EZ Tube Mixer

[ruffrecords]

If you need to, just swap polarity so the pins are where you want them, and routing makes more sense. Transformers don't really care if hot is cold so long as both primary and secondary are wired in correct phase to each other. (I know you're aware of that, just helping others that are lurking the forum)

Thanks for that. Printed out the image for close scrutiny along with data sheets!

Cheers

Ian

 

[gemini86]

Scrutinize away! The way the OEPs are wired right now is what is currently found on the original G9 PCB layout. It's all upside down and backwards from the recommended hookup, but is essentially the same.

 

[ruffrecords]

Scrutinize away! The way the OEPs are wired right now is what is currently found on the original G9 PCB layout. It's all upside down and backwards from the recommended hookup, but is essentially the same.

Thanks for the info. I have now created a new common footprint for the original Sowter plus a Cinemag CMMI-10-PCA and a JensonJT-115K-EPC all of which are 1:10 mic transformers and as luck would have it they have very similar pin outs. Unfortunately the only 1:10 that OEP does has flying leads and the Lundahl 1:10 the LL1636 has two rows of 8 pins on 0.1 spacing so there's no way I am going to be able to squeeze that in.

So now, before I commit this to the PCB layout, I need some kind soul in the USA to buy and send me one of the Cinenmag and one of the Jensen transformers. I could order them from the UK but by the time I pay exorbitant shipping charges plus local taxes plus a fee for collection of local taxes they will cost a fortune. I someone could buy them for me and ship them as a gift I can avoid a lot of unnecessary expense. Of course I will cover all costs in advance.

Any takers?

Cheers

Ian

 

[ruairioflaherty]

So now, before I commit this to the PCB layout, I need some kind soul in the USA to buy and send me one of the Cinenmag and one of the Jensen transformers. I could order them from the UK but by the time I pay exorbitant shipping charges plus local taxes plus a fee for collection of local taxes they will cost a fortune. I someone could buy them for me and ship them as a gift I can avoid a lot of unnecessary expense. Of course I will cover all costs in advance.

Hi Ian,

I'm happy to do this for you.  I travel home from L.A. to Ireland on May 20th so depending on timelines I could even post from there saving more on shipping and speeding things up.  The tricky bit will be whether both companies can get transformers to me before I leave.

Cheers,
Ruairi

 

[ruffrecords]

So now, before I commit this to the PCB layout, I need some kind soul in the USA to buy and send me one of the Cinenmag and one of the Jensen transformers. I could order them from the UK but by the time I pay exorbitant shipping charges plus local taxes plus a fee for collection of local taxes they will cost a fortune. I someone could buy them for me and ship them as a gift I can avoid a lot of unnecessary expense. Of course I will cover all costs in advance.

Hi Ian,

I'm happy to do this for you.  I travel home from L.A. to Ireland on May 20th so depending on timelines I could even post from there saving more on shipping and speeding things up.  The tricky bit will be whether both companies can get transformers to me before I leave.

Cheers,
Ruairi

That would be really great! Drop me an email at ianbellATukfsnDOTorg and I'll Paypal you the necessary money so you can order them.

I trust this will not give you a problem with customs?

Cheers

Ian

 

[ruffrecords]

Quick progress report. Transformers are on the way to me so I can check the new mic pre layout which accommodates Sowter, Cinemag or Jensen input iron. If that works out I'll update the PCB layout and order what will hopefully be the final version prototypes.

The Pultec 3 band and Helios 69 EQ PCB prototypes arrived today. To recap, the Pultec 3 band will do, one one PCB, all the poor man's EQP1A, with or without the mid boost/cut mod and also allows you to build an inductor based hi boost just like in the original Pultec EQP1A. The Helios is a new design that closely follows the original Helio 69 type EQ. This means it can be used in both tube and semiconductor designs.

I also took the opportunity to order some more of the original EQP1A PCBs, plus some poor man's tube gain make up PCBs, plus some of my phantom PSU PCBs and some tube HT PCBs. I plan to offer all of these via the 'White'market in the near future.

Cheers

Ian

 

[timeye]

Nice work Ian.

 

[letterbeacon]

Very excited about this project!

 

[ruairioflaherty]

Hi Ian,

Your Cinemag has arrived, still waiting on the Jensen but they expected to ship either yesterday or today.  I had to postpone my trip to Ireland, too much work to finish. I'll post your transformers from here when they arrive.

Cheers,
Ruairi

 

[ruffrecords]

Hi Ian,

Your Cinemag has arrived, still waiting on the Jensen but they expected to ship either yesterday or today.  I had to postpone my trip to Ireland, too much work to finish. I'll post your transformers from here when they arrive.

Cheers,
Ruairi

I appreciate that Ruairi.

Cheers

Ian

 

[ruffrecords]

I have just about finished the build of the new PCB for the three band Pultec. Just need to attach pots and test. Pic attached.

Cheers

Ian

 

[alexc]

That looks just fantastic. So much looking forward to building some of your designs.

 

[anjing]

Very interesting!

 

[ruffrecords]

I have now tested the 3 band Pultec PCB. I tested the inductive high boost at max and min Q plus the high cut. Then I tested the low cut, the low boost and the simultaneous low boost and cut that gives the well known Pultec bump. Lastly I tested the mid cut and mid boost. I am pleased to say the results are pretty much as expected. There were a couple of capacitors I did not have the correct values of so I used the nearest I had which means a couple of frequencies are not quite spot on but other than that it is looking good. results are in the attached pdf.

Cheers

Ian

 

[funkymonksf]

Dammit Ian! now I want to build an eq with this new design. The poor man is simply not as cool as this latest design. Good work, I'm continually impressed and excited with your work!

Brice

 

[CJ]

who was the highest paid entertainer from 1950 thru 1970?

 

[millzners]

who was the highest paid entertainer from 1950 thru 1970?

Johnny Carson had to be up there.

 

[ruffrecords]

Dammit Ian! now I want to build an eq with this new design. The poor man is simply not as cool as this latest design. Good work, I'm continually impressed and excited with your work!

Brice

Thanks for the kind words Brice. The Poor Man's was aimed to meet a specific need i.e. minimum cost, but then got a bit out of hand as people asked if I could add a mid section. In the end, although it is very cheap, the poor man's needs a lot of wiring up, which is fine for a mono or stereo pair in a box but not so much fun if you want to build a mixer full of them.

So the new design is aimed more at ease of construction than anything else. You can still build it as cheaply as the poor man's by not using the hi boost inductor and using cheap off board switches, but it is much easier to build if you use the on board switches. All you then need to wire up is the external pots and I have even tried to make that as simple as possible by using a preset pot footprint on the PCB for the connections to each pot. So long as you wire up all the pots to these in the same way it should work.

Cheers

Ian

 

[ruffrecords]

A further update: the Jensen and Cinemag transformers arrived in the post this morning (thanks Ruairi). I printed out the current EZ Tube Mixer mic pre PCB layout onto paper an offered up these two transformers to make sure I had got the pin positions right. So far it looks good. I just need to check all the pins are in the right places and tracked correctly, and if they are we'll have a PCB that will accept any of three types of mic input transformer. I'll be ordering some of these in the next week or so, so it would be nice to have an idea how much interest there is in these.

I'll be offering these PCBs and the Pultec and Helios EQ PCBs and all my poor man's PCBs plus the tube gain make up, phantom power and HT PCBs via the White market probably starting next month (July). I'll also be including links to all the documentation for all my projects there as well so there's a one stop shop for information as well.

Cheers

Ian

 

[bieckmusic]

Awesome, I'm definitely interested!!!  I'd love to make at least an 8 channel version.  Once I finish up my TG limiter project...

thanks for all of your hard work 

greg