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Little Dot Tube Amps: Vacuum Tube Rolling Guide - Page 353

post #5281 of 8068

And as the E80CC draws twice the 12AU7's heater current, running one of these using the Ocean's internal heater supply raises same question regarding the maximum heater current available....

post #5282 of 8068

Received three ECC40s today.

 

First up, one with a metal base, 1951, manufactured in Hamburg. Note the interesting getter shape.

 

 

And then two more, apparently manufactured in 1955, but I have no idea where. These factory symbols don't look like anything here:

 

http://tubedata.milbert.com/other/Philips/PhilipsCodeListAB-v10.pdf

 

But maybe a fresh set of eyes can figure this out? :)

 

 

post #5283 of 8068

Sorry guys i know this is not a Bravo thread IMO this the only place i can get help for this Amp.I measured the voltage between Pin 4 & 5 = 0V  Pin 4 & 9 = 21.9V and Pin 5 & 9 = 21.9V PCB pictures to follow.THANKS!

post #5284 of 8068
Quote:
Originally Posted by gibosi View Post
 

And then two more, apparently manufactured in 1955, but I have no idea where. These factory symbols don't look like anything here:

 

That's a 4, and a deformed character probably supposed to be a 4.

post #5285 of 8068
Quote:
Originally Posted by Oskari View Post
 

 

That's a 4, and a deformed character probably supposed to be a 4.

 

4 = Venolanda S.A., Venezuela

 

Ummmm.... Does it seem reasonable to then conclude that these were actually manufactured in Venezuela in 1955 using Philips production equipment?

post #5286 of 8068
post #5287 of 8068
Quote:
Originally Posted by i luvmusic 2 View Post
 

Sorry guys i know this is not a Bravo thread IMO this the only place i can get help for this Amp.I measured the voltage between Pin 4 & 5 = 0V  Pin 4 & 9 = 21.9V and Pin 5 & 9 = 21.9V PCB pictures to follow.THANKS!

 

While the measurements seem strange, I would conclude that that 0V across pins 4 - 5 suggests 6.3 volts.

 

My best suggestion:

 

Send an email to 

 

info@bravoaudio.com

 

And ask two questions:

 

1) Is it safe to roll E80CCs in the Ocean?

 

2) Is the 12AU7 configured in 6.3 mode or 12.6 mode?

post #5288 of 8068
Quote:
Originally Posted by Oskari View Post
 

Eindhoven, again. :smile:

 

 

Oh, this scan is different than the pdf I have been using. But when looking at old tubes this scan looks to be more useful. Thanks! :)

post #5289 of 8068
Quote:
Originally Posted by gibosi View Post
 

 

While the measurements seem strange, I would conclude that that 0V across pins 4 - 5 suggests 6.3 volts.

 

My best suggestion:

 

Send an email to

 

info@bravoaudio.com

 

And ask two questions:

 

1) Is it safe to roll E80CCs in the Ocean?

 

2) Is the 12AU7 configured in 6.3 mode or 12.6 mode?

OK THANKS!

post #5290 of 8068

 

 

 

 

 

 

 

post #5291 of 8068
Quote:
Originally Posted by TrollDragon View Post
 

 

I think it has a lot to do with the way the Bravo provides filament power to the tube, where the Crack has a heater winding directly from the transformer.

 

The Bravo, depending on the version uses a transistor and zener or LM317 regulator to provide the 6.3 VDC heater power... You could probably make enough modifications to the Bravo to allow octals to work but why...

 

 

Would it be feasible to strap a resister across the heater pins to fake the Bravo into "thinking" there is a tube inserted in the socket? And then he could make the appropriate connections from his octal socket to the Bravo and use his external heater PS?

 

(And again, I know just enough about electrical circuits to be dangerous! lol :)

post #5292 of 8068

@ILM2 Excellent!

I'll have to look at the board in a little bit.

 

@gibosi I don't think that would be good a good idea but I'll have a look at the board and see what might be.

post #5293 of 8068

These is the AMP that got me started buying the DT and Q Headphones followed by LD MK III and then the LD 1+  i know it's not the best amp out there but IMO i can plug in any headphone i have and it able to drive them all and the sound from it is not that bad in that price range.If we can manage to run it with 6SN7 tube it would be nice and in end if not then back  into the drawer.

post #5294 of 8068
Quote:
Originally Posted by gibosi View Post
 

 

Would it be feasible to strap a resister across the heater pins to fake the Bravo into "thinking" there is a tube inserted in the socket? And then he could make the appropriate connections from his octal socket to the Bravo and use his external heater PS?

 

(And again, I know just enough about electrical circuits to be dangerous! lol :)

 

 

Quote:
Originally Posted by TrollDragon View Post
 

@ILM2 Excellent!

I'll have to look at the board in a little bit.

 

@gibosi I don't think that would be good a good idea but I'll have a look at the board and see what might be.

THANK YOU!

post #5295 of 8068

Hey ILM2

 

OK looking at the board it appears that pin 9 goes to ground. Can you carefully give me 2 voltage readings from the two points in red with you negative probe on the black point. DC Volts and a 12AU7 tube has to be installed for doing this.

 

Also can you read the numbers off of these two components circled in red, I believe they are LM317's but can't find any pictures on the net to verify.

 

The schematic's I have seen around seem to deal with those ugly Bravo amps in the plexiglass as opposed to the Ocean.

:beerchug:

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