HK T 403 AM/FM Tuner

T

tropicalcb

New Member
G'day....anyone know anything about this ol bugga!? ... I just picked it up on aus e-bay for au$30 & it should b on its way. It looks like an interesting candidate for refurbish/modding ... mainly bcause its got a BIG case from the look of it in the pics. Its '77 vintage so its probably got freaky lil LM833 chips rather than discrete trannies, but not sure whether its Rf section is any good. This is a learning project for me to find out wot can be done in the front end to get better FM signal etc (not into AM)....the output stage of analogue toyz is ok 4 me but never done much with the RF side.
Been to the FMtunerinfo site but they dont list it.....anyone got any clues/experience/suggestions & any recommendations 4 where 2 get a service manual ?
cheers..........cb
 
I think it's basically the tuner from the hk430 and/or 730 (were they different?). I think I have the brochure for the A401, A402, and T403. Some of the most beautiful hardware of its era (IMNSHO)... and pretty decent sounding, too.
 
He probably did... I just didn't wait and give you a chance to reply :)

I jumped in mostly 'cause I think the T403 is one elegant little tuner.
 
T 403

~~~ onya blokes ... no I didnt know about the free manuals...thanks mate!
shit, wot a find! ... well the circuit for the back end looks good - and it uses discrete trannies & its simple!! ... so mayb I won't build a nuvistor output stage into it, in fact, I don't think there's much room left! ....just at a glance, the PS has a bit of reg but the capacitance looks minimalist, & the bridge has gotta go....but I wouldnt have a clue about the front end.... its all new to me, in fact I just did some parts subs in an old rotel 322 ...which is very minimalist but came up sounding good - didnt touch the IF cause I'm clueless at this stage... its about '75/'76 ... and PS was very underrated & electros should be replaced evry ten yrs anyway. & this thing was obviously made in US & designed for max bang for buck. It uses IC's in the front which obviously perform decoding etc functions - is that a good thing or a limiting thing for optimising performance?
thanks again...I'll keep yez posted.........cb
 
I've got one with a broken mode selector switch I wish I was smart enough to fix. It's a handsome tuna.
 
mhardy6647 said:
He probably did... I just didn't wait and give you a chance to reply :)

I jumped in mostly 'cause I think the T403 is one elegant little tuner.
Click to expand...

No probs there. I agree. I am confused when comparing specs, though, some are better than the 730, some are worse. Can't see why h/k would not be consistant, but I awas not there when it was designed. I can say the T403 is more stable the the 7630, less drift and locks in a signal better.

I have wanted for a long time to combine portions of 730 and T403 tuner; I like the quietening meter. Can't understand why h/k didn't put it in the T403, as the A402 has more features, why not the matching tuner? Mind you, at least the T403 has a 75 ohm F connector in the back, while the h/k receivers had to wait for 6 years to get one...
 
tentoze said:
I've got one with a broken mode selector switch I wish I was smart enough to fix. It's a handsome tuna.
Click to expand...


What's wrong with it? I may be able to help.

Cheers,
Joe
 
Broken selector switch

~~~ well uve obviously got some tech proficiency bcause uve deduced that its at the contacts... & u must have got inside the unit. wot exactly is broken at the contacts? ... is it bent mayb? .... turn ur switch while ur looking at it...preferably with a mag glass or similar & see wot happens at the broken contacts vs the unbroken....this may give u more info.....cb
 
tropicalcb said:
~~~ well uve obviously got some tech proficiency bcause uve deduced that its at the contacts... & u must have got inside the unit. wot exactly is broken at the contacts? ... is it bent mayb? .... turn ur switch while ur looking at it...preferably with a mag glass or similar & see wot happens at the broken contacts vs the unbroken....this may give u more info.....cb
Click to expand...

No, I'm dangerous inside eqpt. I broke the damned switch after removing the knobs for cleaning- reinstalling the knob, I was putting pressure on the backside of the switch from inside the unit and the rotating thingamajig BROKE. I've not admitted this in public till now- where's the 12 step method for stupidity?
 
T 403

>>>>>>> Mind you, at least the T403 has a 75 ohm F connector in the back, while the h/k receivers had to wait for 6 years to get one...

.....and that wood b? ie F connector - is it a strap for 75ohm coax shield + screw for signal set-up?
.... so wot r ur impressions of the sound quality? has anything been done to ur 403, like upgrade/replace caps etc or is it in as shipped condition? ... my comments were based on wot I gleaned from the on-line service manual at the site u referred me to, so I haven't actually seen or heard it yet.
....also any idea where it fit in the HK line at the time? .... was it a middle o the range or entry level? or wot ... without any real ref point for tuners I have no idea ....even though Ive been building/modding tube & a bit of ss gear for 20 yrs or so, Ive never taken any interest in tuners, & only ever looked inside a couple of sansui's & wasnt really impressed. the unit in my car sounds good but FM radio stations up here play wot sounds to me like very compressed, pasteurised, homogenised etc etc music with sound to match, so I may never actually get to hear how good it can get with this HK - ironic eh??!! ... ut it'll b fun!
.............cb
 
....ok... betta leave it alone capt clumsy!! .... so wot were/are ur impressions of the 403 on a good station ... as per my previous post? ... I'm tryin to get a handle on wot sort of sound qual to expect, impatient bastard that I am!! ... I read a few of the narratives at fmtunerinfo & these r obviously top o the range tuners, so I'm wondering where the HK 403 fits in stock form. If the Kenwood/Accuphase r 8-9.5 outa 10 .. where would the 403 b?
...........cb
 
Most 70s tuners (and those before) had 300 ohm twin lead connectors for FM. With the advent of cable TV/FM, eventually, tuners added the 75 ohm F connector (same as the screw on coax connector for cable TV).

The T403 was TOTL for the consumer separates, but a large step below the citation components of the same era.

Sounds similar to the 730, with a little less drift. I tried 3 730s and 2 403s and the 730s all drifted more than the 403. Could be because the 403 had cable FM direct ion the 75 ohm connector and the 730s had to use a 75 to 300 ohm adaptor....
 
T403

..... ah thats interesting....the rotel 322 I just did the PS etc on, was showing very low signal strength wen I first fired it up pre refurbish, but I was using a 300-75 ohm balun - which is all that can b hooked up to it. However signal strngth, & sound qual both improved dramatically with replacement & increase in PS capacitance & then replacement of all old electros I could find & subbing of small value electros like 1.0uf with film caps of at least equal or +20% value .... so I figured that there was just not enough juice to handle transients, bass etc....but that still doesn't a/c for the omprovemnt in signal strength given the aerial connection is identical....mayb a couple o electros were feeding the IF stages....any idea where I can get a schematic or service manual 4 the rotel RT 322? Rotel dont know they ever made it, its so old??!!
.........cb
 
Comparing schematics, the T403 is virtually identical to the tuner section of 430 receiver (and fairly different from the 730). The T403 had an added output amp, being the biggest difference between it and the 430. I've seen, but haven't heard the 403. A friend has one in town and he has had held onto it, in contrast to many 'big priced' tuners that he has tried and later sold. I do like the tuner section of the 430 reciever---it has a very good sound.

Steve.
 
tentoze said:
No, I'm dangerous inside eqpt. I broke the damned switch after removing the knobs for cleaning- reinstalling the knob, I was putting pressure on the backside of the switch from inside the unit and the rotating thingamajig BROKE. I've not admitted this in public till now- where's the 12 step method for stupidity?
Click to expand...

If you want me to look at fixing it for you, PM me.
 
Last edited:
You must log in or register to reply here.

Similar threads

gonzothegreat
Pioneer FT-V70 AM/FM/TV tuner find & questions
Replies
0
Views
380
gonzothegreat
gonzothegreat
audmod01
Report on the Fisher FM-2310 AM-FM Tuner
Replies
1
Views
547
SSowner
S
audmod01
Fisher 90-T AM-FM Tuner/Preamp
Replies
14
Views
2K
rickl
rickl
H
Hitachi HA-3400 AM/FM tuner repair
Replies
2
Views
137
Homosapien
H
blhagstrom
Technics SA-5250 FM tuner problem
Replies
0
Views
614
blhagstrom
blhagstrom
Back
Top Bottom