Value Line Output Transformers (last update 1/1/2016
Preface
We are lucky to secure a batch of limited quantity vintage
British made C cores (silicon steel, amorphous steel and amorphous nickel-steel
alloy C cores). Some of them are NOS and some of them are pulls.
It might look a bit worn or rusty due to age but it still functions perfectly.
We have taken this into consideration of the price (cheaper) as compared to a
full price (especially amorphous) C core that is sky high in price in the
market. Please do not order the amorphous C core transformer if you cannot
tolerate this.
Amorphous cores are meant for medium to high frequency use.
Amorphous cores (worse if is or added nickel) are easily saturated and
therefore the low frequency response will not be as great as the Z11 or Z6
cores. Due to such magnetic properties, designing such audio transformers
requires extreme care, and larger cores are required to achieve good low
frequency response.
In order to overcome this limitation, the best way is to
increase the core size, and therefore dual C core and quad C core are called
for in TRUE high fidelity design that excels both in extended refined high
frequencies, dense and warm mids and deep impactful bass.
Why do we need a quad core one might ask? It increases the
core volume by 400% (4 cores!) to give more headroom. With the 4 cores covering N-S-E-W of
the bobbin, it is actually fully utilizing instead of wasting the flux produced
by the coil for increased efficiency and better sound! Imagine retrieving back
of the original signal/energy lost back to your system.
In addition, we prefer the vintage British made C core too,
like many of the excellently made British HIFI gears. Nowadays such high
quality C cores are hard to find and expensive to source. We will not dig
further into the advantages of amorphous core. You can read more of them in the
internet.
I’m keeping a few pairs for myself for various circuits before
it runs out, are you?
Lead time is around 2~4 weeks. Customization services for
different applications, circuit topology, air-gap, configuration or different tubes
are available.
Quad Core
QCAMOPT-L01---(3.5K
OPT for 300B) - $449/matched pair
QCFEIP-S01-------(1:5.8
input/pre-out) - $329/matched pair
QCAMOPT-M01---(2.5K/5K
OPT for 2A3/45) - $209/matched pair (no longer have stock, email to check for availability)
(limited standard units left, cannot offer customization for QCAMOPT-M01 size, 2.5K/5K OPT can still be done using the QCAMOPT-L01 cores)
Double Core
DCAMOPT-X01---(8K/16K
OPT for 211/845) - $659/matched pair
DCAMOPT-L01---(3.5K
OPT for 300B) - $329/matched pair
DCAMIT-L01------(1:2.25
interstage for 211/845) - $329/matched pair
DCAMC-M01------(8H/300mA
choke) - $129/piece
Single Core
SCAMOPT-M01--- 3.5K: 8 Ohm - $269/matched pair
SCAMOPT-M02--- 6.6K: 8 Ohm - $269/matched pair
QC – quad core, DC – dual core, AM – amorphous, FE - ferrous
NOTE: please email us
if you need other specifications.
Transformer Details
Amorphous Quad C Core
Output Transformers (nickel-steel alloy) – QCAMOPT-L01
This is made using 8 pieces of C-core per transformer,
having 16 pieces altogether for a pair of high end amorphous quad C core nickel
steel alloy output transformer for tube amplifier. The amorphous C core is very
thin and extremely brittle. Please do not drop the transformer to prevent
damage. Take precaution when installing the transformer.
- Available types: single ended and push pull
- Primary impedance: 3.5K (standard), other impedances per request.
- Primary inductance: 35H @ 100Hz,
- Primary current: 150mA maximum
- Primary DCR: 98 Ohm, Secondary DCR: 0.45 Ohm (@ 8 Ohm tap)
- Leakage inductance: 6mH, leakage capacitance: 14nF
- Frequency response: 30Hz – 30kHz
- Weight: 2.5KG per piece
- Size: 95mm x 80mm x 105mm
- 3.5K / 4-8-16 Ohm
Amorphous Quad C Core
Output Transformers (nickel steel alloy) – QCAMOPT-M01
This is made using 8 pieces of C-core per transformer,
having 16 pieces altogether for a pair of high end amorphous quad C core nickel
steel alloy output transformer for tube amplifier. The amorphous C core is very
thin and extremely brittle. Please do not drop the transformer to prevent
damage. Take precaution when installing the transformer.
(limited standard units left, cannot offer customization for QCAMOPT-M01 size, 2.5K/5K OPT can still be done using the QCAMOPT-L01 cores)
- Available types: single ended and push pull
- Primary impedance: 2.5K: 4-8 Ohm, 5K: 4-8-16 Ohm (standard),
other impedance per request.
- Primary inductance: 28H
- Primary current: 150mA maximum
- Leakage inductance: 35mH, leakage capacitance: 114nF
- Frequency response: 30Hz – 30KHz
- Weight: 1.5KG per piece
- Size: 70mm x 80mm x 70mm
- Suitable for: 45, 2A3, 6P1, 6P14, 6V6 and etc
Quad C Core Input / Pre-Out
Transformers (steel) – QCFEIP-S01
This is made using 8 pieces of C-core per transformer,
having 16 pieces altogether for a pair of high end quad C core steel input or
pre-out transformer (parafeed).
This is suitable as an input / pre-out transformer between
source and amplifier, pre-amplifier and power amplifier for galvanic isolation,
noise reduction, increase/decrease gain, impedance matching and ground loop
breaker. If you use it as step-up,
please ensure your source impedance is low enough to drive 600 Ohm load.
- Area of applications: SPUD (single tube amplifier), pre-amplifier,
buffer, and etc.
- Available types: 1:5.8 or 5.8:1; 600: 20K Ohm or 20K: 600
Ohm
- Primary impedance: 600 Ohm, secondary impedance: 20K (can be
reversed)
- Inductance: 10H: 80H, DCR: 118: 760 Ohm
- Current: NO DC ALLOWED.
- Secondary inductance: 80H, DCR: 760 Ohm
- Leakage inductance: 0.052H, leakage capacitance: 3.2nF
- Frequency response: 20Hz – 35kHz
- Weight: 1KG per piece
- Size: 80mm x 65mm x 60mm
Amorphous Double C Core
Output Transformers (nickel steel alloy) – DCAMOPT-X01
This is made using 4 pieces of C-core per transformer,
having 8 pieces altogether for a pair of high end amorphous double C core
nickel steel alloy output transformer for tube amplifier. The amorphous C core
is very thin and extremely brittle. Please do not drop the transformer to
prevent damage. Take precaution when installing the transformer.
- Available types: single ended and push pull
- Primary impedance: 8K+8K (16K): 4-8-16 Ohm (standard), other
impedances per request
- Primary inductance:
50H + 50H
- Primary current: 240mA maximum
- Primary DCR: 198 + 198 Ohm, Secondary DCR: 0.70 Ohm (@ 8 Ohm
tap)
- Frequency response: 20Hz – 25kHz
- Weight: 3.2KG per piece
- Size: 100mm x 80mm x 120mm
Amorphous Double C Core
Output Transformers (nickel steel alloy) – DCAMOPT-L01
This is made using 4 pieces of C-core per transformer,
having 8 pieces altogether for a pair of high end amorphous double C core
nickel steel alloy output transformer for tube amplifier. The amorphous C core
is very thin and extremely brittle. Please do not drop the transformer to
prevent damage. Take precaution when installing the transformer.
- Available types: single ended, push-pull(customize)
- Primary impedance: 3.5K: 4-8-16 Ohm (SE, standard), other
impedances per request
- Primary inductance: 16H @ 100Hz,
- Primary current: 150mA maximum
- Primary DCR: 140 Ohm, Secondary DCR: 0.65 Ohm (@ 8 Ohm tap)
- Leakage inductance: 9mH, leakage capacitance: 12nF
- Frequency response: 30Hz – 30kHz
- Weight: 1.5KG per piece
- Size: 82mm x 65mm x 100mm
- 3.5K / 4-8-16 Ohm
Amorphous Double C Core
Inter-stage Transformers (steel) – DCAMIT-L01
This is made using 4 pieces of C-core per transformer,
having 8 pieces altogether for a pair of high end amorphous double C core
inter-stage transformer for tube amplifier.
- Available types: single ended (standard), splitting
(customize)
- Impedance ratio: 1: 2.25(standard), per user request.
- Inductance: 55H: 80H, DCR: 260 Ohm: 540 Ohm
- Current: 100mA maximum
- Suitable driver tubes: 2A3, 300B, 6V6, EL34 to drive 805,
845, 211 tubes.
- Weight: ~1KG / piece
- Size: 60mm x 80mm x 100mm
Amorphous Double C Core
Choke (nickel steel alloy) – DCAMC-M01
This is made using 4 pieces of C-core per transformer,
having 8 pieces altogether for a pair of high end amorphous double C core
nickel steel alloy choke. The amorphous C core is very thin and extremely
brittle. Please do not drop the transformer to prevent damage. Take precaution
when installing the transformer.
- Available types: air-gapped choke (various sizes within core
permit able values)
- Primary inductance: 8H
- Primary current: 300mA maximum
- Primary DCR: 70 Ohm
- Weight: 1.2KG per piece
- Size: 60mm x 75mm x 90mm
Potted Amorphous C Core Output Transformers (nickel steel
alloy) – SCAMOPT-M01 (new)
This is made using 2 pieces of C-core
per transformer, 0.01mm lamination thickness, having 4 pieces altogether for a
pair of high end amorphous C core nickel steel alloy output transformer for
tube amplifier. The amorphous C core is very thin and extremely brittle. Please
do not drop the transformer to prevent damage. Take precaution when installing
the transformer.
- Available types: single ended (300B and etc)
- Primary impedance: 3.5K: 8 Ohm
- Primary inductance: 12H
- Primary current: 100mA maximum
- Primary DCR: 70 Ohm, Secondary DCR: 0.7 Ohm
- Leakage inductance: 3.7mH, leakage capacitance: 10.2nF
- Frequency response: 30Hz – 35kHz
- Weight: 1.5KG per piece
- Size: 80mm x 85mm x 100mm
Potted Amorphous C Core Output Transformers (nickel steel
alloy) – SCAMOPT-M02 (new)
This is made using 2 pieces of C-core
per transformer, 0.01mm lamination thickness, having 4 pieces altogether for a
pair of high end amorphous C core nickel steel alloy output transformer for
tube amplifier. The amorphous C core is very thin and extremely brittle. Please
do not drop the transformer to prevent damage. Take precaution when installing
the transformer.
- Available types: push pull (EL34, 6P3P, KT66 and etc)
- Primary impedance: 6.6K: 8 Ohm
- Primary inductance: 80H
- Primary current: 150mA maximum
- Primary DCR: 837 Ohm
- Leakage inductance: 3.7mH, leakage capacitance: 10.2nF
- Frequency response: 30Hz – 20kHz
- Weight: 1.5KG per piece
- Size: 80mm x 85mm x 100mm
Notes:
- Please do not order if you cannot accept blemished cores.
Some can look as bad as pictures but below, some has only minor oxidation. They're only superficial (on the surface) and does not affect the operations at all.
- There may be slight physical outlook variations between what is posted here and what customers would received as batches of cores might have slight different look and sizes.
- There may be core imperfections and/or slight core misalignment due to the facts that they are refurbished cores. We oversize the core so that this defect will not affect the performance of the units. Please look elsewhere if you cannot accept this.
J&K Audio Design
27 FEB 2014
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* Finished
amplifiers, DACs, audio gadgets, upgrades and repairs - this is not our
core business and we do it out of passion. We do not
have fixed models, fixed price and we customize for each individuals.
The sky is limit of creativity.
* Our product lines are always improving and increasing. If you do not see what you want, contact us!
* Please email for volume discounts, distributor and OEM pricing.
