Hot Rod Deluxe. Fried Resistors... Coulda had a...

[Ericwest53]

Well I did it. After retubing and Blue Dogging a new HRDlx I went out a few times and played it REALLY LOUD at gigs.

Stupid me..

I played it non miked at a "jam", drive channel, full master drive at 5 or so for a couple hours. It kept up pretty good to the PA, drums, and other instruments.

Then..

It snapped and popped, buzzed, and wacked out...Cooled down and did it again. Changed the tubes back. Same thing. Eventually it took just turning it on and playing it moderately. XZZZXxxtztztzzzzztzzztzt..

Well, near as I can tell, it's fried some resistors, and they don't resist anymore.

Am shipping it to a friend for some "better resistors", a "bass mod" and possibly moving a couple resistors so they won't get so hot...

Input Needed.

Is it worth putting a fan in the case?

Will upgrading resistors and killing overblown bass with a mod work?

Since I'll be into it for over 700$, I might as well have bought a.....

?

Rivera 45w?

Laney?

Z?

Are ANY of these amps good for cranking 80% power out of or an extended period of time?

Guess I could buy my friend Scott Dixon's Matchless Chieftain for three grand....

Thanks for any input.

BTW, my Blues JR seems to take punishment better with the same Weber BD and cleaner preamp tube..



EJL

 

[dadm]

Iv'e been waiting for somebody to answer on this one but no one called. Sure you did,t smoke your speaker or something? tube amps don't like that very much. I got a HRDX and it would squeal like a hog with any guitar I got at that setting.

 

[11 Gauge]

What did you retube it with? Did you rebias it?

I've witnessed more than a few failures with the current PCB Fender amps due to subpar power tube swaps...

The most common one - 5881's and too hot of a bias. The B+ on the Hot Rods is really too high for 5881's - put the bias up where it would work with a healthy pair of 6L6's, and the internals just melt.

There are plenty of dodgy 6L6's floating around, as well. I'd NEVER buy GT's for this reason - you don't know what you're getting until you put a mag glass over the tube and check the getters, plates, screens, grids...

I believe that the B+ on the HRDLX is ~420 VDC. This translates to about 33-35 mA for a healthy 6L6. If you're biased at 37 or higher, that could be your problem.

Putting a fan in that amp is like polishing a turd, IMO - sorry. Crappy tube sockets, flimsy PCB, lack of wirewounds on the power tube's screens - you can only offset the heat issue so much.

I've seen the guts of those amps, and yes the resistors can be upgraded, but it'll be a real PITA. Even in the RI's, Fender resorted to wimpy little 1/4 watt resistors for most of the circuitry. Trying to squeeze a good 1/2 watt or higher in the same space is probably going to result in some ripped solder traces.

In Fender's defense, I do think that they put some 2 watt metal oxides (whoopdy doo - an extra $0 .40 per amp!) in for the screens, but what you need are 5 watt wirewounds to make it bulletproof. They really belong right on the sockets, so I can't imagine how you'd get them in that flimsy board without cracking it.

For 700 clams, you should be able to find a SF Fender with less sex appeal (lotsa discussions here about underrated Pro Reverbs lately), but you could make it bulletproof, and maintenance would be a breeze. Guys have been cranking those things up since they first came out, and they just keep going with some TLC.

You'll have to get an assessment from your tech bud on what exactly failed. Be sure to let us know. Lotsa guys rely on those amps for gigs - they have a right to know, IMO.

Those amps also have a test point on them for checking bias, but you're checking the summed voltage drop for the pair, in mV. The voltage drop is negligible (according to many amp experts), so the voltage reading translates into a current reading. HOWEVER - it is the sum of both tubes, so you're looking for 2X the number at the test point. In this case, 33 mA = 33 mV X 2 = 66 mV at the test point. Anything over 70 is gonna be trouble (unless your B+ is a bit lower).

 

[Joe K]

Which brings us to the question that I'd like to have answered...

Do any electrical experts (or others here) know if it is a problem to turn your amp way up and play?

I have a little bet going with a friend. He says that I should not play my old black face amps too loud because I will damage them. I say that if they have new speakers and tubes, I will use the heck of of 'em! What am I risking amp-wise?

 

[11 Gauge]

Which brings us to the question that I'd like to have answered...

Do any electrical experts (or others here) know if it is a problem to turn your amp way up and play?

I have a little bet going with a friend. He says that I should not play my old black face amps too loud because I will damage them. I say that if they have new speakers and tubes, I will use the heck of of 'em! What am I risking amp-wise?

If the design and components are good, you can dime it and play it that way forever. Little tweaks like adding wirewounds where the most stress is incurred can really help, as well as adding a HT fuse.

Most of my amps don't see anything under 6 on the volume dial, and usually I'm closer to 8 or full up. Other than my '67 Champ (which seems to be possessed), all of my amps are fine with this constant cranked usage.

I actually prefer older amps for their bulletproof power transformers. I've yet to have one fail! I actually buy old amps just for the chassis and trannies (at the right price).

I remember getting a Pignose G40V back in the late 90's. I smoked the output tranny with less than 30 hours on the amp! I dropped in a Vibroverb unit and never had a single problem after that (with that part of the amp). You could have put the stock G40V OT in a Princeton and kill it, IMO.

But you're absolutely right. As long as you keep the maintenance up (don't forget filter caps and periodic rebiasing, even if not replacing the power tubes), a solidly designed amp will typically take whatever you can throw at it.

 

[getbent]

I have a 93 blues deluxe eric... I never miked it in my life... I played in a country rock/classic rock band in the 90's and had that thing dimed for most of all third sets and party events outdoors. The problem with those amps is that they can be unreliable which is why the hard core amp guys are not keen on them... and they are a pain to work on ....

As for old amps and not playing with them up... that is crazy talk! it would be like having and old porsche and driving like a granny... I play mostly clean country stuff except for a few tunes... don't think I don't love the sound of a hot (temperature) amp? I crank my tone king and it takes it happily... You gotta play these things!

Sorry about your loss Eric, I'm sure a tech can fix it.... if it is too expensive, you could always buy a kit amp to slide into that enclosure!

 

[11 Gauge]

And for all of you who love your Hot Rods, despite what may happen...

Here is the site for you -

http://studentweb.eku.edu/justin_holton/

This guy LOVES that amp. I'd imagine that he knows more about them than Fender's amp R&D team, at this point...

 

[boris bubbanov]

... if it is too expensive, you could always buy a kit amp to slide into that enclosure!

I think that is the wise move. I want to thank ya'll experts for steering me away from some of these underengineered amps like the HRD.


Bubbanov

 

[11 Gauge]

After perusing the aforementioned website a bit more, I came across a very common scenario with the HRDX's - static, popping, and then a huge loss in volume. It sounds pretty close to what was described here.

This link details this issue:

http://studentweb.eku.edu/justin_holton/plateloads.html

It seems that the weak link in this amp is in many cases a SINGLE DEFECTIVE RESISTOR (R57 on the board) - V3B's plate load resistor, which is 82K, while all of the others are 100K.

A rep at Fender has admitted that the manufacturer of this resistor has supplied a defective part, which is in thousands (maybe more) of these amps. Under stress, the resistor cracks (sometimes internally, and not visible), and you lose some or most of your amp volume, with cracking and popping along the way.

Each preamp tube has 2 plate load resistors, for a total of 6. Even the other 5 chintzy 1/4 watt resistors should be replaced with 1/2 watters while R57 is being replaced.

So, Eric - it just may be a lucky break for you - one resistor to bring it back to life! But while your friend has it apart, he should inspect the wave soldering, replace any other suspect components, and upgrade the cheapo stock jacks, which are another Achilles' heel in this amp. It's all documented in the link(s) that I've provided.

 

[Ericwest53]

Thanks to all.

I really got embarassed at how hard I'd hammered it, and I've got a few other things on my plate to deal with. I swapped V3 with a good used 12AX7 and I have been recording with it, and playing it pretty loud, not TRYING to make it crap like I did before.

So far it is "OK", and it took dozening the Master and diming the "drive" on the OD channel playing a dropped D to crap it before. PLaying it full out on a loud bandstand for a three hour night.

What's going to happen is that My friend IN GA is going to get the amp guts, Mod the Bass, replace ANYthing that won't pass his load or current tests. ALso he says there's a resistor that's in a hot spot that can be moved.

No, the speaker, a Weber BD is fine.

POSSIBLY the ECC83 S that was in it when it crapped got "buzzed" somehow from so much vibration so close to the speaker, and just spazzed...

I'm relatively new to Tube amps, playing pedal steel almost exclusively through Peavey Solid States for probably three thousand gigs, with no more than a Cap replaced, and only one Black Widder speaker after 24 years coming unglued. ( The Session 500 MKIVs stuck the speakers on from the outside with no clamp ring...)

I"m spoiled, but I like tube amps so much that I'm willing to put as much lipstick on as many pigs as I can till I find one that will dance all night....

BTW The "fan" idea doesn't make a lot of sense to me either, but I could see making a little more airflow..

Anyhow. Probably a month before I get it off and back, and in the meantime I'll be gigging with my Bls Jr in stereo with either a Peavey Nashville 112 or it and a Nvl400 through my PodxtLive.

Thanks.



EJL

 

[Dacious]

duplicate post

 

[Dacious]

I would check the soldering on the power tube pins while under the hood. These protrude a little farther then the pins on some of the other components on that board, and I suspect they may not be soldered that well from new.

My bandmates near new BDx stopped working the other week - you could see just by looking they were not soldered well. The heaters cut out on the 6L6s. A reheat and dab of fresh solder and it's boogie-ing again.

My tranny guy - steady, not that sort of tranny guy - also says old amps have no issues with transformers, with the caveat that full-noise use of anything can cause failure. They used to use double-lacquered wire and the wire and lacquer was high-temp.

Today he says they use single-lacquer and any old wire. So now he sees many more rewinds from new amps than he ever saw from old ones when they were up to 3-4 years old. And many of them just 'stop' - no flameouts or showers of sparks or tube failure. It just arcs over a period of time and fails.

The only thing other than sheer abuse or catastrohic failure of a tube that can really kill old transformers is rusted laminates causing flux eddy currents or noises due to bridging the gaps between plates. He's done a couple of rewinds for me where he unwinds by hand, then duplicates the original winding patterm, the owners have not been able to pick the diff.

So old amps - if they are well maintained - no more of a problem with running flat stick and probably less than new amps.

 

[11 Gauge]

They used to use double-lacquered wire and the wire and lacquer was high-temp.

This is what I look for when I'm out fishing for old amp carcasses. Luckily, almost all of them had paper interleave wrapping, so if you can get the endbells off (if it isn't a 'vert mount), you can see how robustly the wire is armored.

On newer ones, if you can actually get a peek at the windings, you'll typically find that you can pull off the coating (I doubt that it's lacquer any more - who knows?) with a fingernail...

By newer, I don't mean the good new stuff by Heyboer, Hammond, MM, et al.

 

[Ericwest53]

Well I got a gig tomorrow night with it, and I'll have a Peavey SS for backup. I'll puch it as hard as I can with the "new" Ax7 in it and see what melts..



EJL

 

[Ericwest53]

Well it died.

Three sets of pretty hard playing in a pretty big venue.

Then, out of the blue:

GGGZZZHHHXXTXTXTtxtxtt..

Twice.

I think rather than scrounge through the local used places, It's narrowed down to between the Clubster 45 ( they say the clean channel's cleaner) and a Pubster45.

Amps going off to my friend in Ga for a bassectomy, and mods that will replace and move the suspect resistors.

Locally I found a Chubster ( 55 I think) for 700$ in 'mint'. That'd be a good deal if it's true, and not too muddy.

I think I'm gonna go plug into it this pm.

Thanks for the responses, past and future.



EJL