Transformers anyone no anything about these ??????

[gary o]

http://smg.photobucket.com/albums/v232/goba22/?action=view&current=DSC00371.jpg

From the left first one has 7606 on the side and on top says AF matching transformer GR118066 Pri 6 might be point so 6.25/25K Ohm Sec 100K
Gardners.............What could I use it for ???????

Same question for Parmeko AP.67669 Neptune model 6000/31 1-2 IP-OP
8-9 IS- 05 P/S Ratio 2/3........any good ???

Next is little square thing not even sure if is tran as you see has 4358 on top and six connections ....doesnt plug into a socket

Next the taller one on the back someone wrote line 600 Ohm.....any use ???

Next is another Parmeko Cat p.2554 Neptune series Model 6000/31 same as other ??? says 8-9-10 100 Ohm CT centre tap I no that much, under that IP OP.......input output ?? under that 2-3 Ratio 1/25 under that IS OS ??

In front is the little black round one its a UTC sadly the writting is half warn off can read only PRI ...............
..........7............
SEC 5............CT
..................3CT
....Ohm -4
Not a lot to go on im afraid................CJ ....move away from the hacksaw :grin:

Lastly is another one like the taller one I got them together, its laying on its side and as you see has 4025A IND.3/16 W/1 printed on it ...any ideas ??????

I dont no much about this old stuff as you have gathered, got them from a vintage audio fair so any info on what they are & or what projects I can use them for ,IM hopeing I can use them for tube mic pres and compressors... maybe transistor, thanks for reading


Gary O.

 

[CJ]

U T C ! U T C!

Hand it over, pal.

No transformer gets out of here alive.

 

[gary o]

No never...the other transformers are forming circle around UTC to protect it withere thicker lams........and more to the point it cost me 3 quid

 

[chrispbass]

Hi all, I'm pretty new around here (asking for help anyway) although I've been following alot of the different projects and have made a start on a G9 and GSSL.

I've recently aquired anumber of audio transformers in a box of electronic 'bits and bobs' which are Parmeko Neptune Series as mentioned in the start of this thread. The picture is active btw and the transformer I'm refering to is the black one, 2nd from the right.
I've tried to get some info from Parmeko, but no luck yet and thought that someone here may be able to help?

Anyway, this is how the label reads...

Firstly, a diagram showing connection pin numbers then...

NEPTUNE    SERIES

    PARMEKO

MODEL    6000/31

8-9-10  600 OHM CT
IP  OP
  6      SCR
  2-3  RATIO  1/1
IS OS

Any thoughts on possible usage for these and how I can decipher the connections? I have ben trying, but I'm new to using audio transformers.

Cheers

Chris

 

[lassoharp]

The first one (7606) sounds like it may be a interstage.

Try using it on a mic pre circuit that uses a low-med mu triode as the 1st tube (6J7/1620, 6SN7).  Use it to couple 1st stage plate to 2nd stage grid. Connect the pri for the 25K operation.

Does the secondary appear to be setup for PP?  4 taps or 2 taps?  Unless it's marked it's hard to know if the pri is rated for unbalanced DC. Try it both ways - direct to 1st tube plate or connected to end of coupling cap in standard RC coupling fashion. If the sec has 4 taps(2 windings) - tie them in series(100K) for single ended use. 

 

[chrispbass]

hi Lasoharp

The above is an old thread I found that had a pic of the transformer I have, the Parmeko Neptune.

Any info on that?

Cheers

Chris

 

[lassoharp]

OOps!  Thanks chris - missed that.

If the Parmeko has a 100ohm winding listed as input and output my first thought is maybe transistor but -who knows. Could be line to line.

Without the rated impedances stated for the pri and sec  it's hard to tell.

Try taking a set of DC resistance and voltage in/out measurments - should get you in the ballpark on the ratios and rated impedances.

 

[chrispbass]

Thanks Lassoharp

I've tried to measure DC resistance and get the reading of about 17 ohms between (8 & 9) and (9 & 10) and 34 ohms between (8 & 10) which I presume are the inputs.

I also get about 40 ohms between (2 & 3) - output.

Given the data plate and a bit of thought now, I think I understand. Please correct me if my assumptions are wrong 

Pin 9 is the center tap and I can wire the primary as either (8 & 9) giving me a ratio of roughly 1:2 input/output or I can wire the primary as (8 and 10) giving me a ratio of roughly 1:1 input/output. Are my assumptions correct?

Since it states 600ohm CT on the plate, would that be the combination of the two primary windings for AC?

Just trying to get my newbie head around this 

Would these be of any use in any projects around here, or are they a bit more mundane? I have several that i'd like to find a use for if poss instead of having several paperweights. I'm planning to build an LA4 once I get my G9 and GSSL finished. I do seem to recall that Luny Tune said that most Tx work in that one.

Chris

 

[chrispbass]

Am I correct in thinking the windings are arranged like below?..


        Input

           CT
8           9          10
--/\/\/\/\-/\/\/\/\--

--/\/\/\/\/\/\/\/\--
2                       3

       Output

Does this mean that the ratio is 1 + 1:2 ?

Given my DC readings, I had a quick look at OEP data sheets and the A262A6E seems to have similar specs although it is 1 + 1:1 + 1

Any suggestions for usage appreciated?

Chris

 

[lassoharp]

It appears that what you have is a single coil primary tapped at the center.  This would be as compared to a primary with two separate coils.  If you had two separate coils they could be joined in series or parallel to give a 1:1 or 1:2 ratio. I'm not 100% on the terminology but I believe that in that case it would be called a 1+1:1 which refers to number of separate windings (1+1) and ratio.  I would call yours simply a 1:1 overall with CT primary.

You can, as you said connect an input to 8 & 9 or 9 & 10 and get a slight step up - it may not give you 1:2 - probably more like 1:1.414.  This is where running voltage tests with a signal generator comes in handy. The CT may have been intended to be used for ground connection.

You can use it as a general purpose balancing or 'coloring' transformer for inputs/outputs.  It would work as the input on a Pultec.  I'm not very familiar with the LA-4 but it appears from the schematic it would work fine as a balancer for the input.

 

 

[chrispbass]

Thanks for your help Lassoharp, much appreciated. I've now tested the Tx with a signal generator and scope and can get 1:1 and roughly 1:2 so hopefully I'll be able to put them to use somewhere 

Chris

 

[Rob Flinn]

Mostly Parmeko transformers were used in UK military radio equipment.  Being military they are really well construcuted.  The black can format is used in everything military for a certain period, mainly when it was all using valves.  This includes mains transformers & chokes, which are normally C core & oil filled to improve cooling.  The mains transformers are basically the best that money can buy, & consequently have shot up in value compared to when I was getting them surplus for a few £.  Gresham is another make that was basically the same as the parmeko.

I have used the Neptune range in various projects, including 436's & an La2a.  They come in many different ratios, & some are input & others output, I have a nice pair of push pull output transformer from the Neptune range 18K ct to 900.  I also have the mic size transformers (like yours) at 1:1, 1:4 & 1:10.  They sometimes have a threaded stud for mounting out of the back, but others need 2 screws a bit like the Marinair transformers.  The 1:10 work quite well in API type circuits.

It is worth knowing that sometimes they don't have massive frequency response, because they were designed for communications use.

 

[chrispbass]

Thanks for your thoughts on this Rob, probably explains why I don't see much mention of them around here. They are as you say, extremely well made so perhaps I may be able to use them to add some 'mojo' to something or do you think I'd be better off ebaying them?

I was hoping to possibly use them in an LA4?

Cheers

Chris

 

[Matthew Jacobs]

Hi chrispbass,

Having built 2 LA4s using Luny Tune boards I would say definitely try this transformer in the LA4 bro... It will work fine on the output.

The LA4 I built using OAPs has a lot of character and color, I think your Pameko transformers will had some nice "mojo" to your LA4. I recommend the LA4 as a cheap easy build. The most expensive component is the transformer which you already have. And it sound good. I track all my vocals through a G9 and a LA4.

J

 

[gary o]

OAPs ....Who said old people are usless bless them hehe...........Is OEPs anyway thanks for the transformer info.

 

[Matthew Jacobs]

OAP.... ha ha ha ha... what was I thinking...

 

[chrispbass]

Yeah, will def try them when I get around to the LA4 Matthew, certainly nothing to loose I Suppose  ;D

Glad you are liking your G9 and LA4 signal path, can't wait to get my G9 finished now 

Cheers for your input

Chris

 

[Vintageaudioholic]

Hello all,
I'm Vintageaudioholic, I'm trying to modify the output transformers of my headphone amp with a pair of 6000/31, 1:1, 600 ohm Parmeko transformers but I've only been able to find 1 up till now. I recently found this thread and I was wondering if anyone would have a spare/ pair of the said transformer you would be willing to part with?
Cheers!