daddyelmis

Myles: Help clear something up, perfesser! I had always understood that if you take a tube amp designed to see an 8ohm speaker load, the risk of blowing the amp was greater with, say, a 2 ohm load and that running a 16 ohm load would not hurt the amp, but would reduce power and affect tone. I've read other places that it precisely the opposite of that (higher ohm load blows the tranny). I understand that we're talking nominal values here, and that some amps (Fenders?) can handle a wider range of mismatch "up and down." Your thoughts?

Myles: My keyboard player's brother (who lives in Australia) bought a Gibson Goldtone (30rvs - the stereo amp combo version) on eBay. The seller did a major busch-league job on packing, and UPS did "bowling for dollars" with it. Long story short, all the tube were smashed (yes, they were left in the sockets for shipping). My key player is handling repairs through a local tech. For retubing this amp, any specific recommendations? It has 2 separate EL84 based amplifiers for stereo operation. I don't know what Gibson uses OEM. I offered my personal thoughts to the owner based on my experience with EL84 amps, and I'd love to get your input as I've never heard or played this amp. Thanks

Myles: Wanted to pass on my recent great experience with Bob Pletka at Eurotubes. Went to him based on your review at amp blueprinting, and it was a great tip. Bob supplied a set of tubes (pre and pwr) for my Pro Jr. to get a bit more clean headroom, and a balanced 12ax7 for the phase inverter -- the set really put that amp in my "sweet spot" with vol at 4-5 and tone at 6-7, and took out some of the "bite" that I perceived in the amp. Bob was great to deal with, and quick to ship. Thought you oughta know.

I'll dig the stock EL84's out of my gig bag and switch them -- my guess was that it was them, but never hurts to ask someone smarter than me (which, come to think of it, includes my 4 year old daughter). Thanks, Myles.

Myles: Update on the Marshall-- the problem is not consistent (or, rather, it's intermittent). Seems like when I powered down, waited a bit, then went through the normal start up (power, wait a minute, standby off) it was fine.

Myles: Your thoughts, please. Marshall DSL201 with JJ EL84's and JAN/Philips 12ax7's. Just today, I've lost virtually all of the clean headroom on the clean channel. I typically dime the master volume to push the power tubes and keep the clean volume at 3-5 so it just at breakup. I also use a Weber Mass attenuator. Today, turned on main power, let it warm for a couple minutes, turned off the standby and with the above settings it was distorted significantly in a more "fizzy" way. Not unpleasing, but not good and certainly not my normal sound. The EL84's and 12ax7's were put in service about 2 years ago -- but this amp doesn't see a lot of action and since I got the Bassman a year ago it hasn't seen much at all. Over the last month I've started using it again. You think bad pwr or pre tubes? Something worse? Many thanks.

Myles: I haven't seen much (any?) info on these Smicz Amplification TADs devices -- 6AK6 tube adaptors that claim to lower output by a 10:1 ratio (50 watt amp goes to 5 watt) without damage. These would seem to be a reasonable alternative to lugging around an attenuator, or for multiple amps. Do you have any experience with these things? Thanks, as always.

daddyelmis ............. The biggest issue with your RI Bassman is not the board, it is that they come stock with a 12AX7 in V1 rather than the original 12AY7, and a solid state rectifier which is thankfully in a socket, so a 5AR4 can be used. This is the first step in the right direction, to change these two things ... fast and cheap. As far as PTP vs PCB, I have a lot of info on my website in my tech tips, some great stuff written by Andy Marshall from THD. Thanks, Myles, I'll check out the web info. Based on your earlier advice I already made the tube switches for V1 and the rectifier.

Myles . . . looking for your opinion on aftermarket point-to-point boards for reissues (in my case, a 59 Bassman RI). On the one hand, companies got away from ptp to avoid the errors introduced by having a roomfull of different schmoes hand soldering 100's of connections. In addition, my logical mind tells me that electrons flowing through the "same" circuit should behave the same, whether it's traces and surface mount components or ptp. On the other hand, you'd think ptp boards were the Holy Grail to see their prices and to hear folks talk about them. I want to get a bias pot installed on the Bassman RI, and I'm thinking that I might just spring for the PTP while I'm at it (I've been emailing the guys at ceriatone about a 5F6-A board). Whaddya think? Hype? Reality? More G.A.S.??? Your opinion is, as always, highly valued.

Myles: Can bridging inputs hurt an amp? I've got a 59 Bassman RI and some guy was talking about running an a/b box with a to Normal 1, "b" to Bright 1, then using a patch cord to bridge Normal 2 and Bright 2. Other folks suggest bridging the two inputs with a patch cord. Possible damage doing this? Does it really add anything (obviously I have not tried this yet for fear of "releasing the smoke" from my amp, which we all know is how amps work, 'cause if you let that smoke out, everything stops working). Thanks

Look on my website, as there are amp techs there which I recommend. Okay, dumb question, but what would be key questions and answers to ask a would-be amp tech before letting him/her do surgery on your amp? I've got a Bassman RI that I want to have a bias pot installed in, and there are no "full time" amp techs in my town (at least none obvious). Asking local musicians leads to "I know this guy . . . " So, how would one determine whether the tech knows their stuff?? (BTW, I checked your amp tech section on the off hand there would be a list for NC, but no luck).

Myles: Bought a 59 Bassman Reissue and love it. Want to replace the solid state rectifier with tube, and from what I've read you can "go downward" on rectifier tubes . . . GZ34/5AR4 to 5U4 or 5y3. I this correct? My understanding is that the lower your go, the less load put on the power tranny. The Bassman RI is spec'd for 5AR4 or 5U4, but can I go lower (the goal is to reduce the output power a bit for club play). Ultimately, I'll likely work a Hotplate or Weber MASS into this amp, but I want to go to a tube rectifier anyway and thought this might be one step in the right direction. Also, have you ever tried an attenuator on this amp (I note that the speakers are hardwired rather than connected with a 1/4" connector). Thanks.

Okay, we all know that putting a lower impedence speaker load on your amp than what it is rated for (ie, 4 ohm speaker load on an amp rated for 8 ohm) is a good way to blow your amp because the amp runs harder without a proper load. What about the opposite? If you run a 16 ohm speaker on an amp rated for 8 ohms, is there danger to the amp or just a loss of power? Inquiring minds want to know.

Okay, this is probably a dumb question, but can anyone tell me the difference between a Fender Vibroverb and a Vibrolux? I'm looking at these amps and cannot discern the difference. The 'Verb has a "SRV used it" mystique, which is about all I can figure out as the difference -- and which doesn't really matter to me because if I sounded like SRV I could quit my day job and buy both amps! Thanks for any clarification.

Myles: I greatly enjoy, and very much appreciate, your input on the Guitar Forum over at Music Player.com. I'd like your opinion on my pending choice of attenuators . . . THD Hot Plate vs Alesandro Muzzle. I'm playing a wide variety of cover material that requires a pretty broad spectrum of tones. I presently play through a Marshall DSL201 with 12AX7WA Philips-JAN and JJ/Tesla EL84s. I think for the money this is a fine amp whose output can be driven to get the power tubes cranking without killing people. I run a Digitech 2101 in the loop for digital effects and rely on a Fulltone Fulldrive 2 for front end overdrive when I need it. However, even at 20w this amp is too loud on many occasions , hence my look into attenuators. I always mic the cabinet to put the guitar into the FOH mix, so the real issue is stage volume and pissing off my keyboard player. I do love using the guitar volume and pick attack to control distortion, and with the Fulldrive going into "bigger" distortion is just a step away. Based on everything I can read, both the THD Hot Plate and the Alessandro are good units, the Hot Plate being a bit more "feature rich." Do you have an opinion on these two units. Is there any risk in buying a used unit (i.e., is there a "life" aspect to these units, and can they themselves be damaged if the prior owner mismatched impedence)? As always, thanks for your input and continued support!