Hacking the Logitech Z5500 - Page 2 - diyAudio
Go Back   Home > Forums > Amplifiers > Chip Amps

Chip Amps Amplifiers based on integrated circuits

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 23rd October 2007, 01:00 AM   #11
Bob25 is offline Bob25  United States
diyAudio Member
 
Join Date: Apr 2007
I rung out the one I have over the weekend. Mine is the one with the spring terminals for the speakers. Also, I tried plugging in the controller to see what voltages I would get. Voila! It was working as normal. Actually, this is my son's unit who is away to college. I guess I can't hack it now since it works.

But this allowed me to measure some voltages while it was properly working. The 'HCT139 inputs are 7 and 8 on the 15 pin D conn. 7 & 8 both measure +3.0 VDC when muted. When 'ON', pin 7 is 0 VDC and pin 8 is +3 VDC.
When I had the box apart, I thought pin 11 was GND and not 13, but could be wrong. I don't know about pin 12 either.

The SW on pin 2 is riding on a DC bias of 2.68 VDC when the unit is on and 1.5 when off. There is very little audio level on the SW pin compared to the others. I think the controller might digitally sample the other channels and extract & route LF audio to the the SW ?? I seems there are two 4580's marked U6 and U7 involved with an active filter/op-amp circuit that is AC coupled to pin 2 of the 15 pin D conn. The SW out is U7, pin 7.

The preamp board is wired to the AMP board with a row of pins across the "top" of the board. The left most pins marked 'WA100' and 'WA123' I have not figured out their function. All of the others are either inputs to the AMP, speaker O/P back to the preamp board, the +8, +/-18 supplies or three other wires involved with the mute & standby. These are marked and have the following functions:

wire color pin # mute VDC ON VDC VDC when unit is OFF
---------------------------------------------------------------------------------
white 120 0.5 5.5 0.5
bl 122 5.9 5.9 -0-
or 121 -0- 5.9 -0-

- Bob
  Reply With Quote
Old 23rd October 2007, 03:16 AM   #12
tashing is offline tashing  United States
diyAudio Member
 
Join Date: Oct 2007
Default Video

Lakata, I just happend to run across the video while searching for info on this sub, I have e-mailed the poster of the Video and gotten no response.

Tim
  Reply With Quote
Old 29th October 2007, 04:04 PM   #13
diyAudio Member
 
Join Date: Jul 2005
Location: Montreal
Quote:
Originally posted by Bob25
I rung out the one I have over the weekend... When I had the box apart, I thought pin 11 was GND and not 13, but could be wrong...
- Bob
Bob!! Sorry I didn't get back to this before, but a big thanks for all this tracing! It's really helping me out. So far the pin assignments you've compiled seem right, even though my board is different from yours. For now, I've made the assumption that the controller must be the same for both versions of the subs, just because it makes more manufacturing sense. I could be wrong... but I'm still tracing unpowered.

I'm still figuring things out but one thing I want to mention to everyone is that on my board pin 11 seems to be audio ground, and not pin 13. In fact, I haven't figured out what pin 13 connects to yet. Blame the use of hot glue instead of proper connector headers ;(

...
  Reply With Quote
Old 29th October 2007, 11:04 PM   #14
diyAudio Member
 
Join Date: Jul 2005
Location: Montreal
OK! I've got it working on the RCA version of the Z5500!

The trick is pin 7 and pin 8, both directly connected to the HCL139 chip. Looking at the truth table for these inputs on the 139 spec sheet, it seemed logical that these two pins should be responsible for the 3 states reported by Bob. BTW, +Vcc to this chip on the board is about 5 volts (a zener?). I also used the ground on pins 11 and 12 (13 isn't a ground on my version of the Z5500)

I tapped a point on the board with that +5 to enable pins 7 and 8: Pin 7 turns the amp on and off and pin 8 enables the mute function, which has a nice fade in/out effect. If pin 7 is enabled without pin 8, there's an awful turn on thump, so it's a good idea to enable 8 before 7, and then disable 8. I suspect it'll be better to use an SPDT, with the alternate logic state grounded.

I connected my generator to pin 2 (using 11/12 as ground) and I have TONS of gain on this channel! Pin 2 leads directly to a cap and LPF as Bob pointed out. I'm sure the other channels work, but I don't need them. I'll probably ground their inputs (should I use resistors or just ground?).

Thanks to all who contributed! If anyone has any questions, I'll be more than happy to discuss.

  Reply With Quote
Old 30th October 2007, 02:18 AM   #15
diyAudio Member
 
Join Date: Jul 2005
Location: Montreal
One more thing: here's a diagram of the pinouts for the record. The view is looking from the rear of the female DB15 plugged into the sub.

Thanks to Bob25 and lakata for the pinouts. Note that I haven't personally checked any inputs other than the sub.

u
Attached Images
File Type: jpg z5500_rcavers_db15.jpg (99.9 KB, 6282 views)
  Reply With Quote
Old 30th October 2007, 03:59 AM   #16
tashing is offline tashing  United States
diyAudio Member
 
Join Date: Oct 2007
Quote:
Originally posted by undertone
OK! I've got it working on the RCA version of the Z5500!

The trick is pin 7 and pin 8, both directly connected to the HCL139 chip. Looking at the truth table for these inputs on the 139 spec sheet, it seemed logical that these two pins should be responsible for the 3 states reported by Bob. BTW, +Vcc to this chip on the board is about 5 volts (a zener?). I also used the ground on pins 11 and 12 (13 isn't a ground on my version of the Z5500)

I tapped a point on the board with that +5 to enable pins 7 and 8: Pin 7 turns the amp on and off and pin 8 enables the mute function, which has a nice fade in/out effect. If pin 7 is enabled without pin 8, there's an awful turn on thump, so it's a good idea to enable 8 before 7, and then disable 8. I suspect it'll be better to use an SPDT, with the alternate logic state grounded.

I connected my generator to pin 2 (using 11/12 as ground) and I have TONS of gain on this channel! Pin 2 leads directly to a cap and LPF as Bob pointed out. I'm sure the other channels work, but I don't need them. I'll probably ground their inputs (should I use resistors or just ground?).

Thanks to all who contributed! If anyone has any questions, I'll be more than happy to discuss.

I am not sure what you mean by "RCA Version". you mentioned using +5 volts to enable pins 7 & 8, did you apply +5 volts to these pins? An earlier post indicated these shoud be grounded.

Thanks for the info by the way.

Tim
  Reply With Quote
Old 30th October 2007, 02:42 PM   #17
diyAudio Member
 
Join Date: Jul 2005
Location: Montreal
Quote:
Originally posted by tashing

I am not sure what you mean by "RCA Version". you mentioned using +5 volts to enable pins 7 & 8, did you apply +5 volts to these pins? An earlier post indicated these should be grounded.

Thanks for the info by the way.

Tim
Hi Tim,

Earlier in this thread there's two links to 2 YouTube videos that show 2 different Z5500 models: one has spring-loaded speaker wire connectors on the back, while the other has RCA jacks to connect the speakers to. If you look carefully at the videos, you'll also notice that the input board on both models is different as well. Mine is the "RCA jack" version. I don't know which is more recent, or if it's a "region" issue. So I made sure I pointed out that mine is the RCA version, as I can't be sure anything I found out about mine applies to the other, though I suspect they're very similar.

As for the +5v, if I ground 7 and 8 it doesn't turn the amp on, but +5 does. BTW I'll have to revise my previous post if I can: it turns out that once either 7 OR 8 is connected to +5, then the other switch will do the fade in/out when connected to +5. AND if I do connect these switches to ground in their alternate state, either switch will turn on the amp and there's no fade in/out mute at all. However, I do get the feeling that pin 8 is "thumpless", so I'm going to simply connect pin 7 to +5 and pin 8 to a SPST switch to +5 for the mute.

The only regulated power on this board is +8 and +/- 18, but there's a +5 for the control logic. I've put together a picture showing +5, ground, and the input pins going straight to the DB15, as mapped by Bob25 and lakata (BTW: "LFt is on the PCB, not the top of the cap...). The "easiest" place to tap pins 7 and 8 seem to be at the DB15 solder points on the underside. BTW the sub input capacitor is only a 0.1 uF so it has to be a high impedance input.

u
Attached Images
File Type: jpg z5500_inboard_top.jpg (92.9 KB, 6766 views)
  Reply With Quote
Old 30th October 2007, 03:09 PM   #18
diyAudio Member
 
Join Date: Jul 2005
Location: Montreal
One more for completeness

This picture shows the location of pins 7 and 8 on the underside of the PCB.

u
Attached Images
File Type: jpg z5500_pins_7-8.jpg (89.0 KB, 6056 views)
  Reply With Quote
Old 1st November 2007, 10:22 PM   #19
diyAudio Member
 
Join Date: Jul 2005
Location: Montreal
Hi all,

I finished the mod a few days ago and it works fine. Sweeping down from 200 Hz (where the LPF seems to start) the sub reponse is quite linear to about 30Hz where it starts losing steam (power that is; the woofer seems to handle 20 Hz but it's just not very loud, but normal if a -3dB point).

Hooking it up to my cheaper surround receiver (a Yamaha HTR-6030) I have one problem: even adjusting the subwoofer level to the minimum the receiver allows, it's still a few dB too loud.

The max output from the receiver is 4 volts and the impedance is 1200 ohms. Now I know the impedance of the sub section is high because of the 0.1uF cap at the input (probably 100-150k) and it oscillates around 180 Hz if not connected.

I tried using a simple passive T attenuator, values set to match 100k, to lower the input gain by about 6dB but it oscillates even when connected to the source. Should I make the attenuator match the source impedance instead? Is a passive attenuator feasible or should I go active?

Thanks for any tips from the more knowledgable than I
  Reply With Quote
Old 2nd November 2007, 03:30 PM   #20
diyAudio Member
 
Join Date: Jul 2005
Location: Montreal
Never mind: found my answer here.

  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
(Hacking the) Logitech Z-5300 pinouts? superxpro12 Chip Amps 2 23rd October 2009 03:02 AM
a big z5500 problem sonofwind Chip Amps 0 12th March 2009 02:07 AM
Z5500 from Home to Truck! fireplug0510 Car Audio 1 3rd February 2008 09:00 PM
Logitech z5500 sattelites TB W3-871s. willhub Full Range 21 18th December 2006 07:50 PM


New To Site? Need Help?

All times are GMT. The time now is 04:25 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2