rafafredd
Well-known member
sure it can. I was talking about PM 1000 output amp. This thing can´t drive a 600 ohms trafo. No way!
Edcor Transformers
- Thread starter analag
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sure it can. I was talking about PM 1000 output amp. This thing can´t drive a 600 ohms trafo. No way!
ioaudio
Well-known member
maybe this question is answered already elsewhere: where can i buy edcors in europe?
Emperor-TK
Well-known member
I wasn't "naysaying" so much as sharing a single anecdote and seeking feedback on it. Naysaying would be saying "I've used Edcors in a 100 different circuits and they always suck, so therefore they must suck in your circuit too". I didn't say anything like that.
I thought it might be something specific to the PM1000, which is why I mentioned the details of my application. I wasn't challenging anyone's ears. Thanks for the feedback Rafafredd. From what I've read here, many folks are sticking 600:600's on the PM1000 outputs to balance them. Perhaps we would all be better off with another solution.
-Chris
I thought it might be something specific to the PM1000, which is why I mentioned the details of my application. I wasn't challenging anyone's ears. Thanks for the feedback Rafafredd. From what I've read here, many folks are sticking 600:600's on the PM1000 outputs to balance them. Perhaps we would all be better off with another solution.
-Chris
[quote author="analag"]What my two naysaying friends need are output amps that can properly drive a transformer.[/quote]
Heh! Funnily enough, you may very well be right... Could the sweet, sweet distortion I'm hearing be caused by wimpy output stages and not the transformers themselves??? Food for thought indeed...
At some point I'll put one of my WSM600/600 on a BigBloak and hook it up to the Sound Technologies to see what's up.
Peace,
Al.
Heh! Funnily enough, you may very well be right... Could the sweet, sweet distortion I'm hearing be caused by wimpy output stages and not the transformers themselves??? Food for thought indeed...
At some point I'll put one of my WSM600/600 on a BigBloak and hook it up to the Sound Technologies to see what's up.
Peace,
Al.
It would be real hard to screw up a 1:1 transformer.
If you find a 1:1 transformer that does not go 10-40 kc, let me know so I can take it apart and find out why.
The real test is when you get into 1:10 and above.
Or 2A3 SE.
If you find a 1:1 transformer that does not go 10-40 kc, let me know so I can take it apart and find out why.
The real test is when you get into 1:10 and above.
Or 2A3 SE.
jetboatguy
Well-known member
[quote author="analag"]I would use the 10K:10K for input instead of 600:10K. On my optical comps (not quite LA2A as I don't really like the LA2A circuit) that's the ratio I use. I kept rebuilding these for 7 years until I got the sound I wanted, then I tried the trannie in one of my mono units and got a even better sound as I am now able to drive the stages at optimum level, with the transformer doing impedance matching and bringing down output drive to a more managable level for the solidstate devices to handle.
analag[/quote]
I see, a 10k:10k ratio would actually sound better for input of LA2a ?... and 10k:600 for output ?
Anybody else try this combo yet ??
analag[/quote]
I see, a 10k:10k ratio would actually sound better for input of LA2a ?... and 10k:600 for output ?
Anybody else try this combo yet ??
clintrubber
Well-known member
[quote author="CJ"]It would be real hard to screw up a 1:1 transformer.
If you find a 1:1 transformer that does not go 10-40 kc, let me know so I can take it apart and find out why.[/quote]
These don't
#2
ADC A11537
1:1 (400mH - 400mH)
1225 - 1600 Hz, 'hipot 500Vrms'
This seems from the telegraph-side of the box,
so likely not usable at all ?
#3, yellow marking
UTRAD 2126
(200mH - 200mH)
1225 - 1600 Hz,
telegraph-side ?
Lame examples ! :wink:
If you find a 1:1 transformer that does not go 10-40 kc, let me know so I can take it apart and find out why.[/quote]
These don't
#2
ADC A11537
1:1 (400mH - 400mH)
1225 - 1600 Hz, 'hipot 500Vrms'
This seems from the telegraph-side of the box,
so likely not usable at all ?
#3, yellow marking
UTRAD 2126
(200mH - 200mH)
1225 - 1600 Hz,
telegraph-side ?
Lame examples ! :wink:
sweep em.
clintrubber
Well-known member
[quote author="CJ"]sweep em.[/quote]
Will try them (when ? :roll: ) The leftmost one will be first.
Just curious, any postman yet ?
Will try them (when ? :roll: ) The leftmost one will be first.
Just curious, any postman yet ?
only mnats so far.
thanks for 1176 and supply board!
thanks for 1176 and supply board!
mikep
Well-known member
[quote author="CJ"]sweep em.[/quote]
actually, who cares about the frequency response. these transformers are rated to 10,000ft altitude. that's good enough for me.
mike
actually, who cares about the frequency response. these transformers are rated to 10,000ft altitude. that's good enough for me.
mike
yes and you know what your ears are like at that alltitude.
Brian Roth
Well-known member
Here's a copy of a message I posted to the Ampex and Backroom mailing lists (via recordist.com) back in 2004:
--------------------------------------------------------------------
I discovered this line of VERY inexpensive line level transformers awhile back and ran some tests
which I distributed off-list. Bill Ruck's test of the isobox prompted me to share the info with
everyone else. Additional info from the manufacturer here (and, they are actually made in the
USA!):
http://www.edcorusa.com/transformers/audio/matching.htm
The replacement Edcors (600:600 impedance versions) arrived today, and the DCR was MUCH more
reasonable. Approx. 54.1 Ohms primary, 54.5 secondary. Level drop from open loading on secondary
to 600 Ohms was just a bit under 1.5 dB, much what I would expect.
[ Added note for this posting at Prodigy-Pro...the first set of 600:600 trannies that I received had a VERY high DC resistance, on the order of several hundred Ohms, on both the primary and secondary. The other correspondents on the Recordist mailing lists were measuring around 50 Ohms DCR on the samples they had bought, so I contacted Edcor. They gave me some "cock and bull story" about a production line design change, but they replaced the units I'd purchased at no charge with the "old" design.]
For testing, I breadboarded a "zero Ohm source" driver with a 5534 opamp running as an inverter:
10K input and feedback R's, 22 pF compensation cap (between pins 5 and 8) and 22 pF in parallel
with the feedback R to tame any overshoot and ringing from the opamp itself. -3 dB response with
the opamp circuit calcs to around 723 kHz. I powered the 5534 with +/- 20 VDC from my bench
supply, which allowed just over + 24 dBu/m at clipping.
1 and 10 kHz squarewave response through the iron looked very good, loaded or unloaded, with just
a
tiny bit of overshoot and ringing. Frequency response was beyond anything I could measure with my
Amber (bandlimited at around 500 kHz or so) which came up with -1 dB at approx 6 Hz and 300 kHz.
Bypassing the Amber and just watching the scope, usuable response was extended, and limited by the
rolloff of the opamp driver on the top end. With a 50 Hz square wave, there was very little tilt
which indicates LF response well below 20 Hz.
[Another sidebar for this posting at Prodigy-Pro...I recall very little difference between open circuit and a 600 Ohm termination.]
Next I measured THD, and at some of the lower levels I was fighting noise picked up from the
breadboarding! Here are various "spot measurements".
1 kHz, 0 dBm = 0.0085% +10 dBm = 0.005% +20 dBm = 0.0025% (noise was an obvious factor!)
100 Hz, 0 dBm = 0.03% +10 dBm = 0.015% + 20 dBm = 0.05% **
50 Hz, 0 dBm = 0.055% +10 dBm = 0.035% +20 dBm = 0.18% **
20 Hz, 0 dBm = 0.07% +10 dBm = 0.085% + 20 dBm = 0.7%
Spot checks at LF and + 20 dBm: 40 Hz = 0.3% 30 Hz = 0.45%
(Actual 20 Hz numbers may be a bit lower since my 20+ year old Amber was having a hard time
nulling
at 20 Hz).
** Notice the THD dip at the "middle" levels at those frequencies. I also think I detected a THD
rise at levels below 0 dBm but was fighting noise issues.
I have a bunch of other numbers, but you get the drift. Looking at Jensen choices, this Edcor is
just a bit "rattier" than a JT-11-EMCF which sells for $66.85. These Edcors are a bargain!!
--------------------------------------------------------------------
I discovered this line of VERY inexpensive line level transformers awhile back and ran some tests
which I distributed off-list. Bill Ruck's test of the isobox prompted me to share the info with
everyone else. Additional info from the manufacturer here (and, they are actually made in the
USA!):
http://www.edcorusa.com/transformers/audio/matching.htm
The replacement Edcors (600:600 impedance versions) arrived today, and the DCR was MUCH more
reasonable. Approx. 54.1 Ohms primary, 54.5 secondary. Level drop from open loading on secondary
to 600 Ohms was just a bit under 1.5 dB, much what I would expect.
[ Added note for this posting at Prodigy-Pro...the first set of 600:600 trannies that I received had a VERY high DC resistance, on the order of several hundred Ohms, on both the primary and secondary. The other correspondents on the Recordist mailing lists were measuring around 50 Ohms DCR on the samples they had bought, so I contacted Edcor. They gave me some "cock and bull story" about a production line design change, but they replaced the units I'd purchased at no charge with the "old" design.]
For testing, I breadboarded a "zero Ohm source" driver with a 5534 opamp running as an inverter:
10K input and feedback R's, 22 pF compensation cap (between pins 5 and 8) and 22 pF in parallel
with the feedback R to tame any overshoot and ringing from the opamp itself. -3 dB response with
the opamp circuit calcs to around 723 kHz. I powered the 5534 with +/- 20 VDC from my bench
supply, which allowed just over + 24 dBu/m at clipping.
1 and 10 kHz squarewave response through the iron looked very good, loaded or unloaded, with just
a
tiny bit of overshoot and ringing. Frequency response was beyond anything I could measure with my
Amber (bandlimited at around 500 kHz or so) which came up with -1 dB at approx 6 Hz and 300 kHz.
Bypassing the Amber and just watching the scope, usuable response was extended, and limited by the
rolloff of the opamp driver on the top end. With a 50 Hz square wave, there was very little tilt
which indicates LF response well below 20 Hz.
[Another sidebar for this posting at Prodigy-Pro...I recall very little difference between open circuit and a 600 Ohm termination.]
Next I measured THD, and at some of the lower levels I was fighting noise picked up from the
breadboarding! Here are various "spot measurements".
1 kHz, 0 dBm = 0.0085% +10 dBm = 0.005% +20 dBm = 0.0025% (noise was an obvious factor!)
100 Hz, 0 dBm = 0.03% +10 dBm = 0.015% + 20 dBm = 0.05% **
50 Hz, 0 dBm = 0.055% +10 dBm = 0.035% +20 dBm = 0.18% **
20 Hz, 0 dBm = 0.07% +10 dBm = 0.085% + 20 dBm = 0.7%
Spot checks at LF and + 20 dBm: 40 Hz = 0.3% 30 Hz = 0.45%
(Actual 20 Hz numbers may be a bit lower since my 20+ year old Amber was having a hard time
nulling
at 20 Hz).
** Notice the THD dip at the "middle" levels at those frequencies. I also think I detected a THD
rise at levels below 0 dBm but was fighting noise issues.
I have a bunch of other numbers, but you get the drift. Looking at Jensen choices, this Edcor is
just a bit "rattier" than a JT-11-EMCF which sells for $66.85. These Edcors are a bargain!!
[quote author="Brian Roth"]I have a bunch of other numbers, but you get the drift. Looking at Jensen choices, this Edcor is
just a bit "rattier" than a JT-11-EMCF which sells for $66.85. These Edcors are a bargain!![/quote]
Yes sir
. I notice that there is a WSM and a XSM range of xformers, $9.17 and $11.59. I'm using the XSM type.
analag
just a bit "rattier" than a JT-11-EMCF which sells for $66.85. These Edcors are a bargain!![/quote]
Yes sir
analag
clintrubber
Well-known member
Hmm, with all those good reports on these TXs... I'm wondering, are we now in the days before the Edcor-prices were 'more brought in line' with the rest of the market ? :roll:
In other words, should we stock up ? :?: :wink:
In other words, should we stock up ? :?: :wink:
NewYorkDave
Well-known member
I don't think it'd be in their best interest to try to compete in the Jensen/Sowter/Cinemag et. al. end of the business. Right now, they are the only game in town (in the USA) for good quality audio transformers in their price range. Why give up that market niche when you have little or no competition there?
As it stands, if you need a good line coupling transformer and only have 9 or 12 bucks to spend, the choice is clear. You can even buy a decent PCB-mount model for less than six bucks. But if you're willing to drop 20, 50 or 100 bucks the options multiply quickly. And who else will wind you a custom for the same (or nearly the same) price as a stock model? They have their market sewn up and, in my humble opinion, it would be foolish to abandon it.
Besides, from looking at their product line, it seems a large percentage of their business must come from the installed sound market--and sound contractors aren't going to pay "Cadillac" prices when they need 100 line transformers for an installation.
As it stands, if you need a good line coupling transformer and only have 9 or 12 bucks to spend, the choice is clear. You can even buy a decent PCB-mount model for less than six bucks. But if you're willing to drop 20, 50 or 100 bucks the options multiply quickly. And who else will wind you a custom for the same (or nearly the same) price as a stock model? They have their market sewn up and, in my humble opinion, it would be foolish to abandon it.
Besides, from looking at their product line, it seems a large percentage of their business must come from the installed sound market--and sound contractors aren't going to pay "Cadillac" prices when they need 100 line transformers for an installation.
clintrubber
Well-known member
Nice, that's reassuring !
(now they just have to reason along those lines themselves :wink: )
(now they just have to reason along those lines themselves :wink: )
Svart
Well-known member
the low prices make me want to buy a handful of each model to have for easy DIY and prototyping.
skipwave
Well-known member
[quote author="rafafredd"]really, I don´t think those TO92 devices in the PM1000 can drive a real 600:600 output transformer well. If you must do it, try a buffer before the transformers.[/quote]
Hmmmm, I've got a WSM600:600 on my PM1000. I'll have to take the time to do some listening tests.
Hmmmm, I've got a WSM600:600 on my PM1000. I'll have to take the time to do some listening tests.
Emperor-TK
Well-known member
[quote author="alk509"]
Sadly, Edcor doesn't make any mic input transformers... :sad:
Peace,
Al.[/quote]
So what are the issues with using a 10K/150 transformer for mic input (turned around of course)? I see the problems with it not being shielded, but what else? Is it that they lack the construction for handling +48V phantom? Could they work for mic inputs intended only for dynamic mics?
-Chris
Sadly, Edcor doesn't make any mic input transformers... :sad:
Peace,
Al.[/quote]
So what are the issues with using a 10K/150 transformer for mic input (turned around of course)? I see the problems with it not being shielded, but what else? Is it that they lack the construction for handling +48V phantom? Could they work for mic inputs intended only for dynamic mics?
-Chris
