Binson Echorec2- here is a schematic! PROBLEM

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loylo

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Dec 20, 2005
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Hi all,

Excuse my bad english because I am a french guy, new to the board.
I am fond of Binson echo, those wonderful pieces of italian technologies. I own a Binson PE603-t solid state and a 60's Binson Echorec 2 tube unit, model T6FA.
I search for informations on the net for years and, let alone the site where people sell the schematics and manual ( :evil: ), I came up with good information such as some operating manual and schematics (PE603 and echorec). I saw few topics on the net and on this forum about Binson, so if anybody is interested in some informations, let me know.
Here is the echorec schematic (just clic on the picture):


Now I have some problems with my Binson Echorec, and I am sure you guys can help me.
Here are some picture of my unit:







Now, the problem is that the drum and the macnetic heads are in bad conditions. I have been offered a complete new plate, with drum and heads, but the new heads have an impedabce of 340 ohms, while my heads are 640 ohms.
I tried one new reading head (of 340 ohms, the other reading heads and the recording one were the original one of 640 ohms) and the signal is nearly inaudible, there is a big drop in volume.
So I wonder if there is a possibility to adapt those new head to my machine. There should be a possibility to bias the heads, but I don't really know.

From the schematic, I understand that half of the tubes n°1 and 2 amplify the signal of each of the reading head. But what do I have to modify to make the new heads work with my binson? A resistor, a capacitor? Nothing (ie perhaps that there is an automatic offset with the recording head and there is nothing to change if the recording head is also 340 ohms, just a suggestion)?


I would be very grateful if someone can help me.
Thanks in advance.
 

Bo Hansen

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Hi Loylo,

This new head`s you have find, is it Binson head`s or normal "tape recorder" head`s ???

Before you change head`s, have you try to clean up the drum, and adjust the head`s in right position and drum tension.
This is very important on a Binson, and if this not is done, you have a big drop of both volume and treble.

--Bo
 

StephenGiles

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I never realised what a messy build they were. I can remember sitting (well standing) in for a lead guitarist around 1964 and used his strat/binson and echolette amp. It was a wonderful sound, screaming treble and crystal clear echoes - in my mind. I daresay that there was hum, crackle and hiss in there too but we didn't worry about that then. That was probably the last time I ever used echo at that time because Da Blues was around the corner!
Stephen
 

loylo

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Dec 20, 2005
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[quote author="Bo Hansén"]Hi Loylo,

This new head`s you have find, is it Binson head`s or normal "tape recorder" head`s ???

Before you change head`s, have you try to clean up the drum, and adjust the head`s in right position and drum tension.
This is very important on a Binson, and if this not is done, you have a big drop of both volume and treble.

--Bo[/quote]
Hi Bo,
They are real Binson head (NOS), not normal tape recorder head.

I have cleaned up the drum and fine tune the heads. That is why I saw the really bad condition in which they are, specially the drum: you can see it on my own page
http://lmeuff.perso.cegetel.net/index2.html

The drop in volume occur with the new reading head I tried, while the others still the original one. That difference should comme from the difference of impedance, that is why I ask if you know how to bias the heads.
[quote author="StephenGiles"]I never realised what a messy build they were. I can remember sitting (well standing) in for a lead guitarist around 1964 and used his strat/binson and echolette amp. It was a wonderful sound, screaming treble and crystal clear echoes - in my mind. I daresay that there was hum, crackle and hiss in there too but we didn't worry about that then. That was probably the last time I ever used echo at that time because Da Blues was around the corner!
Stephen[/quote]
Yeah, that's a wonderful piece of technology. And there is no hum, hiss nor crackle with mine! :thumb:
 

Bo Hansen

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Loylo,

Before you try to do a lot of modifaction work, ask The binson company in Italy, http://www.binson.com , if the still have the orginal record head as spare.

Any way......
Because the construction are very simple, there are not much to do, for match a other head type, but you can try to play with some of the components around the record amp, (ECC82 tube) but I think, it is not with any bigger success.

To increase level: change the 27k in series with the record head.

Change the bias level: adjust variable capacitor that is connectet in series with the record head.

Change the frequency response: play with the capacitors on the tube grid input and cathode. (150 pF and the 10k = 10.000pF and cathode 22k = 22.000pF)

BTW, the magnetic area on the drum/weel are done with some kind of the old time "steel recording wire"
So you can rewind this area by hand, if you can find this old steel wire, maybee you must also grind/plane the surface on the new wire.
(there are two small rivet/pin that hold the two end of the wire)

--Bo
 

loylo

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Dec 20, 2005
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Thanks Bo, you seem to be absolutely right. I have just learned that those new head should be used with solid state model. They can't be adapted on the tube units, as you wrote there is not much to do because of the simple construction.

I'll check at www.binson.com (but it is not really binson, as the company ran out of business a long time ago, it's held by an englishman at a repair shop) if they have some spares.

For the tuning of the recording head, I was already aware of the manipulation. But I don't know if it is possible to tune the bias with the variable capacitor only "by ear" or should I use multimeter (and what is a corret tuning of the bias? I am not sure that somebody can answer...)?

For the information on the magnetic drum, you are very helpful as I didn't know anything. Thanks.

I think I would go buying a new drum and relap my own heads by myself. It seems to be an operation not so difficult, if I can find the correct tools (abrasive paper of only 1 or 2µ). :wink:
 

Bo Hansen

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On old tape or Binson echo machines are the bias level/current adjustment fairly simple and approximate.

So connect a 1kHz tone on the input and a mV meter on the output, and adjust the variable 100 pF capacitor to maximum output volume, (with the direct signal preset resistor in minimum) and you have the optimal bias adjustment.

I find some bias current value in old Binson schematics, and they say that the 50kHz bias current through the record haed shall be aprox. 0,6 to 0,9 mA, for the tube machines, and approx. 2,5 mA for the solid state machines (I think, 2,5 mA, is the bias current for your new head)

The audio record level seem to be same, approx 0,8 V RMS in 1kHz (full magic eye indicating, before the 27k serial resistor, (same for both head types)

--Bo
 

loylo

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Dec 20, 2005
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Thanks Bo! :thumb:
Could I use my computer to inject a 1kHz signal to the input of the Binson? I am afraid I have no other mean to generate that signal...

By the way, do you have a schematic of The Binson PE603T but solid state or any other solid state model of Binson?
If so, I am very interested in those schematics as I also own a PE603T solid state which is in bad shape and need new wiring. I PM you my email adress.
Thanks
 

Bo Hansen

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Yes, you can use any sine like tone, approx. 500 Hz to 5 kHz, from your PC, sampler, synth or simmular.

Sure, I will send you the schematic.

--Bo
 

Polykobol

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Dec 12, 2008
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Bo Hansen said:
Yes, you can use any sine like tone, approx. 500 Hz to 5 kHz, from your PC, sampler, synth or simmular.

Sure, I will send you the schematic.

--Bo

Hi all, Hi Bo,

I have also a Solid State PE 603 Version. Could you please also provide me the schematics?

Thanks in advance,

PK
 

Polykobol

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Dec 12, 2008
Messages
19
loylo said:
Thanks Bo!  :thumb:
Could I use my computer to inject a 1kHz signal to the input of the Binson? I am afraid I have no other mean to generate that signal...

By the way, do you have a schematic of The Binson PE603T but solid state or any other solid state model of Binson?
If so, I am very interested in those schematics as I also own a PE603T solid state which is in bad shape and need new wiring. I PM you my email adress.
Thanks

Salut, As-tu réussi à réparer ton PE 603 solide state?

MErci et À bientôt,

PK
 
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