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REDDI Tube DI Mega-thread-III
- Thread starter Chef
- Start date
- Aug 21, 2003
- 11,588
- 18,607
- Disclosures
- A-Designs Mike Lull GK Tsunami Cables GHS Strings RMI Basswitch Nordstrand Pickups Darkglass
Hey Mark...
That is a JT5-24 with Big Singles and a Bart Pre.
Hahaha! Another one from the same groupdiy thread(s) I mentioned earlier. It's 100% reverse engineered from the REDDI with the exception of the OT which is a custom design. At least this one's a true DIY and not a commercial product being passed off as an original design like the ZOD.
Yeah, another member on that forum hand winds his own transformers and from his posts on there definitely knows what he's doing. Not sure how different from the REDDI's transformer it is but I believe the basic parameters are about the same. It's a cool DIY project because it's pretty simple and sounds great. I doubt it would be less expensive to DIY it in single quantities than it would be to buy a REDDI and would certainly be a lot more work.
He told me what he had invested in it. I forget though but I do know that he said something to the effect of if he sold that one for $350 he could make five more. I think that's what he said? @Dave Hill might remember.
Wow! Definitely not paying Sowter or Cinemag prices for the OT and using a very inexpensive chassis, then.
It was very DIY-cool.
And sounded very convincing back to back.
Is it the OT on these things that makes or breaks them?
And sounded very convincing back to back.
Is it the OT on these things that makes or breaks them?
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The OT definitely has some effect and even with all other circuit parameters the same, different OTs can have significant sonic differences. But that's not the only thing (of course
). The overall circuit topology is important too. The REDDI uses a true OT in that the transformer primary passes DC current to the tube's plate and its inductance is the load for the tube as opposed to the typical tube preamp gain stage that uses a resitor as the load and is coupled to whatever comes next via a capacitor. This loads the tube differently and the circuit behaves differently because of it. The reason those transformers need to be so big is because they pass DC through the primary winding and to do that without saturating the core, they need to have an air gap (which lowers the permeability of the core, FWIW). The problem with this is that you get less inductance per turn of wire in a gapped transformer, and primary inductance is the number one factor affecting low end response. So in order to get good low end performance you need more turns of wire and a larger core in a gapped transformer vs. a non-gapped one. the reason lots of other preamps and DIs can get away with such small transformers is that most of them are resistor-loaded, cap coupled circuits and the cap blocks the DC so the transformer doesn't have to deal with it.
I've done extensive tinkering with transformer-loaded tube circuits similar and dissimilar to the REDDI's and in every case, different output transformers result in different sonic (and measured) behaviour. I think I posted clips at some point of my tube DI project with similarly spec'd Lundahl and Sowter transformers. The transformers were the only change. It's no problem to tell them apart.
The builder of the Fat Box was saying that the REDDI uses a single ended triode line (?) that lets all the harmonics through, as opposed to other circuits that cancel out 2nd order harmonics(?). Lol, WAY over my head, but it does jive with my observation that the REDDI has a harmonically rich tone.
That's part of it but most preamp style circuits (almost all tube DIs) are single ended and the even-harmonic cancelling push-pull circuits are usually (not always) only found in power amplifiers. The magic of the REDDI is in the overall circuit design and IMO, the major contributors to that are the particular distortion characteristics of the 6N1P tube and the transformer loaded/coupled topology.
And my apologies for overly technical yakking about this. I have a tendency to get carried away.
svtb15
Inactive
- Mar 22, 2004
- 13,004
- 4,741
- Disclosures
- I play it all. Whatever works for the gig. Q+
Do you take the REDDI to all your live gigs, or just use DI of whatever head you're using?
svtb15
Inactive
- Mar 22, 2004
- 13,004
- 4,741
- Disclosures
- I play it all. Whatever works for the gig. Q+
The reddi in the photo goes almost everywhere. Except on bar gigs.. For those i just use amp DI out. In a typical bar gig Its usually too loud and a everyone is drinking so they won't know.. and 80% of the time im filling in for someone so its a cluster..
I was in a pit orchestra a few weeks ago and they loved it over the house DI ,
I have a special roadcase for my REDDI. It then travels in a larger case with my basses when i'm out on a road trip. I bought a second one to leave at home in my small studio setup so it doesn't get all messed up .
When I;m home , i do a sort of mega church gig... The Reddi excels on that,, Its not high volume (yeay) and they have a Meyer PA with a great FOH guy so you can hear what the REDDI does . It's all IEMs... I just run a tuner pedal in front of it.. I try Keep it simple as possible as often as possible The less stuff in the path the nicer....
I was in a pit orchestra a few weeks ago and they loved it over the house DI ,
I have a special roadcase for my REDDI. It then travels in a larger case with my basses when i'm out on a road trip. I bought a second one to leave at home in my small studio setup so it doesn't get all messed up .
When I;m home , i do a sort of mega church gig... The Reddi excels on that,, Its not high volume (yeay) and they have a Meyer PA with a great FOH guy so you can hear what the REDDI does . It's all IEMs... I just run a tuner pedal in front of it.. I try Keep it simple as possible as often as possible The less stuff in the path the nicer....
mark beem
Wait, how does this song start again??
I used to bring my REDDI to all my live gigs, but a close call flying with it cured me of that. Makes me a bit sad sometimes, especially on a gig like Sunday's where I'm playing Mohegan Sun Arena with one of the most badass PA's in the business, but I'd sure hate to take it out of my suitcase and find it broken, so I just take a Countryman and go out of the speaker out of the amp instead.
Looks like a wonderful lineup this year. Cara Mia!
When backline is supplied, have you ever tried requesting a REDDI in addition to the amp? Always worth a shot. On the plus side, the Countryman can be easily tucked in with your cables.
LOL! I can't even get the tube SVT on every gig! Fortunately, though, I get it a lot more than I used to, and I always get it on those Mohegan gigs.
And yeah, it's a killer lineup this year. We won't play with Jay Black, but that's OK...we're playing with enough damn acts!
A REDDI rackmount with a few more features would be the Shizuoka. I guess A Designs found their niche, stay busy and just aren't interested (?)
