REDDI DI

[irfrench]

Evening all.

Thought I'd give a final update on the SRPP-DI I posted clips of earlier.

I finally boxed it up using a Hammond box and opted for two cascaded gain stages.

Thanks to all and particularly ruffrecords (Ian) for all the help.

8)

 

[ruffrecords]

Evening all.

Thought I'd give a final update on the SRPP-DI I posted clips of earlier.

I finally boxed it up using a Hammond box and opted for two cascaded gain stages.

It's great to see some of my PCBs in such a professionally constructed project. A couple of questions. Which Hammond enclosure did you use? - I am surprised you found one tall enough to get the tubes in. Also, I am planning on adding a section on my web site showing pictures of projects using my PCBs. Would you be prepared to let me use this project as one of them?

Cheers

Ian

P.S. That's a rather neat toroid mains transformer in there - where did you get that?

 

[irfrench]

Photos - Of course!  Please use them as you see fit, if you want/need other angles etc let me know.  It hardly repays the help you offered though!  :-[


The case is a HAMMOND - 1402FV (Farnell: 1901585  http://uk.farnell.com/jsp/search/productdetail.jsp?SKU=1901585) it took AGES to find one that wasn't ££££ or needed Thor's Hammer to machine/work!  Be aware that there is a lead time on delivery, Farnell says 10-days mine arrived in 7 working days though.

The toroid is from Barry at Ampmaker: http://www.ampmaker.com/store/240V-6.3V-toroid-power-transformer.html.

Front panel was done via Razorlab: http://www.razorlab.co.uk/

I can't remember if I posted the wiring/component .pdf I cobbled together so I've attached it here for posterity!


Thanks again.
Ian

 

[ruffrecords]

@ian

Thanks for the links. I like the Hammond box. it's a good size, it is all aluminium and does not cost and arm and a leg. I just ordered one!

Likewise the toroid transformer. Ideal for small two tube projects.

Razorlab is interesting, not least because they are British. I think I would have discounted them if I had just visited their web site since they don't seem to do aluminium and have some weird preferred material sizes. Did you get then to just do the engraving for the front panel or did they cut the holes too?? What was the process for using your own material of your required size??

The three pics you posted look good to me. Can you email me full size versions please? (and thanks for letting me use them)

Cheers

Ian

 

[irfrench]

Hi,

I'll email those pictures across in a bit.

I'm pretty sure you can contact Razorlab by phone/email and discuss your requirements for materials, I believe Kat is who I've emailed before. I think I used 5mm acrylic for mine, although in hindsight I could have used the 3mm as I tend to use it only as a finishing plate on something else.

To use them you can supply files in a couple of formats, but the thing that attracted me was the Inkscape option - I've used it loads for guitar pedal decals and its FREE!  Hurrah!  They can engrave or cut (including holes) the material for you and you designate what you want the laser to do by colour coding you items.  The material sizes they have are blanks and you cut what you want out of them - I hope that makes sense? e.g:

For the DI - the blue lines are cuts, the black areas are 'deep' etches.  In the DI example I didn't use an aluminium 'backing plate' as I felt it was strong enough anyway.  However I also used Razorlab for my LA4-51x builds:

I felt they needed reinforcement here so I VERY (  ) roughly drilled holes in the 'L' bracket for strength.  It takes the need for accuracy out (which I struggle with on metals - I can't imagine how I would have cut the hole for the meter in that LA4 by hand!?) and makes everything look purdy!

I hope this helps.  I'll happily go into more details but that may be better suited to a separate thread somewhere, The Lab maybe?


Ian

8)

 

[ruffrecords]

Thanks for the detailed info Ian. I had not realised your front panel was acrylic - it looks just like metal. I like the idea of using the stock material size and cutting different parts out of it. I also like Inkscape. I use it a lot because it is a native Linux app.

Cheers

Ian

 

[mylesgm]

What was the final circuit?  Do you have drawing to share?

 

[jandoste]

What was the final circuit?  Do you have drawing to share?

+1

 

[Jim50hertz]

What was the final circuit?  Do you have drawing to share?

+1

+2

 

[geoff004]

What was the final circuit?  Do you have drawing to share?

+1

+2

Page 4 reply #67
PS schematic page 6 #113
Is that what you're looking for?

 

[abbey road d enfer]

PS schematic page 6 #113

Actually, this would deliver only 2.5Vdc; the bottom resistor must be increased to 360r.

 

[erikb1971]

Irfrench: in your hookup pdf, I see one of Ian's valve boards, but in the pic of your DI I see two... the answers a probably quite easy, but:

how are they connected, and why two?

Love your build, am SO going to make that one!

 

[irfrench]

Erik,

I love that unit.  I've been using it loads - really good on keys!

I was originally going to make a stereo pair but decided one was enough, I'd already got the parts (sans output traffo) so decided to cascade them - simply send the output of one into the other.

For mine I opted for a set gain on the first stage (trimmer) and had variable gain on the second.

Enjoy.

 

[erikb1971]

would this be the right hookup? I just need some help with the input...

 

[abbey road d enfer]

I think we're talking about two different animals there, which have in common only the fact they are using vacuum tubes!

The schemo mentioned at post #67, which I believe describes correctly the REDDI, is a standard common cathode stage, where the plate load is the primary of the xfmr, which has to be gapped because of the DC flowing through it.
OTOH the circuit described by erikb1971, which uses Ian's PCB, is a cascode stage, which is characterised by higher gain and lower output impedance (about a few kohms), capacitor-coupled to a transformer.
The interaction between valve and xfmr is very different.
In order to avoid confusion, each new post should clearly indicate which is which.

 

[erikb1971]

oohhh that would have helped to avoid a lot of confusion for me! I could not see a lot in common between the two, but I thought I was just not getting it! So I figured to take it step by step. +It probably would have been clear quite quickly for a bit more trained mind! sorry! Maybe I should move my questions to a separate Rough Red DI (or a smarter / more accurately named) thread?

 

[ruffrecords]

Maybe I should move my questions to a separate Rough Red DI (or a smarter / more accurately named) thread?

I think that would be a good idea. The two designs are quite different so it will save a lot of confusion if this thread is confined to the original REDD DI circuit.

Cheers

Ian

 

[dirty1_1garry]

Here is it!
My Tube DI:



Custom power trans 9V/200V
I have both transformers gxse5-600-5k and cxse25-600-5k (it's really big!!) will try both. Let you know.

 

[ruffrecords]

Here is it!
My Tube DI:

Custom power trans 9V/200V
I have both transformers gxse5-600-5k and cxse25-600-5k (it's really big!!) will try both. Let you know.

That's a beautiful build. A few questions. Which case did you use? I like the tube mounting plate. Is that home made or off the shelf? How does it mount to the case?

CHeers

Ian

 

[flaheu]

great build !

I'm looking forward to hear your conclusions about the 2 different output TX;