This is the fifth and, for now, final installment on input tubes for the Premier 140 power amplifier.  

Although I have some 18 or so small signal tubes still in the queue to try out, I've decided to move onto other topics to cover.  The reasons why I'm moving on are twofold.  First, the number of changes to my system since I've started the review have become too numerous.  Their cumulative affect has so radically changed the sound of my system that comparisons between those tubes auditioned before the changes and any tubes I listen to now, are no longer playing on the same field.  Second, after logging over 185 hours with the same tube complements in the 16LS2 preamp (6922EH) and the 140's power tubes (SED 6550C), I needed a change to keep my own interest fresh and engaged.

The subject of today's report is an Amperex Bugle Boy 6DJ8 with a small halo getter ring made in the Heerlen, Holland plant in 1965.

For those of you interested, my three favorite tubes auditioned so far have been (in order of preference):  the Amperex Pinched-Waist 6922, Mullard CV2493 and Tungsram PCC88.  You'll notice that the Tungsram has the next to lowest Average rating, so, a word to the wise on how meaningful these average scores may be versus what sounds best to you.

Future topics to be covered in these pages will include:

• Power cords by Shunyata -- the Venom3 and the original Taipan Alpha.  The last six feet do indeed make a difference.
• Footers, both brass and carbon fiber.
• Crystal of all sorts.  It's not just something to pour your champagne into. 

The fourth installment of input tubes for the Premier 140 covers the following two types:

1.  Telefunken ECC88 with small halo getter ring.  Presumed 1960s vintage from Berlin plant.

2.  Tungsram PCC88 with large halo getter ring.  March, 1971 production from Hungary.

Telefunken ECC88 front view                                                                Telefunken ECC88 rear view with Berlin plant designation
     

Telefunken Diamond

Tungsram PCC88 front view                                                                Tungsram PCC88 rear view
     

NB:  During the course of reviewing these tubes, there were two changes made to my system.  First, the QUAD 989 speakers were moved an additional 8 inches into the listening room and now stand about 37 inches from the front wall when measured to the midpoint of the front-top of the panels.  As might be expected this resulted in more sound stage depth appearing to come from behind the speakers.  Also, the lateral separation improved with more distinct imaging as well as better extension at both extremes of the frequency range.  Second, a Shunyata Taipan Alpha (original model, not the Helix type I have on the Hydra Model-8) is now pulling electrical duty for the conrad-johnson Premier 16LS2 preamplifier.  The improvements to the system's overall sound was also not subtle and I'll be reporting on this in a separate review in about a week's time.

For those of you counting, that makes four changes to the system in less than a month's time.  The CJD Teflon capacitor upgrade and HiFi-Tuning Gold 38mm Special fuses for the Premier 140, the re-positioning of the QUAD 989s, and the Shunyata Taipan Alpha power cord for the 16LS2.

There will be more input tube reviews to follow in the days and weeks ahead.

The third installment of input tubes for the Premier 140 covers the following two types:

1.  Mullard CV2493 dimple disc getter.  1970 vintage.

2.  Sylvania JAN 7308.  1967 vintage.

Mullard CV2493 front view                                                                  Mullard CV2493 rear view
     

Mullard CV2493 with top seam mark typical of Amperex tooling

Sylvania JAN 7308 front view                                                              Sylvania JAN 7308 rear view showing small halo getter ring
     

More to follow. 

The subject of this review is the German-made HiFi Tuning Gold Fuse.  HiFi-Tuning now produces cryogenically treated fuses in three flavors as follows:

1.  Gold:  This is the original gold over silver over copper end cap design with ceramic body and pure silver element wire.
2.  SilverStar:  Pure silver tip to tip.
3.  Supreme³:  99% silver + 1% gold tip to tip.

The HiFi-Tuning fuses replaced the two KTK-1 fuses which are fast-response 10.3 x 38 mm fuses with melamine bodies and nickel-plated, bronze end caps.  The KTK fuses are rather large and HiFi-Tuning offers them only in the original, Gold version.

Prices range from $39.95 to $89.95 depending upon size and type.  The Gold 38mm Special I purchased are normally $49.95 each but The Cable Company was kind enough to let me have them at their $10 off price even though I ordered the 1A replacement fuse two days before the sale was due to start. The conrad-johnson supplied fuses cost $15 each. 

HiFi-Tuning Gold 38mm Special Fuse                                                    With boxes
      

A Nice Pair                                                                                       Stock Fuse and the 2A Saboteur
     

One word of caution when using the HiFi-Tuning fuses.  Because they are high-precision items, they will blow if the current draw is only slightly above the rated value.  As I understand it, standard fuses will allow something like a 10% above tolerance draw before melting down.  This may not be a problem for most equipment owners, but conrad-johnson utilizes the fuses in their amplifier designs as the first line of defense when a power tube fails.  As a result, should a catastrophic power tube failure occur, or even arcing, you’re going to need to replace the fuse together with the tube(s).  This may happen only every two or three years as tubes age and need to be replaced, but it’s something to keep in mind.

I unwisely decided to replace the 1A HiFi-Tuning fuses in my Premier 140 with 2A fuses after losing one to an arcing output tube.  The next time I experienced a tube failure, the fuse held but the amplifier didn’t and the biasing resistor for the failed tube went up in a puff of acrid smoke.  This is a classic case of being penny-wise and pound foolish.

The fuses are directional and definitely, but subtly, sound better in one orientation over the other.  The usual recommendation is to install the fuse(s) in one direction and after a week or so, reverse it/them and see which orientation you prefer.  I’ve found that they sound better with the fuse oriented with its arrow pointing towards the fuse cap holder.

As those of you who read these ramblings on a regular basis will know, I recently had the capacitors in my Premier 140 upgraded to the CJD Teflon variety.  I had this done while c-j was repairing the damage done by my above-described venture in saving money.

I don’t know if I’m now more sensitive to how these HiFi-Tuning fuses affect the sound or, if the resulting increase in the amplifier’s clarity makes the changes to the system more readily apparent, but replacing the stock KTK-1 fuses with the Gold 38mm Specials resulted in immediately noticeable changes to the sound.

Once the new fuses went in, the sound became clearer and more detailed, more dynamic, with better frequency extension both at the top and bottom.  The sound stage also was more airy and delicately nuanced as well.

The $100 needed to replace both of the external fuses in the amplifier is not a small investment.  However, if you are looking to gain an extra degree of performance from your system, these little beauties may well be worth it.  And, if you’re not restricted by size constraints, you have three flavors, each with its own characteristic sound, to choose from.  The reader is directed to the HiFi-Tuning section of the Ultra Systems home page for more information.

It makes you wonder what are they capable of in a more systematic replacement regimen in the other components in your system?

The second installment of input tubes for the Premier 140 covers the following two types:

1.  GE grey glass 6DJ8.  Unknown vintage but presumed 1960s.

2.  Lorenz PCC88 gray shield with a getter ring fused with splatter shield construction.  1960s vintage with no label for OEM distribution.

GE Grey Glass 6DJ8                                                                            GE Grey Glass 6DJ8 Close-Up
      

Lorenz PCC88                                                                                    Lorenz PCC88 Fused Getter Ring Construction Close-Up
      

Stay tuned.

This is the first installment in a series of postings comparing the effect of various tubes used in the critical input position of the Premier 140 power amplifier. 

The idea is to run both of the c-j components (the Premier 16LS2 preamp and the Premier 140 amp) with their original tube types and brands to form a baseline comparison for the one variable:  the Premier 140 input tube which came stock with an Electro-Harmonix 6922EH.

Tube Configurations:

Premier 16LS2 preamp:  6 x 6922EH with two silicone O-rings per tube

Premier 140 power amp:  1 x 6922 (varies) with a Herbie’s HAL-O, 2 x Sovtek 6H30π-EB, 8 x SED =C= 6550C

 Electro-Harmonix 6922EH                                                                   Amperex PQ Pinched-Waist 6922 
      

Rating System:

Based on a scale of values ranging from -10 to +10 with a baseline value for the 6922EH of 0.

Explanation of Rating Criteria:

Bass:  How does the input tube handle frequencies below 160 Hz? 

Mids:  How does the input tube handle the range of frequencies from 160 – 1300 Hz?

Highs:  How does the input handle frequencies above 1300 Hz?

Detail:  The subtlest, most delicate parts of the original sound.

Grain:  A moderate texturing of reproduced sound. The sonic equivalent of grain in a photograph.  The higher the number, the less grain there is.

Dynamics:  Giving an impression of wide dynamic range; punchy. This is related to system speed as well as to volume contrast.

Sound Stage:  Not only sound stage width, height and depth but also the degree to which the images within the sound field seem to occupy space.  So that, for example, an input tube with a wide and deep sound stage populated by flat, two dimensional individual images will be ranked subjectively lower than a sound stage of similar dimensions having more solid images.

Average:  The simple arithmetic mean of the seven preceding characteristics.  If some of these qualities are more important to you, then you should weight them accordingly.  I'm not even sure if it's valid to average these characteristics to begin with but I know that some readers will do this anyway.  And so I'm including it for their convenience.

Forward:  How close to you does the sound stage appear?  The usual analogy places the listener in a concert hall and then refers to her/his row position.  Therefore, a perceived Row C position is more forward than a Row M position.

Warmth:  A mellow and rich quality in reproduced sound.  Warmth is the audible effect of a frequency response which is clockwise-tilted across the entire range, so that output diminishes to some degree with increasing frequency.  In my opinion, a certain amount of warmth is a normal part of musical sound.

In this installment, the Amperex PQ Pinched-Waist 6922 (November, 1958 vintage) will be compared to the 6922EH.  Here are the results, presented without comment.  There may be a comments installment following the final audition posting. 

* Ratings in this column indicate to what degree the input tube exhibits this characteristic compared to the baseline 6922EH.  Depending on the reader’s personal preferences a lower or higher rating may be a good or bad thing.

Further installments will follow as other tubes are auditioned.

The review set of eight Sovtek KT88 tubes was purchased from an online vendor but I no longer remember which one or their cost.  They are currently available at the Tube Depot for $54.95 a matched pair and at The Tube Store for $63.95, also for a matched pair.

These tubes were all manufactured in 1999 and, as such, may no longer be representative of current production Sovtek KT88s.  They are a top getter-only, three-hole, grey plate KT88 and have a chrome colored collar and black base.  Unusually, and perhaps uniquely for a KT88, they have an ST-shaped bottle normally only seen on certain 6550 output tubes.  Sovteks have a reputation for rugged build quality and good longevity.

The subject tubes had a total time of over 15 hours burn-in on the amp.  Although the Sovtek KT88s had all been used previously, they did exhibit some change as they settled in.  Specifically, the bass became deeper and their sound smoothed-out to a small degree. 

They replaced a well-used set of SED =C= 6550C tubes.  The 6550C was the output tube used by conrad-johnson to voice the 140 during its design and was supplied as stock with the unit.

Listening Impressions:

• The Into the Labyrinth CD by Dead Can Dance clearly depicts the reverb used on voices;  percussion instruments have a nice pop although they lack some heft and do not reach as far and as cleanly into the bass as the SED 6550C.
• Lower bass response extends almost as deep as the 6550C but is a bit more thuddy and less defined.
• Tolling bells sound reminiscent of the GE 6550A with a nice metallic quality although a bit lighter in weight.
• Massed strings are less edgy than solo violin with a feathery quality that is pleasing and the level of detail is borderline reference quality.
• The Pachelbel:  Canon & Gigue CD by Trevor Pinnock and the English Concert reveals plenty of clarity and high frequency energy with massed strings retaining their leading-edge transient snap within a fairly deep and wide sound stage.

In conclusion, although I didn’t dislike the Sovtek KT88s, I also didn’t particularly like them, either.  Even though I wouldn’t have previously imagined myself saying so, they make the SED =C= 6550C tubes sound liquid and smooth in comparison.  In terms of ranking, these would fall very near the bottom, just above the KT88EH and the 6550EH. 

NB:  I believe I will be taking a hiatus in reviewing additional output tubes.  Based on a comment on the importance of the input tube to the overall sound of the Premier 140 by one of this web log's readers, I have started to compile listening notes on various input tubes that I will use in the Premier 140.  Eventually, a comparison of the 6DJ8 family of tubes used for this purpose will be posted.  During the interim, look for postings on various tweaks I've made to my system and who knows what else.

I am keeping careful record of playing time for the amp as the new Teflon capacitors break in.  For the first 18 hours of play time, the tube configuration in my system consisted of the following:

Premier 16LS2:

• Six New Sensor Genalex Gold Lion 6922

Premier 140:

• One Electro-Harmonix 6922EH
• Two Sovtek 6H30π-EB
• Eight SED =C= 6550C

The Russians Are Coming the Russians Are Coming¹

For those of you with a discerning eye, all of these tubes are of Russian manufacture.  The small signal tubes are from the New Sensor Saratov plant while the SED’s are from Svetlana’s St. Petersburg plant.

Even with the minimal break-in received at the conrad-johnson facility and its time so far here, the amplifier sounded noticeably different from its pre-upgrade state.  And unlike many “better here and worse there” differences that occur when we make changes to our systems, all of these are positive.

Listening Impressions:

• There is a dead silence between notes that makes me better understand the audiophile cliché of a “black background.”
• Lower bass and upper treble are more extended.
• The sound is fast, clear, and rhythmic with a bass that has character and is tuneful.
• Initial transients are sharp and clean.
• Piano notes played quickly do not seem to blend together as much.
• The horns on the 1990 English Concert CD of Handel’s Water Music are sweet and burnished.
• The sound stage paradoxically seems to have more well-defined images that better blend into a more continuous presentation.  I know I’m not describing this well.   

I will continue to report on the Premier 140 as the break-in progresses.  One possible installment may be a comparison of the single, and critical, input tube.  I have found in the past that this tube is as equally important to the system’s overall sound as are the small signal tubes in the Premier 16LS2 and the power tubes in the Premier 140.

There will also be future installments on the tubes used in the 16LS2.  I am also contemplating some posts on various tweaks I’ve made to the system.

¹ Those of you who are old enough will remember the Oscar-nominated 1966 comedy to which this allusion refers. 

My Premier 140 amplifier has finally returned from its month-long stay at the conrad-johnson design, inc. facility in Fairfax, Virginia.  The amp was having some repair work done and what they refer to as a C1 Capacitor Upgrade. 

The upgrade entails the installation of proprietary CJD Teflon capacitors about which their web site says:

“The latest CJD Teflon* capacitors offer unique materials and construction simply not available in other capacitors. The dielectric film is a proprietary DuPont Teflon* film made to our specifications. A proprietary copper-rich end spray optimizes the electrical contact between end-cap and foil. Even the leads and solder for attachment were developed specifically for conrad-johnson. Our capacitors are fabricated by a top manufacturer with a proven commitment to the manufacture of audiophile quality capacitors. The CJD caps are hand wound by technicians with twenty years or more of experience, and each finished capacitor is subjected to inspection at three separate QC stations. These unique capacitors are, to the best of our knowledge, not equaled by any other capacitor available today.”

* Teflon is a registered trademark of E.I. DuPont deNemours & Co

These are the basics regarding the Premier 140:

• Power: 140 watts per channel from 30 Hz to 15 KHz at no more than 1.5 % THD or IMD, both channels driven into 4 ohms (also available connected for 8 or 16 ohm loads)
• Sensitivity: 1.1 volt rms to rated power
• Frequency Response (at 10 watts): 20 Hz to 20 kHz, +/- .1 dB
• Hum and Noise: 104 dB below rated power
• Input Impedance: 100 KOhms
• Tube Complement: 1 6922, 2 6N30, 8 6550
• Dimensions: 19D x 19W x 8H inches
• Weight: 85 Lb.

As you can tell from the last two bullet points, this is a big and heavy sucker.  It also generates enough heat to raise the temperature a couple of degrees in a medium-sized room.  Handy in the winter, not so nice during the summer.

The following professional review of the Premier 140 from the February, 2004 online magazine SoundStage!, is recommended to those readers looking for additional information and thoughts on the amp.  I find it particularly useful in that reviewer paired the amp with the c-j Premier 16LS preamplifier, the original incarnation of my own preamp.

Here are some photos documenting its arrival and set-up at my apartment:

Lassie comes home                                                                           I manage to get it out of the shipping carton
     

Rear view:  note single-ended connections                                           Uncaged
     

One of the new capacitors                                                                  Hoisted onto the rack
     

All dressed up

From left to right, the rear features the right and left RCA input connectors, the serial number and model plaque, right and left 1 amp fast-blow fuse holders with problem lights, right and left 5-way speaker binding posts, and the IEC receptacle.  The front of the amp has a single rocker switch to power the unit.  There is no standby mode.  conrad-johnson recommends and supplies two rubber O-rings for the single input tube to help dampen vibration and the resulting microphonics.

This is going to be a protracted break-in period for the Teflon capacitors.  Estimates for full break-in range from 300 hours (conrad-johnson) to 1,000+ hours (owners).  The next installment will cover my initial impressions using the stock input tubes (1 x 6922EH and 2 x Sovtek 6H30) and the 8 SED =C= 6550C power tubes.

Stay tuned.

The review sample was purchased from Jim McShane as a set of seven unmatched tubes for a one-time price of $29.50 apiece.  Jim normally carries the tubes for $44.50 each and many other online dealers sell this tube.  The tubes were made in 2010 and 2011.

The Gold Lion is a dual triode type of the 6DJ8 family.  New Sensor wisely does not refer to the Gold Lion 6922 as a “reissue” since, as far as I can tell, the Marconi-Osram Valve Company (which made and distributed tubes under the GEC, Genalex, Gold Lion, and Gold Monarch labels) never manufactured any tubes in the 6DJ8 family.

The Gold Lion 6922s replaced a set of Amperex JAN 7308 green label in my c-j Premier 16LS2 preamplifier.  The review set has a total of 43 hours of playing time and their sound did change as time progressed.  The changes were primarily in the bass, which became stronger and more extended, and in the treble, which became slightly smoother. 

The tubes used in the Premier 11A amplifier were two RCA 5751 black plates, two RCA 6FQ7 clear tops, and four SED =C= 6550C.  I find these RCA small signal tubes to be neutral and detailed and the 6550C power tubes to be detailed, neutral, extended at the frequency extremes and maybe a tad lean in the midrange.

The concluding portion (nine hours) of the audition had my newly returned, repaired and upgraded  Premier 140 amplifier in the mix.  With the introduction of a new amp (review forthcoming), I was able to evaluate the Gold Lion tubes from a fresh frame of reference.   

Although the Gold Lion 6922 is a Russian-made tube from the Saratov plant and should therefore bear a strong resemblance to its Saratov 6H23π-EB and Electro-Harmonix 6922EH brethren, it seems to surprisingly also have some characteristics of the Mullard PCC88/7DJ8. 

 Listening Impressions:

• Bass response is strong, laying a solid foundation to the music in much the same way as the Saratov (Reflector) 6H23π-EB.
• Although dialogue is clear and easy to follow, vocalists can sound “smaller” than life-size at times with mouth and throat predominating over the chest.
• Treble is open and extended.
• Low level detail is reference level.
• Transient attack is not quite up to the level of reference vintage tubes.
• Soundstage width, depth and height are near-reference grade and most like the Mullard PCC88.
• Macro-dynamics are forceful and are most similar to the 6922EH in this regard. 
• Lacks the tonal smoothness and grain-free quality of the best vintage tubes, as do the 6922EH and to a lesser degree, the Saratov 6H23π-EB.

I’ve found the Gold Lion 6922s to be extremely revealing and my favorite of the three Saratov-produced tubes in this group.  I’m continuing to use them during the initial break-in of the Premier 140 and will report further on it once I use it as the input tube for the amplifier.