REDDI DI

[dirty1_1garry]

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?

I used case that I bought from Moscow local case company. Pretty solid case that have a appropriate dimensions for fitting huge 25W output transformer and still save the form under the weight of it)))

Tube mounting plate from Banzaimusic. I mount it with plastic standoffs.

Weigh of full construction with 25W output trans is about 7kilograms ;D

 

[dirty1_1garry]

Here is a samples:
http://yadi.sk/d/41rjd4y9C6ykG
samples in 48khz 24bit

5W - tube di with edcor 5W output trans.
25W - tube di with edcor 25W trans (Exact names of this trns you could find on pages of this tread).
TT - DI input of TubeTech MP-1A.

bass was recorded with Fender Jazz Bass 78's.

My opinion:
tube di with 5W really sucks after hearing 25W model!
25W transformer variant has much more massive bottom and bass body, slighty less top end compared with MP-1A (and I don't think that it's bad for bass guitar) and it sounds just slightly compressed for my ears.
MP-1A sound really really great too! Massibe bottom, more open top end and slightly more dynamic. Do not forgot that it cost around 2.5K$))
Bass player said that he was more comfortable playing on tube di.


Let's hear your opinion about!!

 

[flaheu]

I have just listened to your samples 

For sure that DI with the 25W TX sounds huge and creamy !!!!!

Thanks for that, now I have to build one or 2 for sure !!!!!

 

[ruffrecords]

Tube mounting plate from Banzaimusic. I mount it with plastic standoffs.

I can't seem to find that tube mounting plate anywhere at Banzai. Can you tell me which category it is under?

Cheers

Ian

 

[dirty1_1garry]

I can't seem to find that tube mounting plate anywhere at Banzai. Can you tell me which category it is under?

Sorry, my mistake.Here is:
https://www.tube-town.net/ttstore/index.php/cat/c377_Accessories.html

 

[ruffrecords]

I can't seem to find that tube mounting plate anywhere at Banzai. Can you tell me which category it is under?

Sorry, my mistake.Here is:
https://www.tube-town.net/ttstore/index.php/cat/c377_Accessories.html

Ah, I know those.

Cheers

ian

 

[Hank Dussen]

Here is a samples:
http://yadi.sk/d/41rjd4y9C6ykG
samples in 48khz 24bit

5W - tube di with edcor 5W output trans.
25W - tube di with edcor 25W trans (Exact names of this trns you could find on pages of this tread).
TT - DI input of TubeTech MP-1A.

bass was recorded with Fender Jazz Bass 78's.

Thanks for the (RATM!) samples! The big Edcor sounds great!

 

[abbey road d enfer]

Here is a samples:
Let's hear your opinion about!!

I am shocked at the difference the small xfmr makes. For me, it doesn't demonstrate that the big one is better, it shows that the smaller one is placed in conditions where it is not operating correctly.
I guess the output xfmr in the TubeTech unit is not bigger than the 5W xfmr.
Unfortunately the specs on the Edcor site are parcimonious, in particular there is no inductance specification.
Apparently, you are running the tube at a total of about 15mA. That may be too much for the small xfmr - remember these xfmrs are of modest quality, using standard M6 lams and non-sandwiched construction. I have no doubt about the power rating, which is probably expressed for 10% THD, but in your application, you need only a fraction of this power.
I would suggest you run the tubes at about 4mA by increasing the cathode resistors to about 1k, maybe even disconnecting one of the triodes, and conduct a new series of tests. Sure, the output level would be much lower, probably about 6dB less, but the quality may be comparable to the big xfmr.

 

[dirty1_1garry]

Here is a samples:
Let's hear your opinion about!!

I am shocked at the difference the small xfmr makes. For me, it doesn't demonstrate that the big one is better, it shows that the smaller one is placed in conditions where it is not operating correctly.
I guess the output xfmr in the TubeTech unit is not bigger than the 5W xfmr.
Unfortunately the specs on the Edcor site are parcimonious, in particular there is no inductance specification.
Apparently, you are running the tube at a total of about 15mA. That may be too much for the small xfmr - remember these xfmrs are of modest quality, using standard M6 lams and non-sandwiched construction. I have no doubt about the power rating, which is probably expressed for 10% THD, but in your application, you need only a fraction of this power.
I would suggest you run the tubes at about 4mA by increasing the cathode resistors to about 1k, maybe even disconnecting one of the triodes, and conduct a new series of tests. Sure, the output level would be much lower, probably about 6dB less, but the quality may be comparable to the big xfmr.

Nice to hear a such quality opinion!


Lamp is very very hot when it's operate. I thing that tube runs in really hight gain mode so may be exact that fact could gives line level signal only from one tube and this fact could give a slightly compression of sound and harmonic distortion.
I think that quality could not be compared to big xfmr because small one has bottom limit at 35Hz)) 5 string bass gives lowest note at 32Hz.

 

[dirty1_1garry]

Here is some new samples!
My Tube DI with 25W edcor trans compared with... original box!!! you know what I mean

http://yadi.sk/d/c38Py0ZdCSZ75

Try to find a diference!

See attached file for how it was recorded.

 

[abbey road d enfer]

I think that quality could not be compared to big xfmr because small one has bottom limit at 35Hz)) 5 string bass gives lowest note at 32Hz.

That's a comment that comes quite often regarding bass amplification. I guess you know that most of the bass rigs cut-off at about 40 to 50Hz. This does not prevent hearing the B string because the hearing process reconstructs the fundamental from the harmonics.
Can you measure the actual frequency response of each variant? You could use the excellent software package from one of your compatriots, RMAA.

 

[dirty1_1garry]

I think that quality could not be compared to big xfmr because small one has bottom limit at 35Hz)) 5 string bass gives lowest note at 32Hz.

That's a comment that comes quite often regarding bass amplification. I guess you know that most of the bass rigs cut-off at about 40 to 50Hz. This does not prevent hearing the B string because the hearing process reconstructs the fundamental from the harmonics.
Can you measure the actual frequency response of each variant? You could use the excellent software package from one of your compatriots, RMAA.

Yeahh, I could.

 

[rock soderstrom]

Thanks for your samples!  8)

I think both units sound pretty similar (..on my headphones in my office!).

Well done!

 

[dirty1_1garry]

Here is a sweep and white noise tests of 5W edcor vs 25W output trans that shows a real frequency response of output transformers.

 

[dirty1_1garry]

What do you think:
how it's possible to change unstabilized B+ power supply for stabilized one with using LM783 for example?

 

[dandeurloo]

seems the 25w is a hair flatter.  How much was the 25w transformer compared to the 5w?

 

[dandeurloo]

Here is some new samples!
My Tube DI with 25W edcor trans compared with... original box!!! you know what I mean

http://yadi.sk/d/c38Py0ZdCSZ75

Try to find a diference!

See attached file for how it was recorded.

I just listened on head phones as well and they are very close.  Both sound really cool.

 

[dirty1_1garry]

seems the 25w is a hair flatter.  How much was the 25w transformer compared to the 5w?

If you mean how much transformer cost, here it is:
5W cost about 20$, 25W about 90$

 

[abbey road d enfer]

Here is a sweep and white noise tests of 5W edcor vs 25W output trans that shows a real frequency response of output transformers.

At what level have these been done? Frequency response shows that it would probably benefit from loading the secondary with 600 ohms. Can you do THD sweep measurements?

 

[dirty1_1garry]

At what level have these been done? Frequency response shows that it would probably benefit from loading the secondary with 600 ohms. Can you do THD sweep measurements?

I don't know a lot about how to done this measurements fully by the rules. So I just send signal from DA > reamp box to get guitar level/impedance signal > tube DI > AD > Blue Cat Freq Analizer> my results.
Let me know how I could done THD mesurements and I'll made it.