Very Excited!

RipVanWinkle · 09-02-2010, 04:28 PM

So, I've been pretty unhappy with the tone of my HRDlx for some time. I got it sometime after I joined CGR...so like, late 2006, early 2007 possibly. The amp itself is a 1996 model (I think the first year of production), and I obviously bought it used.

Fenders are supposed to be known for their cleans, but my amp always seemed to be overdriven, even at lower volumes (like, set at '2' on the clean channel)...and not a nice breakup, but a farty/fizzy sound. The lower the power of the pickup, the less the problem was (or so it seemed).

I've bought and sold 3 or 4 really nice playing guitars because it seemed that they just drove this amp to terrible sounds. I only play the amp about once a week, so I really don't think about it that much. In attempt to fix it, I've done two things.

About 2 years ago, I stumbled upon an antique store that had boxes of old tubes...most were TV tubes, but there were a few 12ax7's and at7's. I bought them, but they didn't seem to help much...They looked pretty rough, but at $5 for 3, it didn't hurt to try.

Last december, I upgraded the speaker to an Emi Cannabis Rex. It did seem to smooth out some of the harshness, but it still sounded fizzy...

I've switched back and fourth from individual pedals and my XT Live. Over the weekend, the problem sounded worse than I had ever heard it. I messed with the output level of my XTL, and even at almost no output, it was still making the fizzy breakup.

So, I decided to take a plunge, I ordered a full set of tubes from Eurotubes. I took them to church (I'm the youth pastor there, so I leave it there), and gave it one last listen. I proceeded to change the power tubes first. I turned the amp back on and the first strum brought happiness to my ears. Much of the fizzy sound was gone. Then I replaced the preamp tubes. I fired it back up, and my ears heard what the Hot Rod Deluxe was supposed to sound like for the first time.

The preamp tubes were EH and whatever old ones I put in there, but I think my main problem was the power amp tubes. They were Tube Amp Doctor (TAD) 6L6GC's...one was brown around the base, and in hindsight, the root of my problem (I think) was a microphonic 6l6. I did some research on that particular TAD, and the reviews are about 5:1, terrible to great. So, thanks for sticking with me through this longish post...I'm very pumped.

I also recently got a 70s Univox LP, and replaced the pickups with a GFS vintage 59 and Dream 90...they sounded excellent to, but thats for the guitar forum

**jamforchrist123** · 09-02-2010, 08:38 PM

Glad you got it fixed man!

I might have to try this, as I took my Blues junior in to get fixed and they couldn't really find anything wrong with it, and it is doing the break up in a gross way at super volume thing that yours is doing. Thanks for the idea!

Stratopastor · 09-03-2010, 11:52 AM

excellent! I'm glad you found the problem. You didn't mention if you checked the bias on the new power tubes.... so for the sake of other readers let me just put in a word of warning - on a lot of amps, changing power tubes without checking the bias can be a gamble.

RipVanWinkle · 09-03-2010, 01:03 PM

Seeing as I have no way of checking, no I haven't...

BUT, I bought a 'kit' of tubes for the HRDlx specifically...they should be within spec already

mikegug · 09-03-2010, 03:16 PM

Tubes have a rating that indicates how soon they will break up and how much clean headroom will be allowed, as I recall. Did you come across that rating? Am I remembering that correctly? I've only bought one set and it was on the box, I know.

Stratopastor · 09-04-2010, 04:34 AM

Rip, there are 2 simple checks you can do in place of an actual bias measurement...

(1) do you like the sound you're getting across the volume range? (you've answered that already)

(2) play the amp hard in subdued lighting while you or someone else can get a clear look at the power tubes. If the plates glow red, the power tubes are running too 'hot' and adjustment will be needed if you want more clean headroom and longer tube life. (The heating element runs up the centre of the tube like its 'spine' - that glows as normal - the flat-metal areas just inside the glass are the plates).

These 2 checks should keep your amp happy but if the power tubes fail, the vendor won't accept that you've adequately checked the bias. And the kit of tubes for the HRDlx probably means they just collected together the amp's full complement of tube types- the tubes weren't individually selected to match some operating characteristic of the HRDlx.

cheers

SP

pooleman0 · 09-04-2010, 10:32 AM

Was your HRDX made in Mexico or the USA?

Major Tom · 09-04-2010, 12:04 PM

Woo Hoo New amp day without putting out the $ for a new amp.

The HR series, unlike other amps, does have a built in bias testing / adjustment circuit with an adjustment pot, but you would need a multimeter to set it. You can get the directions on the web, it is very simple. It is just 2 test points that you put the meter leads on, and then adjust the pot until you get a specific voltage reading. Of course, as usual, since the circuitry of the amp is exposed in that process, and it will be powered up, be extremely careful since there is very high voltage (like close to 500V ) in there. The adjustment range is pretty narrow - If it were mine, and I had no meter, I would maybe open it up and adjust the pot to the center position. Power tubes will work fine within a range of bias, but as was mentioned, if it is too high ( hot ), it will shorten their life.

**Thrash** · 09-04-2010, 12:58 PM

Hey, Jeff, I have a bias probe and a multimeter if you want to use them.

RipVanWinkle · 09-04-2010, 08:06 PM

Quote:

Originally Posted by Major Tom

Woo Hoo New amp day without putting out the $ for a new amp.

The HR series, unlike other amps, does have a built in bias testing / adjustment circuit with an adjustment pot, but you would need a multimeter to set it. You can get the directions on the web, it is very simple. It is just 2 test points that you put the meter leads on, and then adjust the pot until you get a specific voltage reading. Of course, as usual, since the circuitry of the amp is exposed in that process, and it will be powered up, be extremely careful since there is very high voltage (like close to 500V ) in there. The adjustment range is pretty narrow - If it were mine, and I had no meter, I would maybe open it up and adjust the pot to the center position. Power tubes will work fine within a range of bias, but as was mentioned, if it is too high ( hot ), it will shorten their life.

Thanks for the info Tom

Quote:

Originally Posted by Thrash

Hey, Jeff, I have a bias probe and a multimeter if you want to use them.

Sweetness Taylor. Is your multimeter digital or analog?

**Thrash** · 09-05-2010, 12:27 AM

It's just a cheap digital one I got from eurotubes.