[Ichinichi]

what about the 6de7's up front? i know that many have said there are no real appreciable sonic effects, but are they worthwhile replacing? is it prudent to find matched pairs for the two 6de7s?

 

[jamato8]

What do you mean by matched? Electrically matched no but the same manufacture time period and make would be advisable. As far as different sounds from different manufactures there should be a sound difference. I would find as early a date of manufacture as possible like the 1950's. I would also get a pair of black plate tubes, black plate driver section and grey plate power section and all grey plate, just for variety and see for yourself if there is much of a difference. I have many varieties waiting for the 6.

 

[Bob Jones]

Quote:

Originally Posted by Ichinichi /img/forum/go_quote.gif what about the 6de7's up front? i know that many have said there are no real appreciable sonic effects, but are they worthwhile replacing? is it prudent to find matched pairs for the two 6de7s?

I can't say it anymore times about the improvement in the 6de7's by a dip in the old nitrogen,if it's good enough for Ted Williams.I had ge,syl and rca cryoed,it took a week to bring them down and up to protect the disimilar metals ect.IMHO if you don't notice a change then you wouldn't notice a change in rectifier tubes.Please someone else take the plung to spread the word,it isn't even almost expensive.
P.S. By the way,I started with the syl now the ge,the ge is even better.

 

[johnsonad]

Quote:

Originally Posted by Icarium /img/forum/go_quote.gif Johnsonad you better buy those beautiful metal plates (Unless you already have 2 pair) or I'll buy them just to have :/

Got a nice one already

Listening to it right now

You had better start collecting tubes with your new amps on the way!

 

[Agent Kang]

There is a Mullard 50's NOS GZ33 available for sale (sold as a pair). Anyone interested in buying this with me?

 

[jamato8]

What is the price per pair?

 

[Jon L]

I like the directly-headed rectifiers like 5U4G. U52 is nice, but for my money, the common RCA 5U4GB is dirt cheap and veeery good; everyone should try one anyway..

 

[Agent Kang]

I agree. Even the lowly Sovtek 5u4g that comes stock is surprisingly good.

 

[Ichinichi]

Practicing my Date Code reading skills.

A Mullard tube with the code

CV5 745

follows a code convention that is post-1956. Since all Mullard codes prior to 1956 have the form TTC FM [TypeTypeChange FactoryMonth], and only after 1956 do you find codes of the form TTC FYM [TypeTypeChange FactoryYearMonth], then means that the tubes we see are:

CV = GZ33
5 = fifth batch
7 = philips, eindhoven
4 = 1964
5 = may

1964 because it cannot be 1954 since the code formatting is incorrect for a pre-1956 production tube!

edit: a 1954 tube from the same month and factory would've read CVU 7E.

Tube pros? Is this right?

edit2: or am i the only one who was interested enough to study the mullard code system??? hahahahaha!!!


edit3: hmm, looks like any Mullard with any code other than TTC FM is post 1956 - but 5 isn't a valid month code??

 

[Ichinichi]

f31 B4D4

Bogen by Mullard; manufactured in Blackburn, 1964, April, fourth week.

is bogen by mullard a good name?

 

[jamato8]

A Mullard is a Mullard no matter whose name is on it if they made it. In other words, they didn't make lesser quality tubes for others. They would come off of the same line and would be branded at the time or rebranded by others. Yours most likely has the serrated edge with 5 or so notches. The later version had more serrations and does not sound as good. For me the earlier the better.

 

[Ichinichi]

what would you say is a fair price for one of those suckers?

 

[jamato8]

The market is all over the place. Is it branded Mullard or rebranded? Even though it is a Mullard, if rebranded they go for a little less, maybe 15% less even though they are the same tube. NOS or used testing good?

 

[Ichinichi]

tested good. rebranded as bogen.

 

[Rob N]

Quote:

Originally Posted by Ichinichi /img/forum/go_quote.gif Practicing my Date Code reading skills. A Mullard tube with the code CV5 745 follows a code convention that is post-1956. Since all Mullard codes prior to 1956 have the form TTC FM [TypeTypeChange FactoryMonth], and only after 1956 do you find codes of the form TTC FYM [TypeTypeChange FactoryYearMonth], then means that the tubes we see are: CV = GZ33 5 = fifth batch 7 = philips, eindhoven 4 = 1964 5 = may 1964 because it cannot be 1954 since the code formatting is incorrect for a pre-1956 production tube! edit: a 1954 tube from the same month and factory would've read CVU 7E. Tube pros? Is this right? edit2: or am i the only one who was interested enough to study the mullard code system??? hahahahaha!!! edit3: hmm, looks like any Mullard with any code other than TTC FM is post 1956 - but 5 isn't a valid month code??

CV5745 is not the date code.It is simply the 'common valve' number given to the GZ33 by the UK military