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Converting tube types. - Page 2

post #16 of 36
This is a very complex mod. So the 9th pin is going to be a special type of grounding pin. What you need to do is switch the 8 pin socket for a 9 pin socket. The what you need to do is wire the 9th pin to your phone line. Normally what you need to do is make a grounding wire that goes to your physical ground, but I found that using your phone cable works exactly the same way plus it is cheap and easy. Also remember that these are special tubes, and the whole tube glows, not just the filament. So things are going to get a bit toasty.
post #17 of 36
Quote:
Originally Posted by Tjj226 Angel View Post

This is a very complex mod. So the 9th pin is going to be a special type of grounding pin. What you need to do is switch the 8 pin socket for a 9 pin socket. The what you need to do is wire the 9th pin to your phone line. Normally what you need to do is make a grounding wire that goes to your physical ground, but I found that using your phone cable works exactly the same way plus it is cheap and easy. Also remember that these are special tubes, and the whole tube glows, not just the filament. So things are going to get a bit toasty.

 

cant tell if joking. 

 

If the "whole tube" in a small signal tube glows you are probably exceeding the plate dissipation. 

 

Indirectly heated tubes have heaters. PPL call them what they wish they were even though they are not filaments. Directly heated tubes have filaments. 

 

I don't think this amp has an 8pin socket, does it? 

 

Phone line? you still have one of those? VOIP and cell. 

And what are you doing grounding anything to it? 

post #18 of 36
Thread Starter 
Quote:
Originally Posted by Tjj226 Angel View Post

This is a very complex mod. So the 9th pin is going to be a special type of grounding pin. What you need to do is switch the 8 pin socket for a 9 pin socket. The what you need to do is wire the 9th pin to your phone line. Normally what you need to do is make a grounding wire that goes to your physical ground, but I found that using your phone cable works exactly the same way plus it is cheap and easy. Also remember that these are special tubes, and the whole tube glows, not just the filament. So things are going to get a bit toasty.

 

The 9th pin is the heater center tap, not for grounding, that's why it's being connected to one of the heater leads. 8 pin socket? what? Lyr is B9A, the tubes i've mentioned are B9A. popcorn.gif The tube does essentially become 8 pins after the mod (wiring 4 and 5 together) but that's as close as it gets to anything 8 pin.

 

Telephone cable? blink.gif  don't know if you stumbled upon this thread while drunk, or just plain trolling. tongue.gif

post #19 of 36

Ilikepooters/Nikongod----The fellows crazy --DO NOT DO AS HE SAYS-he is also giving potentially amp destroying information.

                                           Transferring pin-8 connection to 9-WOW!!!-thats putting cathode -1 onto the one side[after the mod] of the heater circuit.     Under NO circumstances connect it to the telephone line -You have a ringing current-AC going down that line of-in the UK of 75/80V AC RMS. Not only that Bell telephones can tell what is attached to their land-lines-massive computers-Do want cut off AND sued for -interfering with a communication network.

             You would be lucky in this day and age that you didnt get a visit  from the FBI-no joking!!

                   I think you should have  "a word" with this person-MOD? 

post #20 of 36
Quote:
Originally Posted by nikongod View Post

 

cant tell if joking. 

 

If the "whole tube" in a small signal tube glows you are probably exceeding the plate dissipation. 

 

Indirectly heated tubes have heaters. PPL call them what they wish they were even though they are not filaments. Directly heated tubes have filaments. 

 

I don't think this amp has an 8pin socket, does it? 

 

Phone line? you still have one of those? VOIP and cell. 

And what are you doing grounding anything to it? 

 

 

It was a joke. Quite frankly, I am a bit surprised that people did not figure out it was a joke right off the bat. I mean come on....ground to phone line???? 

 

The tubes in question are just completely different. Unless you have a manufacturing lab in your basement OP, this mod is 100% impossible. 

 

Phone line: Yes I still have one, and I do not own a cell phone because I hate those things. And I am not grounding anything to it. Although, I was curious to see what would happen if you actually did wire your phone line to a vacuum tube. Would it just explode when you get a call???


Edited by Tjj226 Angel - 4/26/13 at 6:21am
post #21 of 36

I still have a land line at home...internet and my sat dish want to be connected to it...there hasn't been an actual phone connected to it in forever.

post #22 of 36

I don't believe this- TJJ226angel=== Need a manufacturing lab in your basement-I have never heard such a  load of rubbish in my  life.

          100% maybe in your brain but not in reality--TECHNICAL FACTS=ECC85=original tube SAME base as=ECC88/ECC189/ECC804

              ECC81--83/=pin 1=plate--pin 2 grid pin 3 cathode pin 6 plate 2 pin 7 grid 2  pin 8 cathode 2 ---pin 9 heater CT.

              ECC85=       pin 1=plate-pin 2 grid pin 3  cathode pin 6 plate 2 pin7 grid 2   pin 8 cathode 2.---pin 9 SCREEN

                   SPOT THE DIFFERENCE  DO YOU!!!===

                         ALL the pins  are the SAME ON BOTH TUBES----EXCEPT PIN  9 which is the CT for the heaters

                             So I REPEAT ALL he would need to do is change PIN 9 removing the earth/to chassis  and soldering on 1 LEG of the HEATERS to it.

                                You lack of knowledge will hurt other posters here - It is plain you do not have a professional  tube manual.

                                      Buy one and apologize!


Edited by duncan1 - 4/26/13 at 10:43am
post #23 of 36
Quote:
Originally Posted by duncan1 View Post

                   SPOT THE DIFFERENCE  DO YOU!!!===

                    

 

The plate curves don't look the same. At all. 

 

What do I win? 

post #24 of 36
Quote:
Originally Posted by nikongod View Post

 

The plate curves don't look the same. At all. 

 

What do I win? 

 

You win one Internet!

post #25 of 36

You asked originally  about fitting a ECC81/82/83. And I gave you the correct technical answer to fitting it.

        If you are checking the spec between an ECC85 and  the ones you talked about fitting then an ECC81 is nearest of the 3 to it.

            plate voltage depends on who manufactured it -ranging from -170--250 grid  slightly lower current drain is 2MA difference-ra -ECC81=11000  ECC85=9700--gain-ECC81 =5.9

                gain ECC85= 5.9   ECC81- cap.g/c =2.3pf p/c=0.2pf --g/p=1.6pf

                                            ECC85-cap g/c =3.0pf  p/c=0.18pf- g/p=1.5pf.

                                               Put ANY tube into a tube tester and increase the plate voltage=increased gain---increase grid-1- voltage -gain lowers

                                                     These values in manuals are set at a FIXED  plate and grid voltage - 

                                                          If you are going by curves -WHY didnt you tell me? It would have saved a lot of posting!

                                                               I gave you an answer to what you wanted to know.

                                                                  Then why not challenge-tube rolling?????   they use VM [variable mutual conductance] these tubes are specially made for radio communications.

                                                                       and are made to VARY the gain automatically along with AVC.  

post #26 of 36
Quote:
Originally Posted by duncan1 View Post

                                                                  Then why not challenge-tube rolling?????   they use VM [variable mutual conductance] these tubes are specially made for radio communications.

                                                                       and are made to VARY the gain automatically along with AVC.  

 

I did challenge tube rolling a page back. A few other people did too. 

 

How did we start talking about VM tubes? I guess a strawman is a good soldier in a loosing battle. 

post #27 of 36

Tell me  WHY you think I have lost the battle- Are you going to dispute the tube socket terminations or the electrical specs.

                 I was asked a question and I gave the CORRECT technical reply are you and "angel" a team?

post #28 of 36

Dude, you already lost for introducing a strawman. If you were right, you would not need it. 

 

VM tubes and their introduction into this thread are a strawman because they are almost never used except in radio recievers AND they had not been brought up before your post. They are seldom used outside of radio receivers because they are extremely non linear. They trade linearity for improved overload characteristics to avoid blowing the heck out of further components when you turn the volume way up high and spin through the channels, getting massive differences between static and program material.

 

You introduced a strawman into this thread. Sorry. 

 

Regarding tube rolling:

Will the tubes fire up with an acceptable plate voltage? 

Will the tubes run at an appropriate current? 

How will the tubes behave if the amp uses Grid bias, LED bias, tail CCS, plate CCS, or some combination thereof? 

Will these answers apply when a non-techy user digs out the adapters someone made to put a who knows what in place of a what should be there and drops them in his shiny new power amp "because they always worked before"?

 

Although this does not apply to the OP's amp it is a valid question since these adapters could find their way into a williamson amp or other amp with external feedback:

Will an amp with external feedback be stable with the new tubes? 

 

PS: Why do you format your replies to start a few spaces further in each line? It is kind of hard to read. 


Edited by nikongod - 4/26/13 at 1:22pm
post #29 of 36
Thread Starter 

Just to put the cat amongst the pigeons, i have indeed rolled in some variable μ tube into Lyr - PCC189 and ECC189. Neither of them sounded as bad as some people said they would.

post #30 of 36

Variable mu tubes have been mentioned several times in posts on tube rolling.-All you are doing is repeating what I said about them.Read my post

          Acceptable plate voltage ?-  That   within a set amount of values  the gain will be X -You are saying that when people put different tubes into an amp socket  that is the right plate voltage 

             for THAT tube-?????-There is NO universal tube UNLESS you put the correct tube that the tube was DESIGNED to work with the ANY other  type plugged in will NOT work to its peak value. So IF he is going for absolute manufacturers spec.-THEN -change plate resistor /CCS- change cathode bias resistor[we are talking  TRIODES so no grid 2

                Current is adjusted by fitting the correct value of plate resistor that allows the RECOMMENDED current drain to be applied -AT a SET voltage. And the grid is set at a set value

                    Grid bias can be adjusted- CCS? -so what  a CCS is what it is it supplies a CC to say a long-tailed pr  or another electronic circuit to stabilize the current.at a set current in relation to the values of the resistors in a dual BJT set up - Yes there are different set up components depending on the types of CCS

                        Why haven't you mentioned a current mirror? You might  as well add that in too.

                             The poster wanted to know if an ECC81 could be fitted I told him are you going to dispute what I said about the changes or the different electrical spec. of the 2 types??

                                     I couldn't CARE LESS about what you think of the way I post- You sound arrogant.-live with it! 

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