First impressions of Jolida int. tube amp

Early B.

Here are my initial quick and dirty impressions of my Jolida SJ502A integrated tube amp vs. my previous system. But first, some background info:

My previous system consisted of a Musical Fidelity A3CR preamp and Odyssey Stratos amp. This has been replaced by the Jolida.

Speakers – Norh 5.1
CD Player – Bada HD-22 (Chinese brand) tube CD player (modded)
Subwoofer – Onix Rocket
Cables – AQ Mammoth speaker cables, Kimber Heros, PS Audio & Custom Audio power cords

Room size – 17’ by 12’

Initial impressions – OH **** !!!
That was my impression after I went through some tube drama for the first couple of days. To make long story short, let’s just say that before the unit was operational, I went through a broken tube, a blown tube, a blown fuse, and a replacement tube that was DOA.

Soundstage – my room is too small for the music!!! I thought I had an expansive soundstage with my previous system, but the tubes have taken the concept of soundstage to a whole different dimension. As the name implies, it appears as though the sound is actually coming from a stage. Tubes make it sound more like a live performance.

Detail – actually, detail was more pronounced on my previous system. I’d like to get a bit more detail, but not too much more.

Vocals – much, much more airy. You know, like a singer should sound if you were hearing them perform it in a concert hall with great acoustics.

Musicality – plain and simple, it sounds more like music than my previous system. The solid state stuff I had, although extremely good (I loved it!), was a bit clinical and a tad harsh. I didn’t know it was harsh until I heard the Jolida. The tubes cleaned all of that up. There were songs that I used to skip because they were too bright, but with the Jolida, no song is off limits. Nearly zero fatigue.

Bass – Since the Jolida does not have output jacks, I have my subwoofer connected to my CD player (it has two pairs of outputs!). This blew me away because now I have much more control over the bass. In fact, I had to turn it down a few clicks from its previous setting. The control over bass is a tremendous benefit for me because I like lots of bass, and since tubes aren’t known for pumping out loads of bass, I’ve got this issue taken care of. The best of both worlds – that’s the biggest benefit I’ve noticed so far.

Volume – interestingly, I can turn the volume up very high and it doesn’t sound harsh at all. The volume on the Jolida (60 wpc) goes as high as my Odyssey (150 wpc). So again, watts don’t mean squat.

Build quality – when I opened her up, I noticed the soldering was very sloppy and the parts looked kinda cheap. And there volume knob is noisy.

Cost -- I sold my MF pre and another amp (I put the Odyssey on HT duty). With those funds, I purchased the Jolida and had about $400 left in my pocket. Better sound for a better price.

WAF – she loves how it looks, buy doesn’t want me to buy any more gear for a while. FWIW, I actually agree with her.

Bottom line – Let me just say that I don’t plan on going back to solid state. Forget it. I got bit by the tube bug. There are some things that need improvement, such as the detail, slightly more impact on some music, and a bit more forward vocals for my tastes. These issues could be cleared up as the tubes break in, or by rolling tubes, or by trying different interconnects, speaker cable, etc. I’ve already noticed an improvement in sound as the tubes have begun breaking in. I plan to do some modifications to the Jolida like changing out the capacitors, diodes and volume pot. I’m hoping these mods and tube break-in will round out the system.

dorokusai

Of course it sounds better, you got rid of the Odyssey. That's a great piece of gear, have fun with it.

Loud & Clear

Good read, Early. I'm sure the mods and some attention to the unit will only improve the good sound you're already getting. It's not a new unit and probably needs a little TLC.

Harsh upper frequencies really ruin the experience; the music may be great, but you just can't listen to it as long as you might otherwise want to.

madmax

Was one of my tubes DOA?

The stock Jolida is known as a slightly less detailed amp than some. KT-88's will give you more detail than the standard 6550's.

Messy solder? Pick up an iron somewhere and clean her up!

BTW, when you mess around inside you should discharge the main supply. It is run through big caps which hold their charge after pulling the plug. It can light you up. :eek:

madmax

Early B.

Was one of my tubes DOA?

No.

OK, I'll try some KT88's later on.

madmax

Sounds like you agree this was more of an upgrade than a downsizing?

madmax

PS: Great writeup!

Early B.

Sounds like you agree this was more of an upgrade than a downsizing?

Well, I upgraded by downsizing.

From now on, I'm just gonna keep it simple.

Early B.

Just got some tube dampers to place on my preamp tubes. I don't care whether they actually work -- I just got 'em for the cool factor. These little rubber band things look kinda neat on the tubes. They sorta have a George Jetson vibe to 'em.

madmax

I got some awhile back but lost them before I got them installed.

One thing to check as far as performance goes. Lay your hand around the top above the volume control and see if it is vibrating. It will be obvious. If so sit something heavy on the big center transformer. It will clean things up at lower volumes.

madmax

Early B.

Took my Jolida to the shop today to get it modded. I'm getting upgraded Audio Theta capacitors, and changing out a bunch of resistors and diodes. Also gonna replace the volume control, by-pass the balance and dampen the chasis. Hopefully, I'll notice a significant difference with these mods. I'll keep you posted.

organ

Great write up, Early. Like MM said, try some KT-88 to get more detail and bass. I believe they're more powerful too. The Shuguang KT-88 are getting a lot of rave lately.

Let me just say that I don’t plan on going back to solid state

:D And another one have crossed over:cool: Tube fetish is extremely fun!.

I'm sure you'll hear improvements after you get it back from the shop. Tweaks and mods are more easily heard on tube gear than ss.

Maurice

Early B.

Anyone ever tried the JJ Tesla KT88's?

00p225

Congrats on getting your Jolida 502. I recently bought an SJ-801 from my local dealer. Since it is integrated, I thought It would have more spouse approval than running all my DIY components in our living room system. I'm running the Svet 6550c's which are the same as the newer SED's. For the 1st gain stage I'm running the Sovtek 12AX7LPS, very open and clean tube. For drivers, a pair of early 80's vintage Raytheons.

These are nice sounding amps with good tone, but do sound somewhat veiled. I think upgrading caps and especially the volume pot will help open things up. Have fun and let me know how the KT88's sound.

Zane

Early B.

These are nice sounding amps with good tone, but do sound somewhat veiled.

Yeah, I suppose the term, "veiled" would be a good one to describe what I'm hearing. It's like there's something missing. Hopefully the removal of cheap parts in my Jolida will provide a cleaner signal path. I'll post my findings next week.

dragon1952

for you tubey dudes, a very good read from audiogon re: the following thread:
http://forum.audiogon.com/cgi-bin/fr.pl?aamps&1099871837&openflup&16&4#16

01-13-05: Zaikesman
FWIW, comments on a few things written above:

KT-88's are beam tetrodes (as Ecclectique alludes to), so there is no pentode connection available as with EL-34's for example. I was under the same misimpression until very recently, and there are good reasons to be confused, because the terms have gotten tossed around somewhat indiscriminately since the time beam tetrodes were first manufactured as an alternative to pentodes. (These technical developments were under patent at the time, and from what I can infer it seems the tube company marketers might have desired the positive association customers had with pentodes).

The connection Eldartford describes actually sounds to me like Ultralinear, rather than straight pentode. I do not know whether any VAC amps employ Ultralinear connection.

As for the sound and theory regarding mode vs. mode, allow me to offer my basic take from my experience with VTL amps using 6550C and KT-88 tubes:

As I see it there are two essential phenomena in play. One is the difference in power: roughly double in tetrode what's available from triode. This changes the sound all by itself, and taken on its own, if no other properties were to change, more power from the same number of otherwise identical tubes ought to sound better, or at least more accurate, given a power supply that can keep up adequately with demand.

But this leaves out the second essential property - the presumable reason for the sonic positives associated with triode mode, despite its lower power. This has to do with how the tubes diverge from linearity, otherwise known as distortion. As I understand things, when compared within comfortable power margins, triode-connected tubes offer lower overall distortion than when run in pentode, and what distortion remains is more benign in nature, i.e., lower in order and more weighted to the even harmonic series. This greater purity is what you trade off to some degree in order to obtain higher power from the same tube connected in tetrode or pentode.

These two characteristics - output power and harmonic distortion signature - taken together, pretty well explain what I hear comparing triode and tetrode modes with my amps.

Higher power sounds like...higher power. Better speaker control, which can translate into a host of audible qualities ranging from increased soundstage size and image separation to more bass tautness and less overhang. Greater dynamic capability, which can translate into less compression, more impact, and better microdynamic expression. The ability to play loud music louder and still maintain dynamic contrast and overall authority. Greater power, considered in isolation, even seems to be able to allow for greater transparency - but the degree to which extra power will benefit the sound has to do with many other variables, including speaker sensitivity and impedance, room size, type of source material played and at what volume, etc.

Experience, though, tells us that in actual practice, many of the positive qualities associated with the higher power of tetrode in theory, are in reality somewhat compromised in their ability to convey musical enjoyment, due precisely to the less agreeable harmonic structure of the more powerful mode. Who wants to hear music played louder, with less compression, if that music has taken on more of an agressive edge? Who needs the clarity of better driver control if a good part of what it lets you do is hear more clearly the extra, higher-order distortion the amp in full-power mode is injecting into the music?

There's another variable at work as well. When we talk about push-pull amps, we're talking about a circuit that inherently works to cancel even-order harmonic distortions. This serves to leave the odd-order distortions more nakedly exposed to the ear. (This fact, rather famously, also goes to part of why people may like single-ended triode amps - despite their very low power - which leave the triode's naturally low-, even-order harmonic products intact, instead of canceling them. The lower power does mean that total distortion levels rise much sooner and higher before clipping than with higher-power push-pull amps [even if SET clipping does approach more gracefully when it comes], but the low-order, even harmonics which the ear finds more musical predominate.)

Thus, a push-pull circuit operating in triode mode gets a double benefit on the distortion front: triode generates mostly low- and even-order harmonic artifacts, which the output stage architecture then tends to cancel out, leaving both less residue, and less objectionable residue. Tetrode or pentode by contrast creates a double-whammy applied in push-pull: higher- and more odd-order harmonics are generated than with triode, and then on top of that the output stage configuration tends to cancel-out what lower- and more even-order harmonic content does exist - content which would otherwise help to mask this less-pleasing timbral quality.

These reasons explain the continuing efforts - necessarily at high cost, since more tubes are required to achieve comparable output - to build high-powered push-pull tube amplifiers wired in triode, instead of simply going for the bigger bang for the buck possible from tetrode or pentode. (Witness, for instance, Atma-Sphere, which uses only triode tubes and many of them; CAT, which uses beam tetrodes but wires them exclusively in triode for sound quality; or of couse VTL, which makes mode-switchable amps so high-powered, you can run them in triode and still have juice to spare. VAC has even gone to the expense of making high-powered push-pull amps using multiple pairs of one of the most expensive triodes, 300B's, which we normally only see used singly in SET's.)

So, especially when played at lower volumes or with music that is not as dynamically demanding, triode will often sound best, this being manifest in a variety of ways, and again dependent on several other circumstances (including the particular output tubes used). But in general, it is possible to say that triode will usually sound more timbrally pure and natural, texturally cleaner, and with less artificial emphasis on silibants and harsher overtones.

A lot of ink is spilled in the above posts trying to make generalizations about the sounds of the two modes, but I think Trelja finally comes closest to the truth when he hits upon the term 'sweetness'. (I don't believe he means to connote the word with the modifier 'cloying' implied, as in added 'sugar', but rather more an absence of bitterness, as with the way really good mineral water can taste 'sweet' in the absence of the usual contaminating pollutants, but with traces left intact that our evolutionary history informs our senses are healthful.) This is cutting to the chase of what's most advantageous about triode and weakest with tetrode, though many other qualities, some of which may be more important with any particular musical program, will always pertain. What I've tried to do here is hopefully help explain why this may be so.

It is also important not to oversell the differences. The same amp, with the same transformers and power supply, fitted with the same tubes, and playing at moderate volume - especially with music of a not too-demanding nature, or not with highly specifically-flawed or extremely revealing recorded sound - will in reality probably not sound revolutionarily different played in one mode vs. the other, and that only makes sense.

As the volume gets turned up though, triode may tend to suffer more audible compression and loss of control, although only because of the lower power available (unless maybe you have one of the monster triode amps and/or easy-to-drive speakers), and not because of any inherent shortcoming about the mode per se. So frequently you're presented, as with so many things in life large and small, with a choice, when playing an average (or averagely bad) recording: to have that kick drum really pound you in the gut the way you know it can, or to keep that high hat from cutting off your head at the ears with what feels like white noise. Or just turn it down and play lute music.

In my amps, for whatever reason, I have found that KT-88's made by Electro-Harmonix tend to thrive more, relatively speaking, in triode mode than did the Svetlana (SED) 6550C's they replaced. So I think it is possible that there are tube-specific differences as to how amps will respond in either mode, and some tubes may do better in one mode than the other, or better in one mode than another tube type or brand will do in that same mode.
Zaikesman

audiobliss

What? No update about what she sounds like after the mods?!

Early B.

audiobliss wrote:

What? No update about what she sounds like after the mods?!

In a nutshell, after the mods the Jolida entered a whole new dimension of higher quality sound. Virtually everything improved, especially the detail and clarity. I became a major proponent of mods once I heard the difference.