Conversion to tube?

Chris H · 680

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Offline Chris H

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on: December 24, 2020, 04:54:11 AM
So, 2020 saw my first build (Crack + speedball) followed a few months later by Eros II which has now replaced my solid state phono stage.
I have loved the build process, loved the sound and love the learning and tinkering opportunity that follows - brings a new dimension to the hobby (not forgetting that first and foremost it's about the music).

My quandry is whether to go full tube or not, replacing my Naim pre and power (I am running 202/200 with PS upgrades).
As some may know, Naim have a clear upgrade path but it gets eye-wateringly expensive - next would be a Nac 282 pre which would likely be at least £2.5k used, £5k new.

I appreciate that everyone's ears are different and only I can decide but would be interested in the views of anybody that has taken a similar path (not necessarily from Naim).
Things like 'better' are subjective so I am more looking for relative comparison; what one will give compared to the other, as vague as that request may seem.

Up until now, I have had the excuse that the BeePre did not have the universal transformer for UK use but following some sterling work which I have followed avidly on the forum, we have the BeePre 2 (at a reduced price too!).
A couple of specific questions if I may:

1. I read that the BeePre would suit higher input impedance of solid-state power amp (would replace power later if I go that route).  Would it work with Naim 200 (18kOhms)?
2. How much space is needed above a tube amp (may need to adjust my rack and try to make space for both pre and power eventually)?

Any thoughts, insights, views are greatly appreciated.

In the meantime, I hope everyon has a happy and healthy Christmas and New Year.

Regards
Chris



Offline Paul Birkeland

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Reply #1 on: December 24, 2020, 05:22:41 AM
18K is on the low end of what would work properly with the stock circuit.  If you installed the first upgrade, which will consist of a large C4S active load for each 300B and a far nicer attenuator, you'd then be looking at a far better match, and the last upgrade with the buffered output would have absolutely no issues driving a 200 (or several of them for that matter).

While this may seem like a bit of an inconvenience, you'll likely end up with a far clearer appreciation for what each bit of the upgrade process offers since your application is so demanding. 

Merry Xmas!

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Chris H

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Reply #2 on: December 27, 2020, 03:10:44 AM
Hi Paul, hope you had a good Christmas.

Thank you for the response.  That's clear and what I suspected.

Any advice on clearance above either BeePre or Kaiju (potential later addition)?  Product page gives width and depth but not height.  I assume a couple of inches of additional space above would also be recommended.







Offline Paul Birkeland

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Reply #3 on: December 27, 2020, 05:45:39 AM
The height is roughly 9.5".  A BeePre doesn't need much extra clearance above the 300Bs, but the Kaiju certainly would!

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Chris H

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Reply #4 on: December 27, 2020, 07:29:46 AM
Thanks Paul, good to know.
Currently only have around 10" clearance so some work needed if I go that route.

In the meantime, have been thinking about S.E.X for the office.
I'm wondering if it is worth testing that in my main system first to see how tubes play with my source and speakers before making the bigger leap to BeePre and Kaiju.
Or is it too different to give me an idea of what the move from Naim to tube will provide?

Sorry for all the questions but still unsure about staying on the Naim treadmill or trying something else and it's difficult without auditioning.

Best
Chris



Offline Paul Birkeland

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Reply #5 on: December 27, 2020, 07:30:45 AM
The SEX won't push those speakers to very loud levels, but you could certainly listen to it! 

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Chris H

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Reply #6 on: December 27, 2020, 09:29:02 AM
Sure, understood.
SEX would primarily be for office near-field set up with pair of overnight sensations (part way through build) and active sub plus headphone listening.
Main set up is pair of 90db floorstanders, not a particularly large listening room but wouldn't expect to be rattling any walls.

Thanks again for the responses.



Offline Paul Joppa

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Reply #7 on: December 27, 2020, 10:38:21 AM
The SEX amp will give you a taste of the SET sound. The bigger amps are more sophisticated, but the sonic character is the same.

The original S.E.X. amp (1996, Bottlehead's first product) was intended for exactly that purpose - finding out if the sonic character of SETs appeals to you, at relatively modest cost. In those days, SET amps were few and far between, at least in the USA, exotic and quite expensive. It has gone through a lot of changes over the years, but retains the tube (6DN7/6FJ7) and operating conditions of the original and can still do the same job.

Paul Joppa


Offline Thermioniclife

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Reply #8 on: December 27, 2020, 12:51:58 PM
Having experience with Sex I can tell you it is good, all kidding aside, I have 2 Sex amps and love them. I think that are a great value.
I built a pair of Overnight's a couple of months ago and I like them in near field. I was skeptical so I tried and I like. I also use the Sex to listen to headphones in my evil laboratory using HD-650's, nice. I can also run the 2 Sex's in mono for a 4 watt output/channel
and squeeze a couple more db out of the Overnights.
Again I will say that the S3x is a great value. If this is your first build it is doable just read the instructions a couple of times and double check yourself after each step (sometimes it's better to have someone else check also, different set of eyes) The parts count is a bit higher than a Crack. This is in no way meant to scare you away. I think you will be very happy with the result. I'm just saying. :)

Lee R.


Offline Chris H

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Reply #9 on: December 27, 2020, 07:48:54 PM
Thank you Paul and Lee for the additional comments.
I think I will take the sensible path and try the SEX first since it will definitely see use in my office set up and I can try in my main system to test the sonic character before taking a blind leap with BeePre and Kaiju.

I must admit it took the lockdown to compel me to do that first solder join on the Crack but having since built the Eros with no major issue I am no longer nervous about the build process.
Between builds, I even managed to 'tune' my main system by experimenting with different home made interconnects (I used to be a "cables have an impact" denier until I purchased a cheaper replacement for a broken cable).
All home made power leads quickly followed and replacement cable for HD600s.
It was a real test of patience threading 5m of Litz wire through 3mm paracord 4 times and then making a 4.5m 4 braid plait but result is pleasing both sonically and aesthetically.



Offline Paul Birkeland

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Reply #10 on: December 28, 2020, 05:48:30 AM
Litz wire will definitely try your patience!

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Chris H

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Reply #11 on: December 28, 2020, 08:31:03 AM
LOL - it certainly did first time working with it.  First time was after buying some shielded Cardas for passive RCA switch box - i didn't even realise it was Litz until solder wouldn't stick.
I then bought some silk covered Litz to try in an interconnect - 81 strand, 0.4mm - twisted with silver clad copper.
Had a load left over and seemed ideal for headphone cable.
I can now braid plaits better than my daughters - there's something I never thought I'd say!