Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: billcreller on October 29, 2010, 08:03:01 pm

Title: OT again....
Post by: billcreller on October 29, 2010, 08:03:01 pm
  I just replaced the OT in one of my clones, which I mentioned in an earlier thread, that was identical to it's so-called twin.  The OT I replace  was a cheapie salvaged from an Alamo.  The new OT is a Hammond 1608, so now both amps have that OT.  But, they don't sound identical.  The first one, with the good OT, still sounds just slightly better.  One thing I haven't compared since, is the voltages. Don't know how much effect slightly different voltages will have (?)   Anyway , it sure does sound better, with a smooth full tone.  One other thing though, the first one has a lot of time on the speaker, and the second one has likely less than an hour, since it sounded so bad to begin with.  I may switch speakers, with cords, to check out any difference.
  The speakers are Weber 12" ceramic types, 12F125S.
Title: Re: OT again....
Post by: jojokeo on October 30, 2010, 03:21:33 am
Many things can make small differences, and add up. Even between the same type or model of tubes and speakers.
Title: Re: OT again....
Post by: HotBluePlates on November 01, 2010, 12:21:24 pm
Play time on new speakers could have a significant effect.
Title: Re: OT again....
Post by: billcreller on November 01, 2010, 05:38:13 pm
  Just switching speakers would be easy enough, same cabinets etc.  Think I'll do that......

  If I had a 15 year-old daughter, I could just wire the speaker to her stereo to break it in!! :grin:
Title: Re: OT again....
Post by: Fresh_Start on November 01, 2010, 06:44:59 pm
  Just switching speakers would be easy enough, same cabinets etc.  Think I'll do that......

  If I had a 15 year-old daughter, I could just wire the speaker to her stereo to break it in!! :grin:

I like to wire up my iPod to the input and put "Electric Ladyland" on infinite loop to break in speakers.  If nothing else, I'm paying homage to Jimi, right?

Cheers,

Chip
Title: Re: OT again....
Post by: LooseChange on November 01, 2010, 06:58:19 pm
Speakers and the OT need time to break in.
Title: Re: OT again....
Post by: jojokeo on November 01, 2010, 11:18:51 pm
I've heard of speakers needing break in time for obvious reasons. I've also heard & read about tubes needing time, especially for burn-in on power types. But, this is maybe the 2nd time I've heard of an OT comment about breaking in? Is there an explanation on this?
Title: Re: OT again....
Post by: eleventeen on November 02, 2010, 09:36:57 am
If you don't have an audio generator, there are a few websites that have an application that will let you download an audio oscillator. My own personal favorite guitar player (and pal) Scott Henderson breaks in new speakers by running them at sub-audio freq for a day or so before putting them into use. It's kind of like calesthenics for speakers!
Title: Re: OT again....
Post by: jojokeo on November 02, 2010, 11:17:53 am
A personal friend is a sales rep manager for Celestion USA and he tells me many pro players replace their speakers before going on tour all of the time. They warm them up initially for the first coule of minutes and that's it. They play as loudly and what ever they normally would do. Some don't even do that much and don't give a second thought to it.

Others have said that there's nothing like playing your own amp & guitar w/ thier inherent frequency response to do the job over many hours over playing an ipod or other music. I have a looper pedal and figure that maybe that's the best of all worlds to help do the job of breaking in that cone?  :rolleyes:
Title: Re: OT again....
Post by: billcreller on November 03, 2010, 02:43:29 pm
After finding a difference with a good OT, I'm now gonna replace the OT in my Princeton Reverb clone. I may get a Fender to sound like I want it to yet!!
 I had an offer of 450 bucks for my Fender Vibrosonic Reverb amp. (like a twin, but with one 15 inch spkr)  If it WAS a twin, I wouldn't likely sell it.
  Does $450 sound OK?  Don't have a clue as to what it's worth.  It's in very nice condition, with a cover, original foot switch etc.
Title: Re: OT again....
Post by: Fresh_Start on November 04, 2010, 01:02:53 pm
Bill - I built two nearly identical Princeton Reverb clones, one with Mercury Magnetics iron (customer insisted) and one with Doug's transformers (that one's mine).  Same cabs, same speakers, etc.  If anything I like the tone of Hoffman's better, especially the high end being a little bit sweeter and less ice-picky.  Lots of bass though, but I think that's typical for the amp.

Cheers,

Chip
Title: Re: OT again....
Post by: billcreller on November 04, 2010, 02:16:19 pm
Thanks Chip.  That's good to know. You described it right, "ice-picky" :grin: That may be my next adventure into the unknown :smiley:, another OT swap....
Title: Re: OT again....
Post by: billcreller on November 07, 2010, 07:28:38 pm
Since the National clone amp sounds "reasonable" now, I'm gonna wire the Fender type reverb circuit back into it.  I blamed the crappy tone on the reverb originally.  I seem to do everything twice anyway :smiley:
Title: Re: OT again....
Post by: HotBluePlates on November 08, 2010, 09:14:14 am
I had an offer of 450 bucks for my Fender Vibrosonic Reverb amp. (like a twin, but with one 15 inch spkr)  If it WAS a twin, I wouldn't likely sell it.
  Does $450 sound OK?  Don't have a clue as to what it's worth.  It's in very nice condition, with a cover, original foot switch etc.

Who did the offer come from? How motivated are you to get rid of it?

I'd think you could get double that price from someone who would actually use it. But if the offer came from someone that is planning to resell it (dealer, pawn shop owner, eBay speculator), then a half-price offer makes sense.

These are not widely-loved amps. But I have recorded a band playing through one in the past, because it is a Twin Reverb with a 15" speaker. People who would gig at medium-size clubs, needing a clean sound or clean reproduction of effects for "Top-40" (that category probably doesn't exist anymore) would readily see the value of this amp. I knew someone who played in a cover band during the 70's and 80's that needed to be able to play every song on the radio; his gigging amp was a silverface Twin Reverb for nearly 25 years.

It's not a top-dollar vintage amp, because it is not "collectable". don't let that translate in "no-value". You just need the right buyer and the right situation.
Title: Re: OT again....
Post by: FYL on November 08, 2010, 01:08:13 pm
Quote
Does $450 sound OK?  Don't have a clue as to what it's worth.  It's in very nice condition, with a cover, original foot switch etc.

Average eBay price is $750 or so. Check http://www.ampwares.com/amp.asp?id=120

 
Title: Re: OT again....
Post by: billcreller on November 09, 2010, 10:00:25 am
Thanks for the price info.  Selling it locally is worth something also, to avoid the hassle of shipping an 8o+ lb crate etc.  We'll see how it shakes out......