'White noise' update Posted by: "Stephen Prior" sjp@sjprior.fsnet.co.uk g4sjp Date: Wed Oct 11, 2006 12:02 pm (PDT) Hello Dietmar Yes, I got the radio back yesterday. It has had the 8kHz mod done and also the white noise mod. However, Icom states in their delivery note that the noise has only been reduced by 3dB, and although it is better, I have to say that I still do not think it satisfactory. One thing which has helped is wiring an 18 ohm resistor across the headphone output, and therefore in parallel with the headphones. This does reduce the maximum output level slightly and also slightly dulls the top end of the audio spectrum, but it makes the use of headphones tolerable for me. I must say that although Icom UK have been very very helpful in all this, I remain fundamentally dissatisfied with the IC-7000 for this reason. Except for in the car, I always use headphones so that others in the house do not have to directly ?shareı my interest in amateur radio! I am seriously considering changing the IC-7000 for a TS-480HX! 73 Stephen G4SJP ------------------------------------------------------------------------------ On 11/10/06 14:56, "dietmarfichter" wrote: Hello Stephen, have you had a chance to evaluate the white noise issue after Icom modified your radio? Dietmar E3CG ------------------------------------------------------------------ In ic7000@yahoogroups.com , Stephen Prior wrote: I have heard from Icom UK this morning; it seems that they received information from Japan only yesterday, concerning a modification to the radio for the 'white noise' issue. This has now been done to my IC-7000, along with the 8kHz fix and I should be receiving it back on Monday. I shall report my findings here. At least they are acknowledging that this is a real problem! 73 Stephen G4SJP ======================================================================= 'White noise' update Posted by: "D C *Mac* Macdonald" k2gkk@hotmail.com k2gkk Date: Wed Oct 11, 2006 2:22 pm (PDT) I'd hazard a guess that you could drop the parallel resistor down to 8 Ohms for further improvement with no harm to the radio. Mac - K2GKK/5 ======================================================================== 'White noise' update Posted by: "dietmarfichter" dfichter@uwo.ca dietmarfichter Date: Wed Oct 11, 2006 7:06 pm (PDT) Hello Steven, thanks for the update. I wonder what Icom actually does to reduce the white noise? The reason I am so interested is that my 7000 is at the Icom (Canada) shop right now for repair. I contacted them right away when I saw your posting that there may be a possible fix for the white noise problem and asked them to update mine as well. I will let you know how mine pans out when I get my rig back. Dietmar VE3CG ======================================================================== 'White noise' update Posted by: "Stephen Prior" sjp@sjprior.fsnet.co.uk g4sjp Date: Wed Oct 11, 2006 7:52 pm (PDT) Hi Mac Yes, you certainly can, but it cuts down the audio to the headphones such that the output from the audio amp starts to distort at higher volume levels, and it just 'dullsı the high frequencies just a little too much. Obviously the parallel resistor is working with some reactance in the AF output stage to produce high frequency roll-off. I havenıt looked at the circuit diagram to verify this. 73 Stephen G4SJP ======================================================================== 'White noise' update Posted by: "Stephen Prior" sjp@sjprior.fsnet.co.uk g4sjp Date: Wed Oct 11, 2006 11:36 pm (PDT) Dietmar The only info I have is this, and it is not clear whether these parts refer to the 8kHz mod or the white noise one or both! Chip capacitor GRM39/0603/C1608 Actually, looking again at that, it looks like only one part to me! Iım confused. Anyway, tell your Icom people that Geoff Boakes at IcomUK did it! 73 Stephen G4SJP ======================================================================== 'White noise' update Posted by: "Stephen Prior" sjp@sjprior.fsnet.co.uk g4sjp Date: Wed Oct 11, 2006 11:41 pm (PDT) 8 ohms I believe, my headphones are higher than this, part of the problem I know. It's just that I don't get the same level of hiss with any other radio I own (which is several more than the XYL knows about!!!). However if I connect an 8 ohm resistor across the headphone output I lose too much audio and a lot of the higher frequencies. I have some very small audio transformers around somewhere, about 10:1 I think, I shall try one of those next. 73 Stephen G4SJP ======================================================================== ======================================================================== ======================================================================== ======================================================================== ======================================================================== ======================================================================== ======================================================================== ======================================================================== ======================================================================== ======================================================================== ======================================================================== ======================================================================== ======================================================================== ======================================================================== ======================================================================== ======================================================================== ======================================================================== ======================================================================== ======================================================================== ======================================================================== ======================================================================== ======================================================================== ======================================================================== ======================================================================== ======================================================================== ======================================================================== ======================================================================== ======================================================================== ======================================================================== ======================================================================== ======================================================================== ======================================================================== ======================================================================== ======================================================================== ======================================================================== ======================================================================== ======================================================================== ======================================================================== ========================================================================