Originally Posted by SemiAudiophile
how do you guys like the 6FD7 tubes over the others? btw, anyone know a list of tubes that are compatible with the WA6? i tried looking for a thread specifically for tube rolling with the WA6 but couldn't find one. what kind of tubes would you suggest if i'm looking for something less bright sounding and maybe more laid-back?
Here are some notes I made reading threads:
gz34 are great as well as the 5r4gy brimar brand. the rca version is good too but softer or rolled at the top compared to the brimar... the metal base
gz34 and the sophia mesh are quite costly
Try a good piece of Metal Base GZ34 - and you will know what your WA6 will be capable of.
The 274B is also nice, but it has a very different character compared to the Metal Base GZ34.
you may want to try a 5R4GA for the rectifier instead of the sovtek 5u4g...
it has a balanced mid/high and well extended/solid mid bass... it has
a very analog sound for me and it's very cheap at around $10... the 5AS4 will
have a deep and very impacting bass but they're a bit more expensive
and harder to find, at around $25... of course, the 5ar4/gz34 has the
"smoothest" mid range that i know of (haven't tried the sophia princess) but
are relatively expensive at around $75 each... hope you find what you're
the 5R4GA is made mostly by RCA and very few other type exists.
the mullard brand of GZ34 is recommended. it's a bit more tricky
to identify mullard consistently because many are rebranded like
telefunken, valvo and amperex... but just be reminded that you
shouldn't pay more than $75 even for a NOS... (except for metal
base and fatbase versions of the GZ34.) the GZ32 is more affordable
at around $35 and the mullard version is considered very good.
it has a warm midrange that's very smooth and has that tube
bloom characteristic which may help with a set up that's lean/cold.
the american version of the GZ32 is the 5v4g but it doesn't have
that blooming thing going for it...
Get some RCA 6DE7 in the oldest version you can find and then spend the money and get a metal base GZ34.
I've only rolled this tube once though and the GZ34/5ar4 makes a much bigger difference. Fkclo and jamato8 have written a few threads on these tubes. Look around for a nice metal base 50's Phillips Miniwatt GZ34. You won't find a better tube for this amp. I picked up a couple 58 Mullard wide base, a 63 Valvo, and a 60's Sylvania big bottle. The best I found was a 57 Phillips metal base and I recommend you start with a metal base
A lot of what sound you get with the driver/power tube (6DE7) will also depend upon when it was made. The GE's, RCA's, Sylvanias where made in the 1950 and some in the 40's and then on into the early 80's. The later tube often suffer from poor quality control and so goes the sound. Earlier is better, for the most part.
yes, i have a mullard made gz34 from the 60's and it's a fine tube...the gz34
made from the late 50's/early 60's are the best exhibiting creamy smooth
mids and fine dynamic punch...same applies to the amperex bugle boys. the
earlier versions, f31, seem to exhibit smoother mids than the later 60's/early
70's version, f33...but i'm nit-picking, really...just avoid the chinese and russian
made gz34...the japanese version "international", as well as "mullard" as jamato8
mentioned above, are the exception and equivalent in SQ to the f32
and relatively cheaper at around $20-$40 per tube...
amperex and mullard really sound very similar...but the amperex seems to
exhibit a very slight higher treble extension than the mullard whereas the
mullards are very consistent in the mid region where it excels...this is what
i hear with the wa-6 maxed...
my favorite gz34 version is the brown fat base mullard made in the late 50's
it has the best mids and bass extension along with a refined treble that
out does a round-plate tungsol 6sn7gt...but it's fairly hard to find nowadays.
the black fat base is nothing special and sounds similar to the standard
sized base...the metal is the most dynamic and i think that takes away a little
from the beautiful mids that is characteristic of the non-metal base types,
but it makes up for it with exceptional resolution and impact...very expensive
yes, the brown fat mullards are my favs amongst the gz34...
I have a JAN Philips 5R4GA (brown base) and a Sophia for my 6SE (maxxed). I, as others, do like the Sophia. But, the 5R4GA does have a nice detailed, punchy, upfront quality. I like it! By the way, I have some GE-labeled (British-made) 6EW7's that go great with the 5R4GA. I prefer 6DE7's with the Sophia... YMMV!
the gz34 is english designation and 5ar4 is american... same tube
made almost exclusively by mullard but rebranded... mullard bought
out philips in the 50's i believe... early metal base are all philips.
the lower output is probably due to early versus later design and
of course a good tube versus a tube in its last days...
the fxx is part of mullards date code. f31 is designating the earliest
version of the gz34 series... f32, f33 came later in the early 60's
and 70's i believe. you can also tell by the getters, a round and
a "D" shaped getter... some say the "D" is earlier, but i've found
early 50's mullard with round getters...
all the metal base, fat base gz34/5ar4 are f31 of the early 50's.
to be more specific, the metal base are rsb for 1951 (earliest that
i know of), rs1 for mid 50's, and tv2 for late 50's. all metal base
is from einhdhoven, holland. regardless of branding.
*imo, the gz34 w/ pair of 6cy7 or 6dr7 output tubes will give you 95% of the
princess sophia and 6DE7. of course, the sophia w/ 6cy7 is even better imo.
for output tubes:
6DE7, 6CY7, 6DR7 offers best prat and impact
6EW7, 6FD7 offers better sounstage and detail at the cost of losing some dynamics
6FQ7, 6CG7, 6GU7 offers the tubeyist sound, ie. soft glowing diffused sonic signature
at cost of soundstage, clarity and some dynamics.
*sorry, i forgot to mention the last 3 needs an adapter. it will not function in the wa6
without the adapter. you can ask jack to make you one but i've no idea how much
he'd charge for the pair. if you're good with soldering and electronics you can make
a pair yourself. it's not very difficult. you're welcome to ask if you need directions.
I have found that the drive/power tubes do have a nice infuence on the sound. The 6de7's have more attack and synergize better with the detailed Bendix tubes in my DAC. The 6ew7's have more decay and a wider, deeper soundstage, and they seem to compliment the WE396A in the Paradisea which exhibits these same traits. In both cases, this is with the Sophia rectifier. (I don't see any reason to roll something else into the rectifier socket - it's that good!)
This is almost like having two different systems to synergize with headphone choices or music genres. I find I prefer the 6ew7 sound and I would choose it if I was forced to pick one combination for all situations. Fortunately, I am not restricted and I can roll these various tubes for the variety.
I suspect that one could find rectifiers to support these two different signatures if a Sophia 274B was out of the price range. I know that the 5R4GYB works very well with the 6ew7's for a wide soundstage and smooth sound. I think that the 5U4G or 5AR4 might be the best match for the 6de7's, but I haven't gotten to experimenting with those yet.
RCA 6DE7 - I am really happy with how these sound. The bass is very deep and tight compared to the other 6DE7's that I have, and much better than the 6EW7. The soundstage and clarity are as good as the Sylvania fat bottle 6EW7, which were my previous best tubes in this area (but with rolled off bass compared to the 6DE7).
I have played with several different tube combinations over the past couple of weeks. I think the choice of power tubes makes a little more difference than I originally thought.
I start with the Sophia Princess in the rectifier slot. This provides a lot of detail and soundstage for either choice of power tube.
If I roll in the 6de7's, the sound is almost solid-state in presentation. The emphahsis is on dynamics, impact, good solid bass, and less air around the notes. With 6ew7's, the amp becomes more tube-oriented. The seductive warmth is there, along with better imaging and more decay, but a bit less impact. I am using Sylvania NOS power tubes in both of these cases.
It almost like having two amps in one. These differences are less apparent to me with other rectifier tubes. Perhaps that is because the rectifier tube choice is impacting the sound in ways that I am not accustomed to and can't describe properly yet.
As I comment about these things, I must say that I am not covering new ground here. These impressions are no different from what jamato8, takezo, and HeadphoneAddict (among others) have said before about these tubes, but it is new and interesting for me to travel down this same path.
The Sylvania 6DE7 are not as tubey as the RCA 6DE7 - I have both and started with the Sylvania and changed to the RCA on Jamato8's recommendation a while back.
You should really try the Mullard GZ30 brown base too
the 5u4g are okay but has flabby bass and not such great control and focus as
the 5V4G... and on top of that, 5V4G has a bloomy/tubey mid that's gorgeous... and
it can be had NOS for $15 to $30 each... the latter 5V4GA is not as transparent
and controlled at the highs and bottom.
those of you with the SE... try the rca 5v4g... it may surprise you. it's on par with the gz30.
All I can say is the Sophia Princess has noticeably better sound stage and treble, with tighter bass than my Philips metal base GZ34 (would cost you $200-400 on eBay) and my Amperex Bugle Boy GZ34 ($90).
However, the different thing is the realization that the Sophia 274B combined with the Sylvania 6de7's provide a sound that is very similar to what I remember from hearing a quality solid-state amp like the GS-1. Perhaps I am imagining this similarity, but there is no doubt that the amp has more impact and less warmth with this tube combination.
Here are some great tubes:
Tung Sol 5U4G / 5U4GB and similar
All are great, but the Sophia is better.
Tung Sol 6DE7s
Aperex 6DE7s (Holland Orange Label)
RCA 6DE7s (50s & 60s)
All are good, but the following are a "hair" better.
The Tung Sols, Amperex and Philco 6DE7s are exceptional, as are the Raytheon and Sylvania 6EW7s (which have more resolution, air and clarity, but a bit less bass drive).
If you want lots of bass drive and impact, and rich mids and highs try the all Tung Sol combo, or Tung Sol / Amperex combo. If you want greater refinement and resolution try the Philco or Sylvania Rectifiers with the 6EW7s. Or a combo of Tung Sol Rectifiers with the 6EW7s for a "happy medium."
If you've got the Sophia - you really don't need more in Rectifiers. Though, if I wanted a bit more warmth and drive - you might get a Tung Sol. I'd tend to focus more on a selection of 6DE7 / 6EW7s.
My initial impressions with the RCA fat bottle 6FD7 are:
- Better soundstage.
- Much better instrument separation and air.
Finally, got to try the RCA Fat Bottle 6FD7 tubes in my SE Maxed with my Philco 5U4GB, at the moment.
My first impressions are consistent with what some of you have reported... they seem to be a bit of a cross between the 6DE7s and 6EW7s - with exceptional bass and treble extension, and pretty good PRAT and impact, though not to the extent of the 6DE7s (especially the Tung Sols). They seem to have a bit greater detail and texture, expecially in the bass. The mids are a bit less prominent and rich, and the upper mids and highs seem a bit more emphasized relative to the lower mids.
The soundstage is far more airy with greater ambience than the 6DE7s, more like the 6EW7s, but even greater - almost to the extent of being too emphasized, and almost artificial like the reverb, and ambience produced by a sound processor. This may be fine for classical music in halls, and larger venues... but... it may be a bit excessive for more intimate venues like jazz clubs, etc. I think I prefer the richer, bolder sounds of the Tung Sol 6DE7s and similar tubes, for jazz clubs, R&B, and intimate vocals.
But... if you like a big, open, airy, more diffuse sound, you'll like the RCA 6FD7s.
Of course, as previously noted, they have about 10-15% more "practical gain" (9 O'clock vs 10-11 O'clock for the same volume), though their MU is much greater... but... don't seem to have a any noticeable noise at reasonable volume levels.
I still think I prefer the 6DE7s for the music I listen to most - to the 6FD7s, or 6EW7s, which both seem to be much more airy and diffuse.
I liked the GZ34 with Grados, but after comparing them to the Sophia I am not impressed with the GZ34. I have an Amperex Bugle Boy and a 1955 Philips metal base worth $300-400 for the two, and the Sophia beats them in clarity, speed, control and spaciousness.
The RCA and Sylvania 5U4G for $20 sound more spacious than the GZ34 but were a little plasticky or artificial in the treble. The Sophia was noticeably better in timbre and tone than these. With anything but the Sophia my Edition 9 and re-cabled HFI-780 were almost unusable (muddy boomy bass and rolled off treble) with the WA6, till I got the Sophia which was a match made in heaven.
And, now with Sophia my WA6 sounds just like Blutarsky's Melos SHA Gold and Zana Deux with anything we threw at them (from RS-1 and HP-1000 to HD6000). With the GZ34 it was still nice but lacked the bigger soundstage and bass control of the other amps. The bass with the Grado PS-1 is a little excessive on my WA6/Sophia but still well controlled.