[Matt]

Hello, all.

I am wondering if there is any way to know if an amp will take an unattenuated Art DI/O signal. Though I understand not a word of it, the amp's specs are:

Solid state
Maximum output voltage: 350V r.m.s.
Input sensitivity: 100mV / 100V Output
Input impedance: 50k ohms
Gain: 60dB

Sorry if some of these mean nothing...if I've left anything out, please let me know.

Anyhow, is it possible to use the DI/O unattenuated?

Best,
Matt

 

[Jeff Guidry]

Love that chicken from Popeye's!

Most people have reported using the un-attenuated ART with no trouble. I don't think you should have a problem, but you might want to query a knowledgeable DIYer for a definitive answer.

 

[Hirsch]

Most amps have very good built in attenuators, otherwise known as volume controls. The situation where you might run into a problem is if your amp has active circuitry before the signal gets to the volume control. None of my amps/preamps has had this issue yet. However, in some cases, you may need to be able to make very small movements of the volume control with the unattenuated signal. I gave up on attenuators early on, because I felt they degraded the signal. However, when I did a resistor swap in the output stage some months later, I was able to drop the voltage at that point.

 

[Matt]

...that's good to hear, fellas. Thanks.

I'm curious to know how I'd know if my amp has active circuitry. It's a Stax SRM-313 (the one that comes in the SRS-3030 Classic System II). Will the published specs tell me this?

- Matt

Jeff: Amen, man...they have a birthday special right now, 3 pieces (leg, wing and thigh) plus biscuit for $2.49, so I've pretty much been living there for the past couple of weeks.

 

[Hirsch]

All amps have active circuitry, or they would have a problem amplifying. However, the question is whether there is any circuitry that can't handle the DI/O's output located between the amp's input and the volume control. This can't be determined from specs, usually, but would require a schematic. Best is to plug it in and listen. If you hear distortion at low volumes, you'd need an inline attenuator, or an attenuating interconnect (such as boldercables, which is a particularly well-made inline attenuator), or a modification to the output of the DI/O.

 

[Lunatic]

Quote:

Originally posted by Matt I'm curious to know how I'd know if my amp has active circuitry. It's a Stax SRM-313 (the one that comes in the SRS-3030 Classic System II). Will the published specs tell me this?

Matt,

I have the same Stax SRS-3030 system and my stock ART DI/O works fine with the SRM-313 amp without attenuation. Hope this helps.

 

[Matt]

Yay! That answers that question.

Thanks.

- Matt

 

[Joe Bloggs]

Does that mean that my Porta Corda might have trouble with the ART DI/O? I've been told by Jan Meier that the PC employs a new circuit that puts the pot at the *end* of all the amp stages. Now this seems to come with its advantages (among them, attenuation of all the noise that is generated by active components upstream of the pot) but this seems to be exactly the problem scenario you've described, Hirsch.

 

[kelly]

The Porta Corda should be fine as it doesn't do anything active BUT amplify. The Natural Crossfeed Circuit is passive. Similarly, the unmodded ART DI/O works fine with the Corda HA-1 albeit with not much play in the volume knob -- not nearly as annoying as the MG Head's stepped and never where you want it volume.

I found Bolder's attenuated cables to both be a little on the dark side and to reduce the clarity/detail of the DAC. I'm finally going the full mod route, myself, but it was not absolutely necessary.

Also, for those who may have this issue -- many receivers DO have active circuitry before the amp stage. Many of the higher end ones, though (and frankly the only ones you should consider buying) have a direct pass button. With direct pass engaged, all of the active circuitry is disabled and you can use your ART DI/O normally with the receiver. This has been the case with my Sony DA80ES receiver.

 

[Matt]

...I cracked the SRM-313 open and found that the RCA inputs go directly to the vol. pot. Goodie.

Gee, now that I'm in here, though I don't know **** about electronics, I'm wondering if a replacement volume pot would do any good for the sound, seeing that it's so terribly in the signal path. Can anyone help with this? It says "Alps" on it, then it says "207t" and then "50K (some Japanese characters) X2."

Is this a crappy pot? Could this be replaced with a superior one while still using the same front knob?

Also, I am a little concerned about the RCA inputs: there are two of them (actually they call the second a tape loop output) and they have three wires which are all rigged up to accept the signal and also put it out right on the spot, and they have metal rod wiring between them to acheive this while still sending the signal to the pot...I'd rather just have it have four leads to one RCA set...is this possible? Will they enhance the fidelity?

My goodness...there are also a bunch of friggin' LED lights in there, on the circuit board. Surely those can't be necessary! What are those used for?

It seems like they are for diagnostics or something...if so, I've got all this superfluous **** in my amp. Grrrrr!

- Matt

 

[Nezer]

Alps are supposed to be pretty good pots. However, the best by far is a stepped attenuator with high-quality balanced resistors. Thats probably the only real upgrade with regards to the pot unless this one is unbalanced or scratchy.

I'll deer the other questions for someone else but generally everything in there serves a purpose (even if it's just to look cool).

 

[Matt]

...I only ever listen to music at 3.5, 4, 4.5 and 5, so I'd imagine a stepped thingie would be kewl. If only I knew about electronics!

Oy...

- Matt

 

[shorton]

It's not the chicken so much for me, but the red beans and rice with a pepper and a coupla biscuits; God, I love it so!

If I understand your circuit discription correctly, the tape loop is just a shorting pin that is putting the RCA jacks in parallel and will have no (or next to no) affect on the sound quality. If it bugs ya, and you know you'll never use the tape loop, and (most importantly) if I understand you correctly, cut 'em.

The internal LED's are not visible to the outside world with the case closed, correct? That means they ain't for us to use or play with. If you had a schematic, at least that'd be something.

"Hey, where'd we leave that schematic the albino had?"

"Over the albino, I think."

"Well, why didn't you list that among our assets in the first place? Hummm?"

ps: I hope someone gets my little inside joke, else I'll be looking real silly right now.