• 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.

Preamp, Euridice?

After reading CLS Euridice thread I remembered my "to be" Euridice, since I never came to add the OT. In this case the tube is a 417A and is absoutly quiet and sounds realy good in it's present resistor loaded incarnation at 18 mA.

But the questions has do do with the attenuators or vol control. Originally I had a Greyhill switch and could control the gain quite easily but they were non shorting type and was almost imposible to use.

I had at hand one 100K black beauty from Alps so decided to change the switches by this one.

The problem now is that I have to much gain and have to use it very near ground and was wonderig which would be the best way to lower the overall gain of the preamp.

Loading more the tube wont get me there and I think the operating point is fine as it is.

Would shunting the input signal with a resistor be a good idea?
 
apassgear said:
Thank you guys, thats what I thought, the OPT will solve all my troubles so its time to decide which one to buy.:cool:

tip:
old BW TV have some sort of OPT in vertical section;
in Europe they were mostly driven with P(E)CL82 ;
if you have any in junk box,you can try it-just to feel what is all fuss about

;)
 

CLS

Member
2005-06-17 6:58 am
Taiwan
analog_sa said:

...
I wouldn't recommend anything less than Lundahl .....

Whew, I passed, barely:D

Anyway I'm very happy with my LL1660 & Raytheon 5842. They sound very clean to my ears. (Maybe I'll try 6C45Pi/6S45PE in this pre amp or try other better transformers.... Pitty that the pin positions of these tubes are not directly replaceable)

I always adore the simplicity of such design.

However, I also begin to think the possibilities to build some Aikido or GG circuits & wonder how they compare....

I think there must be someone here has built them all. Can anyone share some experiences?

:smash:
 
CLS said:


Whew, I passed, barely:D

Anyway I'm very happy with my LL1660 & Raytheon 5842. They sound very clean to my ears. (Maybe I'll try 6C45Pi/6S45PE in this pre amp or try other better transformers.... Pitty that the pin positions of these tubes are not directly replaceable)

I always adore the simplicity of such design.

However, I also begin to think the possibilities to build some Aikido or GG circuits & wonder how they compare....

I think there must be someone here has built them all. Can anyone share some experiences?

:smash:

my experience is that WOT stage is best in energy preservation ,and liimiting factor is only quality of used xformer.
hehe-often "energy preservation" is disguised with words like "microdinamics" , "nuances" , "microdetails" and other audiophile mumbojumbo......


:clown: