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Post subject: DRRI tubes, identifying the culprit
Posted: Wed Aug 03, 2011 6:15 am
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Aspiring Musician
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Hi all, Need some help. Here's my new DRRI. I've had it for over a month now. I've got a noise problem. I think it's probably just a tube issue, & I have two choices, I can drag the amp to the shop & get a cheap tube replacement under the warranty, or I can order some decent tubes. I think I'll get some good tubes. Possibly JJs or something similar; I can't afford NOS ATM.
The noise is coming from the reverb channel. It sounds like AM radio static. My question is, which tube is the most likely culprit? Assuming it's a tube.
Also, Does anybody have a simple diagram of the tube placement & the functions of the tubes? So far I understand the rectifier, power amp, & phase inverter tubes, but not the order & function of the preamp tubes. I have a somewhat basic understanding only. All help much appreciated. cheers

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053 Deluxe Reverb RI by mojjett, on Flickr


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Post subject: Re: DRRI tubes, identifying the culprit
Posted: Wed Aug 03, 2011 6:53 am
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Isn't there a tube chart in the cab, showing the tube locations? Here is the schematic if it is any help, it shows the functions and labels (V1, V2, etc) of the tubes. If it is a tube problem, it could be any of the tubes V2 (first and second gain stage of vibrato channel), V3 and V4 (Reverb driver and recovery), or even V5 (vibrato). I would suspect V2 first.

http://support.fender.com/schematics/guitar_amplifiers/65_Deluxe_Reverb_schematic.pdf

I would definitely use the warranty first, if it is still good at this point, to start with known good tubes, before ordering replacements. And, if it isn't a tube problem, you may be frustrated with new tubes and still have the noise. :idea:

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Post subject: Re: DRRI tubes, identifying the culprit
Posted: Wed Aug 03, 2011 7:51 am
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Thanks Shimmi, I'm assuming the warranty is good. They didn't make any distinction between the amp & tubes, & the warranty is good for a year. I'll have to call them if/before I decide to bring it in. The problem is, it'll cost me more to bring it in than it would be just to buy & replace a 12ax7 myself. i.e. transporting, not to say lugging it up some stairs. :x Again, assuming it's the tube. I may swap some 12ax7s around & see what happens before I decide.
Yea, the chart inside the cab gives the tube placement but nothing more.
I downloaded those diagrams, but they might just as well be in Chinese, but your explanation gives me much of the info I was wondering about. cheers


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Post subject: Re: DRRI tubes, identifying the culprit
Posted: Wed Aug 03, 2011 8:04 am
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Good idea. You could pull the V1 tube for trial substitution in each position, one at a time, to find the bad tube, if any. Make sure to turn the amp power off before swapping tubes, and it is OK to leave the V1 position (or any position) empty and power up the amp. If it is necessary to try a different tube in V3, just try it temporarily, as you typically don't want to replace the 12AT7 with a 12AX7 in that position. I thought that the tubes were covered for 90 days, unless you got some extra extended warranty, but double check that.

Oh, each preamp tube has two halves, and the tubes functions as follows:

V1 is the first two stages of the normal channel only (V1A, V1B)
V2 is the first two stages of the vibrato channel only (V2A, V2B)
V3 is the reverb driver for the vibrato channel only (V3A, V3B)
V4 half is the reverb recovery for the vibrato channel only (V4A)
and the other half (V4B) is another gain stage for vibrato channel
V5 both halves for the vibrato function, vibrato channel only (V5A, V5B)
V6 is the phase inverter (pi) both channels (V6A, V6B)
V7 and V8 being the output tubes.

Look for the V1A, V1B, etc, designations on the schematic near each tube, to get an idea of the tube functions in the amp.

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Post subject: Re: DRRI tubes, identifying the culprit
Posted: Wed Aug 03, 2011 9:03 am
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Shim already gave a good explanation for the tube layout, here's a link that explains it some more...

http://www.kcanostubes.com/content/fender-amp-preamp-tube-layout-and-recommendations

Is this noise only in the reverb channel? V3 and V4 are responsible for reverb, but V2 is also responsible for that channel, so you can try swapping V1 and V2 as a start...

If you're looking to replace your preamp tubes, look into the Mullard 12AT7 for V3 and a balanced one for V6

http://thetubestore.com/mul12atcv.html

I really like the Mullard 12AX7 reissues, they sound great in V1 V2 and V4.

http://thetubestore.com/mu12ax7.html

I'm not a fan of the JJ 6V6, really like the TAD I have in my DRRI right now...

http://thetubestore.com/tad6v6.html

IIRC, tubes have a 90 day warranty, so you could try that first, but you'll probably get the same crappy tubes and will end up replacing them in the future... just a thought.


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Post subject: Re: DRRI tubes, identifying the culprit
Posted: Wed Aug 03, 2011 9:06 am
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Perfect!! Great info, Thanks


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051 guitars &amp; amp by mojjett, on Flickr


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Post subject: Re: DRRI tubes, identifying the culprit
Posted: Wed Aug 03, 2011 10:10 am
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cedarblues wrote:
Shim already gave a good explanation for the tube layout, here's a link that explains it some more...

http://www.kcanostubes.com/content/fender-amp-preamp-tube-layout-and-recommendations

Is this noise only in the reverb channel? V3 and V4 are responsible for reverb, but V2 is also responsible for that channel, so you can try swapping V1 and V2 as a start...

If you're looking to replace your preamp tubes, look into the Mullard 12AT7 for V3 and a balanced one for V6

http://thetubestore.com/mul12atcv.html

I really like the Mullard 12AX7 reissues, they sound great in V1 V2 and V4.

http://thetubestore.com/mu12ax7.html

I'm not a fan of the JJ 6V6, really like the TAD I have in my DRRI right now...

http://thetubestore.com/tad6v6.html

IIRC, tubes have a 90 day warranty, so you could try that first, but you'll probably get the same crappy tubes and will end up replacing them in the future... just a thought.

It seems to me that it's only the reverb channel. Next chance I get, I'll do some tube swapping. You're probably right about getting some cheap a** Groove tube from the shop. One other reason I'm a little reluctant. thetubestore.com looks good. I'll check out a few brands there. I know they got a great selection. I hear some folks aren't crazy about the JJ 6v6s. I'm just now in the searching stage. Thanks CB for the info & recommendations. cheers


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Post subject: Re: DRRI tubes, identifying the culprit
Posted: Thu Aug 04, 2011 8:07 am
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So here's the update. It turns out your initial suspicion was right in part Shimi. The v2 was the main problem. So I did according to the article & I swapped the crappy tube w/the v5 tube. Turns out that was also problematic. It gave that "glassy" sound as it's known by. So I swapped that one w/the v4. It seems OK for now. Actually I can tell the 2 different characters of the channels much more. But 2 lousy tubes? I'll certainly need to get spares now, seeing there's no more options. The project took a couple of hours, thanks to you guys. It would've taken me a lot longer just to find the info otherwise. cheers :D


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Post subject: Re: DRRI tubes, identifying the culprit
Posted: Thu Aug 04, 2011 2:03 pm
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Indeed, these guys are great in giving accurate info.

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Post subject: Re: DRRI tubes, identifying the culprit
Posted: Thu Aug 04, 2011 3:16 pm
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I would think it's V2 as well. I would swap V1 for V2 and see what happens. I would go ahead and put in new tubes anyway in the amp.They usually put the cheapest tubes in that work long enough to pass the warranty period. And they usually don't sound the best. Myself i have been fond on the Tungsol reissue 12ax7 for modern amps


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Post subject: Re: DRRI tubes, identifying the culprit
Posted: Thu Aug 04, 2011 7:32 pm
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joncarr1979 wrote:
I would think it's V2 as well. I would swap V1 for V2 and see what happens. I would go ahead and put in new tubes anyway in the amp.They usually put the cheapest tubes in that work long enough to pass the warranty period. And they usually don't sound the best. Myself i have been fond on the Tungsol reissue 12ax7 for modern amps

It was the v2. That tube is now in the v5 position. & the tube that was originally in v5, is now in v4. A bit confusing. :) I didn't just get rid of the background artifacts, the amps tone also improved. I can imagine the difference w/some good tubes. Tungsols are definitely on my short list, along w/JJs, TAD, Mullard. ATM I'm considering swapping out the whole set & keeping these as temporary replacements.


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Post subject: Re: DRRI tubes, identifying the culprit
Posted: Fri Aug 05, 2011 5:55 am
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mojjett wrote:
joncarr1979 wrote:
I would think it's V2 as well. I would swap V1 for V2 and see what happens. I would go ahead and put in new tubes anyway in the amp.They usually put the cheapest tubes in that work long enough to pass the warranty period. And they usually don't sound the best. Myself i have been fond on the Tungsol reissue 12ax7 for modern amps

It was the v2. That tube is now in the v5 position. & the tube that was originally in v5, is now in v4. A bit confusing. :) I didn't just get rid of the background artifacts, the amps tone also improved. I can imagine the difference w/some good tubes. Tungsols are definitely on my short list, along w/JJs, TAD, Mullard. ATM I'm considering swapping out the whole set & keeping these as temporary replacements.

V5 is a good spot for a noisy tube,as long as the tube works it's fine in that spot


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