• 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.

4P1L DHT Line Stage

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M

michaelvv

Member
Joined 2014
CFT said:
Not yet planned ...like to hear your experience and suggestion on this :D
Click to expand...

Hi.

A Bjarne (Beardman) allready had mention both (Caps or Transformer) sound
very very good.

If you decide for make a ver 1 or 2, with Caps, You need to spend some serious
money on the Caps. If not It would be very inferior to the ones with transformer coupling.

I have tried Clarity MR, Russian PIO, V-Cap Tin Foil with just wasn't good enough.

Ended up using a combination of Rike S-caps (0.33) + V-Cap cuFT(0.1).

If you are on a limited budget , Just try the Rike S-cap(0.33) not that expensive and It sound really good.

Which Power Amp are you using ???

/Michael
 
C

CFT

Member
Joined 2006
1pekingroad.com/zaspx/replies.aspx?topicsno=4&subjectno=4934&uppersubjectno=4934
I am new to this Rike S-cap, thanks for the introduction Michael. Yeah together with the bypass v cap then its not inexpensive....

I see why you asked on the power amp..with RC coupled out its better to have a high input impedance one like a tube amp. I have some SET amps to mate that with. :)

Will consider the tranny out version as I need long interconnect cables etc :D
 
H

Hylle

Member
Joined 2005
Hi Beardman, you asked earlier where i was from in Denmark. I am from Herning area. Infact i am not planing to build this preamp, but another poweramp design using this tube. infact I hope it has gain enough to be used as integrated amp, but a doubt it. It will use 6SN7 as the pre-tube before the output stage.
(by the way I have seen you tread on Hifi4all, but i am not registreded to use hifi4all forum rigtht now, it is so long time ago i have posted, I guess they have shut down my account)
It is good to see others are re-discovering the no feedback tube designs.
 
merlin el mago

merlin el mago

Member
Joined 2009
Paid Member
michaelvv said:
I have tried a pair Svetlana 1963 (more microphonic , very warm) , Svetlana 1965 (great tube as beardman mention) , but now just playing on the standard 1986 4P1L.

The last one has the lowest microphonic level of them all (4 different set tested).

It's absolutely not night and day, on ver 1 "little siberian" I can easily adjust
how much warm I prefer, by adjusting the grid leak resistor (47K to 100K).

Again can't tell what the difference is on ver 3 with transformer coupling.

/Michael
Click to expand...

Much warm near 47K or near 100K?
 
merlin el mago

merlin el mago

Member
Joined 2009
Paid Member
I have the tubes & sockets to make the 4P1L, I make the #26 so the question is related to try in the same place for #26, I use a ladder resistor switch 100K so following your advice for 4P1L I'm in the open zone because actually I use 100K grind leak resistor in my #26?
 
Last edited:
M

michaelvv

Member
Joined 2014
Hi Merlin...

What I can really recommend, you should absolutely try.

Buy these resistor for your grid stopper...

Takman REX (Carbon).
Takman REY (Metal).
Shinkoh (Tantalum).

The difference is huge in my 4P1L. I really like them all. Right now I'm trying the
ShinKoh, witch besides quite expensive, just amazing.

They are warmer and very open, and I have only listening for 1 hour...

Will do an update, when I have 100 hours on them.

PS! When I rob a bank, I'll try these Vishay from mouser , 71-Z201T1K0000TB.

/Michael
 
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