Pseudo-Meazzi drum echo.....

[scmitche]

Hi Ecca,

Just as a point of interest, have you considered using Johan Forrer's idea of having a complete Meazzi circuit (minus the bias oscillator of course) built around a modified version of Piet's DSP programs using the SKRM board. It gets rid of all the maintenance issues as well. The reverb/tremolo has been ditched and the programs rejigged a little to suit the new configuration.
In Johan's case the Dry/Wet mix is done externally using Meazzi 12AX7 valve circuitry with the main echo coming from the Left channel of the SKRM board and regeneration fed back from the Right channel again through Meazzi tone shaping circuitry. He has even added an adjustable drive FET to the record section to better simulate the Meazzi magnetic saturation and compression.

The controls become external Dry, external Wet, external Regeneration (Repeats, Swell) with an Arduino controlling the SKRM board using Johan's Automation code.

His latest results on SoundCloud have some examples of this echo unit played through his various low power DIY valve amps and are as good as I've heard.

I'm sure he'd let you have the HEX file to reprogramme the FV-1 eeprom on the SKRM board and the Arduino Automation. I realise this would change the emphasis of your project from precision mechanical design to one that is mainly electronic but still very interesting.
Regards,
Steve

[ecca]

It does sound interesting Steve.
but......
One thing at a time.

[John M]

Ever considered the use of cassette recorder heads.
More readily available than 1/4 inch tape heads and considerably cheaper ...like these :- http://www.ebay.co.uk/itm/like/151447796572?

[ecca]

I did consider cassette heads John, I still might but in the interim I've spent a lot of money on these.......

http://www.ebay.co.uk/itm/321449627758?_trksid=p2059210.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

[Billyboygretsch]

I see they are coming from Greece good for SummerHoliday numbers

[Didier]

I did consider cassette heads John, I still might but in the interim I've spent a lot of money on these...

What about their impedance ?

Didier

[rogera]

In general tape heads used by transistor equipment are much lower impedance than those used for valve units. I'm sure that was what Didier was referring to.

There is a big disadvantage in using cassette heads due to the fact that they are half the width of reel to reel ones. The heads used by most echo units in the early
60s were full width ie 1/4 inch whereas a mono cassette head has a gap of just 1/16 inch. In addition to that cassette units used transistors/ICs.

[dave robinson]

I had a Melos echo machine in the seventies that used cassette sized heads - not very good.

[Didier]

In general tape heads used by transistor equipment are much lower impedance than those used for valve units. I'm sure that was what Didier was referring to.

That's right, low impedance heads for transistor circuits might not be suitable for valve circuits.

BTW, stereo heads might be used as mono heads with both circuits in serial or parallel connection, which would multiply or divide impedance by 2.

Didier

[keithmantle]

I did consider cassette heads John, I still might but in the interim I've spent a lot of money on these.......

http://www.ebay.co.uk/itm/321449627758?_trksid=p2059210.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

Check your pm's Ecc