Jensen JT-16-A Substitutes and Output

[aortizjr]

I am looking around to build a pre-amp that is simple, but has some transformer coloration.

The plan is to have something that will sound good on guitars, vocals, and general use. But also something I can use as a make-up gain amplifier to be used with a DIY summing/averaging box.

Basically something with linearity, some color, and some "spank" as many refer to it.

Anyway from Jensen's site I found the following:

http://www.jensen-transformers.com/as/as019.pdf

Combined with this:

http://www.jensen-transformers.com/as/as016.pdf

Looks pretty simple. Even though it says balanced out, it isn't.

What can I do to make it balanced? I assume add a tranformer on the end. But which one?

For the input transformer, the Jensen JT-16-A is $100. Not bad, but unfortunately budget calls. Especially since I am building two.

So what would be a good substitute that is available in the US?

I am thinking:

Cinemag CMMI-2P - $60
Lundahl LL1527XL w/ Parallel-serial connection to make it 1:2 - $68
Lundahl LL1358XL - $76

Will those work? Are there better and/or cheaper alternatives that still sound pretty good?

I apologize if this is a re-post. I searched and read through a lot of the Meta's and couldn't find what I was looking for. I found a lot of alternative designs that I might try later. But this one seems the simplest and complete. Basically more for a beginner.

From what I have leared about transformers in the Meta's and other designs, I can make some good guesses. But am not completely sure.

 

[Samuel Groner]

Even though it says balanced out, it isn't.

The output is balanced (so called "impdance balanced"). Save the money for the output transformer and get a true Jensen (expect it to be rather clean though).

Cinemag CMMI-2P - $60
Lundahl LL1527XL w/ Parallel-serial connection to make it 1:2 - $68
Lundahl LL1358XL - $76

I guess you mean LL1538XL? Not a good choice for 1:2.5 connection as the secondary has pretty high DC resistance which will make it relatively noisy (this transformer is usually used 1:5 where this matters much less). The other two are fine and the choice will be a question of taste.

Samuel

 

[CJ]

Check the Transfrmer Meta for Bauer.
The list is noew in alphabetical order, so finding it will be a snap in the park.
Hard to contact, but half the price.

 

[skipwave]

I'm sitting on a pair of JT-16A, intending to use them for the Jung-Markell design preamp. I'm hoping for clean and useful on overheads and passive summing makeup gain.

http://www.groupdiy.com/index.php?topic=8626

One forum member built this design with Sowter inputs.

 

[aortizjr]

Thank you for the input. I will probably go with the Cinemag since it is the cheapest. They of course claim theirs is a better product than the Jensen.

I also looked at the Jung preamp.

I am still going for the Jensen design since it is more complete and has all the options ready. Plus the components you can easily find via DigiKey. Or there are many suitable replacements.

I checked Edcor as well. But since they aren't shielded, it probably wouldn't be the best for the inputs. Outputs would probably work well though.

 

[skipwave]

[quote author="aortizjr"]I checked Edcor as well. But since they aren't shielded, it probably wouldn't be the best for the inputs. Outputs would probably work well though.[/quote]

Yeah, I'm using Edcor WSM600:600 for the output of mine, using switching jacks for unbalanced output. That way it can easily be run unbalanced for cleanliness or through the Edcor for a little something something. If you specifically want the output transformer to add coloration, you might try the WSM (rated 0.5W) instead of the XSM (rated 2.5W).

Another possibility might be the Beyerdynamics. There is a group buy going on in the Black Market. For 20EUR each the price is right. I was considering the TR/BV 1.10.9.01.002 for my preamp.

 

[aortizjr]

Cool, I am buying an Edcor here soon for a Re-Amp box. I will grab a couple of the output transformers as well.

What kind of coloration are you getting? Basically, coloration in a good way, or a bad way