A Tube Works 4001 Direct Box (DI) made 2002 in Taiwan by Genz Benz

[Snaxster]

Since I don't see much info online about the Tube Works 4001 and 4002 model DIs (mono and stereo, respectively), I made some documentation of a 4001 I just acquired:

2002 Tube Works Real Tube DI



That's a Flickr gallery, in which each photo page contains my commentary.

FAQ

Q: What do you think of the 4001 Direct Box so far?
A: I like it very much. It sounds great, is very useful, and is easy to use.

Q: How does this made in Taiwan version sound compared to the earlier made in America ones?
A: I don't know, since I can't recall ever using any other 4001 Direct Box.

Q: How does this DI sound compared to an Aguilar DB 900 (which is also out of production and features post-tube audio in the hi-z output)?
A: I don't know, since I never used the Aguilar model. But for my purposes, at 3 to 4 times the price now, the Aguilar DI would have to sound much, much better than the Tube Works DI to justify its greater price.

Q: Would you use a Demeter, Aguilar, A Designs or other high-end tube DI instead if you could afford to?
A: Probably. The Demeter or other for recording and the Aguilar for live: I want that post-tube audio for the bass amp. I would like to someday directly compare the sound of the 4001 DI to the high-end models. Until then, I think the 4001 DI gives amazing value for money.

I hope this helps others with their research of tube DIs. If you ever owned or played through both U.S. made and Taiwan made versions of the 4001 DI, please post here with any impressions you recall of the two, especially comparing them. Thanks.

Best,

Snaxster

[svtb15]

They dont make that anymore.. sadly...
I think Genz Benz own that stuff now.. not sure.
Im Thinking the 4001 as pictured above would sound very nice from what i have heard others say. No direct experience with it.
I would get the REDDI over the Aguilar if you want big and fat .. Aggy is very nice. Used it a few times. But the A-Design REDDI is deeper and fuller sounding than the aggy with smooth top end clarity. The REDDI is just Huge sounding..
The TW 4001 was said to be a favorite of Lee Sklar for many years. Would love to see a re issue one day.

[smcbass]

Here's the link to the Tube Works 4001/4002 on the Genz-Benz website:
http://www.genzbenz.com/img/manuals/...UserManual.pdf

I just bought one on ebay which appears to never have been used. Where can I get a Ken-Rad 12AX7?

[Snaxster]

Originally Posted by smcbass

Here's the link to the Tube Works 4001/4002 on the Genz-Benz website:
http://www.genzbenz.com/img/manuals/...UserManual.pdf

I just bought one on ebay which appears to never have been used. Where can I get a Ken-Rad 12AX7?

Hello. Thanks for adding that link to the thread.

I will PM you about tubes, to keep the thread focused.

Best,

Snaxster

[Snaxster]

Recently I've been learning about using different op-amps in audio devices. Swapping in alternative op-amps is like "tube rolling" with vacuum tubes.

With the TI TL072CP op-amp that was stock in it, my Tube Works 4001 DI sounds very good. I have read some players describe the sound of this model as "huge".

photo of the stock TI TL027CP op-amp in the 4001 DI



Tonight I swapped a Burr Brown OPA2134PA op-amp into my 4001 DI, replacing its stock TI TL072CP op-amp.

Burr Brown op-amps are widely considered to be at the high end, whereas TL072 op-amps are usually considered to be serviceable. But in the right hands, and to the right ears, any sound can be good.

With the OPA2134PA in it, my 4001 DI sounded very different: it made much less low frequency output than the TL072CP, and it sounded less harsh and aggressive overall. My impression was that low frequencies, especially, now sounded more focused, relaxed and natural.

So I believe that players' description of the 4001 DI as sounding "huge" was in part due to its stock op-amp boosting low frequencies.

As in other instrument audio applications, I like the Burr Brown OPA2134PA op-amp in the 4001 DI for its relaxed, open and honest-feeling sound.

photo of the Burr Brown OPA2134AP op-amp in the 4001 DI



Soon I will upgrade all the capacitors in my 4001 DI. If nothing else, the original caps are now ten years old; but I think better quality caps will improve the audio in any case. Upgrading the resistors to metal film ones is also an option, but its a lot of work, and I haven't yet noticed my 4001 DI being too noisy.

Best,

Snaxster

[smcbass]

I bought a 4001 Real Tube Direct on ebay a while ago. I read some posts on TB recently about "glory tube" DIs. Given the input power of this DI (30VAC/600ma), I wonder if it is a "glory tube" DI. Your comments welcome.

[Ender_rpm]

Thread necropolis bump

I just grabbed one of these NoS for $150! I think I did pretty good any more input on how people like it? Or how it compares t o newer designs? Goin to use this and a Barber Linden as my DI chain in the studio next month.

[Ender_rpm]

Am I reading the manual correctly that there is a speaker sim/ high end roll off built in? Oh baby...