eBay

Single Tube = $45.

NOTE: After spending $$$$ on tooling and various prototypes, we have fitted Special Grade Flying Leads tubes with Custom Bakelite Bases developed in-house. It is a multi-step, labor intensive process. Each lead is straightened and cleaned to ensure perfect fusion with the base pins in the soldering bath. Process is painstakingly slow, so we will be adding a few tubes at a time to the inventory.

Tubes are Plug & Play, Ready to Use,  fitted with our Custom made Bakelite Bases (INTL Patent Application in Process).

Brand New MINT NOS Rare 1960-62 BRIMAR CV4033 Black Plate with Copper Grid Post Military tubes. Factory tested and serialized*. CV4033 Flying Lead is a Premium Grade, High Reliability Long Life version of CV4024/ECC81/12AT7 valves. CV4033 premium grade version of the 1960s Black Plate CV4024/6060 is one of the best from Brimar in the ECC81 types. STC Rochester Plant Date Codes. Made in England. Packed in generic white boxes from bulk.

*From 100 pc bulk boxes, each tube came with two factory stickers (click Larger Photo). A hand written individual serial number on top,and a printed sticker with numbers R811451 PM25525-1 on the side. Tubes were factory tested and serialized for some qualification (R811451 PM25525-1), except we don't have specific details of the qualification.

Tested and matched on Hickok 752, just recently calibrated and modified by Hickok expert to all Solid State to eliminate drift. However, on average 12AT7 measures lower on this 752 than it should. For comparison, 12AT7 measuring 4400-4400 on calibrated Hickok 600 measures 3300-3300 mmhos on this 752. Average new 12AT7 on Hickok 600 is 4000 mmhos. In other words, actual test scores are higher than what we have noted on the tube boxes.

Single Tube = $45. Select 2 for a Matched Pair or 4 for a Matched Quad. Even odd number of tubes will be matched.

NEW Reduced and Streamlined Shipping Rates:

WITHIN USA and US Territories - $4 FLAT Fee for First Class Mail for any number of items or tubes in a single order.

CANADA - $10 (sorry now the USPS rates to Canada are the same as rest of the world).

Rest of the world - $15 FLAT Fee for Registered AIR MAIL for any number of items or tubes in a single order.

Tubemonger.com has been selling tubes directly and on Audiogon for a while. You can see our feedback at Audiogon.

 
                        Review of BRIMAR CV4033 tubes 
                      November 17, 2013
                    
                      Reviewer: 
                        Don Sachs
                        from Canada and US
                        
                  A bit of background.  I rebuild vintage tube amps and 
preamps for my living and while I work on anything with tubes I 
specialize in Harman Kardon Citation tube gear.  I have rebuilt over 40 
Citation I preamps and have heard most of the 12AT7 variants in that 
preamp.  I would say the CV4033 is easily the best I have heard so far. 
 My previous favorite was the Brimar CV4024, but the CV4033 is better 
all around, more extended on top and in the bass.  The best way to 
describe the CV4033 is that is has the clean extended sound of a 
Telefunken married with a touch of British tube warmth and very clean 
and extended bass.  The Telefunken tubes can be a bit clinical sounding 
in some systems, but I doubt that would be a problem with the CV4033 
from what I can hear.  It is a wonderful tube and has the best imaging I
 have heard to date of any 12AT7 variant in my system.   This pair is 
staying in my Citation I.
 
Don Sachs

                        Worthy upgrade 
                      May 24, 2010
                    
                      Reviewer: 
                        George Fink
                        from Beaumaris, Victoria Australia
                        
                  I purchased these to replace the EH 12AT7 tubes in my 
Manley Mahis amps. After contacting tubemonger re suitable tubes they 
suggested a Siemens and 2 Brimars one of which was this type. 

The
 sound of my amps changed quite dramatically. The harshness and coldness
 in the mid was replaced by a much smoother and detailed sound, warmer 
and more involving. Treble is smoother and not as upfront.  Bass is deep
 and more detailed somehow. Overall a great improvement. 

The tubes sit on a black Plastic base and plug in as normal, this base is attached very well and no wobble has been noted. 

I
 tried a Brimar 6060 yellow T in this amp and preferred the cv 4033. 
More life in the music, the 6060T sounded flat in comparison.  

Overall a great upgrade to new tubes, not much cost and 10000 hr life. You can't lose.