Hello All

[needsp]

Hi Guys

Greetings form Norwich in the UK!

For many years making and modifying hifi equipment to best reproduce the music I love has been my major leisure interest. In the mid nineties I became completely committed to valves

My System

Sources-
Modifed Buffalo II/Legato fed from a Cyrus CDXT SE transport (until recently I used a highly modified NOS Monica DAC from DIYParadise, and played a major role in its refinement
Highly modified Trough Line tuner and decoder (also a modified Hitachi FT-5500 II, but the modified Trough runs rings around it). This, I’d guess, is my most treasured possession
Voyd (split phase) + Wilson Benesche Act 2 + Cartridgeman Musicmaker Classic

Amplification-
Valve preamp (phono and line) of my own design (including a LDR-controlled volume setting and some MOSFETS these days)
A home built SE 300B amp
Preamp started life as an Audio Note kit, and the amp was originally a AN Kit1, but little but the casework of either remains. The amp is very similar to a Border Patrol S10 in design, but with several important differences

Speakers- home built Hammer Dynamics Super 12 (modified)

At the risk of sounding facetious, my taste in music is good music! I listen to a very wide range, though perhaps my greatest love is for classical chamber music- Beethoven, Bach etc. But also Bartok, Shostakovich, Coltrane, Monk, Dylan, Leonard Cohen, Joni Mitchell, Lou Reed, Bjork, Ian Dury, to name just a very few off the top of my head

Best wishes

Paul

[Darren]

Hi Paul,
Nice to 'meet' you. Love the sound of that system. Which 300b to you favour? Have you tried a few flavours?

[Spectral Morn]

Welcome to AOS Paul


Regards D S D L

[Jonboy]

Hi Paul and welcome nice to see another valve devotee, Hmm Sets over Push pull theres a very large debate in its self, both good if done right, more of a push pull man myself at the moment.

[Alex_UK]

Welcome, Paul, from a defector who spent 30 very happy years in the "Fine City" and was only persuaded to the "Dark Side" that is Ipswich by a very lovely and beautiful woman! (Just in case she is checking my internet history - again! :rolleyes: - I told her the lady-boy site was a mistake, but I still don't think she believes me! :eyebrows:)

I'm very inexperienced ion the way of the tube, but will hopefully try some one day. On "paper" your system looks fab, and an eclectic music taste to boot.

Enjoy the forum, and good to "meet" you too - whereabouts in Norwich are you (so I can steal your system when you are on holiday) - I grew up just off Earlham Road though my last place was on the cusp of Sprowston.

[Ali Tait]

Hi Paul,welcome.What's the circuit you're using for the 300b amp?

[Barry]

Welcome to AoS Paul.

Good to see another DIY'er. What mods you have made to the Leak Troughline?

Wonderful taste in music, I must say. :)

Welcome again

Regards

[needsp]

Hi Darren

Western Electric- no other possible choice! Very expensive, but last forever, and sound divine. Sadly (temporarily?) out of production

Hi Alex

Good god, she must be special. I only visited Ipswich once, nearly thirty years ago, and have no desire to repeat the experience....;)

Hi Ali Tait

It's a two stage amp (my line stage in my preamp has a suitably high gain to allow the power amp to be somewhat insensitive- about 2V rms in for full output). The driver is a 10000h 6p14p ("EL84M") wired as a triode, cathode biassed with a 8.2V zener diode (sounds much better than the usual resistor/bypass cap, and any noise from the zener is inaudible). Its load is a 1:1 bilfilar interstage transformer which drives the 300B. The latter is fixed biased. Bias, driver and output supplies are all separate, left and right, and are valve rectified and choke regulated (no cap before the choke). The filament supply is from Diy Hifi Supply, but I’m about to try a design from Rod Coleman (Lyrima Ltd)

Hi Barry

Deep breath-

Replaced all resistors with 2Wcarbon film types (very important)
Replaced coupling caps (polystyrene cap before cathode follower, Obbligato 1u after CF)
Changed input stage to use 6922, not original ECC84
Replaced all valve sockets
Replaced all power supply caps with Cerafines and Black Gates
New NOS valves; fitted low microphony E80CF in place of ECF80; fitted low microphony EF800 in place of EF80
Replaced 1k series resistor in PS with a 20H 1k dcr choke
Crucially, rebuilt discriminator with carefully matched AA119 diodes and 0.1% tolerance Welwyn resistors
Fitted MOSFET-based CCS to CF
Powered Tuner and off board stereo decoder from a 1:1 100W isolation transformer
Decoder is a One Thing unit using a LM4500 decoder chip; I‘ve modified this too- off stage transformer, Paul Hynes shunt regulator, passive equalisation, set chip to unity gain JFET output stage, Obbligato coupling caps
Proper aerial socket, new mains switch, new AFC and local/distant switches

For all this to be worthwhile, the unit needs to a late production Trough Line 3or a Trough Line Stereo- for stereo use at least. And, after modification, the tuner was realigned by a master- Ron Best at One Thing Audio (It had been aligned by him before I started too- surprisingly , all my work had little effect on the alignment!) He reckoned the resulting tuner was the best example he’d either heard or measured

I've probably missed something, but there you go

Paul

[Barry]

Hi Barry

Deep breath-

Replaced all resistors with 2Wcarbon film types (very important)
Replaced coupling caps (polystyrene cap before cathode follower, Obbligato 1u after CF)
Changed input stage to use 6922, not original ECC84
Replaced all valve sockets
Replaced all power supply caps with Cerafines and Black Gates
New NOS valves; fitted low microphony E80CF in place of ECF80; fitted low microphony EF800 in place of EF80
Replaced 1k series resistor in PS with a 20H 1k dcr choke
Crucially, rebuilt discriminator with carefully matched AA119 diodes and 0.1% tolerance Welwyn resistors
Fitted MOSFET-based CCS to CF
Powered Tuner and off board stereo decoder from a 1:1 100W isolation transformer
Decoder is a One Thing unit using a LM4500 decoder chip; I‘ve modified this too- off stage transformer, Paul Hynes shunt regulator, passive equalisation, set chip to unity gain JFET output stage, Obbligato coupling caps
Proper aerial socket, new mains switch, new AFC and local/distant switches

For all this to be worthwhile, the unit needs to a late production Trough Line 3or a Trough Line Stereo- for stereo use at least. And, after modification, the tuner was realigned by a master- Ron Best at One Thing Audio (It had been aligned by him before I started too- surprisingly , all my work had little effect on the alignment!) He reckoned the resulting tuner was the best example he’d either heard or measured

I've probably missed something, but there you go

Paul

Thanks for that Paul. I've been going through a programme of 'tube rolling' for the Troughline Stereo (essentially same as the Troughline 3). I too have replaced the ECF80 with E80CF, the EF80 with an E80F and replaced the ECC88 for both the input and cathode follower stages. I have yet to actually replace any resistors or capacitors - that will be the next phase.

Regards

[needsp]

Hi Barry

E80F isn't a beefed up EF80, but an entirely differnet design- even the pinning is different! The EF800 is the one to use (there may be others)

"I've replaced the ECC88 for both the input and cathode follower stages"

I presume you mean input and cascode stages. The cathode follower I meant is the output audio stage- the triode half of one of the ECF80's. BTW, for best sound, feed any external decoder from the cathode follower (after removing the de-emphasis components- this will be done in the decoder), not from the weedy output- direct form the discriminator- that Leak provided.

Many Trough line Stereos were rebadged 3's- check the back panel! It all gets a bit complicated, but some Stereos and 3's wont have the last generation discriminator, which was designed with stereo in mind. Even if a particular tuner has the original ECC84 front end- rather than the later ECC88- it may still have later generation coils! If your tuner's coils have ferrite cores with hexagonal holes (rather than slots), you're probably OK. BTW no Trough Line 2s have this discriminator

Paul

[leo]

Great to see you over here Paul :cool:

[Barry]

Hi Barry

E80F isn't a beefed up EF80, but an entirely differnet design- even the pinning is different! The EF800 is the one to use (there may be others)

"I've replaced the ECC88 for both the input and cathode follower stages"

I presume you mean input and cascode stages. The cathode follower I meant is the output audio stage- the triode half of one of the ECF80's. BTW, for best sound, feed any external decoder from the cathode follower (after removing the de-emphasis components- this will be done in the decoder), not from the weedy output- direct form the discriminator- that Leak provided.

Many Trough line Stereos were rebadged 3's- check the back panel! It all gets a bit complicated, but some Stereos and 3's wont have the last generation discriminator, which was designed with stereo in mind. Even if a particular tuner has the original ECC84 front end- rather than the later ECC88- it may still have later generation coils! If your tuner's coils have ferrite cores with hexagonal holes (rather than slots), you're probably OK. BTW no Trough Line 2s have this discriminator

Paul


Hello Paul,

Yes you’re right – as usual I got my knickers in a twist over valve types and nomenclature. (My mistaking the cathode follower for an ECC88 stems from previous posts here concerning my Leak Troughline Stereo)

This is probably a good place to thrash out the differences between the Troughline III and the Troughline Stereo. The Troughline III (or 3) followed the design of the Troughline II, both of which had the following valve line up:

V1 – ECC84
V2 – ECC85
V3 – ECF80
V4 – EF80
V5 – ECF80
V6 – EM84
V7 – EZ80

The Troughline III had inter alia V1 changed to an ECC88. The Troughline Stereo used the same chassis as the III (in fact some Stereo units had Leak Troughline 3 printed on the rear; my own sample does) and had a solid-state stereo multiplexer unit fitted internally. There were some minor changes around the cathode follower and to the point at which the multiplexer is connected (as you note) as well to some by-pass capacitors and to the power supply.

There were a few Stereo units that were modified Troughline 3 tuners, these had the multiplexer fitted and the front panel volume control replaced with a three - way switch ON/OFF/ mono/stereo, though the legend remains unaltered as ‘volume’.

Initially I found the sound on my sample to be excessively bass – heavy; voices were unnaturally chesty and deep. I cured the problem by replacing the EFC80 cathode follow (not as I erroneously stated an ECC88). Whilst swapping valves around I tried various ECF80s: two NOS Mullard ('yellow shield' logo) ECF80 and a NOS Mullard ('white shield' logo) E80CF.

I have also various tried various ECC88s: NOS Phillips (6992), ECG, Siemens and a NOS Mullard ('M' logo) E88CC, plus trying a variety of ECC85s: Mullard ('yellow and white shield' logos), Marconi, Brimar and Pinnacle. I can’t say that any of these changes have made much, if any, difference.

The Mullard EF80 (white shield logo) was replaced with another NOS Mullard white shield device (and not, as I erroneously stated, an E80F). The use of an EF800 interests me.

I can’t remember if the ferrite cores have slots or hex holes. I think they have slots; but I’m not going to remove the tuner from its wooden sleeve to find out.

That is how things stand at the moment. I may well change/renew the capacitors and upgrade the resistors; I like the idea of replacing R31 with a choke as you have done. I suspect however that updrading the stereo multiplexer with a more modern circuit will make the greatest difference however.

Regards