Alesis HD24XR mods

[chrissugar]

Recently I bought an Alesis HD24XR multitrack machine with the intention to upgrade the audio electronics in a similar way like the Jim Williams mod.
I know that many people tried his mod and consider it an improvement, he even say that the moded HD24XR sounds as good (or better) as the RADAR 24 Nyquist.
The mods include opamp change, polyprop bypass caps, PSU upgrade, fan change. I'm a bit afraid because all the opamps are SMD and have no experience with soldering/desoldering SMD chips.
Here is a quote from him:

"That's still the fan, rated 20 dba vs 28 dba for the stock Sunon fan. Use either 3 or 4 pin, you will cut them off and solder the wires to the old connector off the old fan. I use those Maxtor "low noise" 40 gig hd's at 5400 rpm, they are less "whiny" than the 7200 rpm's. If you want to use the HDR to record live shows, read the posts at the Yahoo user's group regarding vibration issues, loud sources can cause problems with the seating of the drive's connectors.
.........
As to the HD24 mod, I will only do the XR version as the stock XR sounds better at 48k than the modified 48k cards. If you buy the EC-2, it's an extra $900 from Sweetwater. I've seen XR's going for around $1600 from various stores. That 48k version I've seen used for $1000.
The XR mods include the low noise fan and fan filter intake foam to keep the innards clean. The psu is rebuilt with very high voltage poly film caps. All the 30 quad opamps are changed to BurrBrown OPA4134 quad surface mount opamps. The input caps are bypassed with high voltage poly film caps to let the air through. Another advantage of the XR cards is the D/A outputs are direct coupled. Good if you like really deep tight bass."



Anyone tried these mods? I ask because I saw the HD24 in some pics posted by forum members.

chrissugar

 

[Svart]

hmm do you have links to some information? I'm interested because i have a tascam mx2424 that is tired and breaks down all the time and many have said the alesis is excellent.

 

[Guest]

very interested as well....
I think Peter P has a MX2424 as well..
I use a Fostex D108... and am thinking of moving
The onyl reason I am looking at a Radar is because of the VGA screen.. but the cost!!!!
If somebody can not only DIY the Alesis changes Chris has mentioned but also DIY a VGA screen on...
I am well game...

 

[pucho812]

UK have you seen the new T*A*S*C*A*M* x-forty eight.

The X-forty tight is the most advanced standalone multitrack recorder ever released:

? 48-track digital recording at up to 96kHz/24-bit

? 24-track recording at 192kHz/24-bit

? 32-bit floating point audio file recording and playback with no loss of track count

? VGA and PS/2 connections for keyboard, monitor and mouse

? Built-in 48-channel TDIF inputs and outputs

? Built-in S/PDIF I/O

? Two 24-channel option slots support analog, ADAT or AES/EBU expansion cards

? Advanced integrated synchronization and machine control, including HDTV tri-level sync

? Time-stamped Broadcast WAVE file format

? Front-panel transport, track arming, project management and meter functions

? Built-in 80GB hard drive

? Built-in DVD+RW drive for backup and restore

? Two FireWire (IEEE-1394) and four USB 2.0 ports for external hard drive support

? Graphic User Interface for editing, mixing, plug-ins and meters

? ±12.5% varispeed

? Grid-style editing

? Theater Play mode

? Gigabit Ethernet, includes FTP server and drive sharing

? Non-destructive editing with undo/redo

? Built on embedded Windows XP operating system

? OMF, AAF and OpenTL import and export


In addition, the X-48 functions as an all-in-one workstation, with powerful digital editing and mixing facilities:


? Turn-key operation: no software or hardware conflicts to troubleshoot

? 48-channel digital mixing at 96kHz / 24-channels at 192kHz

? 6 stereo returns (60 inputs at mixdown)

? 24 busses

? 6 aux sends

? Stereo buss

? 32-bit floating point mixer resolution

? Full dynamic automation

? Dynamics and four-band EQ per channel

? 4 VST plug-in inserts on each channel, group and aux return

? Controllable using the US-2400 24-fader Universal Controller

? Full graphic user interface

Retail around 5000.00 US
IMO looks good for the $$

 

[Svart]

yeah looks real good until you realize that like the original mx2424 you have to buy all your I/O separate, adding another 4k$ to the price..

I looked up jim williams and audio upgrades.. very poor website with no information except mentioning a "Class A Baby preamp"

from the pictures it has two BJT on the frontend and some kind of Linear Tech opamp.. very simple design. probably like my alesis X2 preamps, two 2n4403 and a dual opamp, one for gain the other servo.

take that and Force Class A with a resistor?

hmm i'd like to see what it is exactly..


I think i'll be adding poly caps to my I/O on my tascam as it only has the elna starget coupling caps. I know the PSU sucks on it too because moving my drives to a separate powered rack has cut the number of lockups in half.. time to upgrade those caps i suspect.

 

[chrissugar]

The new Tascam machine looks like a good thing, in fact it is a PC on steroids. I don't know but I don't like a machine that does too many things because it is a sign that there were made some compromises.

Also don't forget that it is still not available, no tests yet, no info about quality of converters or stability.

About the MX2424 I heard that it had some serious bugs over the years and that it do not pass digital data from in to disk to out unaltered. It is not from my experience, it is what I heard so you should to take it with a grain of salt.


About the HD24XR, I think it is a great machine for the money. I really like the fact that it has no display and serious editing. It is like an analogue tape machine but without the need to wait for rewind.
I have a RME Hammerfall DSP soundcard with 24 ADAT ins and 24 ADAT outs. With the HD24XR it is a nice combination. You can use the HD24XR for recording on location then transfer the tracks into the DAW, edit, process, then use the DA and sum into an analog mixer.
It can behave as a standalone recorder or as an AD/DA converter for the DAW.

Just for curiosity I digitally transfered some reference audiophile recordings (16bit/44.1k classical music, jazz, church organ, quartet) into the HD24 and listened to how it's converters sound. Even unmodified they sound good. I can't say that they sound excellent because I'm in the audiophile camp and my references are much higher but they sound really good. And don't forget that the HD24 cost as much or less than some better sounding two channel audiophile converters, and you have a recorder, 24ch AD and 24ch DA. A lot for the money.
My hope is that with the mod it can be improved to be closer to audiophile level.

In the next days I will take the HD24XR to a friend who has some highend audiophile sistem (Clearaudio turntable, Wilson WATT PUPPY speakers, Boulder preamp, Spectral power amp, Siltec cables) and will do some 24bit/96K recordings from vinyl and compare the recorded sound to the direct sound to see the full potential of this machine unmoded.

chrissugar

 

[chrissugar]

This is the original thread:
http://gearslutz.com/board/showthread.php3?t=11419&page=1&pp=30

and here is the post from Jim about the mod:
http://gearslutz.com/board/showthread.php3?t=11419&page=3&pp=30

Some more links with Jim Williams posts about HD24XR, converters and opamp preferences:
http://gearslutz.com/board/showthread.php3?t=10123&page=3&pp=30
http://gearslutz.com/board/showthread.php3?t=20025&page=1&pp=30
http://gearslutz.com/board/showthread.php3?t=32382&page=2&pp=30

chrissugar

 

[Svart]

isn't this the guy who said the Mx-2424 wasn't doing proper sampling or something?

another thing, I don't like the OPAx134 opamps.. seems that the opa4604 is next to impossible to get.

my tascam uses opa2604s for the I/O for comparison.

I don't see too many features as anything bad, conversion is getting better, cheaper and faster.. remember when 44.1k was going to be the best we would ever need? now look at SuperCD specs.. something like 3.4M sampling.


:thumb:

 

[Svart]

seems that Jim uses an Lt1358 on that little preamp board...

I had to make it out because the picture is so small but reading his posts mentions that one a lot.

BJT frontend though.

 

[mrc]

I guess different strokes, but I find the 2134 much better than the 2604, the 2604 has a lot of noise, and it really jumps out with several in a circuit, where the same number of 2134s in the same circuit (no other changes) are very quiet and still musically sweet.
mrc

 

[Svart]

hmm i find the 2134 very lacking in mids and multiples in a circuit tend to dull cause a very pronounced dip in upper mids. good for bass tracks and tom tracks though!

but yet you are correct, different strokes and also different circuits can bring different qualities out in different parts.

 

[Cainester]

[quote author="chrissugar"]In the next days I will take the HD24XR to a friend who has some highend audiophile sistem (Clearaudio turntable, Wilson WATT PUPPY speakers, Boulder preamp, Spectral power amp, Siltec cables) and will do some 24bit/96K recordings from vinyl and compare the recorded sound to the direct sound to see the full potential of this machine unmoded.[/quote]

I am anxious to hear your comments about that session!

Caine