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AUDIO FORUMS >> General Discussion and Support >> Zrock2 problem
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Message started by johnnycopy on 03/03/23 at 21:18:40

Title: Zrock2 problem
Post by johnnycopy on 03/03/23 at 21:18:40

Sold a perfectly functioning zrock2 and the buyer (Andrew) just got it.

The tube lights but no signal coming through when the front switch is in the up position.

Anyone ever have this problem… Steve?

Thanks for any help troubleshooting.

John

Title: Re: Zrock2 problem
Post by will on 03/03/23 at 21:32:11

Title: Re: Zrock2 problem
Post by DrewDays34 on 03/03/23 at 21:34:55

Thanks for starting this, Johnny.

I'm getting audio when the ZROCK2 is in the down position (bypass).

When I flip the switch up, the audio drops out.

Title: Re: Zrock2 problem
Post by DrewDays34 on 03/03/23 at 21:37:49

Likely already looked at, but... are the IC pairs on the correct jacks of the ZRock. Has an alternate tube been tried? I guess it is possible that a solder joint could have come loose in shipping, but hopefully something simpler.

Hi Will,

ICs are in their proper place. I referenced the manual and quadruple checked.

I haven't had a chance to order a backup set of tubes for all my gear yet, but I'm doing that now. Hopefully that's the issue. Fingers crossed.

Title: Re: Zrock2 problem
Post by johnnycopy on 03/03/23 at 21:38:41

Thanks will i asked the person the same question about interconnect orientation and whether tube was fully seated which Andrew confirmed.

Could the tube light but still send no signal through?

When I got the unit the tube was humming, so I replaced with nos organ grade which I supplied with unit as sold.

Thanks John

Title: Re: Zrock2 problem
Post by CAJames on 03/03/23 at 21:43:12

Quote:

Posted by: johnnycopy Posted on: Today at 13:38:41

...Could the tube light but still send no signal through?

In theory, yes. There are two circuits in a tube amp: a low voltage high current circuit that lights up the filament, and a high voltage, lower current circuit that actually amplifies the music signal.

Title: Re: Zrock2 problem
Post by johnnycopy on 03/03/23 at 21:50:09

Thanks, wish a tube was closer at hand for him to swap.

Thanks again.

Title: Re: Zrock2 problem
Post by DrewDays34 on 03/03/23 at 21:51:51

You and me both, Johnny. ;D Working on getting backup tubes here for all my newfound Decware gear asap.

Title: Re: Zrock2 problem
Post by Geno on 03/03/23 at 22:03:13

Hi Drew.

It appears from your equipment signature, that you are vinyl only?

But, if you have a digital source, you could take the 12au7 out of the ZP3 and try it.

Best,

Geno

Title: Re: Zrock2 problem
Post by DrewDays34 on 03/03/23 at 22:03:42

So I came across this in a thread Johnny shared with me from the ZROCK2 forum.

From Steve Deckert:

"Don't bother trying 12AX7's or anything from that family, it will throw things too far off to sound right. Most likely sound like shit. But a 12AT7 is a different story. Falls in the middle of the two, and in this case amps things up by another 6 dB I'm guessing. It really hits."

I have 3 more 12AX7s in my Mesa Boogie I can borrow. Although Steve doesn't recommend for sonic reasons, it seems safe to try in the ZROCK2.

Title: Re: Zrock2 problem
Post by DrewDays34 on 03/03/23 at 22:17:36

But, if you have a digital source, you could take the 12au7 out of the ZP3 and try it.

Hey Geno,

That's correct, I'm all vinyl. I was able to borrow a 12AX7 from my Mesa Boogie Lone Star.

Unfortunately, the problem is still present. When I flip the front switch up to the on position, the signal drops out. The audio can be heard verrrrrrryyyyyy very faintly in the speakers.

Definitely not operating like it should as shown in this demo:
https://www.youtube.com/watch?v=LfbGUBaofAM

Title: Re: Zrock2 problem
Post by johnnycopy on 03/03/23 at 22:23:56

So sorry to hear drew, keep me informed after talking to Steve.

I assume drew will need an rma number if he has to send it in hey guys?

Title: Re: Zrock2 problem
Post by GroovySauce on 03/03/23 at 23:13:10

Once I tried a 12AX7 in my ZROCK2 and no sound.

Sounds like a replacement 12au7 might fix it.

Title: Re: Zrock2 problem
Post by DrewDays34 on 03/03/23 at 23:41:47

Once I tried a 12AX7 in my ZROCK2 and no sound.

Sounds like a replacement 12au7 might fix it.

Well then... :( That's weird...

I guess I'll have to get my hands on a 12AU7 to be certain. My grandfather might have a guitar amp that uses them. I have a feeling they're all 12AX7s though.

Thanks for sharing your experience, Groovy.

Cheers [smiley=beer.gif]

Title: Re: Zrock2 problem
Post by will on 03/04/23 at 00:31:09

Hey Drew. A new toy and no play. I feel for you (and Johnny too).

One thing that occurs to me that you likely tried also... Have you tried it with the "A-B" switch in the back in the other position? If it happened to work, I think that would rule out the tube circuit anyway.

Title: Re: Zrock2 problem
Post by DrewDays34 on 03/04/23 at 00:35:36

If it helps anyone out there, these are the steps I've tried:

Ensured power cable worked properly, checked fuse for continuity, reseated all cables, reseated 12AU7, swapped the tube out with a 12AX7, and tried the rear switch in both settings.

Looks like my grandfather has a tube after all, so I'm hoping to try an 12AT7 in the morning. Steve has talked about using one successfully for sonic reasons, so if it still doesn't work, I think that'll rule the "bad tube theory."

Title: Re: Zrock2 problem
Post by DrewDays34 on 03/04/23 at 00:59:05

Have you tried it with the "A-B" switch in the back in the other position? If it happened to work, I think that would rule out the tube circuit anyway.

Yeah, I tried that too. No dice. Added that to my list above, forgot to add that.

Title: Re: Zrock2 problem
Post by Lon on 03/04/23 at 01:19:20

If he does need to send it in there's an RMA form on the website to print and use. Here is a link:

https://www.decwareproducts.com/_files/ugd/f1f204_62344b8b61254ed2b8de20fe2dd6bf61.pdf

Title: Re: Zrock2 problem
Post by will on 03/04/23 at 01:26:01

Sorry Drew. I am bad not to reload the page before posting, so I did not see your test method post before asking about the back switch. Glad you found a tube to test with.

In my first version of the ZRock2, with the tube mod only, I preferred 12AT7s for the most part, at least a very sonically balanced and resolving one I have, a particularly complete sounding old Mullard. After I fully modified the ZRock, fine tuned with faster, more transparent parts and wires, and some pretty complex cap bypassing... a 12AU7 is very resolving and plenty dynamic for me. 12AT7s are still more powerful, so bigger, denser and more vivid seeming... seductive for a while, but so far they seem to have moved into an overstated zone for me... in this system anyway.

May be a little different for yours, but on my ZRock2+ version unity gain is below 12 o'clock with a 12AT7, like 11ish, and with a 12AU7 around 1 o'clock give or take.

Title: Re: Zrock2 problem
Post by DrewDays34 on 03/04/23 at 19:27:12

Welp, no luck after swapping the tube with the 12AT7.

Thanks for the link, Lon. Looking like I'll definitely be needing that.

Thanks for sharing your experience, will. Can't wait to have mine up and running.

Does anyone know what the typical turnaround time is for repairs?

Cheers,
Andrew

Title: Re: Zrock2 problem
Post by Lon on 03/04/23 at 19:34:53

Turnaround is generally two weeks or so.

Title: Re: Zrock2 problem
Post by cliffmay on 03/08/23 at 01:43:11

Man... I've had mine for 1 week and I'm having the same issue. I think it's related to the power cord. If I hold it in place it works but if I don't it slowly starts losing power.

Title: Re: Zrock2 problem
Post by Rivieraranch on 03/08/23 at 01:44:44

Maybe there is a ZRock virus going around

Title: Re: Zrock2 problem
Post by cliffmay on 03/08/23 at 01:55:07

Definitely an issue with power cable. Nothing has physically happened. A lot of play up and down in the connection. When seated in a low position in the socket it works. straight on it doesn't.

Title: Re: Zrock2 problem
Post by DrewDays34 on 03/08/23 at 02:03:40

So you’re actually seeing your tube’s glow disappear, Cliff?

If so, that’s not what I’m seeing. All three tubes I’ve tried are glowing strong and never fade out.

This is the response I received from Steve, “ The symptoms you describe are exactly what happens when it is hooked up in reverse. The vertical pair of jacks nearest the outside edge are the output jacks while the inner pair are the input jacks. Another possibility is the fuse holder contains two fuses, a spare in the square tunnel and the active fuse in the clip.”

Unfortunately, both issues he mentioned aren’t the problem. One fuse and the cables are 100% in the correct jacks.

Title: Re: Zrock2 problem
Post by cliffmay on 03/08/23 at 02:14:44

Is there any play in the cord into the socket? If so... Hold it squarely into the socket and wait to see if you get audio with it engaged.

Title: Re: Zrock2 problem
Post by cliffmay on 03/08/23 at 02:21:53

Verified with another power cable. All is good.

Title: Re: Zrock2 problem
Post by DrewDays34 on 03/08/23 at 02:37:45

Is there any play in the cord into the socket? If so... Hold it squarely into the socket and wait to see if you get audio with it engaged.

I've tried multiple power cords. Holding it square into the socket doesn't work either. The issues persists.

Glad you were able to get yours running though. [smiley=beer.gif]

Title: Re: Zrock2 problem
Post by JBzen on 03/08/23 at 09:50:42

Hi Drew

I see that Zrock was described as having tube regulation. Could it be that shipping could have damaged that tube located inside the Zrock?

John

Title: Re: Zrock2 problem
Post by DrewDays34 on 03/08/23 at 14:00:02

I see that Zrock was described as having tube regulation. Could it be that shipping could have damaged that tube located inside the Zrock?

That's a great question. I completely forgot to take pictures of the tube for Steve that show the internal tube glowing. In the pics below, you can see both tubes glowing.

Title: Re: Zrock2 problem
Post by johnnycopy on 03/08/23 at 21:51:00

great catch jbzen. I had completely forgotten about the internal tube while working with Drew, but I guess it's not that either.