | 400 | 5000 | 383 | 27 | 300 | 88 | 32 | 2.57 | 4.8 | 0.5 | 3.65 |
6L6GC | 400 | 5000 | 384 | 27 | 330 | 83 | 30 | 2.68 | 5.1 | 0.5 | 3.58 |
6L6GC | 400 | 5000 | 384 | 28 | 360 | 79 | 28 | 2.79 | 5.4 | 0.5 | 3.51 |
6L6GC | 400 | 5000 | 385 | 29 | 390 | 75 | 27 | 2.91 | 5.7 | 0.5 | 3.45 |
6L6GC | 400 | 5000 | 386 | 30 | 430 | 70 | 25 | 3 | 6 | 0.5 | 3.37 |
6L6GC | 400 | 3000 | 391 | 26 | 270 | 97 | 36 | 3.51 | 6.1 | 0.5 | 2.74 |
6L6GC | 400 | 3000 | 391 | 27 | 300 | 91 | 34 | 3.62 | 6.6 | 0.5 | 2.68 |
6L6GC | 400 | 3000 | 392 | 28 | 330 | 85 | 32 | 3.74 | 7 | 0.5 | 2.63 |
6L6GC | 400 | 3000 | 392 | 29 | 360 | 80 | 30 | 3.58 | 7.1 | 0.4 | 2.58 |
6L6GC | 400 | 3000 | 393 | 30 | 390 | 76 | 28 | 3.71 | 7.6 | 0.4 | 2.54 |
6L6GC | 400 | 3000 | 393 | 31 | 430 | 71 | 26 | 3.79 | 8.1 | 0.4 | 2.49 |
6L6GC | 350 | 5000 | 330 | 19 | 180 | 103 | 32 | 1.41 | 3.5 | 0.4 | 3.95 |
6L6GC | 350 | 5000 | 331 | 20 | 200 | 97 | 31 | 1.52 | 3.7 | 0.4 | 3.88 |
6L6GC | 350 | 5000 | 332 | 20 | 220 | 92 | 29 | 1.64 | 4 | 0.4 | 3.81 |
6L6GC | 350 | 5000 | 333 | 21 | 240 | 88 | 28 | 1.76 | 4.2 | 0.5 | 3.75 |
6L6GC | 350 | 5000 | 334 | 22 | 270 | 82 | 26 | 1.86 | 4.5 | 0.5 | 3.67 |
6L6GC | 350 | 5000 | 335 | 23 | 300 | 77 | 24 | 1.78 | 4.5 | 0.4 | 3.59 |
6L6GC | 350 | 5000 | 336 | 24 | 330 | 72 | 23 | 1.88 | 4.8 | 0.4 | 3.52 |
6L6GC | 350 | 5000 | 336 | 25 | 360 | 68 | 22 | 1.99 | 5.1 | 0.4 | 3.46 |
6L6GC | 350 | 3000 | 340 | 19 | 180 | 107 | 35 | 2.12 | 4.6 | 0.4 | 2.9 |
6L6GC | 350 | 3000 | 341 | 20 | 200 | 101 | 33 | 2.26 | 4.9 | 0.5 | 2.85 |
6L6GC | 350 | 3000 | 341 | 21 | 220 | 95 | 31 | 2.17 | 4.9 | 0.4 | 2.8 |
6L6GC | 350 | 3000 | 342 | 22 | 240 | 90 | 29 | 2.31 | 5.3 | 0.4 | 2.75 |
6L6GC | 350 | 3000 | 342 | 23 | 270 | 84 | 27 | 2.42 | 5.7 | 0.4 | 2.7 |
6L6GC | 350 | 3000 | 343 | 24 | 300 | 79 | 26 | 2.53 | 6.2 | 0.4 | 2.64 |
6L6GC | 350 | 3000 | 343 | 24 | 330 | 74 | 24 | 2.65 | 6.6 | 0.4 | 2.59 |
6L6GC | 350 | 3000 | 343 | 25 | 360 | 70 | 23 | 2.77 | 7.1 | 0.5 | 2.55 |
6L6GC | 350 | 3000 | 344 | 26 | 390 | 66 | 22 | 2.66 | 7.2 | 0.4 | 2.51 |
Tube Type | B+ voltage | Load Z | Vp | Vk | Rk | Ik | Diss (idle) | Pwr Out | Dist - 2nd | Dist 3rd | DF |
---|---|---|---|---|---|---|---|---|---|---|---|
KT88 | 500 | 5000 | 480 | 43 | 430 | 100 | 44 | 6.29 | 4.8 | 0.3 | 4.44 |
KT88 | 500 | 5000 | 482 | 44 | 470 | 93 | 41 | 6.44 | 5.1 | 0.3 | 4.34 |
KT88 | 500 | 5000 | 483 | 45 | 510 | 88 | 39 | 6.58 | 5.3 | 0.3 | 4.25 |
KT88 | 500 | 5000 | 484 | 46 | 560 | 82 | 36 | 6.69 | 5.6 | 0.3 | 4.14 |
KT88 | 500 | 5000 | 485 | 47 | 620 | 76 | 33 | 6.77 | 6 | 0.2 | 4.03 |
KT88 | 500 | 5000 | 486 | 48 | 680 | 70 | 31 | 6.85 | 6.4 | 0.2 | 3.93 |
KT88 | 500 | 5000 | 487 | 49 | 750 | 65 | 29 | 6.9 | 6.8 | 0.1 | 3.82 |
KT88 | 500 | 3000 | 490 | 44 | 430 | 102 | 46 | 9.42 | 6.9 | 0.2 | 3.25 |
KT88 | 500 | 3000 | 491 | 45 | 470 | 95 | 43 | 9.08 | 7.3 | 0.1 | 3.17 |
KT88 | 500 | 3000 | 492 | 46 | 510 | 90 | 41 | 9.19 | 7.8 | 0.1 | 3.1 |
KT88 | 500 | 3000 | 492 | 46 | 560 | 83 | 38 | 9.22 | 8.4 | 0.1 | 3.03 |
KT88 | 500 | 3000 | 493 | 48 | 620 | 77 | 35 | 9.18 | 9.2 | 0.2 | 2.95 |
KT88 | 500 | 3000 | 493 | 48 | 680 | 71 | 33 | 9.15 | 10 | 0.4 | 2.87 |
KT88 | 500 | 3000 | 494 | 49 | 750 | 66 | 30 | 8.69 | 10.7 | 0.6 | 2.79 |
KT88 | 450 | 5000 | 429 | 36 | 330 | 109 | 43 | 4.66 | 4.1 | 0.3 | 4.63 |
KT88 | 450 | 5000 | 430 | 37 | 360 | 102 | 40 | 4.82 | 4.3 | 0.3 | 4.53 |
KT88 | 450 | 5000 | 431 | 38 | 390 | 96 | 38 | 4.99 | 4.5 | 0.3 | 4.45 |
KT88 | 450 | 5000 | 432 | 39 | 430 | 90 | 36 | 5.12 | 4.7 | 0.3 | 4.34 |
KT88 | 450 | 5000 | 433 | 39 | 470 | 84 | 33 | 5.26 | 5 | 0.3 | 4.25 |
KT88 | 450 | 5000 | 434 | 40 | 510 | 79 | 31 | 5.41 | 5.3 | 0.3 | 4.16 |
KT88 | 450 | 5000 | 436 | 41 | 560 | 73 | 29 | 5.24 | 5.4 | 0.2 | 4.06 |
KT88 | 450 | 3000 | 440 | 37 | 330 | 111 | 45 | 6.83 | 5.6 | 0.3 | 3.39 |
KT88 | 450 | 3000 | 440 | 38 | 360 | 105 | 43 | 7.01 | 6 | 0.2 | 3.32 |
KT88 | 450 | 3000 | 441 | 38 | 390 | 98 | 40 | 7.19 | 6.3 | 0.2 | 3.25 |
KT88 | 450 | 3000 | 441 | 39 | 430 | 91 | 37 | 7.3 | 6.8 | 0.2 | 3.18 |
KT88 | 450 | 3000 | 442 | 40 | 470 | 85 | 35 | 7.42 | 7.3 | 0.1 | 3.11 |
KT88 | 450 | 3000 | 442 | 41 | 510 | 80 | 33 | 7.16 | 7.6 | 0 | 3.04 |
KT88 | 450 | 3000 | 443 | 42 | 560 | 75 | 31 | 7.23 | 8.2 | 0.1 | 2.97 |
KT88 | 400 | 5000 | 375 | 28 | 220 | 126 | 44 | 3.03 | 3.3 | 0.3 | 4.92 |
KT88 | 400 | 5000 | 376 | 29 | 240 | 119 | 42 | 3.2 | 3.4 | 0.3 | 4.84 |
KT88 | 400 | 5000 | 378 | 30 | 270 | 110 | 39 | 3.33 | 3.6 | 0.3 | 4.72 |
KT88 | 400 | 5000 | 380 | 31 | 300 | 102 | 36 | 3.48 | 3.8 | 0.3 | 4.62 |
KT88 | 400 | 5000 | 381 | 32 | 330 | 96 | 34 | 3.62 | 3.9 | 0.3 | 4.52 |
KT88 | 400 | 5000 | 382 | 32 | 360 | 90 | 32 | 3.78 | 4.2 | 0.3 | 4.43 |
KT88 | 400 | 5000 | 383 | 33 | 390 | 85 | 30 | 3.93 | 4.4 | 0.3 | 4.3 |
KT88 | 400 | 3000 | 388 | 30 | 240 | 123 | 45 | 4.83 | 4.5 | 0.3 | 3.55 |
KT88 | 400 | 3000 | 389 | 31 | 270 | 114 | 41 | 4.99 | 4.8 | 0.3 | 3.46 |
KT88 | 400 | 3000 | 390 | 32 | 300 | 105 | 38 | 5.15 | 5.1 | 0.3 | 3.38 |
KT88 | 400 | 3000 | 391 | 33 | 330 | 98 | 36 | 5.32 | 5.5 | 0.2 | 3.31 |
KT88 | 400 | 3000 | 391 | 33 | 360 | 92 | 34 | 5.49 | 5.9 | 0.2 | 3.24 |
KT88 | 400 | 3000 | 392 | 34 | 390 | 87 | 32 | 5.64 | 6.3 | 0.2 | 3.18 |
KT88 | 400 | 3000 | 392 | 35 | 430 | 81 | 29 | 5.45 | 6.5 | 0.1 | 3.11 |
KT88 | 350 | 5000 | 323 | 21 | 150 | 138 | 42 | 1.79 | 2.6 | 0.3 | 5.14 |
KT88 | 350 | 5000 | 324 | 21 | 160 | 133 | 40 | 1.95 | 2.8 | 0.3 | 5.08 |
KT88 | 350 | 5000 | 325 | 22 | 180 | 124 | 38 | 2.08 | 2.9 | 0.3 | 4.98 |
KT88 | 350 | 5000 | 327 | 23 | 200 | 116 | 35 | 2.23 | 3 | 0.3 | 4.89 |
KT88 | 350 | 5000 | 328 | 24 | 220 | 109 | 33 | 2.37 | 3.2 | 0.3 | 4.8 |
KT88 | 350 | 5000 | 330 | 25 | 240 | 103 | 32 | 2.32 | 3.2 | 0.3 | 4.72 |
KT88 | 350 | 5000 | 331 | 26 | 270 | 96 | 29 | 2.44 | 3.4 | 0.3 | 4.61 |
KT88 | 350 | 3000 | 337 | 22 | 160 | 139 | 44 | 3.06 | 3.5 | 0.3 | 3.74 |
KT88 | 350 | 3000 | 338 | 23 | 180 | 129 | 41 | 3.24 | 3.7 | 0.3 | 3.66 |
KT88 | 350 | 3000 | 339 | 24 | 200 | 120 | 38 | 3.43 | 4 | 0.3 | 3.59 |
KT88 | 350 | 3000 | 339 | 25 | 220 | 113 | 36 | 3.33 | 4 | 0.3 | 3.52 |
KT88 | 350 | 3000 | 340 | 26 | 240 | 107 | 34 | 3.52 | 4.3 | 0.3 | 3.46 |
KT88 | 350 | 3000 | 341 | 27 | 270 | 99 | 31 | 3.67 | 4.6 | 0.2 | 3.38 |
KT88 | 350 | 3000 | 341 | 28 | 300 | 92 | 29 | 3.83 | 5 | 0.2 | 3.3 |
Tube Type | B+ voltage | Load Z | Vp | Vk | Rk | Ik | Diss (idle) | Pwr Out | Dist - 2nd | Dist 3rd | DF |
---|---|---|---|---|---|---|---|---|---|---|---|
6V6GT | 375 | 6000 | 368 | 25 | 680 | 37 | 13 | 2.02 | 4.4 | 0.2 | 2.84 |
6V6GT | 375 | 6000 | 368 | 26 | 750 | 35 | 12 | 2.11 | 5 | 0.3 | 2.78 |
6V6GT | 375 | 6000 | 369 | 27 | 820 | 33 | 11 | 2.05 | 5.3 | 0.4 | 2.74 |
6V6GT | 375 | 6000 | 369 | 28 | 910 | 30 | 10 | 2.12 | 6 | 0.5 | 2.68 |
6V6GT | 375 | 6000 | 370 | 28 | 1000 | 28 | 10 | 2.19 | 6.7 | 0.7 | 2.63 |
6V6GT | 350 | 6000 | 342 | 22 | 560 | 40 | 13 | 1.64 | 3.7 | 0.1 | 2.92 |
6V6GT | 350 | 6000 | 343 | 23 | 620 | 37 | 12 | 1.73 | 4.1 | 0.2 | 2.86 |
6V6GT | 350 | 6000 | 343 | 24 | 680 | 35 | 11 | 1.68 | 4.3 | 0.2 | 2.81 |
6V6GT | 350 | 6000 | 344 | 24 | 750 | 32 | 10 | 1.77 | 4.9 | 0.3 | 2.76 |
6V6GT | 350 | 6000 | 344 | 25 | 820 | 30 | 10 | 1.86 | 5.4 | 0.4 | 2.71 |
6V6GT | 325 | 6000 | 317 | 19 | 430 | 44 | 13 | 1.16 | 2.8 | 0 | 3.02 |
6V6GT | 325 | 6000 | 317 | 20 | 470 | 41 | 12 | 1.26 | 3.1 | 0.1 | 2.97 |
6V6GT | 325 | 6000 | 318 | 20 | 510 | 39 | 12 | 1.37 | 3.4 | 0.1 | 2.93 |
6V6GT | 325 | 6000 | 318 | 21 | 560 | 37 | 11 | 1.33 | 3.5 | 0.1 | 2.88 |
6V6GT | 325 | 6000 | 319 | 21 | 620 | 34 | 10 | 1.42 | 4 | 0.2 | 2.83 |
6V6GT | 325 | 6000 | 319 | 22 | 680 | 32 | 10 | 1.38 | 4.2 | 0.2 | 2.78 |
6V6GT | 300 | 6000 | 292 | 16 | 360 | 45 | 12 | 0.937 | 2.4 | 0 | 3.06 |
6V6GT | 300 | 6000 | 292 | 17 | 390 | 43 | 12 | 0.919 | 2.5 | 0 | 3.02 |
6V6GT | 300 | 6000 | 292 | 17 | 430 | 40 | 11 | 1.01 | 2.8 | 0 | 2.98 |
6V6GT | 300 | 6000 | 293 | 18 | 470 | 38 | 10 | 0.989 | 2.9 | 0.1 | 2.93 |