Pye PTC4001 Tulip microphone - UK Vintage Radio Repair and Restoration Discussion Forum

Sparks · 21st Jan 2018, 2:57 pm

I've been reading about this item recently. I note the impedance is 2400 ohms which strikes me as very high. Does anyone know why this is ? I'm not an expert on these matters but I would have expected a value of between 200 and 600 ohms.

The only audio transducer I'm aware of with 2400 ohms impedance is a type 4T rocking armature earphone/microphone insert, made by A.P. Besson.

Biggles · 21st Jan 2018, 3:34 pm

We used to have these at work in the eighties but I must admit I never thought much about their impedance. As far as I can remember we didn't have much trouble with them. The transducer must have had a lot of turns of very fine wire to give that impedance. I can't remember ever having to change a transducer in one.
Alan.

AC/HL · 21st Jan 2018, 4:21 pm

Most PMR kit seems to have used those earpiece inserts, certainly the ones I came across did (Pye & GEC). The tulip mic was popular with base station operators, easy to use and stable when put down.

Sparks · 21st Jan 2018, 5:10 pm

Thanks folks. I have never seen one of these microphones in the flesh but it would seem likely one of the 4T inserts I mentioned would be the microphone. Perhaps easily changed for an insert with a different resistance.

Biggles · 21st Jan 2018, 7:04 pm

When everybody used Pye equipment, tulip mics were the norm. Every control room had them. Quite a well designed stable bit of kit. Most were that blue colour although I seem to remember a couple of green ones. It's a long time ago. Memories of Pye Mascot 200's and RTC controllers...
Alan.

CambridgeWorks · 21st Jan 2018, 8:27 pm

Tulip mics were blue at first, then green and finally brown. About the only failing was intermittent audio (Norman Collier effect) caused by the screen cable fracturing at the base just where it was always being bent. The mic audio used just the outer screen and the red inner conductor. The simple repair was to disconnect the (blue?) wire from the ptt N.O. micro-switch contact and parallel it with the mic insert audio screen. The more professional repair was to replace the entire cable, then include the above modification. I still have some original cable....somewhere? I do not recall ever replacing the insert or the micro-switch. FM and AM inserts were different. Early fm inserts had several largeish holes, just like all the am ones. These were sought after in the 1970s by amateurs. Later and the more common fm inserts just had 3 very small holes in the aluminium face.
The thin woven cloth covering across the insert was unceremoniously known as a "gob guard!!".
Rob

Graham G3ZVT · 22nd Jan 2018, 12:22 am

Comparatively recently, by which I mean in the last 15-20 years ago, I passed by a little taxi station, the door was open and I did a double take when I saw on the desk in front of the operator a Pye Tulip.

Do taxis still use voice on their radios?
There was at least one company near here (North Manchester) that used FM voice as well as data until about 4 or 5 years ago.

David G4EBT · 22nd Jan 2018, 10:28 am

I've got one I rescued from work in 1985. It was new and boxed - one of several spare mikes that the comms Dept chucked out when Pye equipment was replaced in the control room at work when I was manager at B.G. at Sheffield. Of no particular use to me, but an attractive looking mike (to my eyes) and it seemed a shame for them to be skipped. Still on the shelf gathering dust, but looking nice. (The new equipment used Shure 444 mikes - of much more interest to amateurs as they were optimised for SSB as well as AM/FM. Dual impedance - 200 -Ohms-1K, 15K - 10M and could be use PTT or VOX).

G6Tanuki · 22nd Jan 2018, 10:31 am

Quote:

Originally Posted by rambo1152

Do taxis still use voice on their radios?
There was at least one company near here (North Manchester) that used FM voice as well as data until about 4 or 5 years ago.

My local minicab company [to whom I used to supply and fit various bits of Motorola and Simoco low-band FM gear in the 1990s] went all-digital around 2005: I forget whose gear they ended up using, but it's rather nifty for the minicab to send you a text message when it's about half a mile away, and another when it's outside your door.

Uber, of course, lets you watch your ride's approach in real-time. "Glympse" - http://www.glympse.com/ - is rather handy too, if you're making a significant journey and the people at your destination want to know how you're progressing. I followed a friend's journey all the way from Switzerland to Wiltshire using this.

Sparks · 22nd Jan 2018, 12:14 pm

I shall buy one if these microphones one day, provided it doesn't cost more than about £20.00. Not sure what I'll do with it but I can worry about that later !

21st Jan 2018, 2:57 pm	#1
Sparks Heptode Join Date: Oct 2006 Location: Leeds, West Yorkshire, UK. Posts: 597	Pye PTC4001 Tulip microphone I've been reading about this item recently. I note the impedance is 2400 ohms which strikes me as very high. Does anyone know why this is ? I'm not an expert on these matters but I would have expected a value of between 200 and 600 ohms. The only audio transducer I'm aware of with 2400 ohms impedance is a type 4T rocking armature earphone/microphone insert, made by A.P. Besson.

21st Jan 2018, 3:34 pm	#2
Biggles Rest in Peace Join Date: Feb 2004 Location: Hexham, Northumberland, UK. Posts: 2,234	Re: Pye PTC4001 Tulip microphone We used to have these at work in the eighties but I must admit I never thought much about their impedance. As far as I can remember we didn't have much trouble with them. The transducer must have had a lot of turns of very fine wire to give that impedance. I can't remember ever having to change a transducer in one. Alan.

21st Jan 2018, 4:21 pm	#3
AC/HL Dekatron Join Date: Nov 2003 Location: Heckmondwike, West Yorkshire, UK. Posts: 9,642	Re: Pye PTC4001 Tulip microphone Most PMR kit seems to have used those earpiece inserts, certainly the ones I came across did (Pye & GEC). The tulip mic was popular with base station operators, easy to use and stable when put down.

21st Jan 2018, 5:10 pm	#4
Sparks Heptode Join Date: Oct 2006 Location: Leeds, West Yorkshire, UK. Posts: 597	Re: Pye PTC4001 Tulip microphone Thanks folks. I have never seen one of these microphones in the flesh but it would seem likely one of the 4T inserts I mentioned would be the microphone. Perhaps easily changed for an insert with a different resistance.

21st Jan 2018, 7:04 pm	#5
Biggles Rest in Peace Join Date: Feb 2004 Location: Hexham, Northumberland, UK. Posts: 2,234	Re: Pye PTC4001 Tulip microphone When everybody used Pye equipment, tulip mics were the norm. Every control room had them. Quite a well designed stable bit of kit. Most were that blue colour although I seem to remember a couple of green ones. It's a long time ago. Memories of Pye Mascot 200's and RTC controllers... Alan.

21st Jan 2018, 8:27 pm	#6
CambridgeWorks Nonode Join Date: Jun 2010 Location: Spalding, Peterborough, Cambridgeshire, UK. Posts: 2,859	Re: Pye PTC4001 Tulip microphone Tulip mics were blue at first, then green and finally brown. About the only failing was intermittent audio (Norman Collier effect) caused by the screen cable fracturing at the base just where it was always being bent. The mic audio used just the outer screen and the red inner conductor. The simple repair was to disconnect the (blue?) wire from the ptt N.O. micro-switch contact and parallel it with the mic insert audio screen. The more professional repair was to replace the entire cable, then include the above modification. I still have some original cable....somewhere? I do not recall ever replacing the insert or the micro-switch. FM and AM inserts were different. Early fm inserts had several largeish holes, just like all the am ones. These were sought after in the 1970s by amateurs. Later and the more common fm inserts just had 3 very small holes in the aluminium face. The thin woven cloth covering across the insert was unceremoniously known as a "gob guard!!". Rob __________________ Apprehension creeping like a tube train up your spine - Cymbaline. Film More soundtrack - Pink Floyd

22nd Jan 2018, 12:22 am	#7
Graham G3ZVT Dekatron Join Date: May 2010 Location: Greater Manchester, UK. Posts: 18,724	Re: Pye PTC4001 Tulip microphone Comparatively recently, by which I mean in the last 15-20 years ago, I passed by a little taxi station, the door was open and I did a double take when I saw on the desk in front of the operator a Pye Tulip. Do taxis still use voice on their radios? There was at least one company near here (North Manchester) that used FM voice as well as data until about 4 or 5 years ago. __________________ -- Graham. G3ZVT

22nd Jan 2018, 10:28 am	#8
David G4EBT Dekatron Join Date: Feb 2003 Location: Cottingham, East Yorkshire, UK. Posts: 5,763	Re: Pye PTC4001 Tulip microphone I've got one I rescued from work in 1985. It was new and boxed - one of several spare mikes that the comms Dept chucked out when Pye equipment was replaced in the control room at work when I was manager at B.G. at Sheffield. Of no particular use to me, but an attractive looking mike (to my eyes) and it seemed a shame for them to be skipped. Still on the shelf gathering dust, but looking nice. (The new equipment used Shure 444 mikes - of much more interest to amateurs as they were optimised for SSB as well as AM/FM. Dual impedance - 200 -Ohms-1K, 15K - 10M and could be use PTT or VOX). Attached Thumbnails __________________ David. BVWS Member. G-QRP Club member 1339.

22nd Jan 2018, 12:14 pm	#10
Sparks Heptode Join Date: Oct 2006 Location: Leeds, West Yorkshire, UK. Posts: 597	Re: Pye PTC4001 Tulip microphone I shall buy one if these microphones one day, provided it doesn't cost more than about £20.00. Not sure what I'll do with it but I can worry about that later !