Iron loaded preamp, any thoughts?

[hollow_man]

After much frustration with a 6H6Π LTP design intended for SE to balanced conversion, this is my new line stage plan. Please openly comment/suggest!

[hollow_man]

Mind you, them 6j5's, they don't go cheap eh? Not to mention the god**mn Lundahls, but will it play music?

[Zen Mod]

did you calculate gain ?

anyway - I like big xconductance tube in that position .....

WOT preamp and battery charger

[hollow_man]

x19 from 6j5 = 25.5dB
-2.5dB from shunt volume control
-13dB from tranny
=9.6dB, if I am correct.

[Zen Mod]

Originally Posted by hollow_man

x19 from 6j5 = 25.5dB
-2.5dB from shunt volume control
-13dB from tranny
=9.6dB, if I am correct.

[martyh]

HI,

I built a transformer coupled pre that was originally going to use 6j5Gs but sticker shock got me to wire it for ½ 6sn7. I still used two tubes but set it up so that the two channels used opposite triode sections. That actually worked out pretty well as I was able to get some good tube matches by swapping channels.

[hollow_man]

I thought of that too Martyh, and I think it's a sound idea if you have access to good 6sn7's. How is the sound? and what trannies did you use?

[martyh]

Originally Posted by hollow_man

I thought of that too Martyh, and I think it's a sound idea if you have access to good 6sn7's. How is the sound? and what trannies did you use?

I used a couple of types of vintage transformers, originally some rcas that were built by utc. They were very nice in the midrange but were limited on the bottom end, I switched them pretty quickly for utc ha133s which were much better in that regard.

My long term commercial reference is an ARC LS2, compared to that the sound was warm and full bodied but not in a bloated way. More musical is probably a good way to describe the difference. Vocals in particular had an uncanny realism compared to my reference, more of a “they are here” than a “you are there” presentation if that makes any sense

I listened to it until my marginal filament supply died and rather than rebuild it I am using the output transformers for a version using the 26. I’ve set that up so that if I can’t get the 26s quiet I can switch back to 6sn7s using the unregulated supplies and call it a day. I’m hoping that the 26s give me more of the more I got with transformer coupling but I really enjoyed the 6sn7s and if I need to switch back I’m ready to call it day in my preamp search.

[Bandersnatch]

Originally Posted by hollow_man

After much frustration with a 6H6Π LTP design intended for SE to balanced conversion, this is my new line stage plan. Please openly comment/suggest!

What about the LTP 6H6Π circuit frustrated you so thoroughly? Just curious, I'm currently listening to a linestage with 6S4Π-EB as LTP and loaded with 20k:600 output TX's and find it quite nice.
cheers,
Douglas

[zigzagflux]

Ditto, currently listening to a PP 6n6p linestage into amorphous Lundahl. Sheer bliss. What kind of problems? Those little tubes are like tanks; no noise, hiss, or hum, and never had a problem with RF or oscillation. They like their current, tho.

Not meant to distract from your topic.