Grundig was a full daughter from Philips
THE CD 7550 IS exactly the cd304 (not MKII)
every thing in it is simply interchangeble. (except from some rear connections)
And btw this is a cd104 tweak tread
look at
http://www.diyaudio.com/forums/showthread/t-74728.html
Best regards,
Onno
THE CD 7550 IS exactly the cd304 (not MKII)
every thing in it is simply interchangeble. (except from some rear connections)
And btw this is a cd104 tweak tread
look at
http://www.diyaudio.com/forums/showthread/t-74728.html
Best regards,
Onno
OK so as I see it there are 2 differences between the 7550 and the CD104 or CD304 MK1 :
1) Signal ground is decoupled from chassis ground by 2.2nf cap
2) From IAN01's excellent pictures I can see that the unit is more spread out. I guess the 7550 is 'standard width' whereas the 104 is Peter Walker 'standard width' 🙂 So the decoder and servo boards have a good air gap between them and the transport.
So mythbusters , does that account for the better sound of the Grundig ?
1) Signal ground is decoupled from chassis ground by 2.2nf cap
2) From IAN01's excellent pictures I can see that the unit is more spread out. I guess the 7550 is 'standard width' whereas the 104 is Peter Walker 'standard width' 🙂 So the decoder and servo boards have a good air gap between them and the transport.
So mythbusters , does that account for the better sound of the Grundig ?
I would pretty much agree with your summing up jives11 but possibly add a third which is not so obvious from photographs but strikes you when actually looking at a CD7550 and a CD104 along side each other.
3) The CD7500's decoder and servo boards are actually completely contained within a die cast chamber which extends from the bottom to the top of the unit. So when the top and bottom panels are in place these boards are effectively completely shielded. There are just two cable entry slots carefully placed at the front and rear of the chamber.
This contrasts with the 104 which has the servo board pretty much exposed on the top and no rear section to the chamber leaving the back end of both boards exposed to the power supply pcb
Otherwise, the only other difference I can see is the power supply pcb itself, which is certainly different to the one fitted to the 104, but then as this is generally accepted to be based on the 304 Mk1 it may well be the same as that. I've never seen a 304 Mk 1 apart! The CD7550 has 5 regulators as opposed to the CD104's 4 regs.
3) The CD7500's decoder and servo boards are actually completely contained within a die cast chamber which extends from the bottom to the top of the unit. So when the top and bottom panels are in place these boards are effectively completely shielded. There are just two cable entry slots carefully placed at the front and rear of the chamber.
This contrasts with the 104 which has the servo board pretty much exposed on the top and no rear section to the chamber leaving the back end of both boards exposed to the power supply pcb
Otherwise, the only other difference I can see is the power supply pcb itself, which is certainly different to the one fitted to the 104, but then as this is generally accepted to be based on the 304 Mk1 it may well be the same as that. I've never seen a 304 Mk 1 apart! The CD7550 has 5 regulators as opposed to the CD104's 4 regs.
Onnosr - I hope you don't mind the exploration of what might make the CD7550 different from the parent Philips machines. These are regarded by many as being sonically superior to their Philips counterparts as as such many CD104 owners have expressed an interest in exactly what the differences are and if those differences can be applied to the 104. I promised this thread some time back that the next time I took it apart I would take some detailed photographs and post them here.
I think it is generally accepted that the onboard electronics is identical, I believe that Philips actually owned Grundig during this period so it would be highly surprising if this was otherwise. Most people believe that the differences are more subtle, being down to layout and earthing arrangements. Mythology or fact ... we are simply trying to find out!
I think it is generally accepted that the onboard electronics is identical, I believe that Philips actually owned Grundig during this period so it would be highly surprising if this was otherwise. Most people believe that the differences are more subtle, being down to layout and earthing arrangements. Mythology or fact ... we are simply trying to find out!
[ - I hope you don't mind the exploration of what might make the CD7550 different from the parent Philips machines. These are regarded by many as being sonically superior to their Philips counterparts as as such many CD104 owners have expressed an interest in exactly what the differences are and if those differences can be applied to the 104. I promised this thread some time back that the next time I took it apart I would take some detailed photographs and post them here.
I think it is generally accepted that the onboard electronics is identical, I believe that Philips actually owned Grundig during this period so it would be highly surprising if this was otherwise. Most people believe that the differences are more subtle, being down to layout and earthing arrangements. Mythology or fact ... we are simply trying to find out! [/B][/QUOTE]
Hi IAN01
No I don't mind at all in the contrary I like it.
I own 7 cd104 one is still original the other 6 are modified
see some posts from me in this thread.
I changed the clock, the DEM clock, made them NOS, in 2 of them I changed the two tda 1540 by 2 tda 1541a's singel crown etc etc.
In an other one I changed the decoder board with the decoder board from a cd304mkII.
I own a cd304 and a cd304 MKII and a marantz CD94 mark II
The only thing I can say they all sound different from each other.
That makes me to believe that there are fi no 2 cd104's (with the same mods) sounding identical.
This makes me very sceptical about mythes and statements that this player sounds superior than an other.
Fi comparing a bad sounding CD7550 with a good sounding CD304 ore visa versa What does it say ? imho nothing!
Your point about earthing is indeed something to look at.
In the original cd 104 (like all cd 104's) there are two regulators on the heathsink direct mounted without insulating resulting in a very nice ground loops :--((( ! (also Philips can be stupid)
Putting simple a mica in between solves the problem.
(see a post from me in this thread about it)
Further the power PCB is direct gounded with two bolds to the chassis. Cut one out on the PCB and the remaining grounding has to be the ONLY grounding to the cabinet.
It is possible that the Grundig version of the CD304 has done something about grounding in that way.
Further changing al power caps and the diodes by fast recovery ones does wonderfull things.
My last creation of a cd104 has now a low jitter clock a separate dem clock it has the decoder board from cd304 mkII it is NOS but still hase a digital out it has inside the USB strip from EC desings
(automatically switching to USB DAC) is has two TDA 1541a's S1 in parallel and it has a remote control. And there is only one grounding point to the cabinet !!! and the (stupid) fet killers in the audio output are changed with the nice reed relais from a cd104 board. and what is very important it has two very large monacor MKP 6.8 mf capacitors in the outputlines.
Succes in founding out the differences and if you have found them let us know it.
Best regards
Onno
I think it is generally accepted that the onboard electronics is identical, I believe that Philips actually owned Grundig during this period so it would be highly surprising if this was otherwise. Most people believe that the differences are more subtle, being down to layout and earthing arrangements. Mythology or fact ... we are simply trying to find out! [/B][/QUOTE]
Hi IAN01
No I don't mind at all in the contrary I like it.
I own 7 cd104 one is still original the other 6 are modified
see some posts from me in this thread.
I changed the clock, the DEM clock, made them NOS, in 2 of them I changed the two tda 1540 by 2 tda 1541a's singel crown etc etc.
In an other one I changed the decoder board with the decoder board from a cd304mkII.
I own a cd304 and a cd304 MKII and a marantz CD94 mark II
The only thing I can say they all sound different from each other.
That makes me to believe that there are fi no 2 cd104's (with the same mods) sounding identical.
This makes me very sceptical about mythes and statements that this player sounds superior than an other.
Fi comparing a bad sounding CD7550 with a good sounding CD304 ore visa versa What does it say ? imho nothing!
Your point about earthing is indeed something to look at.
In the original cd 104 (like all cd 104's) there are two regulators on the heathsink direct mounted without insulating resulting in a very nice ground loops :--((( ! (also Philips can be stupid)
Putting simple a mica in between solves the problem.
(see a post from me in this thread about it)
Further the power PCB is direct gounded with two bolds to the chassis. Cut one out on the PCB and the remaining grounding has to be the ONLY grounding to the cabinet.
It is possible that the Grundig version of the CD304 has done something about grounding in that way.
Further changing al power caps and the diodes by fast recovery ones does wonderfull things.
My last creation of a cd104 has now a low jitter clock a separate dem clock it has the decoder board from cd304 mkII it is NOS but still hase a digital out it has inside the USB strip from EC desings
(automatically switching to USB DAC) is has two TDA 1541a's S1 in parallel and it has a remote control. And there is only one grounding point to the cabinet !!! and the (stupid) fet killers in the audio output are changed with the nice reed relais from a cd104 board. and what is very important it has two very large monacor MKP 6.8 mf capacitors in the outputlines.
Succes in founding out the differences and if you have found them let us know it.
Best regards
Onno
My CD304 MkI inside:
My CD7550 inside:
They look pretty much identical to me. After all I guess it's all about the visual design:
😀 😀 😀
An externally hosted image should be here but it was not working when we last tested it.
My CD7550 inside:
An externally hosted image should be here but it was not working when we last tested it.
They look pretty much identical to me. After all I guess it's all about the visual design:
An externally hosted image should be here but it was not working when we last tested it.
😀 😀 😀
I couldn't agree more. Thats the first time I have seen the inside of a 304 Mk1. So I guess we can rule out the chassis and the component distribution.
I have to agree strongly with this observation too. I have 2 Philips CD100s, a CD303, 2 CD104s and the Grundig CD7550 and they all sound different. As it happens, in my case, I prefer the sound of the CD7550 from the rest, it has greater transparency and stereo imaging than the others. I personally have never claimed that this is due to some inherent advantage that these players have design wise, but I know others have. I have failed to find anything so far that would adequately account for the difference.
However, I have never heard any convincing explanation to why there are such differences sonically between the same model players when up to the TDA1540 the music is all in the digital domain (1s and 0s) and after that the analog circuitry is identical. In fact it remains virtually unchanged from the CD100 to the CD104.
For something that would seem to be an exact science, in practice it would seem it is anything but 😉
IAN01 said:
Not quite true.
After the laser has read the disk, the signal is RF analog up to the processor. The servo mechanisms are also analog.
The CD100 used the CDM0 mechanism whereas the CD104 uses the CDM1. (I cannot remember the other variations .......)
Several versions of the electronics were also used, from the board on the CDM to microprocessors, etc.
Andy
Whilst this is true Andy, it's still carrying a digitally encoded stream otherwise there would be nothing to decode from it.
I was referring to the final analog audio section. There are of course differences between the models as you point out but these are all again involved in extracting, assembling and manipulating the digital data and if working within normal operating parameters should not unduely effect the acurate transmission of that data. The whole concept of the CD player surely relies upon this!
The Grundig's power pcb is grounded with two bolts directly to the heatsink which is in turn bolted directly to the chassis.
jives11 said:
Take an (defect) powersupply from a PC and in it you will find what you need !
Onno
Upon thorough examination I've discovered that My CD304 had no AC filter. Disassembling the CD7550 revealed existing of one. The PCB is present inside CD304 but the components are replaced by bridges. Shunt capacitors were simply not soldered. My CD104 has no AC filter either. I assumed it was because it was some how the "304's little brother", meaning it suffered some privations, but i guess I was wrong 😀
The AC filter itself is quite simple - just two shunt caps and ferrite choke.
The AC filter itself is quite simple - just two shunt caps and ferrite choke.
IAN01 said:
I Have seen many cd304''s with and without the filter transformer
(a ferrit biwired transformatorlook trafo that you can find in many pc power units)
I have seen also many cd 104 with and without.
(The PCB with the drilled holes for the trafo and caps are still in there.)
Putting in a trafo and caps costs let's say about one euro but on a production of how many it differs a lot.
So saving productioncosts lets the trafo out !!!
I did put in the ones without the trafo etc a trafo and the caps.
IHMO no difference in sound helas !
But go on searching the units you own for more differences.
Regards
Onno
CD104 manual and some questions
Hi all!
I am new in the forum, but I need help finding a full service manual for CD104, since it turned out that I accidently found a decoder PCB from the same model. You can mail the file to: radko71@abv.bg
The mailbox can accept attachments up to 10Mb.
I have the idea to make it an external DAC and use a SONY CD as a transport.
Can anybody give me some guidance as to how do I connect the digital output from the CD to the decoder board I have. I found the datasheets for the chipset, so I will figure out the power supply and outputs, the only doubts I have are is there any enabling pulse in order for the decoder to pass the data on to, and through the TDA1540s
Thanks for any information in advance!
Hi all!
I am new in the forum, but I need help finding a full service manual for CD104, since it turned out that I accidently found a decoder PCB from the same model. You can mail the file to: radko71@abv.bg
The mailbox can accept attachments up to 10Mb.
I have the idea to make it an external DAC and use a SONY CD as a transport.
Can anybody give me some guidance as to how do I connect the digital output from the CD to the decoder board I have. I found the datasheets for the chipset, so I will figure out the power supply and outputs, the only doubts I have are is there any enabling pulse in order for the decoder to pass the data on to, and through the TDA1540s
Thanks for any information in advance!