DV Mark Little Jazz - Disassembly

[Gitterbug]

For instance, and taking your words, it’s not natural to me to use hot glue to stabilize (from what?) welded small components on a PCB. And those boards are crammed, as you said, not exactly compacted. Why don’t they use that extra time you refer to improve the engineering design on the desk instead of the factory?

Obviously, this is not a German or Danish concept amplifier, Everything suggests me an amateurish planning on such a well succeed product (maybe because of it) and I think it’s possible to do the same amp with better procedures while keeping the price. In fact, there’s some alternative products in the same range and some examples are shown, but allow me to present another one: Kestrel - '57 Princeton / Champ - 10 Inch | BirdSong

See the price? Hand made in Europe, point to point, tubes... etc.

I made my comments based on the OP, that gives some reason to other complaints about the consistency of the amp, and I’m not engaged on having reason on my comments, certainly I haven’t, but it’s not bad to be more demanding with the suppliers of our gear. If they improve their products everybody will win something. And chatting with you contributes to my lockdown.

Stabilization is needed in combos due to constant vibration from the speaker. The Kestrel amp is intriguing, but I bet the volumes are too low and waitlists too long for a realistic alternative to a mass produced amp. There are small boutique makers of tube amps in almost every country, but at least the ones I know admit it's a hobby rather than business - even at a multiple of Kestrel's pricing.

[christianm77]

For instance, and taking your words, it’s not natural to me to use hot glue to stabilize (from what?) welded small components on a PCB. And those boards are crammed, as you said, not exactly compacted. Why don’t they use that extra time you refer to improve the engineering design on the desk instead of the factory?

Obviously, this is not a German or Danish concept amplifier, Everything suggests me an amateurish planning on such a well succeed product (maybe because of it) and I think it’s possible to do the same amp with better procedures while keeping the price. In fact, there’s some alternative products in the same range and some examples are shown, but allow me to present another one: Kestrel - '57 Princeton / Champ - 10 Inch | BirdSong

See the price? Hand made in Europe, point to point, tubes... etc.

Lovely! Maybe if I'm a good boy, that might be a little pressie for myself. Seems like an amazing deal compared to what Fender puts out for the same money.

So points about construction and engineering aside - (and it might worth saying good pro solid state amps such as AER, Mambo (now), Henricksen etc seem to cost about the same as valve amps...) - comparing an LJ to a Champ is not like with like. First of all - valves respond differently? Colour the sound. What's the headroom on that? Might need modding (maybe speaker, valve changes) to make it viable as a live jazz amp, and not everyone is up for the fun of that.

Also, for some situations and certain instruments I prefer playing solid state actually.

The LJ came across as a fairly flat response solid state sort of sound. I find these amps a lot more immediate for one. Little valve amps sound great but they have strong opinions about how you should be playing.

Furthermore, 10KG is IMO too heavy for a public transport amp. LJ is 6.9 KG, about the same as my AER Alpha, and that's a bit annoying even at that weight.

I would get that Champ clone and use it as a recording amp. Tweak it if necessary for low level warmth and hair. My Princeton has been too loud in that situation.

EDIT: I see now it's a Princeton/Champ sort of hybrid. This is definitely getting the GAS going, naughty boy! Bad boy!

[DonEsteban]

I am the happy owner of a Little Jazz and found this post interesting.

I don't know how Cordalis comes to his harsh judgment just by looking at it, but as a trained electronics engineer all I can say is that I don't find anything unusually bad or cheap about this device. It is a PCB based SMD device like any other mass-produced electronic device.

It's indispensable to secure electrolytic capacitors mechanically especially with a device that is intended for permanent transport. Hot glue has more than proven itself in this regard. All cable connections are well secured (cable ties), the structure is clear.

It goes without saying that different modules are used today, because you reuse assemblies in other devices, having an extra PCB for effects or the power amplifier is nothing unusual, this increases profitability and is not uncommon.

So I can see - at least due to the photos provided - nothing extraordinarily "cheap" or "bad" and want to thank the OP for posting the pictures, because I also like to know how my devices look from the inside.

[waltf]

the birdsong is about 80 euros more expensive, does not have the headroom of the lj, does not have a di out and is a lot heavier.. apples and oranges and they both are great value.

[Durban]

The speaker looks nothing like Neo to me. .
Pardon me, but what has forced you to disassemble your LJ (again)? Haven't visited your previous posts on the subject.

Hi G
how can i tell if its a Neo?

I have not posted on this before, the first time i took apart i never took photos. Why who knows?

[Durban]

I have a 73 deluxe reverb, a babybrute and an LJ and love all 3 of them and they all have their purpose. Actually, most of the time i plug in the LJ. Guess i don't hear well...

you are right, i am not at all unhappy with my LJ overall they are pretty good, and reasonably priced. It's just i can get the perfect sound out of my other amps, MMV

Little Jazz is compromise. its almost there. the Reverb is crap. size weight power all good.

re your hearing it may be just a spec of wax.................. ha

[sgosnell]

I bought the Little Jazz because I wanted a light, easily transportable amp that didn't cost a lot but sounded good and would work when plugged in. I have a tube amp, and I seldom bother to turn it on, even at home. Tube amps are heavy and unreliable compared to solid state. I do use it as a speaker cabinet for my lightweight heads now and then. I do not want a point-to-point handwired tube amp. I don't want another tube amp at all. The Little Jazz fills my combo amp needs nicely, whatever is inside it. And looking at the photos, that looks almost exactly like every modern electronic device I've seen. The amplifier section doesn't look all that different from my AI Clarus, which has never been criticized as being cheap or haphazardly constructed. It seems perfectly ordinary to me, and I see nothing surprising nor disappointing in the layout or construction, especially at the price point. It's not a German nor Danish design, of course. It's Italian, and Italian design has been widely admired for a very long time. Personally, I don't care at all where, nor by whom, a piece of equipment is designed. Looks are not as important as function, and the Little Jazz functions more than well enough for my needs. It's light, loud, dependable, and sounds good. That's all I expected or needed. YMMV.

[mr quick]

Hm, maybe the DV Mark stuff is only worth $20 - but that cheap amp phased out every single other amp I had, and after going over to fully digital rigs, is the only amp I kept (two of)!

[rpjazzguitar]

I looked around the internet for pictures of the circuit boards of other amps. I couldn't find Henriksen or Mambo, but I found AER.

Looks similar to my untrained eye, including have the pots soldered into the board (which you won't see on a Mesa).

So, is the complaint about the sloppiness of the hot glue in the LJ?

I confess that I don't know if it's a bug or a feature.

My thumbnail review of the LJ: It sounds terrific for what I do. I'm now using it in my own rehearsal room, with my beloved '64 Ampeg Reverberocket in the closet. And, oddly enough, they didn't sound all that different (with external reverb). It's light and I think it's a good value at the usual price of around $350, compared to the alternatives at that weight. Seems well made to me, but I claim no expertise. Negatives: maybe one. The Aux input doesn't seem to work quite right with my phone, but this may be a connector issue. About the reverb: it's ok for me at fairly low settings. My son liked it higher than that, but I don't. However, I always play with an ME80 adding some reverb. Then I add more with the LJ, knob at 9 o'clock. Sounds great to me. I've posted several clips. Oh, maybe another negative is that pots and jacks seem to be soldered into the board (same as the AER) -- over time, the mechanical force applied when you plug in and out and rotate the knobs can crack those solder joints and you have to open the thing up and reheat them, which can be a pain in the neck.

[Durban]

i have come to my sense's re L Jazz, looking inside my Baby Brute and Mega there is not a lot in there. but according to the old fellow who did work for, he said both Roland And Polytone used good mosfets etc. they also used computer connectors i think. Just that fibre glass was a goofy idea.

There really cant be much in those Boss Katana amps not that iv seen one.

[Gitterbug]

Good. Let's be grateful when somebody cares to produce dedicated gear for jazz guitarists and bassists, at affordable prices. If they make a profit, it's ok IMHO. A major difference to the point-to-point days of yore is that soldering alloys containing lead are no longer allowed. Here may loom a Brexit benefit for UK makers. However, even if they could legally turn back the clock in the home country, the products could not be sold wherever RoHS is required.

[christianm77]

Yeah, I'm quite happy to continue have amp manufacture that doesn't involve a neurotoxin.

[Gumtee]

Is the white stuff glue or RTV silicone adhesive? It's used to prevent component vibration, mostly on larger components like capacitors to prevent movement and broken solder joints and is non-corrosive. It's a good thing, specially for a amp that often gets moved or transported.

As for the shoddy looking application, it looks the same as on the higher end Class D boards I'm about to order for my hifi hobby amp project. Mass production I suppose. As long as it does the job.

[MaxTwang]

Gitterbug

.bored with virus lockdown, Took it apart because my very nature NEEDS to know whats in there. its not that difficult to disassemble but one needs to just be very careful, it is not complicated in the slightest , just strongly glue.in

Reminds me of being a kid: Xmas morning was for opening gifts, Xmas afternoon was for disassembling and reassembling those gifts. Never saw much use for the toys once I understood how they worked.

[Gitterbug]

Tell me about that. Our family was returning from a two-year stint in Washigon, D.C. back in 1975, when our three-year old son managed to disassemble a drinking fountain at the airport bare-handed. We could not visit a family without checking their heating settings on departure. He became constructive as opposed to destructive at around 11, with model airplanes, a classical guitar, drones, pedalboards and, recently, professional video accessories under his belt. Plus, a much better guitarist than his daddy.

[Durban]

Good. Let's be grateful when somebody cares to produce dedicated gear for jazz guitarists and bassists, at affordable prices. If they make a profit, it's ok IMHO. A major difference to the point-to-point days of yore is that soldering alloys containing lead are no longer allowed. Here may loom a Brexit benefit for UK makers. However, even if they could legally turn back the clock in the home country, the products could not be sold wherever RoHS is required.

[ agree i have no p;roblem with people masking profits whatsoever, i just have very healthy sense of curiosity how much is that worth, what does it cost to make???? etc, nothing bad,

.

I dont think there is much difference in making a Jazz Amp imo to any amp itsd just a different voicing in fact easier, what is really hard i think is to get a loud sustain and singing amp (not that i can play any rock music)

[Little Jay]

As long as it works, it works. I don’t think the way the innards of the LJ look will have a negative impact on the way it sounds though. Just tough to repair if it breaks down...

Solid state PCB will always look messy and ‘un-amp-like’ to me, but it can be done better dan that DV LJ, although pots and connectors directly soldered to the PCB is pretty much standard nowadays:


AER Alpha:



Award Session BluesBaby:

[Tcaron20]

I love my DV Mark Lil Jazz but lately the volume fades in and out for a while when turning it on then settles down and is fine. I cleaned the pots with component cleaner but problem is still there.

I have the newer model with the noiseless fan.

Ideas?

Thanks,
tom

[Durban]

I love my DV Mark Lil Jazz but lately the volume fades in and out for a while when turning it on then settles down and is fine. I cleaned the pots with component cleaner but problem is still there.

I have the newer model with the noiseless fan.

Ideas?

Thanks,
tom

Since you have time on your hands, AMUSE yourself by sending them a mail, you will find they are
A. either on Corona lockdown,
B. about to enter early summer holiday, then you may get
C. we will be in touch, then you might get
D. F--- all.

I mailed them, i got a blend of B&C and then D.

I dont think your beloved LJ should do that,

[DonEsteban]

I love my DV Mark Lil Jazz but lately the volume fades in and out for a while when turning it on then settles down and is fine. I cleaned the pots with component cleaner but problem is still there.

Doesn't sound like a pot. problem to me. Obviously a thermo - related problem in a component, my guess is an op amp or even the power amp transistors.

The classic method to narrow it down is using cooler spray to selectively cool components and so find the guilty one.

But once found, with a smd device like the LJ you can do repairs only if you have the right tools like a hot air soldering unit (and some experience), so the help of a trained technician may be required.

smd = surface mounted device, these tiny components you see on the pcb

[lstelie]

For instance, and taking your words, it’s not natural to me to use hot glue to stabilize (from what?) welded small components on a PCB. And those boards are crammed, as you said, not exactly compacted. Why don’t they use that extra time you refer to improve the engineering design on the desk instead of the factory?

Obviously, this is not a German or Danish concept amplifier, Everything suggests me an amateurish planning on such a well succeed product (maybe because of it) and I think it’s possible to do the same amp with better procedures while keeping the price. In fact, there’s some alternative products in the same range and some examples are shown, but allow me to present another one: Kestrel - '57 Princeton / Champ - 10 Inch | BirdSong

See the price? Hand made in Europe, point to point, tubes... etc.

I made my comments based on the OP, that gives some reason to other complaints about the consistency of the amp, and I’m not engaged on having reason on my comments, certainly I haven’t, but it’s not bad to be more demanding with the suppliers of our gear. If they improve their products everybody will win something. And chatting with you contributes to my lockdown.

Hello

Sorry to jump in, but the amp's back clearly states "made in China" not at all Hand made in Europe

[Cordalis]

Thanks Istelie, I didn’t notice that. In fact, it was very strange to me being so cheap and hand made in Europe but I was misleading by a friend who bought one. However, I rest my case, the price is almost the same of the DV (also made in China) but the components are welded point to point and not glue helped on a PCB.

[lstelie]

Thanks Istelie, I didn’t notice that. In fact, it was very strange to me being so cheap and hand made in Europe but I was misleading by a friend who bought one. However, I rest my case, the price is almost the same of the DV (also made in China) but the components are welded point to point and not glue helped on a PCB.

I just wanted to point out it was Chineese (therefore the price), i didn't mean it was bad quality
They are several low priced little P2P Chineese tube amps that work quite well.
This one (sold in Europe by German mail order under the Fame brand, but in fact it's a rebranded Joyo product) is quite well regarded (for it's price)

Fame JTA-05 Sweet Baby Combo | MUSIC STORE professional | fr-FR

[Cordalis]

I have the same opinion. I think is just a matter of planning and Quality Control from the mother brand companies.

[iug]

Hi,

I am looking for a flat frequency response because I love polytones...
I have sent a pink noise to a DVMark Jazz 12 and recorded it back with a MXL 603 small capsule static mic pointed toward the center of the speaker.
Here is its frequency response with bass mid and treble at 5, or 12 am.

So with a MXL 12 bands Eq, to have a flat Eq, one can add :

• 3 dB at 63 Hz
• 6 dB at 125 Hz
• 5 dB at 1 kHz

I have made other measurements:

• The bass knob changes the frequency mainly around 50Hz but affect all the mids.

• The mid knob is centered around 1 kHz and is very broad.

• The treble kno is centered around 2.5 kHz and also boosts through 5 kHz.

Those three eqs do not overlap well so you cannot tweak the Eq to set it flat. To be quite close, maybe put bass and mids at 6 ad treble at 4...

I don't like the straight sound of that amp, if not played with my tone rolled off. However with an Eq it can sound very fine. It is cheap, with almost no noise. I also play the bass and double bass through it... and it is light.