Ampex 440B transort with 440C electronics. Will it work?

Sammy2000

New member
I have the Ampex 440B transport (4020271-9) in perfect condition with no heads and electronics.
A friend of mine has 440C electronics and a head stack for sale from an old Ampex as spare parts in very good condition.
Will my 440B transport work with electronics and heads from 440c?
Will any change be needed to make it work together?

I will be very grateful for your help.
 

RRuskin

Rick Ruskin
I have the Ampex 440B transport (4020271-9) in perfect condition with no heads and electronics.
A friend of mine has 440C electronics and a head stack for sale from an old Ampex as spare parts in very good condition.
Will my 440B transport work with electronics and heads from 440c?
Will any change be needed to make it work together?

I will be very grateful for your help.
Since all the transport does is move the tape across the heads as precisely, logic dictates that as long as the heads & electronics match, it should work. You could ask or search through the archives of the on the Ampex listserv for a definitive answer and other pertinent info.
 

Sammy2000

New member
Since all the transport does is move the tape across the heads as precisely, logic dictates that as long as the heads & electronics match, it should work. You could ask or search through the archives of the on the Ampex listserv for a definitive answer and other pertinent info.

I'm more interested in whether the 440B transport electronics will work with the 440C preamps.
I mean the right connections and voltages.
 

sweetbeats

Reel deep thoughts...
Not without a lot of modification to the transport control box. There are significant differences to the transport control electronics and how they interface with the signal electronics modules between the 440B and the 440C. I’ve done a lot of senseless stupid things when I ignored folks’ advice. In many cases I felt accomplished having done what people said either couldn’t be done or wasn’t worth doing. Trying to hack C electronics to a B transport really doesn’t make sense, particularly when B electronics are easy to find. Even if you find B electronics without the plugin cards you can use the cards from your C electronics in the B chassis.
 

Sammy2000

New member
Not without a lot of modification to the transport control box. There are significant differences to the transport control electronics and how they interface with the signal electronics modules between the 440B and the 440C. I’ve done a lot of senseless stupid things when I ignored folks’ advice. In many cases I felt accomplished having done what people said either couldn’t be done or wasn’t worth doing. Trying to hack C electronics to a B transport really doesn’t make sense, particularly when B electronics are easy to find. Even if you find B electronics without the plugin cards you can use the cards from your C electronics in the B chassis.

Thank you very much for the answer.
I read all your Ampex threads and actually I was waited for your post :)
I have a few more questions.
Can heads from 440B be used with 440C preamp and vice versa?
Does anyone manufacture heads for Ampex in this days (Flux Magnetics, Saki, …)?
 
Last edited:

sweetbeats

Reel deep thoughts...
Thank you very much for the answer.
I read all your Ampex threads and actually I was waited for your post :)
I have a few more questions.
Can heads from 440B be used with 440C preamp and vice versa?
Does anyone manufacture heads for Ampex in this days (Flux Magnetics, Saki, …)?
Yeah the heads are compatible. With a caveat of sorts. I mean, they are the same impedance, track spacing, etc. The 440C heads have triple the number of laminations and better HF response as a result, but in order to take advantage of that on a 440B you have to have C revision reproduce cards which have a resonance trimmer to tune the HF response. So, C heads will work with a B transport and B electronics, but you won’t get the advantage of the better HF response potential without the C revision repro cards. No worries, it’ll be B version HF response which is fine. Just want you to be aware. You should literally be able to plop a C headblock assembly on a B transport with B electronics, plug in the head connectors and off you go.

As far as head manufacturers that’s a good question…not sure if Flux, Sprague, IEM and others are still making heads but my opinion your first and best place to check is JRF Magnetic Sciences. John may have stock of new and/or used tested and inspected heads and would also know who is still in the business of making heads. Be prepared for sticker shock.
 

Sammy2000

New member
Yeah the heads are compatible. With a caveat of sorts. I mean, they are the same impedance, track spacing, etc. The 440C heads have triple the number of laminations and better HF response as a result, but in order to take advantage of that on a 440B you have to have C revision reproduce cards which have a resonance trimmer to tune the HF response. So, C heads will work with a B transport and B electronics, but you won’t get the advantage of the better HF response potential without the C revision repro cards. No worries, it’ll be B version HF response which is fine. Just want you to be aware. You should literally be able to plop a C headblock assembly on a B transport with B electronics, plug in the head connectors and off you go.

As far as head manufacturers that’s a good question…not sure if Flux, Sprague, IEM and others are still making heads but my opinion your first and best place to check is JRF Magnetic Sciences. John may have stock of new and/or used tested and inspected heads and would also know who is still in the business of making heads. Be prepared for sticker shock.

Thanks again for your help. I have one more question. Can I use reproduce B cards with C transport and electronics?
I think that I need to make some modifications to the B repro cards. From what I can see in the diagram, just add an R32 trimmer and replace the R1 1K resistor with 220 Ohm. What do you think about it?
Im asking because I have bunch of European tapes recorded in CCiR and also 2 type B reproduce cards which I can use for the CCiR option.
 

sweetbeats

Reel deep thoughts...
Thanks again for your help. I have one more question. Can I use reproduce B cards with C transport and electronics?
I think that I need to make some modifications to the B repro cards. From what I can see in the diagram, just add an R32 trimmer and replace the R1 1K resistor with 220 Ohm. What do you think about it?
Im asking because I have bunch of European tapes recorded in CCiR and also 2 type B reproduce cards which I can use for the CCiR option.
That’s what I was saying about the repro cards…see my previous post. You can use B revision repro cards in the C electronics chassis, but the B revision cards do not have the HF resonance trimmer incorporated into the circuit to take advantage of the improved heads on the C revision transport. This does not mean the B cards won’t work. It just means they don’t have the ability to be tuned for the improved HF response afforded by the C revision heads…otherwise the B cards should be plug and play in the C revision electronics chassis. You can add the components if you want…you can also just pop the cards in and go.
 

Sammy2000

New member
Many users prefer the sound of version B. I wonder why?
Maybe because the B version of the card has a slight lack of high frequencies and sounds nicer? Or maybe the rest of the electronics (apart from the reproduce card) decide about the sound?
 

sweetbeats

Reel deep thoughts...
The signal path is essentially in the plug in cards. The output transformer is in the chassis. But it’s not a great transformer in either case. I’ve not heard, at least in my circles, there’s a preference for the B over the C, so I’m not really sure what that’s about, but on paper the B has poorer HF performance potential (but still performs beyond the range of most peoples capabilities), and the C has better potential but it needs to be tuned as part of the calibration process. So either some people prefer the lower performance of the B or they’re not setting the C up correctly. My opinion is in many cases where people form these (arguably) illogical opinions, they are based on misuse/misapplication/improper setup of the device. You have to know the whole picture to really answer the question.
 

Sammy2000

New member
It will be best if I compare the B repro version with the C version, properly calibrated of course.
It is worth omitting the output transformer via the headphone output. I have read that there is a significant improvement.
I will also install the input Lundahl transformer in the repro card.
Only then will I be able to decide on the best configuration.
Ampex is a beautiful and solid machine that is worth bringing back to life.
 

sweetbeats

Reel deep thoughts...
Let your ears decide.

Using the headphone output is a quick and super easy way to bypass the O/P transformer and let your ears decide. Keep in mind you lose…I can’t remember…7dB at the headphone output because it is unbalanced and the O/P transformer is a step-up transformer? But it will bypass the transformer. There are lots of options to replace the O/P transformer if you want the balanced output and the higher signal but want a better transformer. Lots, and lots and lots of people use the stock transformer…lots and lots and lots of hit recordings were multitracked and mastered with that stock transformer in the signal path. So keep that in mind. I plan on modifying the B electronics in my MM-1000 someday to repurpose the 600R termination switch in the back as a transformer bypass switch for the XLR output.

Regarding the Lundahl transformer, also keep in mind the countless hits that were multitracked and mastered through the stock Beyer transformer. They’ve gotten a bad rap. Try the stock stuff before assuming you must make a better mousetrap.

Do you have the list of more important must-do tasks for the plug in cards and the chassis before jumping to replacing transformers? I guess this is more about the B electronics since that’s what I have and about which I am more familiar…but maybe you can correlate the chassis stuff to the C chassis…but the O/P coupling cap should be replaced and increased in value…there is also, if you are not using the plugin octal socket mic transformer, a redundant 5uF cap on the internal side of the octal socket that should be bypassed. You should replace the tantalum cap C32 on the record card with an electrolytic. Those are some important must-do things for safety and signal quality. Are you aware of those?
 

Sammy2000

New member
Let your ears decide.

Using the headphone output is a quick and super easy way to bypass the O/P transformer and let your ears decide. Keep in mind you lose…I can’t remember…7dB at the headphone output because it is unbalanced and the O/P transformer is a step-up transformer? But it will bypass the transformer. There are lots of options to replace the O/P transformer if you want the balanced output and the higher signal but want a better transformer. Lots, and lots and lots of people use the stock transformer…lots and lots and lots of hit recordings were multitracked and mastered with that stock transformer in the signal path. So keep that in mind. I plan on modifying the B electronics in my MM-1000 someday to repurpose the 600R termination switch in the back as a transformer bypass switch for the XLR output.

Regarding the Lundahl transformer, also keep in mind the countless hits that were multitracked and mastered through the stock Beyer transformer. They’ve gotten a bad rap. Try the stock stuff before assuming you must make a better mousetrap.

Do you have the list of more important must-do tasks for the plug in cards and the chassis before jumping to replacing transformers? I guess this is more about the B electronics since that’s what I have and about which I am more familiar…but maybe you can correlate the chassis stuff to the C chassis…but the O/P coupling cap should be replaced and increased in value…there is also, if you are not using the plugin octal socket mic transformer, a redundant 5uF cap on the internal side of the octal socket that should be bypassed. You should replace the tantalum cap C32 on the record card with an electrolytic. Those are some important must-do things for safety and signal quality. Are you aware of those?
I should write this at the beginning that I will use Ampex for home listening.
I am using a SET tube amplifier, therefore I will not use the balanced XLR output. In my case, omitting the output transformer makes perfect sense.
I am also thinking about installing separate RCA sockets so that I do not have to use an adapter from the headphone socket.

I read your threads twice :) and thanks for lots of valuable information such as replacing the tantalum C32 capacitor. Remind me which is the output couplig capacitor and what values should it be if you will have a time?
 

sweetbeats

Reel deep thoughts...
Yes. I know you are asking about the output coupling capacitor. I’m just verifying you are asking about the C electronics. I’m not familiar. I will have to research.
 

sweetbeats

Reel deep thoughts...
It looks like the output coupling capacitor in the C revision electronics is C6, a 250uF 50V part. It is mounted to the underside of a terminal barrier strip that is mounted to the left side panel of the the electronics chassis (below the output transformer). I recommend replacing this with any good quality 105C temp rated low ESR 470uF 50V or 63V cap. I’ve used Nichicon PW series caps for this application in the B revision electronics. But there are good offerings from Panasonic and others.

The other cap I mentioned that’s worth bypassing in the C revision chassis is C10, a 4uF 25V cap. This cap is strapped between pin 6 of the octal socket and the wiper of the record level pot. It is an input coupling cap, but it is ONLY needed if you are using the optional mic level input transformers plugged into the octal socket. If you are not using those optional transformers, like for instance if you are using the bridging transformers or matching transformers -OR- if you have no transformers installed and instead have dummy plugs installed, in any of those cases the input coupling cap C10 is not necessary. I suggest bypassing it (like soldering in a solid wire jumper across the terminals of the cap) to make it easier to remove the modification if you ever do want to use the mic level input transformers. If you never ever think you will use the mic level input transformers, you can remove the cap and replace with straight wire.
 

Sammy2000

New member
It looks like the output coupling capacitor in the C revision electronics is C6, a 250uF 50V part. It is mounted to the underside of a terminal barrier strip that is mounted to the left side panel of the the electronics chassis (below the output transformer). I recommend replacing this with any good quality 105C temp rated low ESR 470uF 50V or 63V cap. I’ve used Nichicon PW series caps for this application in the B revision electronics. But there are good offerings from Panasonic and others.

The other cap I mentioned that’s worth bypassing in the C revision chassis is C10, a 4uF 25V cap. This cap is strapped between pin 6 of the octal socket and the wiper of the record level pot. It is an input coupling cap, but it is ONLY needed if you are using the optional mic level input transformers plugged into the octal socket. If you are not using those optional transformers, like for instance if you are using the bridging transformers or matching transformers -OR- if you have no transformers installed and instead have dummy plugs installed, in any of those cases the input coupling cap C10 is not necessary. I suggest bypassing it (like soldering in a solid wire jumper across the terminals of the cap) to make it easier to remove the modification if you ever do want to use the mic level input transformers. If you never ever think you will use the mic level input transformers, you can remove the cap and replace with straight wire.
Thanks a lot! I don't know how to repay you for your help
 
Top