TOA Idea..

[b2]

Hi all,

For some week, I'm interested  in some investigations in Tube operational amplifier :..I've found some nice  schemo (F.Forssel tube amp,Borbely and the old K2-V),nice read about the subject in the Meta.My holy Goal may seems as..

TOA:

-Design on 2 tubes ecc86 dual triodes (this one was used in car radio set).
-One for Diff.input pair.
-V+ and V- low voltage (+-24v to +- 48v).
-Pin as 2520.

TOA 2:

-Design on 2 tubes as 6111 or 6021 dual triodes.
-One for....
-V+ and V- high voltage (+- 100v to 150v).
-Pin as 2520.

Mother board:

-Pad.
-48V.
-Phase.
-may be Line in.
-Tx In (1:10 Transformer for some gain).
-Line driver as Srpp output stage or XX oneTransformer out

So, I wanted to know if someone as an  idea for the electronical design for the stage after the  Diff.Input tube  :,I didn't have tube simulator for design it ,so I still with my pen  ;D and going to build one  by trivial and make an Holy and beautiful burn on my bench

..Best regards,Bruno.

 

[shabtek]

interesting read:
http://www.dogstar.dantimax.dk/tubestuf/sapover.htm

 

[Samuel Groner]

Do you want an all-tube opamp or something hybride?

Pinout as 2520.

Have you thought about the space requirements of the vacuum? And how do you get the heater supply onto the board with just 6 pins?

Samuel

 

[b2]

Do you want an all-tube opamp or something hybride?

Pinout as 2520.

Have you thought about the space requirements of the vacuum? And how do you get the heater supply onto the board with just 6 pins?

Samuel

Hi,
I've seen the design  of Hybrid (Erno Borberly) very nice one!! BUT If I can build one all tube,it's will be great this is what i've plan :

Yes, you're right the pcb for this will be more larger than an 2520.For sure  the size of the ecc86 is 22mm by 45mm so for 2 if i go on all tube design...I need space but this tube please me cause it can run on low voltage,But..For the 6111 and 6021,it could be possible to go on 2" by 2" pcb size,This miniature are not too expensive  and they  can run  on +-100v and may  be they can do a nice job in this configuration .

For the heaters ,i will do it with 2 wires going from the Toa to mother board (heaters psu).

Thank for the reply

Best regards,bruno.

 

[Samuel Groner]

All-tube opamps are difficult as there is no P-channel part which can be used as level shifter. Some sort of interstage AC-coupling is usually employed--not really "opamp-like".

Samuel

 

[clintrubber]

Do you want an all-tube opamp or something hybride?

Pinout as 2520.

Have you thought about the space requirements of the vacuum? And how do you get the heater supply onto the board with just 6 pins?

Samuel

Going for other tube-types with say a Nuvistor-package might help here, you could put a few on such a board, but I don't know how many you'll be needing.
Don't know if Nuvistors also come in doubles, never done anything with them.

Don't know the heater-requirements of usable Nuvistors, but who knows simply in series & then connect them between the already present power-rails
(possibly using a series-resistor or something fancier).

Apart from that you might soon lose any sonic benefits, performance may suffer etc, but if it has to be a TOA with 2520-footprint then it should be possible.

BTW, note that vacuum tubes can also be integrated, so using tubes is no insurance against integration


Enjoy !

 

[b2]

Hi,

Thanks for reply,

Yes Nuvistor can de used for smallest integration ...the one I know is the 7586.This one is nice BUT it's only one Triode inside.For this idea of TOA, I may used Both Triode inside as 6110,6021 so it will be more easy to match Differential Input pair with one tube and with the 2nd tube the "driving stage" as the topology  I've seen in the K2-V.. :May be  it's an idea

I'm going to search another info on the subject...The defficience of this TOA design  may be..the job of the 2nd tube ;D

Thank,

Best regards,Bruno.

 

[clintrubber]

-V+ and V- high voltage (+- 100v to 150v).
-Pin as 2520.

I later realized that I didn't understand this combination... you want to make it compatible with present motherboards
out there but then spice these with HT ? Obviously, be sure to replace any electrolytics on the mobo
with types with higher voltage ratings (either before or after the 'ka-boom'  .

 

[analag]

This particular idea is a much better conversation piece than a practical design...carry on gentlemen maybe we will experience a miracle here.

 

[ppa]

This particular idea is a much better conversation piece than a practical design...carry on gentlemen maybe we will experience a miracle here.

Regarding mass production the problem is the cost of a TOA, how much should be its price for the audio engineers?
Is the price for the audio engineers is lower than the minimum price that a manufacturer can do?

However it's interesting designing a TOA. the problem of the heather is a small problem. It should be possible use the 2520 footprint for the standard pins and adding a connector on top side of the TOA for the heather, so it's possible using it into very famous 312/512 pre adding a power supply for the heather. BTW it's not possible use the GND pin for the heather.  

 

[clintrubber]

Uhh, again... after having found some sort of solution for how-to-heater,
don't we keep the issue of the values of the V+ & V- supplies ?
+/- 24V will be fine & can be accounted for when selecting the mobo-e-caps,
but much beyond that (say that mentioned +/-100V) AND 2520, I don't see the practical
value of using this standard footprint anymore.

Which doesn't mean that it can't represent some other value, but
we've left swap solid-state for hollow-state territory here,
if that might have been one of the goals.

Like Mr From Mars said, fun to talk about, and can be reason enough, but that's about it...

Bye

 

[ppa]

Uhh, again... after having found some sort of solution for how-to-heater,
don't we keep the issue of the values of the V+ & V- supplies ?
+/- 24V will be fine & can be accounted for when selecting the mobo-e-caps,
but much beyond that (say that mentioned +/-100V) AND 2520, I don't see the practical
value of using this standard footprint anymore.

Which doesn't mean that it can't represent some other value, but
we've left swap solid-state for hollow-state territory here,
if that might have been one of the goals.

Like Mr From Mars said, fun to talk about, and can be reason enough, but that's about it...

Bye

the TOA I've mind run with +-16V and +-24V (better), has 2520 socket , an added connector on the top for hedher.........it runs in my simulator...............

 

[spreemusik]

Use direct heated russian miniature tubes, you can heat them with a 1.2V battery.

 

[blue_luke]

*** Have you thought about the space requirements of the vacuum ? ****

Sometimes, taken out of context, we say very funny things without realizing it!

No offense meant Sam, I am very capable of the same thing!!  ;D but this one brought a good chuckle

Luc