• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

why not E88C

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#22
Oops!!

Quote: "That just so happened to be me...."

Oops! sorry....:dead:

Quote: "Use a OPT, it doesn't have to be Tam(b)ura, does it?"

Oh, c'mon! this circuit is all about OTL!

So, what do you think about the hi-ohm resistor idea??
Just give me a comment...
 
#25
Hi,

Improved opt Power?
Click to expand...

Well, the Philips AG9015 (which is what I had) does give you two options, either capacitor out to 800 Ohm speaker (their own model) or you couple through a small xformer into a 8 or 16 Ohm speaker.

That's how I listened to it.

While it sounded surprising powerful in the bass department, it did sound rather errr...old fashioned.

What I'm trying to tell you is that it's a nice idea for a highimpedance headphone, other than that you'll still need a OPT.

I've suggested a White CF before but even that won't reach down to a Zout below 8 Ohm with a pair of EL86s.

Cheers,😉
 
#26
fdegrove said:
Hi,



The sound of a tube is very much dependent on the way it is used.
Click to expand...
I think that, that's true too, Fred.
However, I've had a recent expereience of swapping tube brands in a 6CG7 and 12AX7 line-stage + cathode follower.
I was suprised that the 'sonic flavors' of these tube tubes that I'd previously observed in a simple line-stage circuit, also seemed to be reflected (admittedly to a lesser extent) when used in a cathode follower position too. (ie if it was a Mullard 12AX7 then the "Mullard mid-range" followed it into the cathode follower circuit position as well. Dittio for the 6CG7 types I tried). So there seems to still be something inherent about the tubes' themselves, in addition to the (major) contribution of the surrounding circuit.

This kinda bothered me, since I have a burgeoning preamp design which was going to employ a CF and I was hoping to be able to use a 'non-audiophile' caliber tube in this position. Now, I'll have to rethink this...




If you consider building a MC capable phono stage and not sitting on a stash of EC88s,
Click to expand...
Is my tube 'stash' that transparent!?!!? 😀 :clown:
:bullseye: I think I can count my good 6DJ8's on one hand, at the moment... :ashamed:



I'd consider the EC86 instead.

It's slightly quieter and has a little higher mu too...
More importantly I have used it already in that application and it works fine except for, perhaps, the lowest of low output MCs.


I'm using the ECC88 in a MC headamp with two of them in // per channel; search for MC Hammer here.

An other circuit that has been built by at least one member using the ECC88 in this application is the Hampton MC.
Click to expand...

Thanks for your interesting suggestion, Fred. I'll definately look into that one a little further.

Any comments or opinions about it's approximate sound quality vis-a-vie the ECC88 family?
 
#28
This single-ended circuit is the one that our old (beginning of the sixties) black & white Philips telly was using. It was also using an 800 Ohms speaker with the magnet mounted inside the basket.
It is quite astonishing that this is regarded audiophile nowadays 😉 :devilr:

Regards

Charles
 
#29
SY said:


Hmmm, I wonder which of the two of you has been more insulted, Fred or Frank.😉
Click to expand...


😱 Well I'm not sure that any insult was intended to anyone from my end; so, I'm definately not clear on whom I'm supposed to be backhanding!

(...But if whatever it was happens to be astoundingly super-witty, then I claim full responisibility 😀 😉 )
 
#30
Hi,

So there seems to still be something inherent about the tubes' themselves, in addition to the (major) contribution of the surrounding circuit.
Click to expand...

Certainly, different brands, slightly different parameters and different materials would make for a perceived audible difference even from different batches form the same manufacturer.

It is quite astonishing that this is regarded audiophile nowadays
Click to expand...

Why, it's just another SRPP circuit so it's already OUT of fashion...probably not old enough.

Hmmm, I wonder which of the two of you has been more insulted, Fred or Frank.
Click to expand...

We all know Fred won't comment on that...😉

Any comments or opinions about it's approximate sound quality vis-a-vie the ECC88 family?
Click to expand...

Most of those belong to the same folded anode family and were design for VHF use as cascode stages.
I quite like them as they have very good electrical properties and often are very low noise....
Depending on how and where you'd use them, I think you can make very good sounding circuits with them.

Cheers,😉
 
#35
Hi,

Read them and you will see that kevinkr speaks the truth.
Click to expand...

Or read the first page of this thread. 😉

That said, too bad there isn't a twin triode version of some of these valves around. Twin EC88 or twin EC86s would be nice.

Note also these are high gm valves so oscillation will occur just by thinking about them. 😉


Best, 😉
 
#38
1/2 12at7 ?

Just found a e88c..gold pin......had a quick look at the data sheet....it has similarities to 1/2 a 12at7...U=65 , low noise , sounds ideal for hifi

grid 1 @-1.3v ...a @ 200v about 14 or so ma ....

I wish I had another one now !!!!
 
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