?What’s this? A DAC4800A/MEGA hybrid ??

0 Members and 1 Guest are viewing this topic. Read 1406 times.

AmpDesigner333

  • Facilitator
  • Posts: 2518
  • Detailed AND Musical
    • Digital Amplifier Company
?What’s this? A DAC4800A/MEGA hybrid ??
« on: 16 Jun 2019, 10:38 pm »
This just happened....  We had an old enclosure with some wiring and a beat up faceplate....

An old transformer from prototype amp.  Old euro-style binding posts.  ....and a MEGA MK1 2-ch board set modified with MK2 updates.  The result is a fantastic sounding amp that looks “retro”!!






AmpDesigner333

  • Facilitator
  • Posts: 2518
  • Detailed AND Musical
    • Digital Amplifier Company
Re: ?What’s this? A DAC4800A/MEGA hybrid ??
« Reply #1 on: 17 Jun 2019, 04:05 am »





RonN5

Re: ?What’s this? A DAC4800A/MEGA hybrid ??
« Reply #2 on: 17 Jun 2019, 03:20 pm »
Could this end up as the basis for a new and more upscale integrated amp from Cherry?

AmpDesigner333

  • Facilitator
  • Posts: 2518
  • Detailed AND Musical
    • Digital Amplifier Company
Re: ?What’s this? A DAC4800A/MEGA hybrid ??
« Reply #3 on: 17 Jun 2019, 05:12 pm »
Could this end up as the basis for a new and more upscale integrated amp from Cherry?
Probably a limited production special version of the Stereo MEGA, but we’ll see. It’s a stand-alone amp either way, not “integrated”.  There are also DAC4800A users out there that want to upgrade to MEGA.  Now, there’s a way to do that!  Thanks.

Jonathon Janusz

  • Full Member
  • Posts: 826
Re: ?What’s this? A DAC4800A/MEGA hybrid ??
« Reply #4 on: 18 Jun 2019, 03:33 am »
This is a really cool thing to come about, as not only does it keep old tech from needlessly going to the landfill (for those who are passionate about stewardship of the environment) but now Digital Amp Co. has an upgrade path to support customers all the way back to the beginning.  Offering generous trade-in and trade-up offers is commendable, but I think it means something to folks that buy in to the idea of getting something built to last to be able to build on what they've already got rather than just replace and keep buying new.  Maybe I'm just showing my age (or maybe my dad's age :lol:) but all in all I think this is pretty neat!

(...not to mention breathing new life in to a chassis design with a power button where nature intended it!)

Some questions about this upgrade based on the pictures shown:

It may be just cosmetic, but could some of the multicolored LEDs be swapped out to have them all a consistent color on the front face plate, to bring the look a little closer to the modern aesthetic?

I noticed a few open spots for capacitors on the boards.  Would doing the rail capacitance upgrade like on an all-in new MEGA Mk2 bring anything to the table when paired with the power supply already in the DAC4800A, or is this upgrade only really worthwhile if one also has the 1500W transformer in the top shelf version of the MEGA Mk2?  I'm thinking if there is some advantage there, it might be a worthwhile incremental upgrade to get the MEGA Mk2 board maxed out, and then someone could save up a bit of money down the line to later upgrade the power supply (or not).

I remember a brief conversation in the GR-Research circle discussing Danny's tube connectors.  Is there room in the chassis to use these instead of a traditional binding post if someone wanted to go that route?  I'm guessing also then that if someone wanted to go spec-for-spec to the full MEGA Mk2 in one of these chassis, the standard upgraded DAC recommended binding posts and XLR connectors could also be used?

Thanks!

Jon

AmpDesigner333

  • Facilitator
  • Posts: 2518
  • Detailed AND Musical
    • Digital Amplifier Company
Re: ?What’s this? A DAC4800A/MEGA hybrid ??
« Reply #5 on: 18 Jun 2019, 02:41 pm »
This is a really cool thing to come about, as not only does it keep old tech from needlessly going to the landfill (for those who are passionate about stewardship of the environment) but now Digital Amp Co. has an upgrade path to support customers all the way back to the beginning.  Offering generous trade-in and trade-up offers is commendable, but I think it means something to folks that buy in to the idea of getting something built to last to be able to build on what they've already got rather than just replace and keep buying new.  Maybe I'm just showing my age (or maybe my dad's age :lol:) but all in all I think this is pretty neat!

(...not to mention breathing new life in to a chassis design with a power button where nature intended it!)

Some questions about this upgrade based on the pictures shown:

It may be just cosmetic, but could some of the multicolored LEDs be swapped out to have them all a consistent color on the front face plate, to bring the look a little closer to the modern aesthetic?

I noticed a few open spots for capacitors on the boards.  Would doing the rail capacitance upgrade like on an all-in new MEGA Mk2 bring anything to the table when paired with the power supply already in the DAC4800A, or is this upgrade only really worthwhile if one also has the 1500W transformer in the top shelf version of the MEGA Mk2?  I'm thinking if there is some advantage there, it might be a worthwhile incremental upgrade to get the MEGA Mk2 board maxed out, and then someone could save up a bit of money down the line to later upgrade the power supply (or not).

I remember a brief conversation in the GR-Research circle discussing Danny's tube connectors.  Is there room in the chassis to use these instead of a traditional binding post if someone wanted to go that route?  I'm guessing also then that if someone wanted to go spec-for-spec to the full MEGA Mk2 in one of these chassis, the standard upgraded DAC recommended binding posts and XLR connectors could also be used?

Thanks!

Jon
Jon,

Some comments on your post....

"Digital Amp Co. has an upgrade path to support customers all the way back to the beginning." -- yes, the DAC4800A goes back more than 12 years!

"....power button where nature intended it!" -- the MEGA has auto-sleep, so you can leave it on all the time.  The DAC4800A button on the front toggles standby mode, equivalent to sleep mode (amps are powered, but outputs are electrically disabled).

"....could some of the multicolored LEDs be swapped out to have them all a consistent color on the front face plate" -- yes, but upgrades will use the existing front LED board unless customized.

"Would doing the rail capacitance upgrade like on an all-in new MEGA Mk2 bring anything to the table when paired with the power supply already in the DAC4800A" -- yes, there's a measurable advantage to more rail caps, and we can add them in this case just as with any Cherry MEGA.

"....or is this upgrade only really worthwhile if one also has the 1500W transformer" -- I'd rather have more caps than the bigger transformer, given the choice.  Transformer upgrades can also fit into the DAC4800A chassis.

"....someone could save up a bit of money down the line to later upgrade the power supply (or not)." -- yes, upgrades to the power supply can also be provided later.

"....Is there room in the chassis to use these instead of a traditional binding post if someone wanted to go that route?" -- I'll send a message to Danny asking him to comment.  Not sure of the mechanicals for his binding post replacements.  We discussed these post replacements at length, months ago.  He didn't have a contact resistance measurement back then, and unless there's less than a few mΩ end-to-end with this connection, it won't outperform the binding posts used on the MEGA (soldered Gold WBTs).

Upgrading the binding posts on newer DAC4800As is possible.  Upgrading the XLR connectors to those used on new MEGAs (Neutrik gold plated) is also possible.

Thanks!

-Tommy O

Jonathon Janusz

  • Full Member
  • Posts: 826
Re: ?What’s this? A DAC4800A/MEGA hybrid ??
« Reply #6 on: 19 Jun 2019, 11:33 pm »
"....power button where nature intended it!" -- the MEGA has auto-sleep, so you can leave it on all the time.  The DAC4800A button on the front toggles standby mode, equivalent to sleep mode (amps are powered, but outputs are electrically disabled).

Tommy,

Maybe this is general MEGA Mk2 question, but regarding the auto sleep, as I know this was a feature implemented in the Golden Maraschino and because I'd guess someone at some point would maybe want or ask for it, is there a "no sleep" mod available for the MEGA Mk2?  In particular with a DAC4800A upgraded chassis already with the additional front power/sleep button, this might be somehow a nice to have.

Thanks!

Jon

Danny Richie

  • Industry Contributor
  • Posts: 12713
    • http://www.gr-research.com
Re: ?What’s this? A DAC4800A/MEGA hybrid ??
« Reply #7 on: 20 Jun 2019, 04:45 pm »
Thanks Tommy,

I am going to answer this in parts.

First of all installation. The tube connectors are designed to press fit through a 7/16" diameter hole in MDF. And the MDF can be any thickness.

There is really nothing there in a thin metal plate to hold them in. I have used them quite a few times mounted in amp chassis as have many of our customers. You just need to drill a 7/16" hole and hot glue them in on the back side. It's not pretty, but works just fine. I also have guys drilling out an MDF panel and fixing it to the back side of the steel plate. So the tube connector is going through them both and locking into the MDF. That works great too, but is more involved.

Secondly, I would recommend the same thing that I recommend to guys that are somewhat skeptical of the performance difference using them on their speakers. Instead of replacing their stock binding posts, add a set of tube connectors. Just add them as a second set and parallel them to the binding post. First wire straight to the tube connectors and run a jumper of the same wire to the binding posts. Now you can use either/or and compare. So far I have not had a single guy wire them up that way, make a comparison, and not favor the tube connectors.

This brings me to the last point. How much difference will they make?

Well for guys like Tommy or anyone else that doesn't believe that connectors, internal wire, interconnects, power cables, or speaker cables can make any difference, nothing is going to change that by me saying otherwise. And this isn't a place for a debate on that.

And on that subject, while Tommy and I have disagreed on these issues in the past, our exchanges on this subject has been very professional.

Now, back to the sound difference. If the whole system is a budget level system, or if you are using stock power cables, and interconnects and speaker cables from Home Depot, then the difference in the sound of tube connectors verses binding post will be very subtle at best.

On a top level system that has had attention spent to every detail, then the differences between tube connectors and binding posts can be very surprising.

So depending on where you are, your results will vary.



AmpDesigner333

  • Facilitator
  • Posts: 2518
  • Detailed AND Musical
    • Digital Amplifier Company
Re: ?What’s this? A DAC4800A/MEGA hybrid ??
« Reply #8 on: 20 Jun 2019, 06:22 pm »
Thanks Tommy,

I am going to answer this in parts.

First of all installation. The tube connectors are designed to press fit through a 7/16" diameter hole in MDF. And the MDF can be any thickness.

There is really nothing there in a thin metal plate to hold them in. I have used them quite a few times mounted in amp chassis as have many of our customers. You just need to drill a 7/16" hole and hot glue them in on the back side. It's not pretty, but works just fine. I also have guys drilling out an MDF panel and fixing it to the back side of the steel plate. So the tube connector is going through them both and locking into the MDF. That works great too, but is more involved.

Secondly, I would recommend the same thing that I recommend to guys that are somewhat skeptical of the performance difference using them on their speakers. Instead of replacing their stock binding posts, add a set of tube connectors. Just add them as a second set and parallel them to the binding post. First wire straight to the tube connectors and run a jumper of the same wire to the binding posts. Now you can use either/or and compare. So far I have not had a single guy wire them up that way, make a comparison, and not favor the tube connectors.

This brings me to the last point. How much difference will they make?

Well for guys like Tommy or anyone else that doesn't believe that connectors, internal wire, interconnects, power cables, or speaker cables can make any difference, nothing is going to change that by me saying otherwise. And this isn't a place for a debate on that.

And on that subject, while Tommy and I have disagreed on these issues in the past, our exchanges on this subject has been very professional.

Now, back to the sound difference. If the whole system is a budget level system, or if you are using stock power cables, and interconnects and speaker cables from Home Depot, then the difference in the sound of tube connectors verses binding post will be very subtle at best.

On a top level system that has had attention spent to every detail, then the differences between tube connectors and binding posts can be very surprising.

So depending on where you are, your results will vary.

Danny,

Thanks for commenting.

Regarding the statement "....guys like Tommy or anyone else that doesn't believe....", I just want to be clear that I DO believe things like this can make a difference, but there's always a logical explanation when they do.  In this case it's simple resistance.

I'd like to know what the difference in resistance is between a Gold WBT binding post and your connector.  The Gold WBTs have about 2-3mΩ contact resistance with banana plugs as the other side of the connection.  To test this without a milli-ohmmeter, you can use a current source (1-10A) and measure the voltage drop.  The resistance measurement of a standard voltmeter doesn't have the accuracy or range to measure such small resistance, but a decent one can measure single-digit millivolts or tenths of millivolts.  Here's a "real" milli-ohmmeter, for example (approx $400):
http://www.testequipmentdepot.com/bk-precision/milliohmmeters/310.htm

Here's a little about Kelvin connections (the current based measurement technique):
https://www.electroschematics.com/6959/kelvin-connection/

-Tommy O
« Last Edit: 20 Jun 2019, 08:23 pm by AmpDesigner333 »

AmpDesigner333

  • Facilitator
  • Posts: 2518
  • Detailed AND Musical
    • Digital Amplifier Company
Re: ?What’s this? A DAC4800A/MEGA hybrid ??
« Reply #9 on: 20 Jun 2019, 06:23 pm »
Thanks Tommy,

I am going to answer this in parts.

First of all installation. The tube connectors are designed to press fit through a 7/16" diameter hole in MDF. And the MDF can be any thickness.

There is really nothing there in a thin metal plate to hold them in. I have used them quite a few times mounted in amp chassis as have many of our customers. You just need to drill a 7/16" hole and hot glue them in on the back side. It's not pretty, but works just fine. I also have guys drilling out an MDF panel and fixing it to the back side of the steel plate. So the tube connector is going through them both and locking into the MDF. That works great too, but is more involved.

Secondly, I would recommend the same thing that I recommend to guys that are somewhat skeptical of the performance difference using them on their speakers. Instead of replacing their stock binding posts, add a set of tube connectors. Just add them as a second set and parallel them to the binding post. First wire straight to the tube connectors and run a jumper of the same wire to the binding posts. Now you can use either/or and compare. So far I have not had a single guy wire them up that way, make a comparison, and not favor the tube connectors.

This brings me to the last point. How much difference will they make?

Well for guys like Tommy or anyone else that doesn't believe that connectors, internal wire, interconnects, power cables, or speaker cables can make any difference, nothing is going to change that by me saying otherwise. And this isn't a place for a debate on that.

And on that subject, while Tommy and I have disagreed on these issues in the past, our exchanges on this subject has been very professional.

Now, back to the sound difference. If the whole system is a budget level system, or if you are using stock power cables, and interconnects and speaker cables from Home Depot, then the difference in the sound of tube connectors verses binding post will be very subtle at best.

On a top level system that has had attention spent to every detail, then the differences between tube connectors and binding posts can be very surprising.

So depending on where you are, your results will vary.
Danny,

Can you please post a photo of your tube connector?  Thanks again.

-Tommy O

Danny Richie

  • Industry Contributor
  • Posts: 12713
    • http://www.gr-research.com
Re: ?What’s this? A DAC4800A/MEGA hybrid ??
« Reply #10 on: 20 Jun 2019, 07:15 pm »
I just want to be clear that I DO believe things like this can make a difference, but there's always a logical explanation when they do.

Agreed.

Quote
In this case it's simple resistance.  I'd like to know what the difference in resistance is between a Gold WBT binding post and your connector.  The Gold WBTs have about 2-3mΩ contact resistance with banana plugs as the other side of the connection.

It is not about resistance. If lower resistance sounded better than we should just use some 8 gauge jumper cables for speaker cable.

I can't wait to have you come down for a weekend for some listening.

AmpDesigner333

  • Facilitator
  • Posts: 2518
  • Detailed AND Musical
    • Digital Amplifier Company
Re: ?What’s this? A DAC4800A/MEGA hybrid ??
« Reply #11 on: 20 Jun 2019, 07:28 pm »
Agreed.

It is not about resistance. If lower resistance sounded better than we should just use some 8 gauge jumper cables for speaker cable.

I can't wait to have you come down for a weekend for some listening.
If it's not about resistance, then what is it about?  This is rhetorical question since I want to keep this thread about the DAC4800A/MEGA hybrid, not speaker connectors and the like.  Impedance is too low in this case for practical values of inductance and capacitance to make a significant difference.

I'd like to get together either here or there at some point, and thanks again for the invitation.  We're super busy, especially considering that it's summer, when there's usually a lot more time to play with.  We are inundated with inquiries, so my comments here will be limited until things clear up a little....

AmpDesigner333

  • Facilitator
  • Posts: 2518
  • Detailed AND Musical
    • Digital Amplifier Company
Re: ?What’s this? A DAC4800A/MEGA hybrid ??
« Reply #12 on: 20 Jun 2019, 07:32 pm »
Agreed.

It is not about resistance. If lower resistance sounded better than we should just use some 8 gauge jumper cables for speaker cable.

I can't wait to have you come down for a weekend for some listening.
By the way MEGA Snakes (see photo, 8-ft length, $99/ch with new Cherry Amp purchase) are 9-gauge equivalent.  I do believe lower resistance to the speaker is audible, and lower resistance simply means better control !!

What we claim about these speaker cables: LOW resistance, very flexible for easy setup, reliable (can withstand many connect/disconnect cycles), and they LOOK COOL!  Note that we're not using phrases like "expands imaging" or "opens up the sound stage".  That's because we're honest (:



Danny Richie

  • Industry Contributor
  • Posts: 12713
    • http://www.gr-research.com
Re: ?What’s this? A DAC4800A/MEGA hybrid ??
« Reply #13 on: 20 Jun 2019, 08:54 pm »
Quote
If it's not about resistance, then what is it about?

Regarding cables, transmission or rejection of noise (both FRI and EMI).

Nice looking cables by the way. And great pricing. Have you tried the same cables without the braiding? As you may know, the braiding works great as a filter to block a lot of FRI noise. I have found that different types of braiding can even have quite an effect on the sound.

Jonathon Janusz

  • Full Member
  • Posts: 826
Re: ?What’s this? A DAC4800A/MEGA hybrid ??
« Reply #14 on: 21 Jun 2019, 12:23 am »
Danny,

Can you please post a photo of your tube connector?  Thanks again.

-Tommy O

Tommy,

I think this got lost in your exchange with Danny.



and here is a link to Danny's product page to get all the info on these:

http://gr-research.com/electracabletubeconnectors.aspx

Jon

AmpDesigner333

  • Facilitator
  • Posts: 2518
  • Detailed AND Musical
    • Digital Amplifier Company
Re: ?What’s this? A DAC4800A/MEGA hybrid ??
« Reply #15 on: 21 Jun 2019, 01:44 am »
Regarding cables, transmission or rejection of noise (both FRI and EMI).

Nice looking cables by the way. And great pricing. Have you tried the same cables without the braiding? As you may know, the braiding works great as a filter to block a lot of FRI noise. I have found that different types of braiding can even have quite an effect on the sound.
Thanks for the compliment.  Note we don’t mention EMI.  The reason is that you’d need a nuclear explosion nearby to generate enough EMI/RFI to affect the speaker side connection. This is simply due to low impedance.


Danny Richie

  • Industry Contributor
  • Posts: 12713
    • http://www.gr-research.com
Re: ?What’s this? A DAC4800A/MEGA hybrid ??
« Reply #16 on: 21 Jun 2019, 01:59 am »
Thanks Jon,

Thanks for the compliment.  Note we don’t mention EMI.  The reason is that you’d need a nuclear explosion nearby to generate enough EMI/RFI to affect the speaker side connection. This is simply due to low impedance.

But just a small amount of Stillponts ERS material can make a notable difference in how things sound.

https://www.tweekgeek.com/stillpoints-ers-rfi-killer/

And trying different braiding technics yield different results as well, and that's using the same wire.

So I don't think we need a nuclear explosion nearby create audible interference.

AmpDesigner333

  • Facilitator
  • Posts: 2518
  • Detailed AND Musical
    • Digital Amplifier Company
Re: ?What’s this? A DAC4800A/MEGA hybrid ??
« Reply #17 on: 21 Jun 2019, 02:18 am »
....can make a notable difference in how things sound....
Properly designed equipment doesn’t require “fixes”.

Let’s get back to the topic at hand, the DAC4800A/MEGA Amplifier hybrid.

Specifications include 120dB SNR, 0.001% THD+N over a wide power range, about 600Wpc, DC Coupling end-to-end, TRUE balanced inputs, auto sleep (you can leave the amp on), 150kHz bandwidth, and a chassis “built like a tank” !!






Freo-1

Re: ?What’s this? A DAC4800A/MEGA hybrid ??
« Reply #18 on: 21 Jun 2019, 02:39 am »
Properly designed equipment doesn’t require “fixes”.

Let’s get back to the topic at hand, the DAC4800A/MEGA Amplifier hybrid.

Specifications include 120dB SNR, 0.001% THD+N over a wide power range, about 600Wpc, DC Coupling end-to-end, TRUE balanced inputs, auto sleep (you can leave the amp on), 150kHz bandwidth, and a chassis “built like a tank” !!





Those are nice specs.  Wouldn't mind giving it a listen sometime. 
Good to see products like the Cherry offer good value for the money.   :thumb:

However, even a properly designed amp can benefit from occasional updates (especially if they are firmware orientated). 

Speaking of specs, here are the specs from my current rig:


SNR: 133 db in dual mono  (A-weighted)
THD: 112dB / 0.00025% in dual mono  (Full Power)
IMD:  112dB / 0.00025% in dual mono  (SMPTE)
Zout:  1 mΩ  (Full Bandwidth)
Damping Factor:  8000 (Full Bandwidth)
Bandwidth:  DC~30kHz -0.1 dB                    
                  DC~95kHz -3 dB
Phase:  0.2° in dual mono 20 kHz               
              0.9° in dual mono 40 kHz

Thermal Distortion: Not measurable
Power Out: 500 watts @ 6 ohms


AmpDesigner333

  • Facilitator
  • Posts: 2518
  • Detailed AND Musical
    • Digital Amplifier Company
Re: ?What’s this? A DAC4800A/MEGA hybrid ??
« Reply #19 on: 21 Jun 2019, 06:16 am »
Those are nice specs.  Wouldn't mind giving it a listen sometime. 
Good to see products like the Cherry offer good value for the money.   :thumb:

However, even a properly designed amp can benefit from occasional updates (especially if they are firmware orientated). 


Thanks for the compliments!

I'm a big fan of measurements, but at this level, some specs are past the point of applicable differentiation.  An amp with 0.0001% THD+N isn't necessarily going to sound better than an amp with 0.001% THD+N, for example.  Another example....  What good is 1mΩ output impedance when adding binding posts and 8 feet of 10-gauge speaker cable leaves you with only 5% of your original damping factor!

I've heard amps that have even better specs than the Cherry MEGA MK2, yet sound "dry" or "stifled".  This reminds me of the 1980s spec wars when cranking up the feedback was considered the silver bullet.  Knowing what makes a sonic difference takes decades of experience, but that topic is adequately covered elsewhere in this circle.

"If you want sound that's simply juicy, go for the Cherry"  8)
« Last Edit: 21 Jun 2019, 07:23 am by AmpDesigner333 »