Lombardi Echo Mixer containing Binson Echorec Magnetic Drum Recording System

[nevetslab]

I got an email from one of my clients who brought back a mid-70's Lombardi Echo Mixer, which has a built-in Binson Echorec Rotating Drum Echo Memory System, multihead that he found in a pawn shop in Italy. It did have a wooden case, though wasn't built real well....sleezy case latches broke in transit, but overall, the ruggedness of the mixer appears to have survived the trip. 220VAC unit, so he had picked up a step-up power xfmr to run it. I haven't yet powered it up. I only got as far as removing the large hinged lid portion of the case, and set that aside for the wood-working tasks, and fitting typical road case dished clasps and take-apart hinges for the one end that current has mom-and-pop hinges installed.

I see a date code on of the three Ducati Electrolytic Caps in the power supply chassis, to which the Binson Echorec Rotating Drum system is mounted. Guillermo tells me it has hum/buzz in the audio, and needs basic clean-up work. With date code of 9/73 on one of the cap cans (Sept 1973), and the power xstr on the heat sink being a 2N6259 250W NPN TO-3 Power Xstr, I'd say this is full of aged electrolytic caps. There are tiny input xfmrs, that at a glance, look like Beyer input transformers. I haven't dug in far enough to get a close up look at those. On the preamp modules, there's only two transistors total. TWO. Interesting how the change from vaccum tubes to xstrs began...I'd guess this is one such example.





Some close-up views of the Preamp boards:



Guillermo sent me a link that goes into detail describing the Binson Echorec Rotating Drum Memory System:

https://www.effectrode.com/knowledge...memory-system/

So, this looks like another interesting adventure, to see if I can get this working better than it is at present. After having done a full re-cap of that Vox Beatle amp, this looks easier, though not necessarily....I see what looks like buss wires passing thru each and every preamp PCB, suggesting another build done in sequence, so, if you have to remove a circuit board from that channel array, you're in for a tedious adventure.

The wooden case needs about $75 worth of dished road case clasps, hinges and a couple handles for the upper cover. Jigging time with the router for that task.

[vintagekiki]

About Binson Echorec

https://www.effectrode.com/wp-content/uploads/2018/08/binson_echorec_manual.pdf
https://soundgas.com/resources/binson-echorec-care-maintenance/
http://tylergrund.com/binson/images/Binson_operation_manual.pdf
https://amp-fix.com/For_Sale-Binson.htm
http://tylergrund.com/binson/
https://groupdiy.com/threads/looking-for-binson-echorec-ii-solid-state-circuit-diagram-s-possibly-manual.59833/
https://elektrotanya.com/showresult?what=binson
https://schematicheaven.net/effects.html >> Delay (Electro-Static Disk)

[nevetslab]

Today, I moved the step-up transformer to the bench, connected it so the mixer had 220VAC (haven't verified the actual step-up voltage yet), but it powered up. Below the faders, each channel has it's own On/Off switch, which also lights up a RED horizontal lamp, similar to a 3AG fuse cartridge. I plugged my transformer-sourced burst pink noise, it having a step attenuator as well as transformer coupling, and plugged the source into the input XLR. I went thru the eight channels, finding Channel 3 not working, nor was Channel 8. I plugged in a male XLR connector to return what I assumed was the output signal from the mixer back to my balanced input analyzer, though I'm not seeing any signal thus far.



So, the male XLR connector on the top row of connectors doesn't appear to provide output from the mixer. On the bottom rear panel, to the right of the AC Mains input connector are three 4-pin Male XLR connectors, each with a Cliff phone jack. I haven't tried those yet, but, as there are three meters, each with a control below it that sets the output level shown on the meter, it's a good bet those connectors on the bottom panel are associated with those.

To the right of the meters, there are four toggle switches. I'm assuming those to be the playback heads on the rotating drum echo. I'm about to follow the internet links vintagakiki kindly provided above, to see what additional details I can find there. More to follow.

The first listing led to an operators manual that provided useful cleaning information on the magnetic drum/heads. Intended for a stand-alone unit, but useful information.

The phone jacks at the bottom ARE the outputs from the mixer, one per meter channel. Right below the LOMBARDI name on the meter panel are four toggle switches. Those turn on/off the heads relative to the source (record head), as with signal applied, you can hear the delay change from each switch position. The rotary controls below...left is Echo Volume, middle is Repeat, which can lead to total overload if turned to far up, and the last appears to be a tone control, though not really sure. At present, I'm just feeding it burst pink noise...and listening to the output thru the Amber analyzer feeding my headphone amp.

The switches below the Echo controls turn on the Power to the mixer (1st two switches from the right), and the third switch from the right turns on the Binson Echorec unit. You can hear the rotary drum spin up switching it on.

Each channel has an Echo Send (top control), Treble (middle control) and Bass (bottom control). The controls below the meters are the channel output masters, meters follow their settings. I don't yet know what the male XLR is, nor the two female XLRs to the right of a rotary control.

Anyone out there fluent in Italian? I've no idea what the control/connector labels say.

[nevetslab]

I dug further into the rear of the unit, removing the upper connector panel, to have a look at the input xfmr wiring and wiring of the meter panel. Then, after putting that panel back into place, I released the mounting hardware of the power supply chassis at the base of the bottom panel. I had to unplug the two power supply connectors to free it from the chassis wiring first.



In looking close at the two rear connector panel photos, I see there are eight input xfmr and a ninth one....that's wired to the male XLR , and I had found before pulling this apart further, the rear panel control below the male XLR connector controls the output level from that connector. It also appeared to have lower bandwidth from the waveform I saw on the scope, relative to what I see on the three output phone jacks next to those 4-pin XLR male connectors.

When I went to release the two rear panel power supply connectors, I felt the smaller cable bundle break away, but couldn't yet see what I had done. There was black electrical tape wrapped around the connector body holding it to the chassis mounted receptacle that had to be removed. Got it released, then I found the ground braids of the wiring had broken free from the male harness connector, so this could be the source of the hum/buzz that was heard.



I recognize the connectors, though can't recall the mfgr's name. Seems I saw those on some early Neumann Power Supplies I was servicing when I worked for Westlake Recording Studios in West LA. I was then able to turn the power supply chassis over for inspection and photo documenting.





Looking at the output connector wiring, they're strapped as unbalanced. No Output Xfmrs in this chassis nor above, and this era was prior to creating balanced output circuits in place of transformers. Looks like various regulated supply PCB's in the chassis. Those three large Ducati Electrolytic caps are soldered into place, that being the ground connection, with a single insulated wire coming thru from the cap can. 2200uF/100V ratings. These boards are, at least, easier to replace the early 70's vintage electrolytic caps. I'll have to tally up all of the electrolytic caps used on the preamp boards, as well as these supply board to come up with materials cost. But first, I'll have to restore that smaller connector who's ground wires broke off.

Onward......

[drewl]

Wow, that's clean.
I got in an original Echorec, the wiring is all corroded and falling apart, plus board corrosion everywhere.

The whole thing needs to be re-wired.

[J M Fahey]

Brings old memories,
My own mixers were built that way, old time state of the art.

Suggest you remove those rigid bus wires and somehow install at each channel some connector which takes flat cable, so you can remove each board at will, multiple times.

Mixer is VDRY clean inside, but it is a long job.

Fine for a DIYer/Fan but not so sure for a Tech who charges by the hour, cost wil quickly surpass mixer value, I guess.

Your decision anyway.

[nosaj]

Those connectors look like Cinch Jones connectors.
nosaj

[nevetslab]

The smaller one looked like a Tuechel, but I think I saw Amphenol's name on it. Both, actually. I had to go up the cable a ways on two of them to get enough clean spiral wrap shield to work with. Then, after soldering that together, extended the length to reach the connector, and tie-wrapped it back into place, so it's back in place. Didn't make any difference with the hum/buzz. Not surprised with original 46 year old electrolytic caps.

Ch 3 and Ch 8 didn't pass signal. I found a broken wire on Ch 3's shielded core wire from the input xfmr, so that was an easy fix. Ch 3 was another matter. I found the travel of the actuator wasn't as long as the other faders. Then I saw what I assumed to be part of the wiper assembly, having broken free from the slide actuator, as can be seen thru the actuator opening in the panel.



It looked like the faders were glued to the back of the panel, not finding the fasteners, and glue seeping out from the body of the fader on the back side of the panel. Though I couldn't imagine a company doing that. Looking closely at the edge of the fader panel, I didn't see what looked like a thin escutcheon panel mounted over the metal panel. I reluctantly unsoldered the buss wire, the resistors and the switch wire from the fader, and then released the metal tabs that hold the innards in place, and lifted those out. Sure enough, that metal piece somewhat visible in the opening was the stamped spring-loaded contact fingers that had come off of the nylon actuator assembly. Registration holes stamped into the base, and what was left on the actuator wasn't enough to push it back on and hold it, but was enough to register it to glue it into place. So, I cleaned out 40 years of grease from the insides, and then applied a thin film of super glue onto the nylon block portion of the slider actuator, and glued it back on, held in place with a spring-loaded tweezers, and set to cure overnight.



After cleaning out the grease from the body, I found threaded screws present, so there ARE indeed mounting screws used to mount the faders. Only NO ACCESS to them! The owner had received a recommendation from Lombardi when he was over in Italy to replace the faders, install transformer coupled direct outputs from the two-transistor preamps, recalibrate the pickups of the magnetic drum and displacement of the external feeder (whatever THAT means).

While I was checking the input circuit of Ch 3, not knowing if there was an issue from the input connector, thru the transformer and the wiring to the preamp input connections, after having cleaned up the solder joints on that input, I jumpered the adjacent channel's xfmr secondary over to it, to see if I had an input circuit issue. Wasn't that....that was prior to finding this fader issue.

So, tomorrow I'll see how the surgery went. I've taken faders apart for years, but not having to leave one mounted like this.

I think this fader may be a result of the shipping damage to the protective case it was packed in. I need to confirm that all eight channels were functional before it was shipped from Italy back to the US. There's insurance claim for this, so this repair will be one of those. Probably the broken wire of Ch 8 from the mic input xfmr to the fashioned input wire sockets receiving those shielded cable leads. The wire did break off, and quite possibly a result of shock-flexing of a non-perfect solder connection.

Onward....

[nevetslab]

Brings old memories,
My own mixers were built that way, old time state of the art.

Suggest you remove those rigid bus wires and somehow install at each channel some connector which takes flat cable, so you can remove each board at will, multiple times.

Mixer is VDRY clean inside, but it is a long job.

Fine for a DIYer/Fan but not so sure for a Tech who charges by the hour, cost wil quickly surpass mixer value, I guess.

Your decision anyway.

I was looking at the preamp board mounting, and soon realized getting any of them off the panel is a real PITA!



There's a ground buss wire runing from the fader body on up to pick up the case of each of the rotary pots, along with a shielded wire up to the Echo Send pot at the top, then there's the cheese-head slotted screws passing thru the mounting bracket and thru the PCB, with mating hex nut on the opposite side, no visible lock washers on either side. Then, of course, the power and ground buss wires passing thru each board. So, getting these two-transistor preamp boards off of the panel looks like a very-determined effort to make it happen. I found one of these models (just like this one) on Reverb.com

https://reverb.com/item/41068643-rar...viced-warranty

Comments of the unit like 'creamy-smooth preamp'. Sure a lot of original Ducati electrolytic caps for a two-transistor preamp circuit.

If this project goes forward, it would have be another one of those fixed-price projects. There was shipping damage to the protective case, which looks just like the one in the Reverb.com photos. I wondered for a moment if this WAS what I had on the bench, until I saw in the description of the Reverb listing that it had been fully recapped. This one definitely still original. So, I haven't found any evidence of damage to the mixer, though the case took a beating. Speaks highly of the build factor of this heavy mixer.

[J M Fahey]

Thereīs a Plan B.

Boards are separate enough that you CAN work on them without removal.

Not exactly comfortable but doable.

My main problem was with solder suckers, the resulting 45 degree angle mouth (because sucker entering from one side gets angled for lack of space) does not seal properly around pad/molten solder but I cut the nylon tip at 45 degrees to compensate and it started working.

OR I melted solder , pulled component and later cleaned the mess.

Again, old memories, and funny enough, an old customer brought his 80īs made 8 channel 200+100W (main+monitors) box mixer for servicing.

Same kind of solid copper bus bars, of course, although I always too the precaution of installing them with some slack , I soldered first channel, pushed wire down with my thumb do it was curved, say 5-6 mm down, soldered next and so on, so if needed I *can* cut wires right and ledt of any channel (or master board), pull it out for servicing and then mount it back.
Now I can pull wire ends together, slightly overlapping, and safely solder them.

Not too doable in your case since best case they will be butt joined.
Of course, you can later add 6 to 10mm wire stubs to rejoin them safely.

[nevetslab]

I took yesterday off to relax, and resumed this morning back at the shop, once I was able to find an alternate way out of my driveway. Some idiot parked their Volkswagen Jetta across the driveway, blocking it. Called the Glendale Police to report it, hoping they'd have it towed away. All they did, though, was leave a parking ticket under the windshield wiper. If it's still there when I get home, hopefully I can get it towed away.

So, I put the fader parts back together, after lubricating the resistance track/wiper and mechanical path with red grease. That did restore Ch 3, so all eight channels are working. Just not working the same. Ch 4's LF control doesn't work, and Ch 6 has low gain. Increasing the input level and it sounds like the others, so more work....may be failed electrolytic caps as far as the low gain goes. One XLR has intermittent contacts, so cleaning to do. A couple tone controls needed to be exercised. Those issues aren't involved filing for damages in the insurance warranty, so at present, just dealing with those aspects.

When I turn on the Echo system, using the third Power Switch to the left, below all the Echo controls, I hear this hum/buzz noise appear. I can't say just what's causing that. Could still be related to all the old electrolytics. I need to find out if that was occurring in Italy. I can't imagine rough handling/dropping the unit would cause that.

[nevetslab]

After more evaluation on this mixer, not yet even back inside the power supply chassis to see what's what, I set up the controls with the faders up full, Echo System off, Echo Send off, EQ set flat, all eight channels on. Had one of the three output channels feeding the Amber 3501a Audio Analyzer which feeds my storage scope. With the analyzer set for 10mV FS, A-Wtd Filter engaged (20k/80k filters both in), I was hearing and seeing random bursts of noise coming from something. Might be just one of the eight modules, might be post mix buss in one of the output amps that follow the three Master Level Controls below the meters. Not sure yet.



I next turned the HF EQ to the first hash mark past 12 o'clock, and with all eight channels on, I was getting oscillation. I could change it by how much HF EQ was turned up, or by lowering faders, or turning channels off, but, this isn't something one would normally expect out of a simple 8-channel mixer!





With the HF EQ controls flat, residual noise is still on the high side...before I found I was getting random transient noise bursts.





When I turned the Echo System on, things on the mixer get nasty, which is the main complaint I'm getting from the client. No idea yet what is causing this. I haven't yet heard whether this problem was present prior to shipping, or if something has radically changed from the rough handling it received in transit. Still in the look and see mode, and documenting what I find.

Instrumentation note: On the Amber 3501a, the 30kHz LPF has been changed to 20kHz LPF, and engaging both 20kHz & 80kHz, it switches in an A-Wtd Filter.
Also, I'm using the analyzer in Extended Level mode. Input Level set for 1V, and using the Extended level/distortion level control to get all the system gain as needed....it can take me down to -100dB below 1V RMS, with HP, LP, A-Wtd Filters switchable, as well as 1/3 Oct BandPass and HP Filters available.

I'll show these details in the following post.

[nevetslab]

Now on to the nastiness present when you reach up and turn on the Echo System's power switch. There's tremendous HF Hash Noise and hum that comes up. I turned to the scope storage system to try and capture these details.







The last two images are with the Echo System turned back off, and residual noise less than 3mV RMS. I'm not yet sure what/where this is occurring, and whether this issue IS from shipping damage. It renders the mixer useless with this happening.

[nevetslab]

Thereīs a Plan B.

Boards are separate enough that you CAN work on them without removal.

Not exactly comfortable but doable.

My main problem was with solder suckers, the resulting 45 degree angle mouth (because sucker entering from one side gets angled for lack of space) does not seal properly around pad/molten solder but I cut the nylon tip at 45 degrees to compensate and it started working.

OR I melted solder , pulled component and later cleaned the mess.

Again, old memories, and funny enough, an old customer brought his 80īs made 8 channel 200+100W (main+monitors) box mixer for servicing.

Same kind of solid copper bus bars, of course, although I always too the precaution of installing them with some slack , I soldered first channel, pushed wire down with my thumb do it was curved, say 5-6 mm down, soldered next and so on, so if needed I *can* cut wires right and ledt of any channel (or master board), pull it out for servicing and then mount it back.
Now I can pull wire ends together, slightly overlapping, and safely solder them.

Not too doable in your case since best case they will be butt joined.
Of course, you can later add 6 to 10mm wire stubs to rejoin them safely.

I was thinking in terms of cutting the insulated buss bars in the middle, and once the ground buss wire is unsoldered from the pots, pot mtg hardware removed, and remove the two screws holding the PCB onto the right angle bracket, I'd remove insulation from the power and ground buss, slip in heat shrink for re-installation when that's ready, and be able to work on the modules outside the chassis. I thought about trying to tackle the component work with them mounted, but claustrophobia in such tight spaces would drive me nuts.

I'm not yet sure what sort of project budget this unit has. I think it's all going to depend on what is covered from the shipping insurance damage. Don't yet know if what we're seeing/hearing in the Echo system is from shipping damage, or just age. This is uncharted territory for me in the Binson Echorec department.

Looking at the photos I took inside the power supply, I see more single-transistor circuits feeding the output connectors, with more single-xstr circuits being used elsewhere, yet to be determined.

Thus far, no documentation to assist. The preamp circuit doesn't look complicated, nor do any of the circuit modules in the power supply chassis. Just time consuming. I'm already 3 months behind in owed labor (for covering my shop space), and not looking to increase that.

[J M Fahey]

IF this job does not count towards "rent", I suggest keeping at it while thereīs "nothing else" to do (for "landlords" that is), idle time serves nobody, but as soon as one of "their" jobs appears, set this one aside and get busy on the rental paying one.

Just thinking aloud.

As of the mixer, oscillations, etc.; personally Iīd cut channel mixing busbar to Master connection and concentrate on getting Master working flawlessly, then on the Echo module which is the elephant in the bazaar, and only after that, reconnect channels one by one repairing whatīs necessary.

You donīt have the Lombardi schematic but I BET that Binson Echorec is 99% same as others, get *any* schematic and it must be close enough.
Only difference being that most are Tube based, so thereīs only 2 or 3 SS versions.

I bet Lombardi designed the mixer but got the Echo units as a sort of "black box" device, only interfacing it with his own mixer.

Same way as today Belton Bricks are being interfaced in all kinds of amps and pedals.