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Little Dot Tube Amps: Vacuum Tube Rolling Guide - Page 273

post #4081 of 10502

Thanks Gibosi and AFB, you convinced me not to try it.

 

Just out of curiosity, why cannot it be done? Too much current draw?

post #4082 of 10502
Quote:
Originally Posted by gibosi View Post
 

I received a nice little package today....

 

The tube on the right is a DARIO / RT / La Radiotechnique E88CC manufactured in the Philips-owned Mazda factory in Suresnes, France. Tube code is F7B1, so manufactured in February, 1967. And it appears that it was silk-screened and packaged in February, 1968 (6802). 

 

And the vendor threw in a free Tesla E88CC with gold grids! What a nice surprise! :)

 

A nice surprise indeed lol; curious as to how both tubes sound now!

 

Quote:
Originally Posted by gibosi View Post
 

 

Ummm... How serious are you? 6.3 volts... .3 amps....  I could certainly do this very easily with my Vector-breadboard adapter.....  

 

Actually fairly serious since the basic specs seem to match pretty well, so it's worth a try. The recommended cathode bias resistor values seem a bit off though (200-240 ohms recommended for class A operation, LDs have 780 ohms if I recall), but we never used to check that anyway and many tubes still worked regardless...

 

This tube could even be a good candidate for a paralleled use (one tube for each channel, strapped cathodes, strapped grids, strapped anodes) since it has medium gm (unlike the 6DJ8's high gm), and because of our amps' cathode bias value (maybe?). Again, bear in mind, half of this is speculation. Then, again, speculation has gotten us this far lol...

post #4083 of 10502
Quote:
Originally Posted by Audiofanboy View Post

 

Actually fairly serious since the basic specs seem to match pretty well, so it's worth a try. The recommended cathode bias resistor values seem a bit off though (200-240 ohms recommended for class A operation, LDs have 780 ohms if I recall), but we never used to check that anyway and many tubes still worked regardless...

 

This tube could even be a good candidate for a paralleled use (one tube for each channel, strapped cathodes, strapped grids, strapped anodes) since it has medium gm (unlike the 6DJ8's high gm), and because of our amps' cathode bias value (maybe?). Again, bear in mind, half of this is speculation. Then, again, speculation has gotten us this far lol...

 

Paralleled use? Well, first things first! lol

 

I have ordered an inexpensive pair of CBS 5670 / 2C51 / 396A with black plate and a D-getter....   And if they sound good, will consider getting another breadboard 9-pin socket and trying them paralleled..... :)

post #4084 of 10502
Quote:
Originally Posted by mordy View Post
 

Thanks Gibosi and AFB, you convinced me not to try it.

 

Just out of curiosity, why cannot it be done? Too much current draw?

 

Mordy... I think the answer is that we just don't know what will happen. But it is hard to imagine that it would sound good. And it is easy to imagine that the resulting electrical demands might exceed anything the the LD was designed to handle....

post #4085 of 10502
Quote:
Originally Posted by gibosi View Post
 

The tube on the right is a DARIO / RT / La Radiotechnique E88CC manufactured in the Philips-owned Mazda factory in Suresnes, France. Tube code is F7B1, so manufactured in February, 1967. And it appears that it was silk-screened and packaged in February, 1968 (6802).

 

I have been listening to this tube on and off today during burn in, and Brent Jessee's description is spot on:

 

"They are sweet like the Holland tubes, with a bit better detail and punch at the top end, and still have nice balanced warmth."

 

http://www.audiotubes.com/6dj8.htm

 

If you like the Holland sound these would be a great addition to your collection.

post #4086 of 10502
Quote:
Originally Posted by gibosi View Post
 

 

Paralleled use? Well, first things first! lol

 

I have ordered an inexpensive pair of CBS 5670 / 2C51 / 396A with black plate and a D-getter....   And if they sound good, will consider getting another breadboard 9-pin socket and trying them paralleled..... :)

 

Apparently, there are or have been adapters made to use 2C51 tubes instead of 6SN7 tubes.

 

So, since we managed to:

- Adapt two triodes instead of two pentodes

- Adapt 12Ax7 (and 6DJ8) double triodes instead of two single triodes

- Adapt 6Sx7 tubes instead of 12Ax7 tubes

 

And since it seems one can adapt 2C51 tubes instead of 6Sx7 tubes, at least electrically: one could assume that we could use 2C51 tubes in our amps!

 

Yeah, I know... The method is a bit weak in this reasoning lol... Real weak.

post #4087 of 10502
Some octal's with the grid post on top would look great, better yet the dual top posts. I want to see that nice blue plasma glow as well as the filament glow. biggrin.gif
post #4088 of 10502

Roll me some of this...

*

Just look at the envy in her eyes... :D

post #4089 of 10502

Hi guys.

 

These will be my last musings on the Telefunken ECC88 - I should imagine by now everyone is fed up with my rantings!

 

After many (happy) hours of revisiting my favourite CDs used for tube comparison, I continue to be blown away. Over the past months, successive tube types have given tangible if often only gradual improvements. And sometimes one can almost give credence to the school of thought that says we rollers are deluding ourselves - tubes being 'merely' vehicles for signal gain (of course we ALL know differently!)...

 

Anyway, the immense leap I am hearing now TOTALLY blows said school right out of the water...and to a degree that I truly cannot fully understand. The differences are not in just 1 or 2 areas, which is usually the case, but EVERY SINGLE ONE. And as for bass, I never believed headphones could deliver such bone-shaking magic - and my HD650s are not even right there at the top of the heap! All I can think is that these tubes are not just extremely good generally at what they do, but also that they are matching in some really special way the rest of my equipment - the hackneyed saying about the "whole being greater than the sum of the parts?"

 

Whatever, all I can say is look out for some reasonably priced used tubes - you may need to be patient! - mine cannot be the only set-up that is transformed beyond all expectation...

 

Good luck...

post #4090 of 10502
Quote:
Originally Posted by hypnos1 View Post
 

Hi guys.

 

These will be my last musings on the Telefunken ECC88 - I should imagine by now everyone is fed up with my rantings!

 

After many (happy) hours of revisiting my favourite CDs used for tube comparison, I continue to be blown away. Over the past months, successive tube types have given tangible if often only gradual improvements. And sometimes one can almost give credence to the school of thought that says we rollers are deluding ourselves - tubes being 'merely' vehicles for signal gain (of course we ALL know differently!)...

 

Anyway, the immense leap I am hearing now TOTALLY blows said school right out of the water...and to a degree that I truly cannot fully understand. The differences are not in just 1 or 2 areas, which is usually the case, but EVERY SINGLE ONE. And as for bass, I never believed headphones could deliver such bone-shaking magic - and my HD650s are not even right there at the top of the heap! All I can think is that these tubes are not just extremely good generally at what they do, but also that they are matching in some really special way the rest of my equipment - the hackneyed saying about the "whole being greater than the sum of the parts?"

 

Whatever, all I can say is look out for some reasonably priced used tubes - you may need to be patient! - mine cannot be the only set-up that is transformed beyond all expectation...

 

Good luck...

 

Yup, this is what it's all about, basically.

 

See, I had the exact same troubling impression my first few days with the Amperex Orange Globes tubes, and in turn, again and even moreso with my current Amperex 6922.

 

It feels like I'm no longer hearing music or sound through my headphones for the first time, in a way. Of course, I've made a bunch of changes throughout the years that gave me this same "feeling", but never that pure and unadulterated. Using a pretty solid pair of orthos on my MK IV SE with the Amp'ex 6922 & a pair of 6N30P-DR, I really do get the sensation I've reached a breaking point. There's just a sense of music being "right" that I never quite managed to get up to now. I'd reached several plateau-like level a few times, but never that good and mesmerizing ! I mean, drums and bass guitar now sound better on my headphones than in the real world (think live concerts and such)... It's actually kind of scary...

 

Anyway, yes, the Amp'ex tubes were that much of revelation, and these tubes are definitely worth the money, so there is no reason to hesitate.

post #4091 of 10502
Quote:
Originally Posted by Audiofanboy View Post
 

 

Yup, this is what it's all about, basically.

 

See, I had the exact same troubling impression my first few days with the Amperex Orange Globes tubes, and in turn, again and even moreso with my current Amperex 6922.

 

It feels like I'm no longer hearing music or sound through my headphones for the first time, in a way. Of course, I've made a bunch of changes throughout the years that gave me this same "feeling", but never that pure and unadulterated. Using a pretty solid pair of orthos on my MK IV SE with the Amp'ex 6922 & a pair of 6N30P-DR, I really do get the sensation I've reached a breaking point. There's just a sense of music being "right" that I never quite managed to get up to now. I'd reached several plateau-like level a few times, but never that good and mesmerizing ! I mean, drums and bass guitar now sound better on my headphones than in the real world (think live concerts and such)... It's actually kind of scary...

 

Anyway, yes, the Amp'ex tubes were that much of revelation, and these tubes are definitely worth the money, so there is no reason to hesitate.

 

Hi AFB.

 

Sounds like your Amperexes gel with the rest of your equipment (as with Gibosi's) the same way my TFKs do with mine - I'm quite sure the 6N30P-DRs help a good bit too, especially with the bass! Thank goodness the DRs should have a VERY long life!...And the TFKs, hopefully - swapping the triodes over regularly should see to that, fingers crossed...

I agree with your 'kind of scary' - I'm still shaking at just the mere thought of what has been transpiring the last couple of days! WONDERFUL...Let's just hope everyone else is able to experience this same magic soon, if they haven't already - as you say "this is what it's all about".

post #4092 of 10502
Quote:
Originally Posted by Audiofanboy View Post
 

 

Yup, this is what it's all about, basically.

 

See, I had the exact same troubling impression my first few days with the Amperex Orange Globes tubes, and in turn, again and even moreso with my current Amperex 6922.

 

It feels like I'm no longer hearing music or sound through my headphones for the first time, in a way. Of course, I've made a bunch of changes throughout the years that gave me this same "feeling", but never that pure and unadulterated. Using a pretty solid pair of orthos on my MK IV SE with the Amp'ex 6922 & a pair of 6N30P-DR, I really do get the sensation I've reached a breaking point. There's just a sense of music being "right" that I never quite managed to get up to now. I'd reached several plateau-like level a few times, but never that good and mesmerizing ! I mean, drums and bass guitar now sound better on my headphones than in the real world (think live concerts and such)... It's actually kind of scary...

 

Anyway, yes, the Amp'ex tubes were that much of revelation, and these tubes are definitely worth the money, so there is no reason to hesitate.

 

As an addendum to my last post, I think I may have finally sussed the extra, magical ingredients that are creating that feeling of being "right" - elements that once again up until now I hadn't fully grasped/comprehended (in my ignorance), although I did have the odd glimpse now and again...ie firstly "attack" - different instruments seem to come in bang on time, with controlled definition and 'purpose', cleanly and without blur/confusion/dominance (hope I'm on the right track here...). And secondly "dynamic range" - I have easily grasped the concept in film soundtrack, where certain special effects are accompanied by massive surges in sound, but have never fully realised and appreciated its more subtle use in plain music, viz its impact when volume, throughout the full frequency range, shifts so smoooothly and effortlessly from soft through loud without coloration, individual element dominance, or distortion.

On reflection I think these 2 aspects contribute far more  to that "pure and unadulterated" experience you mentioned than is usually covered in reviews - it has taken my current tubes, as with you and yours, to educate me in this...well that's my interpretation, anyway - but who am I?...

 

Someone who is still on cloud nine!...

post #4093 of 10502

I have a question considering channel dropout due to tube failure:

 

as my hifi chain has shown left channel dropouts recently i have swapped cables from the amp to the headphone and the headphone so now i'm at the amp stagewise going backward down the chain.

Could it be that a faulty tube causes channel dropouts and has anyone of you experienced this before? I'm still not sure and have changed the voskhods for different tubes and am still testing.

post #4094 of 10502
Quote:
Originally Posted by superdux View Post
 

I have a question considering channel dropout due to tube failure:

 

as my hifi chain has shown left channel dropouts recently i have swapped cables from the amp to the headphone and the headphone so now i'm at the amp stagewise going backward down the chain.

Could it be that a faulty tube causes channel dropouts and has anyone of you experienced this before? I'm still not sure and have changed the voskhods for different tubes and am still testing.

 

Have you tried swapping tubes? Moving the right tube to the left socket and the left to the right socket?

post #4095 of 10502

Yes i should have done that instead of swapping them completely....i didn't switch on my brain:)

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