TUBES NOS NIB

 

Considered the exponential progression of the historic valves prices we believe we have to give more guarantees to investors in this particular segment.

Since the inception of the webshop all valves "new old stock" or "new in box" sold by Audiogears are tested and priced based on measured performance and matching.

From now on, this selection is pushed to the extreme level that the equipment in our possession allow us, and we believe we are the only worldwide retail outlet that offers the tubes with the system described below.

All tubes proposed by Audiogears will have a unique code that will allow us to locate them in time and retrieve the test done before the sale even after many years 

The results collected will be printed on a label on the box of each tube together the factory codes basic measures and the unique code Audiogears.

The tubes will be selected individually, in pairs or multiples, and all parameters will be reported online. The selection will be made by the method which you can read below. The photos will refer ALWAYS commissioning tube for sale. Basically what you see in the image will be what you are really buying.

The expenditure of time is huge but we believe it's worth it. The valves from Audiogears definitely cost a few euro more than the competition, but you will have the absolute guarantee that you are going to buy. 

To better relate to our competitors we made sample purchases both by the most popular eBay resellers who by the most accredited independent competitors and we had incredible surprises, in the negative. 

Of course in the description you can see the year of production (where this can be determined) and the actual tube manufacturer which is not always the brand printed on the glass. 

Proposals tubes are all NEW and classified as NOS (new old stock) or NIB (new in box) the difference among these is the presence of the original box (NIB) or not (NOS)

There may be some cases where, since the extreme rarity of the item, there is a certain degree of use, in this case also be clearly stated, whether it is virtually impossible to estimate the number of hours of use. 

To get a first idea of quality level it will be indicated under the initials of the tube the fundamental fact: the Mu for triode preamp and GM for the power tubes. Below we will see why. 

Then opening the valve page to which you are interested you will find all other parameters 

Method of tubes selection 

To proceed with the selection of the valve and matching we note the following parameters

transconductance

anodic emission 

plate Resistance

Gain 

microphonic 

also it is checked: 

Gas presence 

Loss of grid

 

almost all of historic valve retailers (exceptions can be counted on the fingers of one hand) proposed as a method of selection the only Ia: the anode emission. 

In fact this has a relative weight if linked to the matching process 

The reason that the Ia is the most widely used reference is that most of the sellers is equipped with tube testers able to give an indication of the type "good" or "bad" while in the best cases precisely detect the anodic current. 

Very few historians testers are capable to detecting the transconductance and as we will see later is a fundamental fact to derive a key value into pairs of preamp tubes: the Mu ie the gain.

Mu, Gm and Rp that is to say the basic parameters

 Mu (voltage gain), GM (transconductance) and Rp (plate resistance) are the three basic electrical characteristics for a vacuum tube. 

Mu is the product of two data: GM and Rp 

What does GM? incremental variation of plate current / incremental variation of the grid voltage to a specific working point and is the primary measure to detect the gain of the tetrodes and Pentodes. The GM decreases with the aging of the tube, is therefore an important fact to get a first rough idea of the fact that our valve is new or not (but is not an absolute certainty)

 TRIODES 

In triode two fundamental parameters: GM and Rp will produce a third Mu. These parameters are in a relationship such that knowing any two you will get the third. Just as Ohm's law. In the case of triodes, Mu = Gm x Rp. GM is measured in mhos, (micromohms) and Rp is measured in ohms between them is obtained by multiplying the MU, a Mu of 30 means that what enters the valve comes out in principle 30 times more great.

 Triodes are mostly used for voltage amplification in our preamplifiers. Here the Mu (voltage gain) is the most important parameter to be measured and the one that most directly effects what we're going to listen. 

 So let's say that if you get two triode combined using as a parameter the only GM there is no guarantee that these pipes will have an equal voltage gain. 

 But the Rp is hardly ever measured, the value that the passionate search is normally the anode output (Ia). Our tube tester, Amplitrex AT1000, can measure each parameter as those cited above we are therefore able to propose matched tubes and, in the case of double triode, with sections balanced as it should be. 

 Some famous tester, Hickock for example, are sought after for their ability to measure the Gm, but if it is not able to detect the Rp as well will not be possible to calculate the Mu with a simple multiplication. The reason that almost never gets the data from Rp valve suppliers is that it is difficult to measure, and with the old commercial tester has never disclosed this parameter. 

Many of you are buying pairs of tubes because the seller says they are matched, if you look on popular online sales sites or on ebay you will notice that almost all vendors offer their matchate valves only according issuance anode. Very very rarely you find Gm and practically never the MU 

then is FUNDAMENTAL into pairs of preamp tubes that, both the two inner sections (in the case of double triodes), and between the tube and tube there is a given Mu as similar as possible.

Typically in the case of the most thrusts selections this should be below the 5% 

Audiogears will put on sale the triode with MU values significantly unbalanced to the lowest figures of the average market value. Keep in mind that much of what you buy at full price by the majority of sellers does not take any account of this fundamental fact. 

PENTODES, tetrodes etc. 

The pentodes are an entirely different matter. For pentode, such as those used in the output stages of the amplifiers, the Gm is actually essential for good performance. So to match our pentodes we will have to rely on this data. 

Pentodes in the Rp assumes less importance as related to the output transformer. So the GM is the parameter to be considered in the matching But even in this case the old meters are not all'atezza of the situation because they can not detect this parameter (the few who are able to do so) under the actual working conditions to ' internal of the circuit.

Amplitrex once again is able to do so.

Couples or quartets that you will find here are paired taking as the main parameter precisely the transconductance.


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PHILIPS 100TH

Product code: NOS1000001

300,00

PHILIPS 100TH

MATCHED PAIR

Shipping on: 20 Nov 2019
 

 


GE 12BH7 A

Product code: NOS12BH0001

85,00

12BH7 A GE COPPIA

Mu 15.8-15.5 / 15.8-16.5

Shipping on: 20 Nov 2019
 

 


GE 12BH7 A

Product code: NOS12BH0002

60,00

12BH7 A GE COPPIA

Mu 16.5-16.3 / 17.5-18.3

Shipping on: 20 Nov 2019
 

 


GE 12BH7 A

Product code: NOS12BH0003

70,00

12BH7 A GE COPPIA

Mu 16.8-16.3 / 17.8-17.3

Shipping on: 20 Nov 2019
 

 


ATES-RCA 12BH7 A

Product code: NOS12BH0006

70,00

12BH7 A RCA ATES COPPIA

Mu 16.5-16.0 / 15.5-16.0

Shipping on: 20 Nov 2019
 

 


ATES-RCA 12BH7 A

Product code: NOS12BH0007

70,00

12BH7 A RCA ATES COPPIA

Mu 16.4-16.5 / 15.5-15.5

Shipping on: 20 Nov 2019
 

 


SYLVANIA 12BH7 A

Product code: NOS12BH0011

40,00

12BH7 SYLVANIA 

Mu 16.0-16.2

Shipping on: 20 Nov 2019
 

 


SELECTRON RCA 12BH7 A

Product code: NOS12BH0012

55,00

12BH7 SELECTRON RCA PAIR

Mu 15.2-15.3 / 15.2-16.6

Shipping on: 20 Nov 2019
 

 


MULLARD CV181

Product code: NOS1810002

550,00

CV181 MULLARD PAIR 

Mu 31.0-31.3 / 30.9-31.0

Shipping on: 20 Nov 2019
 

 


VALVO-PHILIPS E188CC

Product code: NOS1880012

360,00

E188CC VALVO-PHILIPS PAIR

Mu 29.9-31.3 / 30.1-30.6

Shipping on: 20 Nov 2019
 

 


VALVO-PHILIPS E188CC

Product code: NOS1880013

360,00

E188CC VALVO-PHILIPS PAIR

Mu 33.1-32.6 / 33.1-33.6

Shipping on: 20 Nov 2019
 

 


RCA 211 VT4C

Product code: NOS2110021

1.900,00

RCA 211 VT4C pair

Shipping on: 20 Nov 2019
 

 


GE 211 VT4C

Product code: NOS2110023

560,00

GE 211 COPPIA 

GM uMhos : 4090-4110

 

 

Shipping on: 20 Nov 2019
 

 


GE 211 VT4C

Product code: NOS2110026

570,00

GE 211 COPPIA 

GM uMhos : 4310-4410

Shipping on: 20 Nov 2019
 

 


GE 211 VT4C

Product code: NOS2110027

570,00

GE 211 COPPIA 

GM uMhos : 4160-4190

Shipping on: 20 Nov 2019
 

 


GE 211 VT4C

Product code: NOS2110028

550,00

GE 211 COPPIA 

GM uMhos : 4060-4170 

Shipping on: 20 Nov 2019
 

 


GE 211 VT4C

Product code: NOS2110029

540,00

GE 211 COPPIA 

GM uMhos : 3980-4090

Shipping on: 20 Nov 2019
 

 


GE 211 VT4C

Product code: NOS2110030

540,00

GE 211 COPPIA 

GM uMhos : 3920-4080

Shipping on: 20 Nov 2019
 

 


SIEMENS E288CC

Product code: NOS2880001

280,00

SIEMENS E288CC PAIR

Mu 28.0-28.0 /29.0-28.0

Shipping on: 20 Nov 2019
 

 


SIEMENS E288CC

Product code: NOS2880002

280,00

SIEMENS E288CC PAIR

Mu 28.8-28.0 /29.0-28.0

Shipping on: 20 Nov 2019
 

 


SIEMENS E288CC

Product code: NOS2880003

120,00

SIEMENS E288CC PAIR used

Mu 23.0-24.0 / 23.0-24.0

Shipping on: 20 Nov 2019
 

 


FIVRE 2A3 "SINGLE PLATE"

Product code: NOS2A0021

2.800,00

FIVRE 2A3

"MONO PLATE" PAIR

Shipping on: 19 Nov 2019
 

 


MARCONI 2A3

Product code: NOS2A0036

400,00

MARCONI 2A3  DUAL GETTER

GM uMhos : 5150-5250

Shipping on: 20 Nov 2019
 

 


MARCONI 2A3

Product code: NOS2A0037

420,00

MARCONI 2A3  DUAL GETTER

GM uMhos : 5800-5700

Shipping on: 20 Nov 2019
 

 


MARCONI 2A3

Product code: NOS2A0039

350,01

MARCONI 2A3  DUAL GETTER

GM uMhos : 5300-5600

Shipping on: 20 Nov 2019
 

 


MARCONI 2A3

Product code: NOS2A0040

370,00

MARCONI 2A3 SINGLE GETTER

GM uMhos : 5450-5540

Shipping on: 20 Nov 2019
 

 


MARCONI 2A3 "ENGRAVED BASE"

Product code: NOS2A0041

500,00

MARCONI 2A3 "BLACK PLATE"GM uMhos : 5450

Shipping on: 20 Nov 2019
 

 


PHILCO 2A3

Product code: NOS2A0042

289,99

PHILCO 2A3 COPPIA

GM uMhos : 5250-5550

Shipping on: 20 Nov 2019
 

 


PHILCO 2A3

Product code: NOS2A0043

350,01

PHILCO 2A3 COPPIA

GM uMhos : 5800-5650

Shipping on: 20 Nov 2019
 

 


RCA 2A3

Product code: NOS2A0053

400,00

RCA 2A3 1950 PAIR

GM 5050 uMohs 5150 uMohs

Shipping on: 20 Nov 2019
 

 


RCA 2A3

Product code: NOS2A0055

400,00

RCA 2A3 1950 PAIR

GM 5200 uMohs 5300 uMohs

Shipping on: 20 Nov 2019
 

 


GEC GZ30

Product code: NOS300001

45,01

GZ30 5Z4 GEC

four pcs availables

Shipping on: 20 Nov 2019
 

 


STC NORTHERN ELECTRIC 310A

Product code: NOS3100004

600,00

310A STC NORTHERN ELECTRIC

PAIR

Shipping on: 20 Nov 2019
 

 


WESTERN ELECTRIC 310A

Product code: NOS3100005

220,00

310A WESTERN ELECTRIC

Shipping on: 20 Nov 2019
 

 


PHILIPS 310A

Product code: NOS3100006

250,00

310A PHILIPS

Shipping on: 20 Nov 2019
 

 


SVETLANA 310A

Product code: NOS3100007

40,00

310A EVETLANA

Shipping on: 20 Nov 2019
 

 


MULLARD GZ32

Product code: NOS320002

80,00

MULLARD GZ32

USED

Shipping on: 20 Nov 2019
 

 


MULLARD GZ32

Product code: NOS320003

80,00

MULLARD GZ32

USED

Shipping on: 20 Nov 2019
 

 


MULLARD GZ32

Product code: NOS320004

80,00

MULLARD GZ32

USED

Shipping on: 20 Nov 2019
 

 


MULLARD GZ32

Product code: NOS320005

90,00

MULLARD GZ32

USED

Shipping on: 20 Nov 2019
 

 


MULLARD-COSSOR GZ32

Product code: NOS320006

169,99

GZ32 54KU

MULLARD

Shipping on: 20 Nov 2019
 

 


MULLARD GZ32

Product code: NOS320010

140,00

MULLARD GZ32

Shipping on: 20 Nov 2019
 

 


HALTRON-MULLARD GZ32

Product code: NOS320012

130,00

HALTRON MULLARD GZ32

Shipping on: 20 Nov 2019
 

 


CIFTE-PHILIPS GZ32

Product code: NOS320016

170,00

CIFTE-PHILIPS GZ32 COPPIA

Shipping on: 20 Nov 2019
 

 


RADIOTRON GZ32

Product code: NOS320017

60,00

RADIOTRON GZ32 COPPIA

Shipping on: 20 Nov 2019
 

 


HALTRON GZ32

Product code: NOS320018

45,00

HALTRON GZ32 COPPIA

Shipping on: 20 Nov 2019
 

 


COSSOR MULLARD GZ32

Product code: NOS320019

330,00

GZ32 54KU

COSSOR MULLARD

Shipping on: 20 Nov 2019
 

 


MULLARD GZ32 B2E1

Product code: NOS320020

230,00

MULLARD GZ32 COPPIA

Shipping on: 20 Nov 2019
 

 


WESTERN ELECTRIC 328A

Product code: NOS3280001

480,00

328A WESTERN ELECTRIC

Shipping on: 20 Nov 2019
 

 


MULLARD CV2821 ECC33

Product code: NOS330001

580,00

CV 2821 ECC33 MULLARD PAIR Mu 34.0-35.0  35.0-36.0

Shipping on: 20 Nov 2019
 

 


MULLARD ECC33

Product code: NOS330003

580,00

ECC33 MULLARD PAIR

Mu 34.0-35.0  35.0-36.0

Shipping on: 20 Nov 2019
 

 


MULLARD ECC33

Product code: NOS330010

250,00

ECC33 MULLARD

Mu 36.0-36.0

Shipping on: 20 Nov 2019
 

 


MULLARD ECC33

Product code: NOS330011

220,00

ECC33 MULLARD

Mu 31.9-32.3

Shipping on: 20 Nov 2019
 

 


MULLARD ECC33

Product code: NOS330012

150,00

ECC33 MULLARD

Mu 43.0 - 38.0

Shipping on: 20 Nov 2019
 

 


MULLARD ECC33

Product code: NOS330013

190,00

ECC33 MULLARD

Mu 30.6 - 32.9

Shipping on: 20 Nov 2019
 

 


MULLARD ECC33

Product code: NOS330014

210,00

ECC33 MULLARD

Mu 32.0 - 32.0

Shipping on: 20 Nov 2019
 

 


PHILIPS GZ34

Product code: NOS340023

190,00

GZ34 PHILIPS

Shipping on: 20 Nov 2019
 

 


PHILIPS-MULLARD GZ34

Product code: NOS340025

130,00

GZ34 MULLARD

Shipping on: 20 Nov 2019
 

 


PHILIPS-MULLARD GZ34

Product code: NOS340026

130,00

GZ34 MULLARD

Shipping on: 20 Nov 2019
 

 


MULLARD GZ34

Product code: NOS340027

140,00

GZ34 MULLARD

Shipping on: 20 Nov 2019
 

 


PHILIPS-MULLARD GZ34

Product code: NOS340028.1

140,00

GZ34 MULLARD

Shipping on: 20 Nov 2019
 

 


PHILIPS-MULLARD GZ34

Product code: NOS340031

135,01

GZ34 MULLARD

Shipping on: 20 Nov 2019
 

 


LA RADIOTECHNIQUE GZ34

Product code: NOS340034

180,00

GZ34 RT LA RADIOTECHNIQUE

COPPIA

Shipping on: 20 Nov 2019
 

 


COSSOR 53KU

Product code: NOS370003

750,00

COSSOR 53KU PAIR

Shipping on: 20 Nov 2019
 

 


HIGH WYCOMBE 53KU CV378

Product code: NOS370004

350,01

HIGH WYCOMBE 53KU

Shipping on: 20 Nov 2019
 

 


COSSOR 53KU

Product code: NOS370005

199,99

COSSOR 53KU USED

Shipping on: 20 Nov 2019
 

 


MULLARD GZ37

Product code: NOS370006

110,00

GZ37

CV378 MULLARD

Shipping on: 20 Nov 2019
 

 


MULLARD GZ37

Product code: NOS370007

80,00

GZ37 broken key pin

CV378 MULLARD

Shipping on: 20 Nov 2019
 

 


MULLARD GZ37

Product code: NOS370008

140,00

GZ37

CV378 MULLARD

Shipping on: 20 Nov 2019
 

 


HALTRON-AMPEREX 417A

Product code: NOS4170001

60,00

HALTRON-AMPEREX 417A

5842 VK5 CODE

Shipping on: 20 Nov 2019
 

 


NATIONAL UNION NX 45

Product code: NOS450005

350,00

NATIONAL UNION NX 45 pair

GM 2150 uMohs 2250 uMohs

Shipping on: 20 Nov 2019
 

 


RCA UX245

Product code: NOS450010

120,00

RCA UX245

Shipping on: 20 Nov 2019
 

 


RCA UX245

Product code: NOS450011

180,00

RCA UX245

Shipping on: 20 Nov 2019
 

 


HYTRON VT52

Product code: NOS45S0001

480,00

HYTRON VT52

45 SPECIAL

Shipping on: 20 Nov 2019
 

 


RCA 5R4GY

Product code: NOS5R0002

39,00

RCA 5R4GY BLACK PLATEBROWN BASE

Shipping on: 20 Nov 2019
 

 


FIVRE 5U4GB

Product code: NOS5U0003

39,00

FIVRE

5U4GB

Shipping on: 20 Nov 2019
 

 


HYTRON CBS 5U4G

Product code: NOS5U0006

49,00

HYTRON CBS 5U4G

BLACK PLATE

Shipping on: 20 Nov 2019
 

 


SYLVANIA 5U4GB

Product code: NOS5U0008

35,00

SYLVANIA 5U4GB

BLACK PLATE

Shipping on: 20 Nov 2019
 

 


RAYTHEON 5U4GB

Product code: NOS5U0009

25,00

RAYTHEON 5U4GB

BLACK PLATE

Shipping on: 20 Nov 2019
 

 


PHILIPS 5U4G

Product code: NOS5U0010

39,00

PHILIPS 5U4G

BLACK PLATE

Shipping on: 20 Nov 2019
 

 


MARCONI 5Z3

Product code: NOS5Z0003

120,00

MARCONI 5Z3

MADE IN ITALY

Shipping on: 20 Nov 2019
 

 


MARCONI 5Z3

Product code: NOS5Z0004

90,00

MARCONI 5Z3

MADE IN ITALY

Shipping on: 20 Nov 2019
 

 


Marconi DA60

Product code: NOS600001

1.900,00

MARCONI DA 60 

PAIR

Shipping on: 20 Nov 2019
 

 


KT66 G.E.C. quartet

Product code: NOS660003

1.200,00

KT66 G&C

quartet

Shipping on: 20 Nov 2019
 

 


KT66 MARCONI G.E.C.

Product code: NOS660004

600,00

KT66 MARCONI G&C

PAIR

Shipping on: 20 Nov 2019
 

 


KT66 MARCONI G.E.C. single

Product code: NOS660005

300,00

KT66 MARCONI G&C 

Shipping on: 20 Nov 2019
 

 


KT66 G.E.C. single

Product code: NOS660006

300,00

KT66 G&C 

Shipping on: 20 Nov 2019
 

 


ULTRON SYLVANIA 6973

Product code: NOS69730001

190,00

ULTRON SYLVANIA 6973

QUARTET

Shipping on: 20 Nov 2019
 

 


ULTRON SYLVANIA 6973

Product code: NOS69730002

170,00

ULTRON SYLVANIA 6973

QUARTET

Shipping on: 20 Nov 2019
 

 


SYLVANIA 6973

Product code: NOS69730003

100,00

SYLVANIA 6973

COPPIA

Shipping on: 20 Nov 2019
 

 


SOVTEK 6C33C-B

Product code: NOS6C0001

20,00

SOVTEK 6C33C-B

TESTED

Shipping on: 19 Nov 2019
 

 


SOVTEK 6C33C-B

Product code: NOS6C0002

35,00

SOVTEK 6C33C-B

PERFECT MATCHING

Shipping on: 19 Nov 2019
 

 


PHILIPS ECG 6J5 WGT

Product code: NOS6J0002

35,00

6J5 WGT PHILIPS

PAIT

Shipping on: 20 Nov 2019
 

 


WESTINGHOUSE 6SN7GT

Product code: NOS6S0038

60,00

6SN7GT WESTINGHOUSE - RCA

Shipping on: 20 Nov 2019
 

 


PHILIPS-SYLVANIA 6SN7GT

Product code: NOS6S0039

55,00

6SN7GT PHILIPS

Mu 19.4-19.2

Shipping on: 20 Nov 2019
 

 


SYLVANIA 6SN7 WGTA

Product code: NOS6S0080

110,00

6SN7 WGTA SYLVANIA

Mu 19.7-19.0   19.1-19.9

Shipping on: 20 Nov 2019
 

 


EMERSON SYLVANIA 6SN7 WGTA

Product code: NOS6S0081

55,00

6SN7 WGTA EMERSON SYLVANIA 

Mu 20.0-21.0

Shipping on: 20 Nov 2019
 

 


RCA 6SN7GT

Product code: NOS6S0086

170,00

6SN7 GT RCA PAIR

Mu 18.5-19.0 / 18.5-19.2

Shipping on: 20 Nov 2019
 

 


GE 6SN7 GTA

Product code: NOS6S0088

99,00

6SN7 GTA GE COPPIA

Shipping on: 20 Nov 2019
 

 


RCA 6SL7GT

Product code: NOS6SL0011

120,00

6SL7 5691 RCA PAIR

Mu 68.8-69.3 / 69.4-69.4

Shipping on: 20 Nov 2019