Voskhod 6N23P (6Н23П) tubes: equivalents, compatibility and buying notes

The 6N23P (written 6Н23П in Cyrillic) is a Soviet-era miniature double triode, and Voskhod is one of the factories associated with it. Audio owners look for it as an alternative to the better-known 6DJ8, ECC88, E88CC and 6922 in preamps, phono stages and some headphone amplifiers. Before buying, the useful questions are: will it work in my equipment, how does a Voskhod differ from other makers' 6N23P, and how do I buy one with reasonable confidence?

In this guide

What it is and what it replaces

The 6DJ8 was developed by Philips and launched in Europe as the ECC88. It is a medium-gain dual triode with very high transconductance, thanks to its frame-grid construction, originally designed for VHF/UHF television tuners and test equipment and later adopted for hi-fi.¹ The industrial 6922/E88CC variant came in around 1959 to 1961, and the 6N23P is listed as the Soviet equivalent.¹

Radiomuseum records the 6DJ8 as a nine-pin Noval (B9A) base tube with a 6.3 volt heater drawing 0.365 amps, and lists the 6Н23П as electrically identical, alongside the CV5358, M3624 and ECC88 designations.² Wikipedia's 6N1P article, in contrasting the two Soviet types, says the 6N23P has the same transconductance (12.5 mA/V) and gain as the 6DJ8.³

In practice, the same slot covers 6DJ8, ECC88, E88CC, 6922 and 6N23P, and a forum discussion about Voskhod 6N23P describes people using them as substitutes in 6DJ8/6922 sockets in preamps and audio equipment.⁴ That is common practice, but equipment designers sometimes select a particular type, so check the manual.

Compatibility checks

• Not a 6N1P. The 6N1P looks similar and has been mislabelled in the past, but it needs almost twice the heater current and has about a third of the transconductance of a 6DJ8, so the two are not directly interchangeable.³
• Not an ECC82/12AU7 or ECC83/12AX7. Those are different tubes, with different gain and heater arrangements. Do not substitute a 6N23P for them unless the equipment is designed for it.
• Heater supply. The 6DJ8 family uses a 6.3 volt heater, and the data above gives about 0.365 amps.² Make sure the equipment's heater supply can provide the current for the number of tubes fitted.
• Gain and bias. A 6N23P has much higher transconductance than the tubes in many classic circuits. If a circuit was designed for a lower-gain tube, check with the maker before swapping.
• Special variants. Names with suffixes, such as 6N23P-EV, are reported to be ruggedised, long-life or military-grade versions. One review site describes the Reflektor 6N23P-EV as a direct replacement for the 6922/6DJ8.⁵

If you are not sure about your amplifier, ask its manufacturer or a technician. Tube amplifiers contain lethal voltages, and the tube socket and bias circuits should be worked on only by someone competent.

Voskhod and Reflektor

Two Soviet factories are most often named for this type. A vendor selling used pairs describes Voskhod "SWGP" tubes as bent-wire construction like the sought-after Reflektor type but with a silver shield.⁶ A forum thread in which Voskhods are discussed mentions grey-shield and silver-shield variants and tubes from the 1970s and a 1985 CCCP-marked variant, and members describe the Voskhods as some of the better Russian tubes.⁴ A Tube Maze review, which is a review site rather than a manufacturer, says the Reflektor EV is built like a tank and sounds warm with good bass.⁵

Tube sound is subjective. Vendors and reviewers use terms such as "weighty" or "less extended in the treble", and those are opinions: one vendor's customer comments say the Voskhod 6H23P is good with jazz and vocals but less open than another type.⁷ Try one in your own system if returns are allowed.

Buying NOS tubes safely

Little reputable documentation exists on counterfeit 6N23P tubes, so the following is general practical advice and not a documented list of fake marks.

• Look at the printing on the glass and base for consistency: a rocket or factory logo, type designation, date code and any CCCP markings should be consistent with the stated source. Sellers tend to describe tubes by factory, shield colour and year.
• Prefer a seller that tests tubes on a calibrated tester and gives the readings, matches pairs by plate current, and states clearly whether tubes are NOS or used. One vendor lists a pair tested at 50 per cent of NOS values, for example.⁶
• Check microphonics and noise in your own equipment. A tube that looks perfect can still be noisy.
• Buy matched pairs for stereo use if your circuit needs it.
• Look for a returns policy or warranty; vendor guarantees vary. One retailer shows a three-month warranty for the standard Voskhod.⁷

Where to find data

For precise electrical limits, use a proper manufacturer or reference data sheet for the 6DJ8/ECC88 family (Philips and Mullard sheets are widely reproduced) and the 6Н23П sheet from a Russian tube archive, and compare maximum ratings against your circuit.

Transliteration: why one tube has several search names

Search Voskhod 6N23P, Voskhod 6H23P and the Cyrillic Восход 6Н23П. The Latin-looking H in a Cyrillic marking is a transliteration trap, so a listing's spelling alone should not decide whether the tube is the type you need. Ask for a readable photo of the printed designation and any suffix.

Keep variants separate in your shortlist. Do not assume that a suffix, factory name or shield colour guarantees the same electrical ratings, remaining life or sound. Match the exact type to your equipment's permitted substitutions before comparing collector descriptions.

What does “matched pair” actually tell me?

Ask what was matched, on which tester and under what conditions. Two tubes with similar readings on one test are not automatically tested for noise in a sensitive phono stage. Request the readings for both triode sections, the seller's pass criteria and whether the pair was screened for noise or microphonics.

Is NOS the same as tested good?

No. “New old stock” describes the seller's claim about use and storage, not a fresh performance test. Ask whether the tubes were measured recently, whether they have been used for auditions, and what remedy is offered if one is noisy in your equipment.

Choosing for listening rather than collecting

Prioritise compatibility, quiet operation and a clear return policy. A sought-after production year may interest collectors, but it does not remove the need to test the particular tube. Compare listening impressions as subjective reports, and avoid treating a factory or date code as a guaranteed upgrade.

Sources and further reading

1. 6DJ8, Wikipedia: origin, uses and equivalents.
2. Tube 6DJ8, Radiomuseum.org: base, heater data and equivalent designations.
3. 6N1P, Wikipedia: comparison of 6N1P and 6DJ8/6N23P.
4. Looking for Voskhod 6N23P tubes, Polk Audio forum: owner opinions.
5. Reflector 6N23P-EV, Tube Maze: review site; the EV designation and sound impressions.
6. 6N23P Voskhod SWGP matched pair, tubes.rs: vendor listing.
7. JSC Voskhod 6H23p standard preamp tube, The Tube Store: vendor listing with customer comments.