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PRO AUDIO ARCHIVE
Type No. PRIMARY SECONDARY RATIO SCR Pct Sct Input V/Hz. Code Patt. Size Core Use/comments
2350 600CT 600 1:1 n y n   h 39 .375 Mu HJ Leak
3128 600 tap at 60 5k 1:2.9 n       e 187 .5 Mu Dolby labs (As 3678 but no 200 Ohm tap)
3197 10KCT 10K 1CT:1 n             Mu Klark Tecnic DN27 EQ
3229 150 600 1:2 y       h 39 .38 Mu Alice
3233 250/1000 25k 1+1:10CT y   y   f 21 .44 Mu Calder
3241 10k 10k 1CT:1 y y n   f 21 .44 Mu Calder
3257 150+150 600CT 1+1:2CT y     +12/50 Hz f 21 .44 Mu Gardner 7524
3267 2.5k 10k 1:2 n n n   e 187 0.5 Mu Alice
3270 150+150 600 1+1:2         h 39 .375 Mu Vulcan Studios
3276 5k 5k 1CT:1 y y     f 21 .44 Mu Calder
3284 600 5k 1CT:2.9 y y     f 21 .44 Mu Calder
3360 200 47k 1:10 y     +8dBu/50 f 21 .44 Mu Mydas
3361 200 47k 1:10 y n n   c s218x   Mu Midas
3379 200 7.2k 1:6 y n n   f 21 .44 Mu Sound Techniques
3423 20k 600+600 6:1+1 y n n   f 21 .44 Mu Midas
3450 10k 10k 1:1 y n n   f 21 .4 Mu Midas
3497 600ct 600ct 1:1 y y y   i 39 .75 Mu Anvil Film and Rec Ltd
3528 600 tap60 1350 1:1.5 n y n   d 187 x1 Mu Walsall Electric
3557 200 200+200 1:1+1 n n n   i 39 x2 MuRa Centroson
3586 200 200 1:1 n     +11dBu/20 f 187   Mu Current
3603 600 600 1:1 y y   2.8 e 187 0.5 Mu  
3612 600 2000 1:2CT y   y     39   Mu Midas 
3622 600 600 1:1 Y n n   h 39 .75 MuRa Soundcraft
3672 600 2400 1:2 y n y   f 21 .44 Mu Quad (J Walker)
3740 150+150 150+150 1:1 y     7.75V/30Hz A 35   MuRa Klark Tecnic DN27 EQ
3769 10k 10k 1;1 Y   Y     187 0.5 Mu 3575 more level
3819 200 600 1:73 n n n     187 0.25 Mu Pace
3829 200 47k 1:10 y       e 187   Mu Midas
3902 150 25k 1:12.9       0 dBu/20 h 39 .325 Mu MTE Queensland
3919 200 50k 1:5 n n n   d 187   Mu Helios
3991 600 600 1:1 y       f 21 0.44 mu  
4069 1.2k 1.2k 1:1.12 y       e 187 0.5 MuRa Soundraft
4079 200 200 + 200 1:1+1 n y     f 21 0.44 mu Mic splitter
4057 1k 5k 1:2.25  y       e 187 .5 Mu Amek line IP
4076 300+300 1250+1250 1+1:2+2 y       e 187   Mu Pye TVT
4118 600 600 1:1 n n n +15/40Hz e 187+ 224   Mu Helios
4119 600 50k 1:9.1 n y n   e 187 0.4 Mu Bulmershe
4126 10k 10k 1:1 y n n +24/30Hz e 187 0.5 Mu Pye TVT
4169 200 12.8k 1CT:8 n y n   e 187 0.5 Mu M
4219 50 50 1:0.9:0.08         j 18 9/16 M6 BBC AL/78/J9
4220 10k 500 4.71:1 y n n   e 187 0.5 Mu BBC LG/93A
4231 600 600 1:1 n ? ?   B 35   Mu/Rad Calder
4242 25k 600 1CT:6.5 y n y   e 187 0.5 Mu  
4252 200 200 1CT:1 n y n +10 dBu e 187 0.5 Mu 1978 Private
4257 300 30k 1:1.297 y n n   e 187 0.5 Mu BBC LG/96A
4258 0.5 1200 1:3.7:0.1         j 18 9/16 M6 BBC AL/73J9
4297 200 200 + 200 1:1+1 n y yy   f 21 0.44 mu  
4357 600 60k 1:10 n       d 187   Mu VB PA Hire
4498 As 4219 Both secondary windings       brought out         P Drake
4555 10K 600 4.08:1 n n n   e 187   Mu Ampco
4567 10k 10k 1:1 y y y   e 187 0.5 mu  
4590 10k 10k 1:1.1 y   y   e 187 0.5 mu  
4593 600 600 1:1 y       i 38 .79 Mu  
4757 150+150 600CT 1+1:2 y y y   f 21   Mu Same as 3257
4791 600 600 1:1 n n n   f 21 1x Mu 20 Century
4799 600+600 2.4k 1+1:2 n n n +17 dBu e        
4836 200 1200 1:3.16         e 187 0.5 Mu Raindirk 1980
4837 10k 1100 3CT:1 y y     e 187 0.6 Mu/Ra Raindirk 1980
4894 200 5k 1:5 y y y   e 187 0.5 Mu  
5110 5k 5k 1:1 y n n   f        
5162 Equivalent to current type 3257                  
5265 200 200 1:1 n n n   c 218 0.38 Mu Soundcraft
5525 Equivalent to current type 3575                  
5571 150+150 150+150 1+1+1+1         j 18 0.5 M6 CTVC
5574 600 600 1:1 n n n   c 218 0.38 Mu Radio City
5794 50+50 5k .5+.5:5 y y y   e 187 .5 Mu Surry
5813 10k CT 10k CT 1:1 y y y   f 21   Mu Soniflex
5931 10k 10k 1:1 y y n   f 21 0.44 Mu Calder
6762 Equivalent to current type 3257                  
7254 1000 1000 1:1.125 n n n +10 dBu e 187 .5 Mu HHB
7987 600 600 1:1.00 y n n 33.96   18 0.56 m6  
7988 50 4.3 1:3.41 n n n 0.757/   21 0.87 mum  
7989 600 600 1:1.00 n n n 7.692/   187 0.50 radi 7989B second iteration
7990 10000 10000 1:1.00 n     9.604/   187 0.50 mum 7990B second iteration
7993 166.67 8 1:4.56 n n n 100/   120 1.50 m6 Tapped 100v line
7994 20000 200 1:10.00 y n y 8.562/   218 0.38 mum  
                         
7995 600 600 1:1.00 y n y 100.2/   35 0.75 radi  
7999 600 1200 1:0.71 y     66.16/   187 0.50 m6  
8995 2500 16 1:0.08 n n n 116.6/30   35 1.50 mum6 Parafeed 2A3
8996 10000 1 1:0.01 n y n 2077/300   29 1.25 m6 ESL 300Hz. 1:100 2000Hz
8983 5145 16 1:0.06 n n n 204.2/20   35 23 m6 Parfeed output non original
8980 10 9000 1:30 y n n 0.185/20   224 0.50 mum 1:30 low Z Cart
8956 4000 1000 1:0.5 n n n 1.863/20 d 187 0.25 mum Mic cathode folower
8940 450 50 1:0.33 y n n 23.29/20 k 35 0.75 mum6 Cathode follower to line
8935 10000 600 1:0.24 n n   3.822/60 a 301 0.19 mum Gardners SM111
8934 600 600 1:1 n y   0.999/60 a 301 0.19 mum Gardners SM111
8931 100000 1000 1:0.1 y y n 12.81/20 e 187 0.50 mum DI 4243 with 2 secondaries
8920 100000 100000 1:1 y n n 8.547/20 f 21 0.44 mum IP Phase Splitter 10k:10k+10k
8918 100 6.25 1:0.25 y n n 17.48/20   18 1.00 m6 Output splitter
8917 200 3200 1:4 y y n 8.844/20 j 18 0.56 mum6 High level mic
8907 200 200 1:1 y y n 1.227/30 c 218 0.38 mum  
8960 8 800 1:10 n n n 2.721/20 j 18 0.56 m6 For balloon LS
8882 5000 8 1:0.04 n n n 155.8/20   35 1.50 mum6 8983 with ohm tapped at 4 ohm
8878 2500 8 1:0.06 n n n 116.8/30   35 1.50 mum6 8995 with 8 tapped at 4 ohm
8792 8 9800 1:35 n     43.39/250   29 2.50 m6 Similar to 8729
8791 600 1 1:0.04 n     2.517/20 e 187 0.50 m6 Choke 30 mH with taps
8790 600 1 1:0.04 n     2.248/20 e 187 0.50 m6 Choke 85 mH with taps
8786 200 200 1:1 y n n 5.009/50 e 187 0.50 mum 3603 with tapped secy
8784 30 30 1:1 y n n 8.390/200 d 187 0.25 m6  
8782 600 600 1:1 n     50.29/300 d 187 0.25 m6  
8776 16 1600 1:10 n     8.206/20   35 1.00 m6 LS output to grids
8773 600 600 1:1 y y n 3.736/100 d 187 0.25 m6 Ship intercom
8772 8 12800 1:40 n   y 43.04/200   29 2.00 m6 Similar to 8729
8766 200 9800 1:7 y y   0.871/20   224 0.5 mum 4935 improved (2 x 224 lams)
8765 38.53 2300 1:7.73 n     22.33/800 e 187 0.50 m6 7.5 watt 800 Hz 17v tp 130v
8762 16 8 1:0.71 n     24.10/50 k 35 0.75 m6 Auto for tweeters
8754 30 600 1:4.47 y n n 0.388/20 e 187 0.50 mum Catalogue item?
8752 12500 600 1:0.22 y   y 52.85/20 j 18 0.56 mum6  
8751 100 225 1:1.50 n n n 32.32/20   35 1 m6 Neve mic amp OP
8750 8000 8 1:0.03 n y n 364.7/35   29 1.25 m6 EL84 Pentode
8745 3500 3500 1:1.00 n n n 117.9/20   18 1 m6 For DSM cart amp
8744 100 280 1:1.67 n n n 0.632/20 c 218 0.38 mum Corrected Ratio
8729 8 20000 1:50 n   y 38.19/250   29 2 m6  
8725 600 50000 1:9.13 y     1.528/5 e 187 0.50 m6  
8723 1000 100000 1:10 n n   4.395/30 f 21 0.44 mum Phase splitter for input level
8722 8 20000 1:50 n n y 40.21/250   29 1.25 m6 8713 redesigned
8714 150 2400 1:4 n     1.310/100 d 187 0.25 mum 1:2:2 BT Lines
8713 8 20000 1:50 n     42.16/250   29 1.2 m6 2000 volts 250 Hz
8704 3 12 1:2 y   y 0.140/10   21 0.33 mum 8055 but 1:2
8703 10 56250 1:75 n     2.659/1000 c 218 0.38 mum  
8682 1800 1800 1:1.00 n     4.693/40 e 187 0.50 mum 3 ways splitter for talkback
8677 10000 600 1:0.24 n n y 70.62/20 k 35 0.75 mum6 8650 ratio 4.08:1
8676 600 600 1:1.00 n     11.06/50 d 187 0.25 m6  
8673 3 0.00 1:10.00 y n y 0.151/   21 0.33 mum 8055 modified for 6 ohms
8670 600 600 1:1.00 n n y 59.75/32   18 1 m6 Hammond Organ Tremolo
8666 200 20000 1:10.00 y n n 2.329/50 e 187 0.50 mum Mic trans 1:10 with 1:1 tap
8665 5760 40 1:0.08 n     54.62/20 k 35 0.75 mum6 Similar to 8664
8664 5760 40 1:0.08 n     54.62/20 k 35 0.75 mum6 Cathode to headphone AC couple
8647 8 72 1:3.00 n     5.889/50 j 18 0.56 m6  
8635 1500 54000 1:6.00 n     1.743/20   224 0.50 mum Cartridge
8632 1 324 1:18.00 n     50.51/300   120 3.00 m6 Modified 8626 (more turns)
8630 3500 600 1:0.41 n     463.4/50   35 1.50 m6 Single ended low dc no gap
8629 150 600 1:2.00 y n n 4.587/50 e 187 0.50 mum6 Similar to 7930
8629 600 60000 1:10.00 y n n 0.851/20 e 187 0.50 mum 600 ohm to grid low noise
8626 1 0.1 1:18.00 n     40.20/300   120 3.00 m6 Transducer driver
8625 600 600 1:1.00 y y y 0.774/30 b 218 0.19 mum  
8623 20000 200 1:0.10 n y y 28.43/20 k 35 0.75 mum  
8622 10000 50 1:0.07 n y y 103.8/50 f 21 0.44 m6 Sample P16991
8621 600 50 1:1.00 y n n 0.987/30 c 218 0.38 mum 600/600 + -35 dB tap
8619 50 800 1:4.00 y y   0.553/20 e 187 0.50 mum 50 ohm to 200/800
8616 600 600 1:1.00 n     66.75/50 j 18 0.56 m6 4652 with +20% turns
8608 200 5000 1:5.00 y y   3.015/20 g 21 0.87 mum Corrected version
8607 30000 600 1:0.14 n y y 63.31/20 k 35 0.75 mum6 Tube compressor to 600 ohms
8603 5000 78.2 1:0,13 y n y 87.31/20 k 35 0.75 mum6 ECF80 SE+cap tp 600 8:1
8572 600 5400 1:3.00 n n n 8.167/20 k 35 0.75 mum  
8477 28.8 3.2 1:0.33 n n n 29.94/1500 e 187 0.50 m6 1500Hz Power dist 24v to 8v
8474 10000 40000 1:2.00 y n y     224 0.50 mum 10k 1:2 amp input
8467 0.1 25.6 1:16.00 y n n 0.488/50 j 18 0.56 mum Sea type redesign Thinner wire
8466 10 2560 1:16.00 y n   1.916/50 j 18 0.56 mum "Land" type
8462 6400 100 1:0.13 n y   120.9/20 k 35 0.75 mum6 Revised with NFB
8416 10000 10000 1:1.00 y   n 5.028/20   224 0.50 mum Dual input 600CT/10k:10k
8452 30 600 1:4.47 y   y 0.389/20 e 187 0.50 mum Gardners MU7561
8444 9 16 1:1.33 n n n 14.54/25   29 1.25 m6 FET OP
8421 6.25 0.5 1:0.28 n     6.191/150 f 21 0.44 m6 0.5 ohm loop
8420 100 100 1:1.00 y n y 10.30/15 a 35 0.75 m6 Test set output
8419 60000 600 1:0.10 y n n 29.36/50 f 21 0.44 mum AC coupled Anode to line
8414 4.57 714 1:12.50 n n n 7.998/40   35 1.25 m6 LM1875 to 100v
8413 100 100 1:1.00 n   y 32.32/100 j 18 0.56 m6 Phantom dist amp op
8408 10 277777 1:166.67 n     19.50/150   29 1.25 m6 Second iteration of 8401
8403 600 600 1:1.00 y n n 41.26/50 j 18 0.56 m6 Similar to 4652 but balanced
8401 10 277777 1:166.67 n n n 20.82/150   29 1.00 m6  
8394 200 20000 1:10.00 y   y 1.085/20   224 0.50 mum Mic to valve
8393 7.4 150 1:4.50 n     9.894/300 f 21 0.44 m6 Pass 2 of 8360
8392 150 150 1:1.00 n     6.753/40 e 187 0.50 m6 Headphone Ms decoder
8387 2 4 1:1.41 n     11.00/40   29 1.50 m6 Sub Woofer output
8386 200 20000 1:10.00 y   y 0.882/50 c 218 0.38 mum 1+1:20 for 50/200 ohm mic
8380 50 5000 1:10.00 n     0.245/50 b 218 0.19 mum 1:10 Mic replaces 8376
8379 300 300 1:1.00 y y   0.737/20 c 218 0.38 mum AB/MS decoder W/Phantom
8377 50 50 1:1.00 y     10.32/20 g 21 0.87 m6 Distribution amp OP
8376 50 5000 1:10.00 n     0.281/50 a 301 0.19 mum 1:10 Mini mic
8375 600 600 1:1.00 y n y 40.50/300 d 187 0.25 m6 Gardners AM109
8374 600 600 1:1.00 n y y 1.1222/20 a 301 0.19 mum Highest level on 301 for tub
8372 1000 5000 1:2.24 n n y 2.915/50 e 187 0.50 mum  
8370 600 600 1:1.00 y     32.01/30 j 18 0.56 m6  
8369 600 600 1:1.00 y     58.10/30 k 35 0.75 m6  
8362 100 2500 1:5.00 y n y 1.322/20   21 0.41 mum 75 ohm Cartrodge
8360 12.25 150 1:3.50 n     10.72/300 f 21 0.44 m6  
8359 200 200 1:1.00 y     1.002/50 b 218 0.19 mum CAT: Low cost mini splitter
8356 600 300 1:0.71 y y n 4.362/50 e 187 0.50 mum Hybrid Similar to 7684
8351 100 17 1:0.40 n n n 95.46/15   120 3.00 m6 6C33C-B SE No DC
8347 25 8836 1:18.00 y n y 0.103/5   21 0.41 mum 1:18.8 for PC67 DAC
8338 40 4000 1:10.00 n     0.348/15   224 0.50 mum 40 ohm 1:10 cartridge
8330 4 8 1:1.41 n     63.24/25   248 3.00 m6 Auto 4 to 8 ohms
8329 200 200 1:1.00 y   y 1.531/200 a 301 0.19 mum 1:1 Mic screen
8321 300 600 1:0.71 y n n 4.688/60 d 187 0.25 mum6 Hybrid MU7525 reduced spec
8313 600 10000 1:4.08 y n y 4.369/40 e 187 0.50 mum 600 ohm valve PP input
8311 600 600 1:1,00 y n n 12.27/100 d 187 0.25 m6 Dist amp low cost
8309 6 6 1:1.00 n n n 11.81/100 j 18 0.56 m6 Auto for testing 5W
8306 32000 2000 1:4.00 y n n 1.749/30 e 187 0.5 mum Actually step down
8305 600 600 1:1.00 y n n 20.49/50   18   m6 Dist amp op
8289 1000 5000 1:2.24 n n y 3.961/30   21 0.41 mum  
8288 600 600 1:1.00 n y n 1.585/20 e 187 0.50 mum LL/88ASC Equivalent
8280 1000 5000 1:2.24 n n y 3.958/30   21 0.41 mum  
8219 4800 19200 1:2.00 n n y 4.811/20 h 39 0.38 mum 3 x 600ohm with turns 1:6
8196 5 1125 1:15.00 n n n 0.209/200 a 301 0.19 mum 5 ohm intercom mic (aircraft)
8194 80 47500 1:24.37 y     0.241/20   224 0.50 mum 1:24 Cart Low Z/High perf
8191 200 12800 1:8.00 y     7.023/50 j 18 0.56 mum High lev mic
8190 6000 600 1:0.32 y     38.85/50 j 18 0.56 mura Mic amp OP
8181 5400 40 1:0.09 n n n 1.718/20   301 0.19 mum AKG C-28C Valve mic
8180 600 600 1:1.00 n y n 1.585/20   187 0.50 mum LL/88ASC Equivalent
8178 10 1000 1:10.00 n n n 0.098/20   218 0.19 mum Standard low cost cartridge
8174 38000 600 1:0.13 n n n 70.03/50   187 0.25 m6  
8161 5.1 1.28 1:0.50 n n n 12.55/20   120 1.00 m6 2:1 Special fet op
8160 12.5 1250 1:10.00 n n n 3.548/20   35 0.75 m6 Interstage 1+1:10+10
8158 600 600 1:1.00 y n y 4.264/   187 0.50 mum TV time code balancer
8156 5000 50 1:0.10 y n n 7.789/   21 0.41 mum ECC83 (5k) to 600 ohm line
8155 2500 16 1:0.08 n n n 604.4/   120 3.00 m6 300B 2500 ohms - Gapped m6
8154 10000 10000 1:1.00 y n n 4.521/   301 0.19 mum  
8143 40 0.1 1:0.05 n n n 0.234/   301 0.19 mum  
8142 31 600 1:4.40 y n n 6.299   18 0.37 m6 Distribution amp OP
8129 300 300 1:1.00 y     46.93/   187 0.50 m6  
8128 600 60 1:0.32 y n n 2.454/   187 0.25 mum Version 2
8116 1000 600 1:0.77 y n n 2.591/   187 0.25 mum Revision 2
8115 600 1.5 1:0.05 n n n 44.16/   187 0.25 mum Revised for 60:1 ratio
8105 6 2400 1:20.00 n     20.03/   35 1.00 m6  
8104 2 802 1:20.02 n     18.72/   29 1.00 m6  
8100 8.25 8 1:0.98 n y   15.99/   35 1.00 m6 Cost reduced 6286
8099 2000 4500 1:1.50 n n n 113.2/   196 1.13 m6 Failed on test
8096 40 57760 1:38.00 n n n 0.340/   21   mum 40 ohm cartridge
8088 150 150 1:1.00 y y y 2.081/   187 0.50 mum 2 way splitter 66J0036B
8082 6 5400 1:30.00       21.19/   18 0.56 m6  
8081 600 40000 1:8.16 y     1.591/   21 0.33 mum  
8079 9500 200 1:0.15 y n n 7.303/   21   mum Neumann mic/triode
8078 600 2400 1:2.00 y     28.29/   18 0.56 m6 Like 4652 with screens
8074 0.3 600 1:44.72 n     0.021   218 0.38 mum Ribbon mic
8066 200 16200 1:9.00 y y n 1.081/   218 0.38 mum Belclere CN 6347
8055 3 300 1:10.00 y   y 0.637/   21   mum Cartridge
8051 480 120 1:0.50 n y   27.07/   21 0.44 m6  
8050 2200 350 1:0.40 n n y 49.65/   21 0.44 m6  
8045 200 6100 1:5.52 y     1.752/   187 0.50 mum UN/1012/0
8044 14400 100 1:12.00 y     8.714/   187 0.25 mum Jensen RE-DB-E DI box
8043 200 5000 1:5.00 y     1.060/   21 0.33 mum Supermic LL1538 improved 8030
8032 55 27.5 1:0.71 y     2.479/   18 0.56 mum BBC standard stereo/mono
8031 500 500 1:1.00 y     18.16/     0.65 m6 LL1539 competitor
8030 200 5000 1:0.20 y     2.417/   224 0.50 mum Recording mic LL1538
8028 100 100 1:1.00 y     6.185/   21 0.33 m6 LL5402 equlvalent (Version 2)
8022 8 80000 1:0.01       15.11/   120 1.50 m6 ESL 500Hz
8021 25 25 1:2.50 y n n 7.985/   18 1.00 m6  
8005 10000 10000 1:1.00 y n y 2.843/   218 0.38 mum Redesigned
8003 150 15000 1:0.10 y     0.635/   218 0.38 mum Jensen JT-115K-E 1:10 mic
8002 150 3600 1:0.20 y     0.635/   218 0.38 mum Jensen JT - 13K6-C 1:5 mic
9095 10 10k + 10k 1:10+10 n n n 0.32 g 21 0.87 mu DAC 100 ohm
9094 2 12.8k 1:80 y n n 0.04 e 187 0.5 mu 70Hz magnometer
9093 600 2.4k 1;1+1 n y n   j 18 0.56 mu Tango NN6
9087 1 100k 1:6000 n       k 35 0.75 mu Deep sea transducer
9086 1 100k 1:1000 n       k 35 0.75 mu Deep sea transducer
9082 600 600 1:1 y n n   k 35 0.75 mum6  
9077 200 7.2k 1:6 y       f 187 0.5 mu Haufe RK729
9099 10k 10k 1:1 n n n 70.7 i 39 0.75 mu Autoformer