|
|
I thought it was about time Stu had his subject back about
qualifications, bI guess we took it over about other things .. Sorry
Stu.
Here, listed below, is what was said about the "other" stuff, hopefully this new thread will allow the two subjects to diverge a bit.
Francis Williams wrote:- " I had a G.E.C. radio at school .. does that help Stu?"
Anthony Eccles wrote:- "Oh by the way Bill, have you still got it and if so dos it still work, unlike some of us."
5 days ago
Francis Williams wrote:-
Tony,
Regretably the small 3" x 4" G.E.C transistor in its little leather
case did not survive the rigours of adolescence .. but there is good
news; .. A larger Sobell, (aka G.E.C) I bought with my first weeks wages
from the co-op at Shearns in the Oval has (minus the screw-on back).
Haven`t switched it on in ages, it`s in the loft. Has some nice big
juicy AF117? transistors inside. Runs on 4 x A.A. battereies, has Long,
M.W. and S.W. bands only.
Another radio, (Hacker Sovereign, that uses 2 x big PP6 batteries,
with F.M. and a 8"x 6" speaker) I bought in 1968 at Ryland Huntley, Old
Bond St. Bath (worked there when I was 15, bought it in 1968 aged
20) is still working o.k. in my work-room. I have a spare, that I
bought at a boot sale in the 80`s tucked away safely under wraps.
I also have a Eagle microphone, and a pair of full-range Eagle
8" speakers (with horn tweeters & crossovers all from
c.1963) somewhere in the loft. I don`t however have the crystal
set in the matchbox that a few of us made while at school. Still,
we must move on .. shame.
Stu, I`m glad Tony & Rich managed to help out with the
serious stuff (I`m not too good at that these days .. ha ha). I`m still
in two minds about the reunion. Carole is not against the idea,
especially when I said we could stop overnight after getting merry. I`m
off to browse the Web, and have a look on Wikipedia before retiring for
the night. Catch you guys later maybe....
5 days ago (Edited 5 days ago
John Stickland wrote:-
Hi all,
All this talk about old transistor radios brings back some happy
memories. In the 1960s I was working on PA systems quite a lot, but
still running on valves, some of the earlier ones were still using 807s
with 500V on the anodes (which was the top cap), used to catch out the
unwary, or just plain dumb, occasionally. The later amps were all KT66,
KT77 and KT88s in parallel push pull, a much safer option, but not
nearly as reliable. Oh by the way the earlier ones also had 'Soft'
mercury vapour rectifier valves, should see them glow when they were
being driven hard. Where was health and safety in those days?
Happy days.
Sticky.
Francis Williams wrote:-
Hello John,
Quad 50e`s come to mind when you mentioned the "KT" range of
pentode valves. Got a feeling they used EY51 rectifiers. Pre-amp stage
was ECC83 I think (double triode). 100v line transformers were quite the
norm as well in those days. Lowther, Goodmans, Wharfdale, Stenorian
speakers (to name a few) were prevelant. Early model speaker units had a
spiral paxoline suspension arrangement, it was not uncommon to have to
re-centre the voice coil units after much abuse at bass frequencies.
I expect you will recall that in the late 50`s and early 60`s that
the best "Hi-fi" cabinets used to be sand, filled twin walled stiffened
ply, corner reflex units with tuned bass porting. 3000 cu.in. cabinet
design was typical domestic dimensions for 8" bass units.
Horse-hair absorbency lining was used to assist damping. Paper cones
were popular, but bextrene (doped) cones were becoming favourites
(humidity problems with earlier paper construction) . Trebax made a
wicked range of horn tweeters in those days too.
Look at the changes in technology today John, multiple small wide
range drivers appear to be the norm. The bass range from these
(relatively tiny) speakers is amazing. I have a digital piano with 8
small drivers, and the bass is unbelivable. I use a pair of modified
Teak Spendor BC1 monitors in the lounge, and modified medium
size Warfdales in the workroom. Well, done my bit for today to
bore the majority about sound .. ha ha
Chris Wiltshire wrote:-
I used to have a pair of BC1's, Bill and they were a
revelation when I first heard them. They are still in action in my
Brother in laws home. With regards to Valves I regularly turn to
my Quad II's for a bit of warmth (in all senses) from the
KT66's....athough I also have an Affordable Valve Co KT88 powered
integrated amp which sounds fabulous and also warm the room very well.
I
built a pair of "folded horn enclosures" designed bt John Crabbe and
with Wharfedale units. They sounded................dreadful!!!!
Until I inserted, in a kind of medical proceedure, a mass of Dr Baileys
long fibre wool up their fundaments....then OK until aforementioned B in
law destroyed them at a party with an underpowered amp.
Viva olldenn technology.
5 days ago
John Stickland wrote:-
Hi all.
Nice to know that you are still a 'valve' man Chris, what does Parrotty make of that?
Yes, Bill, on all PA the 100V line transformer was the norm and in
the days of KT 66 etc the pre-amps and phase splitters were usually
ECC83s, never much trouble in spite of their diminutive (comparitively)
size. Earlier amps used 6SN7GTs. Used to have trouble with output
stages mostly, cathode decoupling caps exploding and spilling their
contents all over the underside of the chassis, and short valve life.
Bad design initially, insufficient neg bias and valves operating class
AB driven (partly) continuously. Lower bias voltage so that valves moved
towards class B operation cured the problem completely without any
deterioration in performance.
I tried it on one job with complete success, told my boss and he
didn't believe me! However, head office engineering came out with a mod
sheet shortly after, so I guess he passed it on (And probably claimed
all the credit) but who cares, it worked.
In the early days of my apprenticeship I used to work around the
Bristol and Swindon areas sometimes, and used to try to pair up with an
old boy called Win Shepperd he was an absolute wizard with amps and he
would take the time to explain the principals and theory behind the
operation of all the main features. I owed him a great deal for all
the tuition and encouragement he gave me.
Enough of the boring stuff already!
Have to go now, back to insanity soon.
Have fun.
4 days ago
Mar. 8, 2010
(Edited Mar. 10, 2010)
|
Available