DIY Tube Tape Echo

[jyrki3101]

I've been doing a struggle with this tape echo project for a long time. Not an easy one for sure. Mostly everything's built from scratch 'cause I haven't found any useful information on DIY tape echoes with google .
I like the features of the Roland space echo(201) with those multi-head type echoes, and that endless feedback which you can achieve easily...But I have had this obsession to build a tube based echo unit with the same kind of features...I already have the chassis, tape transport parts and tape heads(from amp-fix,UK).Tape/DC motor speed is controlled by a PWM module which I bought from ebay. Tape transport is already working.
There are 2 channels, each using a 1/2x12ax7 for the first preamp stage.1x12ax7's in the Recording amp stage w/local NFB loop, like in a Klemt Echolette NG51. Playback amp has two 12ax7's ,with a cathode follower at the output.
I copied the tape bias oscillator circuit from an old Dynacord echocord S-62(schematicheaven.com) unit. It's using one 12au7.
I've found it very hard to find a suitable osc.transformer,The original in the dynacord echo is chassis mounted, but I would prefer a pcb mounted transformer(lack of space inside the chassis). Don't have a glue about the specs...
I have read that the F******E  T*T*E Tube Tape Echo has also a 12au7 in the osc. circuit.
1. Has anyone information how it' built and what kind of osc.transformer has been used in that machine..
2.I WOULD GREATLY APPRECIATE of any kind of help, resources, links etc., anything that's related with my ambitious project( maybe TOO ambitious....
                              Regards, Jyrki

 

[dfer]

Hey jyrki3101,

Check out the Maestro Echoplex EP1/EP2 , they are tube tape echos, I think it was used by Jimmy Page on "Dazed and Confused", EP3 and EP4 are solid state. The echoplex is a very sought after echo... one day i will get one!!  


Sorry i cannot be more help to you.   :-\   But please check out the Echoplex (if you have'nt already?!!)


Dfer

 

[mad.ax]

I wonder how much a tube osc affect the sound in this application? Its purpose is to erase the tape, but it is not in the signal path...

I have seen tape echo (and tape recorders)  using just a magnet for that purpose.

You could build a transistor or IC based osc, or grab one inside any recorder that may rest in your junk box...

If you are building only one unit, you could look for one of those old Phillips or Grundig mono tube recorders as they can be found for cheap.

axel

 

[pucho812]

some stuff is not cost effective to DIY. As expensive as it is, might consider buying a fulltone tube tape echo.

 

[tardishead]

I have seen a few panels on Ebay over the last couple of years which are described as Automatic Double Tracking recorders from the 1960s.
They are basically a 4-5u panel with a tape motor - some guides and heads that can be positioned along the tape path.
One I saw had 1 input and 2 output tube amps with UTC A10 and UTC A24 transformers. The 2 machines I used were custom made for studios.
Did not look very complicated.

Old tube tape machines are abundant and not too expensive.

Tape echos are very common but I have not seen many at all that are designed for studio use. Space Echo 555 rackmount is but I prefer the sound of the older tube driven tape echos. Has anyone ever seen a product that was designed for line level studio use. Most are for guitars.

 

[ritz]

Not sure if this is of any use to you as it's not tube, but it is related to this topic. A DIY tape echo made from a couple of cassette decks... this one works at line level. Be sure to check out the sound clips too; pretty cool stuff.

http://www.mzentertainment.com/studio_workshop_zdlctd105.html

 

[burdij]

You could use a solid state bias/erase oscillator. Just get the circuit out of a junked reel-to-reel. You need to be in the 100KHz range for a pro device, though. Or you could use the bias/erase circuit from an Ampex 440 type machine. The bias osc is in the power supply section since all channels use the same source. Its a very simple circuit that uses two transistors. To wind your own transformer, determine the inductance you need from the circuit values. The transformer is resonated with a 2500pf capacitor at 100KHz. Grab a form and core from the IF section of a junked AM radio. You should get a fairly large one since you will have to wind more wire.

 

[joe-electro]

Look for a good deal on an Ampex 600 or 601 series reel-to-reel. It has everything you need electronics-wize. You might even be able to adapt the transport.

---Joe