Jolida Glass FX Dac

[bhjazz]

Yet another futher different dac.

Seems like a decent product, the Joloda Glass FX tube dac. I agree, the name is a little pretentious. I have a Jolida tuner here somewhere, the JD 402. (Out of production now.) After digging around, there were a few places for a while that offered some upgrades to the unit, which caught my attention. And when I got inside it myself, I saw that yes, there were some obvious things to change that would be both easy and useful. For starters, caps, wiring, wire routing, tubes, etc.

So on to the tube dac. A standard round of questions apply. Anyone heard it? Anyone have one? Anyone think this is a great/crappy buy? I'm asking since there are very few reviews of this unit online. The price seems decent at ~$375. For any DIYer it might also hold some "ultold riches" once it's been hotrodded...

Thanks.

(I am adding the upgrade items for the tuner here just to give an idea what might be able to be done with the dac....)

This is Underwood Hi-Fi's ungodly price for upgrades on the old tuner. $400! Jebus. Here is the list. (Thank God I can do these on the cheap all by meself)

New Jolida JD-402 tube tuner modification

Jolida JD-402 Level-1 mod - $790 plus freight ($400 retrofit) -

Our Level-1 mod installs

4 x small EAR brand compliant Sorbothane isolation feet

2 sheets of SoundCoat chassis damping material

3 feet of DH Labs 23-gauge pure 99.999% silver signal wirewith foamed Teflon tape-wrap dielectric

2 x Auricap signal path metalized polypropylene coupling capacitors

3 x Soeln feedback coupling and power supply decoupling metalized polypropylene film capacitors

12 x Kiwame brand carbon-film 0.5 and 1-watt signal path resistors

TRT WonderSolder used throughout

3.5 hours labor

Edited April 25, 2011 by bhjazz

[manaox2]

I'm poor at best at judging DACs by their design, but I can tell very little by the specs that underlie the tube stage. I guess someone who has knowledge of the Burr-Brown 1793 can chip in on that, but I don't have my hopes up for this DAC yet.

Edited April 25, 2011 by manaox2

[Dusty Chalk]

...someone who has knowledge of the Burr-Brown 1793 can chip in on that...

Nice.

I am fond of Jolida, but would be hesitant to get the DAC based on that fondness. I say, take one for the team, and DEW ET.

[Filburt]

1793 is BB's performance grade voltage output dac. It's OK; nothing amazing. Then again, with a distortion spec that high on the final output, I'm not sure how much it matters.

[bhjazz]

1793 is BB's performance grade voltage output dac. It's OK; nothing amazing. Then again, with a distortion spec that high on the final output, I'm not sure how much it matters.

I know. I was thinking that might be due to the tubes. Not sure.

I found this. Includes some crappy cellphone pics of the internals. He has left the thread hanging so who knows. Sounds like the build quality was iffy, but that happens once on a while.

[dsavitsk]

12AX7 cathode followers are worthless, even paralleled. They just don't have enough current across them or Gm to drive anything. Generally, for lowest distortion, a tube wants to see a load several times higher than its rp (even when the load is on the cathode). rp on an AX7 is ~80K, both sides ||, 40K. That means that if your next stage has an input Z of lower than 250K, distortion will be high. Maybe it will sound toobey.

What's with the Ultra Linear class AB, 1W into 8 ohms, and the 240W power requirement? Just a sloppy cut and paste job?

[mypasswordis]

Forgive my naivete, but what exactly do you use in a single ended tube output stage other than a cathode follower, eg in a headphone/speaker amplifier? As in, wouldn't the output distort as speakers are 4-8 ohms, most tube amplifiers have output impedances at best of roughly the same, and the distortion is based on the ratio of the rp of the output tubes to the headphones/speakers? And in a push pull output stage, which typically uses pentodes, the rp is even much higher.

Edit: Nvm, forgot about the output trafo.

Edited April 25, 2011 by mypasswordis

[bhjazz]

What's with the Ultra Linear class AB, 1W into 8 ohms,

Of all the values posted at Jolida, that one puzzled me the most. It seems it would be fairly simple to implement Class A, right? That might bring the distortion numbers down some.

[dsavitsk]

It appears that someone cut and pasted a different web page and just didn't edit a few of the values. That stuff is clearly from a power amp page.

Anyway, I don't see any untold riches to be found here, but to each his own.

[recstar24]

My first real CDP was a jolida. Tubes output. It was weird.

[Filburt]

I know. I was thinking that might be due to the tubes. Not sure.

I found this. Includes some crappy cellphone pics of the internals. He has left the thread hanging so who knows. Sounds like the build quality was iffy, but that happens once on a while.

Well, overall output stage design (as opposed to just the tubes) is likely the determinative factor. This product doesn't seem very interesting to me from a performance or design standpoint.

[mypasswordis]

Any voltage output DACs you like, Filburt?

[Filburt]

Any voltage output DACs you like, Filburt?

Uh...I guess the WM8740/41, and AK4396/7 are decent. You can use an ESS Sabre in v-out mode which may be better than the other four due to the filter and modulator design but I've never tried it. I'm not a big fan of voltage output dacs for applications where you don't need that specific functionality as they're uniformly lower performance than what can be obtained with current output dacs.

[mypasswordis]

Cool, thanks for that.

[HiGHFLYiN9]

[bhjazz]

I sent a polite email to Jolida about the supposed specs. After two days, I am also unimpressed with their lack of response.

[Filburt]

They can't hear you over the Ultra Linear, Class AB.

[Fastlane Audio]

I purchased this DAC, and it was a huge mistake. It is noisy, and the support from Jolida and AudioForce is not good. I purchased this unit based on the good experience I have had with my Jolida 502 power amp.

This is my first bad exprience with Jolida product and service, hopefully its just a fluke. I was looking forward to trying the JD-9A phono stage as well, but a noisy DAC is keeping me from pulling the trigger on that purchase.

I emailed Michael Allen at Jolida regaurding the specs, as well, (no reply).

Dave

[bhjazz]

I see a trend forming for the new Jolida. Bummer. I don't think it's a fluke fastlane.

[Fastlane Audio]

I see a trend forming for the new Jolida. Bummer. I don't think it's a fluke fastlane.

I agree, and also found out there is 2 Jolida's, the Maryland based Jolida.com and the Chineese based Jolida.net.

This is an interesting read. http://jolida.net/fedcourt.htm

Jolida.net has signifigantly better prices as well.

Dave

[bhjazz]

Ouch that.

As for Michael Allen, he just sent me an email reply. I guess I have to remember that in much of the world, people just don't worry a lot about email. There is other work to do. Here is what he wrote:

FX Tube DAC Specifications

Inputs : 1 x coaxial

1 x toslink

1 x USB PC digital input

Audio outputs : 1 x pair gold plated RCA outputs

D/A converters: Texas Instruments PCM1793

USB Transceiver: CM102S

Tubes: 2 x 12AX7

Frequency response:10Hz to 70KHz (±1dB)

THD: <0.02% Tube Out(1kHz)

SNR: 80dB

Dynamic Range: 113dB

Supported digital input upsampling frequencies:

32kHz, 44.1kHz, 48kHz, 88.2kHz, 96kHz

Audio output upsampling:Fixed 24 bit 192kHz

Power consumption: <25W

Dimensions: (H x W x D) 52 x 215 x 191mm (2.0 x 8.6 x 7.6")

Weight: (net) 6.2 lbs., 2.8 kg

Finishes: Silver / Black

[Knuckledragger]

I don't know a tub DAC from a hole in the ground, but man that is one fugly website.

[bhjazz]

No kidding. That Celine Dion-looking person is too obtrusive.

[Fastlane Audio]

Ouch that.

As for Michael Allen, he just sent me an email reply. I guess I have to remember that in much of the world, people just don't worry a lot about email. There is other work to do. Here is what he wrote:

FX Tube DAC Specifications

Inputs : 1 x coaxial

1 x toslink

1 x USB PC digital input

Audio outputs : 1 x pair gold plated RCA outputs

D/A converters: Texas Instruments PCM1793

USB Transceiver: CM102S

Tubes: 2 x 12AX7

Frequency response:10Hz to 70KHz (±1dB)

THD: <0.02% Tube Out(1kHz)

SNR: 80dB

Dynamic Range: 113dB

Supported digital input upsampling frequencies:

32kHz, 44.1kHz, 48kHz, 88.2kHz, 96kHz

Audio output upsampling:Fixed 24 bit 192kHz

Power consumption: <25W

Dimensions: (H x W x D) 52 x 215 x 191mm (2.0 x 8.6 x 7.6")

Weight: (net) 6.2 lbs., 2.8 kg

Finishes: Silver / Black

That just sucks, the SNR is worse than the published specs.

I made a poor DAC choice, but thankfully it's going back today.

Dave