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How do I interconnect a 1745M for use in a live situation?

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jagulow
Joined: Apr 24 2013
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How do I interconnect a 1745M for use in a live situation?

jagulow (My Eventide Gear)
March 18, 2019 - 01:26 pm

Hello, all-

I am the proud owner of a 1745M. It has 3 standalone delays, as well as the "double wide" Delay/Flange/Pitch option. My question is HOW, exactly, do I interconnect the 1745M for use in a live situation? I already know that I cannot send a lot of preamp voltage into the DDL without frying everything inside into oblivion. I know that the volume has to come post-1745M. I want to use my 1745M with live bands (specifcally the bass guitar and vocals) and I am having great difficulties getting it to produce output at volume. The repair technician (he's Eventide certified. I found him here on the forum) has told me that, after burning in the device for over a week, as far as his meters and scopes display, the device is 100% functional.

How do I get the output volume to a usable level for a club? Thank you all, very much, in advance.

John

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nickrose
Joined: Jan 17 2008
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nickrose
March 19, 2019 - 01:09 pm

As you will understand, this unit is older than most of the people at Eventide, and there is nobody here who knows anything about them.

But, I spoke to the designer, who although in his dotage, still has a few cells left, and he tells me the input clipping level is about  +18dBm with about 90dB dynamic range. While lower than our more modern rack units, this is still respectable. It can be used with a nominal +4dBm line level circuit, with slightly reduced headroom (not usually a problem for a unity gain unit like this).

So, it should be entirely useable. Since you don't say how you are driving it, it is hard to know what problems you are having. You should be able to connect it to a mixing desk send and return, probably using balanced line XLRs (depending on your 1745's configuration). Adjust the input level for occasional flashing of red LIMIT indicator.

Do be aware that this is a very old unit, not really designed for modern live use. You should use it at line level, not guitar level.

Note that the manual says "Without transformers, input should not exceed 40V p-p, or 12V p-p on either line." These are quite high levels, so it should be easy to keep within this range.

 

 

 

 

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jagulow (My Eventide Gear)
March 19, 2019 - 02:09 pm

Hello, Nick-

Thank you for your reply! Yes- I'm aware this unit is a dinosaur. I definitely won't be taking it out on tour! To fill you in on things- I haven't decided how best to hook anything to it. I did try using my litttle Tom Scholz "BassAce", belt-worn, personal practice amp as a preamp, but I couldn't hear any output at all from the output amp I used. I was thinking, maybe, I just wasn't giving it enjoy juice, up front, to drive it (I am aware the 1745M is passive). I was thinking to, next, try running it thru an active DI, maybe (such as Whirlwind's HotBox Quad)? I am not, at all, certain about how best to interconnect one of these vintage DDLs, so I'm asking other's advice before just blindly jacking it into anything- only to find that I've just fused everything into a useless mass of garbage. I've spoken in great depth with Jerome Hyman at Eventide/Little Ferry, and he has been positively indispensible, answering my every question. He talked with one of the last remaining engineers still on-staff from "the old days" on my behalf, and fed me the results of those conversations via e-mail. I even conversed with Mr. Factor about the device. I was floored to actually talk with him. I couldn't believe my luck!

Can you tell me if my thought of using an active DI as a preamp will sufficiently drive the 1745M? What is the best way to hook it up for a live sound situation. I am a complete noob in this field, as well a blonde! So, if you could, please, talk slow- and use small words! :) Thank you, once again, for your reply.

John

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jagulow
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jagulow (My Eventide Gear)
March 20, 2019 - 04:09 pm

Hello again, Nick-

I'm trying to avoid going through a mixing board, as I don't own one. I'm wondering if I can run the 1745M thru the effects send/return jacks on my vintage BOSS BE-5B Multieffects pedal. The send/return jacks are used to involve other stomp boxes. I am uncertain if the jacks are powered or not. Can you tell me if this type of seup would work?

John

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nickrose
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nickrose
March 21, 2019 - 07:46 am

I'm not familiar with your Boss pedal, but suspect that it will operate at guitar level, while the 1745 will expect line level. You will be hard put to get a good signal to noise level. It really wants to be driven from a mixer or similar.

 

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jagulow (My Eventide Gear)
March 21, 2019 - 08:59 am

Ah. I see. It's never easy, is it? I guess I'm going to have to look for an inexpensive 4-channel mixer (one channel for each working output on the 1745M). Do I need a board with phantompower? What about my earlier question about an active DI if the board is passive? You had also asked about transformers earlier. Yes- my 1745M has transformers. 4 of them. It's also fully balanced. I did notice that the pinouts on the 1745M's XLRs were different than modern pinouts, so I bought a set of 6 Hosa Technology, 1.5' long, balanced interconnect cables, and had the pinouts on the XLRs connecting to the 1745M rewired to match the pinouts of the 1745M's XLRs. Am I on the right track here?

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nickrose
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nickrose
March 21, 2019 - 10:31 am

Alas, I cannot design your setup for you, especially using a 50 year old unit with which I am unfamiliar.

I would recommend that you find a local tech who should be able to make sense of it.

.

 

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jagulow (My Eventide Gear)
March 21, 2019 - 10:34 am

I thank you very much for your time, Nick! :)

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Lincoln989
Joined: Apr 15 2020
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Lincoln989
June 27, 2020 - 01:10 pm

Hi Nick and John,

I'm also the proud owner of one of these. With the help of Richard Factor I got hold of a service manual which was enough to fix the few chips in the unit that were causing chaos. However having sorted out the delays I still have an issue with the Harmonizer for which my manual has no details as it was a later addition. Nick do you think I could trouble you to ask the designer for any schematic or info on the Harmonizer? It's more than just a slight variation on the delay despite running on the same Read/Write and Address system.

I adore servicing old gear and the 1745M has got to be in the very top flight of rarities in this software driven age.

All the best to you both!

Lincoln

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rfactor
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rfactor
June 27, 2020 - 02:43 pm

Lincoln989 wrote:

I'm also the proud owner of one of these. With the help of Richard Factor I got hold of a service manual which was enough to fix the few chips in the unit that were causing chaos. However having sorted out the delays I still have an issue with the Harmonizer for which my manual has no details as it was a later addition. Nick do you think I could trouble you to ask the designer for any schematic or info on the Harmonizer? It's more than just a slight variation on the delay despite running on the same Read/Write and Address system.

Thanks for your comments!  I haven't seen a schematic for this module in decades.  Assuming one has survived, it will only turn up by accident during an aperiodic cleanup, and then only when the pandemic is resolved. 

My only memory of this product was the general way it worked.  A variable oscillator controlled by the front panel knob clocked the output of an exotic, now- (and possibly even then-) obsolete FIFO chip at up to 2x the sample rate.  The chip had a "half full" flag which triggered TWO reads of the memory, for which there would be plenty of room in the FIFO.  Depending on the output sample rate determined by the knob, you could get up to a 2x pitch increment.  The rest of it was probably similar to the standard output modules.

Good luck on your somewhat quixotic quest.  BTW, anyone else looking for the 1745 manual should check out this under-construction, messy, inaccurate, and very incomplete page:   http://priups.com/manuals.htm

Richard

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Lincoln989
Joined: Apr 15 2020
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Lincoln989
June 27, 2020 - 03:44 pm

rfactor wrote:

Lincoln989 wrote:

I'm also the proud owner of one of these. With the help of Richard Factor I got hold of a service manual which was enough to fix the few chips in the unit that were causing chaos. However having sorted out the delays I still have an issue with the Harmonizer for which my manual has no details as it was a later addition. Nick do you think I could trouble you to ask the designer for any schematic or info on the Harmonizer? It's more than just a slight variation on the delay despite running on the same Read/Write and Address system.

Thanks for your comments!  I haven't seen a schematic for this module in decades.  Assuming one has survived, it will only turn up by accident during an aperiodic cleanup, and then only when the pandemic is resolved. 

My only memory of this product was the general way it worked.  A variable oscillator controlled by the front panel knob clocked the output of an exotic, now- (and possibly even then-) obsolete FIFO chip at up to 2x the sample rate.  The chip had a "half full" flag which triggered TWO reads of the memory, for which there would be plenty of room in the FIFO.  Depending on the output sample rate determined by the knob, you could get up to a 2x pitch increment.  The rest of it was probably similar to the standard output modules.

Good luck on your somewhat quixotic quest.  BTW, anyone else looking for the 1745 manual should check out this under-construction, messy, inaccurate, and very incomplete page:   http://priups.com/manuals.htm

Richard

Thanks so much for your help, Richard. The quest will continue. Have a great weekend!

Lincoln

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jagulow (My Eventide Gear)
June 27, 2020 - 05:06 pm

I have a manual for my 1745M. I purchased it direct, through Eventide. It has a schematic bound in its pages. There is no direct info on the Pitch Change function. I recently purchased a Samson*MDR1064 and have interfaced the 1745M through it. I had a custom-made combiner cable made for it ( LR into 1/4”, with the + and - wires reversed to match the modern wiring of the mixing board. I was getting a wicked phase inversion hum before having the + and - wires flipped!). The cable sends all 4 output XLR’s signals simultaneously into an Aux (Left/Mono) Return 1/4” jack on the mixing board. Another custom-made cable sends the 1745M’s input XLR signal into the mixing board’s Aux Send 1/4” jack. The sounds I’m getting are amazing. I’m having a problem isolating each output’s signal individually, though. Do I have to give eqch channel on the 1745M its own channel on the mixing board? Also, with the Pitch Change module, I’m not getting the 1-2 octave range promised in the specs in the manual. How can I accomplish this? I’m so psyched that I was finally able to revive my 1745M! Now I just need some finepoint instruction on how to bring out its uniquenesses! Thank-you SO very much, Mr. Factor!

John
Caldwell, NJ

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jagulow (My Eventide Gear)
June 28, 2020 - 09:20 am

I found some images of my interconnects. 

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jagulow (My Eventide Gear)
June 28, 2020 - 09:53 am

I found this in an search. It shows the LED readouts for the Pitch Change Module (PCM) of a 1745M.

Attachment
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jagulow (My Eventide Gear)
June 28, 2020 - 01:36 pm

I found all my interconnect cables. All connectors are made by Switchcraft. Their functions are as follows:

Top 4 XLRM into 1 XLRF connector combiner cable: DI XLR to channels 3-6 on my Samson*MDR1064 mixing board.

Middle 4 XLRF into 1-4"M connector combiner cable: Eventide*Model 1745M outputs into Samson*MDR1064 mixing board Aux 1 Left (Mono) Return 1/4" connector

Lower 1 XLRM into 1/4"M connector cable: Eventide*Model 1745M input in Samson*MDR1064 mixing board Aux 2 Send 1/4" connector

Bottom 2 XLRM into 1 XLRF connector combiner cable: Shure*SM57 mic to Samson*MDR1064 mixing board Channels 1-2 Mic In XLRs

Attachment