Vacuum Tube - KT88, JJ Electronics
Click to zoom in
Customer Images:
Starting at: $56.95
Product Options
- Apex Matched Quad (T-KT88-JJ-MQ)
This product has substitutes available! Check them out.
The JJ Electronic KT88 is a sonically faithful reproduction of the original tubes with a robust construction encased in a thick glass envelope. The JJ KT88 delivers a powerful 42 Watts with plenty of headroom to spare. This tube has a tone that is warm and lively with a detailed and balance response. The JJ KT88 is an excellent choice for Hi-Fi stereo equipment as well as guitar amplifiers. It can be used in place of 6550 tubes.
Matched versions of this tube use Apex Matching
RoHS Compliant
Accessory Items:
| Single or Matched | Our Part Number | UPC/EAN | JJ Electronics Part Number |
|---|---|---|---|
| Apex Matched Pair | T-KT88-JJ-MP | 609722123235 | |
| Apex Matched Quad | T-KT88-JJ-MQ | 609722123242 | |
| Apex Matched Sextet | T-KT88-JJ-MS | 609722123259 | |
| Single | T-KT88-JJ | 609722123228 | KT88 |
| Body Height | 110 mm | |
| Cathode Current (Ik) | ≤ 230 mA | |
| Filament Current (If) | 1.6 A | |
| Filament Voltage (Uf) | 6.3 V | |
| Gain (μ) | 8 | |
| Grid 1 voltage (Ug1) | -15 V typical | |
| Grid 2 current (Ig2) | ≤ 7 mA | |
| Grid 2 dissipation (Wg2) | 8 W | |
| Grid 2 voltage (Ug2) | ≤ 600 V, 250 V typical | |
| Grid capacitance (cg1) | 16.5 pF | |
| Grid to Plate Capacitance (ca/g) | 2.3 pF | |
| Internal Resistance (Ri) | 12 kΩ | |
| Item Diameter | 52 mm | |
| Item Height | 125 mm | |
| Plate Capacitance (ca) | 10 pF | |
| Plate Current (Ia) | 140 mA | |
| Plate Dissipation (Wa) | ≤ 42 W | |
| Plate Voltage (Ua) | ≤ 800 V, 250 V typical | |
| Transconductance (S) | 11.5 mA/V |
| Packaging Dimensions | Apex Matched Pair version | T-KT88-JJ-MP | 5.3 in. × 4.5 in. × 2.3 in. |
| Apex Matched Quad version | T-KT88-JJ-MQ | 5.3 in. × 4.5 in. × 4.5 in. | |
| Apex Matched Sextet version | T-KT88-JJ-MS | 6.8 in. × 5.3 in. × 4.5 in. | |
| Single version | T-KT88-JJ | 2.3 in. × 2.3 in. × 5.1 in. | |
| Weight (Packaging) | Apex Matched Pair version | T-KT88-JJ-MP | 0.54 lbs. |
| Apex Matched Quad version | T-KT88-JJ-MQ | 1.08 lbs. | |
| Apex Matched Sextet version | T-KT88-JJ-MS | 1.62 lbs. | |
| Single version | T-KT88-JJ | 0.27 lbs. |
| T-KT88-JJ-MP - Apex Matched Pair version | Body Height | 110 mm |
| Cathode Current (Ik) | ≤ 230 mA | |
| Filament Current (If) | 1.6 A | |
| Filament Voltage (Uf) | 6.3 V | |
| Gain (μ) | 8 | |
| Grid 1 voltage (Ug1) | -15 V typical | |
| Grid 2 current (Ig2) | ≤ 7 mA | |
| Grid 2 dissipation (Wg2) | 8 W | |
| Grid 2 voltage (Ug2) | ≤ 600 V, 250 V typical | |
| Grid capacitance (cg1) | 16.5 pF | |
| Grid to Plate Capacitance (ca/g) | 2.3 pF | |
| Internal Resistance (Ri) | 12 kΩ | |
| Item Diameter | 52 mm | |
| Item Height | 125 mm | |
| Plate Capacitance (ca) | 10 pF | |
| Plate Current (Ia) | 140 mA | |
| Plate Dissipation (Wa) | ≤ 42 W | |
| Plate Voltage (Ua) | ≤ 800 V, 250 V typical | |
| Transconductance (S) | 11.5 mA/V | |
| T-KT88-JJ-MQ - Apex Matched Quad version | Body Height | 110 mm |
| Cathode Current (Ik) | ≤ 230 mA | |
| Filament Current (If) | 1.6 A | |
| Filament Voltage (Uf) | 6.3 V | |
| Gain (μ) | 8 | |
| Grid 1 voltage (Ug1) | -15 V typical | |
| Grid 2 current (Ig2) | ≤ 7 mA | |
| Grid 2 dissipation (Wg2) | 8 W | |
| Grid 2 voltage (Ug2) | ≤ 600 V, 250 V typical | |
| Grid capacitance (cg1) | 16.5 pF | |
| Grid to Plate Capacitance (ca/g) | 2.3 pF | |
| Internal Resistance (Ri) | 12 kΩ | |
| Item Diameter | 52 mm | |
| Item Height | 125 mm | |
| Plate Capacitance (ca) | 10 pF | |
| Plate Current (Ia) | 140 mA | |
| Plate Dissipation (Wa) | ≤ 42 W | |
| Plate Voltage (Ua) | ≤ 800 V, 250 V typical | |
| Transconductance (S) | 11.5 mA/V | |
| T-KT88-JJ-MS - Apex Matched Sextet version | Body Height | 110 mm |
| Cathode Current (Ik) | ≤ 230 mA | |
| Filament Current (If) | 1.6 A | |
| Filament Voltage (Uf) | 6.3 V | |
| Gain (μ) | 8 | |
| Grid 1 voltage (Ug1) | -15 V typical | |
| Grid 2 current (Ig2) | ≤ 7 mA | |
| Grid 2 dissipation (Wg2) | 8 W | |
| Grid 2 voltage (Ug2) | ≤ 600 V, 250 V typical | |
| Grid capacitance (cg1) | 16.5 pF | |
| Grid to Plate Capacitance (ca/g) | 2.3 pF | |
| Internal Resistance (Ri) | 12 kΩ | |
| Item Diameter | 52 mm | |
| Item Height | 125 mm | |
| Plate Capacitance (ca) | 10 pF | |
| Plate Current (Ia) | 140 mA | |
| Plate Dissipation (Wa) | ≤ 42 W | |
| Plate Voltage (Ua) | ≤ 800 V, 250 V typical | |
| Transconductance (S) | 11.5 mA/V | |
| T-KT88-JJ - Single version | Body Height | 110 mm |
| Cathode Current (Ik) | ≤ 230 mA | |
| Filament Current (If) | 1.6 A | |
| Filament Voltage (Uf) | 6.3 V | |
| Gain (μ) | 8 | |
| Grid 1 voltage (Ug1) | -15 V typical | |
| Grid 2 current (Ig2) | ≤ 7 mA | |
| Grid 2 dissipation (Wg2) | 8 W | |
| Grid 2 voltage (Ug2) | ≤ 600 V, 250 V typical | |
| Grid capacitance (cg1) | 16.5 pF | |
| Grid to Plate Capacitance (ca/g) | 2.3 pF | |
| Internal Resistance (Ri) | 12 kΩ | |
| Item Diameter | 52 mm | |
| Item Height | 125 mm | |
| Plate Capacitance (ca) | 10 pF | |
| Plate Current (Ia) | 140 mA | |
| Plate Dissipation (Wa) | ≤ 42 W | |
| Plate Voltage (Ua) | ≤ 800 V, 250 V typical | |
| Transconductance (S) | 11.5 mA/V |
 Specification Sheet | All Models |
My Project Lists
Specifications, Files, and Documents
Questions and Answers
Click each question to see its answers.
1 answers
I am using 6550a tubes in a ham radio modulator can I use these KT88 tubes to replace the 6550A tubes and if so will I squeak a bit more power out of these???
Asked by Anonymous on May 21st, 2016.
May 23rd, 2016
Staff MemberTop Contributor
The KT88's are similar in construction and power to the 6550's but they may not be drop in replacements depending on the unit. I would suggest referencing the spec sheet for both found on the product pages for absolute compatibility.
1 answers
el34 is too treble oriented in my bivalve 30 thd/orange cab set up. I want to get more balanced. needs more low end. I was thinking kt77 or kt88. Your opinions and suggestions are needed as I am new at this. I always bought combos now I am trying to shape my sound.
Asked by Anonymous on May 26th, 2017.
May 26th, 2017
Staff Member
The KT 77 and 88 will give you more lows but not necessarily less highs. Our experience has been that swapping preamp tubes has more of an effect on the high end than the power tubes. Also, if you have an older bivalve the KT88's will be to big for the top to fit.
1 answers
What's the warranty on your new production (the JJ KT88) tubes for defects?
Asked by Anonymous on February 11th, 2023.
February 13th, 2023
Staff Member
We offer a 90 day warranty for any defective items, including tubes.
Substitute Products
The following items can be substituted for this product. While not necessarily exactly the same, they will function as replacement items in your project.
Product Reviews
It took two matched sets to get one that wasn't noisy. Had to return the first set - customer service was tremendous but the noisy set made me think twice about JJs again. The price is good, though.
This is really a great tube at this price range. Apex matched quad, shipped immediately, arrived on time, well-packaged as is the standard from Antique Electronic Supply. Biased properly right off the bat and kept the bias which tells me they were properly burned in. The tubes are heavier than the Tung-Sol 6550 they are replacing if that means anything. I thought I had a great tube in the Tung-Sols but the JJs sound fuller across the whole audio spectrum without colorations. I’ve only had them for a couple of days now so I can’t really say much about longevity but overall impressed with the build quality and sonically how musical they sound. I noticed some loss of authority in the lower frequencies but only in very specific cases of music with continuous, low frequency passages. And then it might have had more to do with my speakers than anything else. Overall a well-made, well-balanced, clear and musical tube.
Robust build handles plenty of current. Ordered matching which worked out well. Working well in a stereo hifi power amp.
I inserted them in the sockets of my Sunn 200S adjusted the bias and the amp is alive.
Brought a much warmer sound to the entire frequency range in my Willsenton R8. A must have upgrade to this amplifier. Great value from a great vendor that appreciates their customers and is focused on customer service. Thanks.
I've been using J/J tubes since they first became available. I use them in my own gear and the gear I service. Only 2 tubes had to be replaced in all that time. They work well and can take the abuse of guitar amplifiers on the road.
Quick delivery and great tubes.
Thank you.
These are great tubes for my Leslie 122. Great sound, nice drive. Works as a modern replacement for these amps.
I have heard about the kt88,but I never tried them. So I brought these tubes and man I never go back to the 6550 power amp tubes.gives you all the lows you need. I use them in my 122 Leslie speaker,
Lovely tubes. Solid construction. Typical KT88 sound, as it should be.