It is currently Mon Mar 16, 2020 10:06 pm

All times are UTC - 7 hours



Post new topic Reply to topic  [ 50 posts ]  Go to page Previous  1, 2, 3, 4  Next
Go to page Previous  1, 2, 3, 4  Next
Author Message
Post subject: Re: Excelsior is still surprising me.
Posted: Sun Feb 02, 2014 12:27 am
Offline
Rock Icon
Rock Icon
User avatar

Joined: Wed Mar 31, 2010 12:48 am
Posts: 26417
Location: Tombstone Territory
IM4Tone wrote:
I must say though, I don't favor the idea of impedance mismatch, especially on the lower cost amps who's OT may not be the most robust.


He'll find out......later or sooner.

:wink:

Arjay

_________________
"Here's why reliability is job one: A great sounding amp that breaks down goes from being a favorite piece of gear to a useless piece of crap in less time than it takes to read this sentence." -- BRUCE ZINKY


Top
Profile
Fender Play Winter Sale 2020
Post subject: Re: Excelsior is still surprising me.
Posted: Sun Feb 02, 2014 6:20 am
Offline
Rock Icon
Rock Icon
User avatar

Joined: Tue Jun 29, 2010 1:20 pm
Posts: 9640
Location: Indiana
IM4Tone wrote:
...I must say though, I don't favor the idea of impedance mismatch, especially on the lower cost amps who's OT may not be the most robust.


What is it about putting less power through the OT with the impedance mismatch that you don't favor? In this case the OT, PT, and tubes will run cooler and all will be less stressed than when running at full power with a "matched" impedance. This type of impedance mismatch is no worse than wearing mismatched socks. :wink:

_________________
---> "The amp should be SWITCHED OFF AND UNPLUGGED before you do this!" <---

Por favor, disculpe mi español, no se llega a la práctica con mucha frecuencia.


Top
Profile
Post subject: Re: Excelsior is still surprising me.
Posted: Sun Feb 02, 2014 8:32 am
Offline
Hobbyist
Hobbyist

Joined: Mon Jan 06, 2014 3:16 pm
Posts: 15
A couple people have asked BillM this same question and he has responded "The 16 ohm speaker will work and won’t hurt anything. It will not reduce loudness unless it is a very inefficient speaker."
http://billmaudio.com/wp/?page_id=1203&cpage

_________________
1980 Fender Lead II (modified), 1994 Fender Blues Deluxe, 1980's Maya Les Paul copy, 1976 Yamaki acoustic with LR Baggs Element PU


Top
Profile
Post subject: Re: Excelsior is still surprising me.
Posted: Sun Feb 02, 2014 9:38 am
Offline
Rock Icon
Rock Icon
User avatar

Joined: Wed Mar 31, 2010 12:48 am
Posts: 26417
Location: Tombstone Territory
With all due respect, BillM hasn't pushed one of these amps for hours on end at full rated power using a mismatched impedance load. And if/when your amp takes a dump because of it, he won't be paying for the repairs......

You will.

Arjay

_________________
"Here's why reliability is job one: A great sounding amp that breaks down goes from being a favorite piece of gear to a useless piece of crap in less time than it takes to read this sentence." -- BRUCE ZINKY


Top
Profile
Post subject: Re: Excelsior is still surprising me.
Posted: Sun Feb 02, 2014 10:07 am
Offline
Hobbyist
Hobbyist

Joined: Mon Jan 06, 2014 3:16 pm
Posts: 15
True that. I just put it in last night. No noticeable volume loss, perhaps even more. I may get the 8 ohm Legend in time. Don't know just yet. More consultation from expert tech's first.

_________________
1980 Fender Lead II (modified), 1994 Fender Blues Deluxe, 1980's Maya Les Paul copy, 1976 Yamaki acoustic with LR Baggs Element PU


Top
Profile
Post subject: Re: Excelsior is still surprising me.
Posted: Sun Feb 02, 2014 12:09 pm
Offline
Rock Icon
Rock Icon
User avatar

Joined: Wed Mar 31, 2010 12:48 am
Posts: 26417
Location: Tombstone Territory
The Emi Legend would, I suspect, be an excellent option. Superior even to the Blue Marvel.

Arjay

_________________
"Here's why reliability is job one: A great sounding amp that breaks down goes from being a favorite piece of gear to a useless piece of crap in less time than it takes to read this sentence." -- BRUCE ZINKY


Top
Profile
Post subject: Re: Excelsior is still surprising me.
Posted: Sun Feb 02, 2014 12:16 pm
Offline
Professional Musician
Professional Musician
User avatar

Joined: Fri Nov 09, 2007 7:46 am
Posts: 1019
Location: State of Confusion
shimmilou wrote:
IM4Tone wrote:
...I must say though, I don't favor the idea of impedance mismatch, especially on the lower cost amps who's OT may not be the most robust.


What is it about putting less power through the OT with the impedance mismatch that you don't favor? In this case the OT, PT, and tubes will run cooler and all will be less stressed than when running at full power with a "matched" impedance. This type of impedance mismatch is no worse than wearing mismatched socks. :wink:

Tell me why manfacturers like Fender (referring to models with single tap OT's) will OK running 4 ohm total load (in their manuals) for an 8 ohm designed OT, but warn against a 16 ohm load. (DRRI and SS22 as two examples...correct me if I'm wrong about these as far as single tap OT's).

We've discussed this before and I know your opinion differs, but I had received an email from Fender stating the above (warning against a 16 ohm load on my SS22). I certainly highly respect your technical knowledge on tube amps...more than mine....but I will follow Fender's advice as the manufacturer.

And BTW, I NEVER wear mismatched socks (intentionally) :lol:

_________________
The quintessential sound of 60/70's R&R:
Fender Tube Amps
Gibson Guitars


Top
Profile
Post subject: Re: Excelsior is still surprising me.
Posted: Sun Feb 02, 2014 2:56 pm
Offline
Rock Icon
Rock Icon
User avatar

Joined: Tue Jun 29, 2010 1:20 pm
Posts: 9640
Location: Indiana
For the same reason that people here fear using an impedance mismatch, they really don't fully understand the electronic principles involved, and fear of the unknown is very powerful. Can't blame people for thinking that they are playing it safe.

Tell me why MB states that twice the speaker impedance is a safe mismatch. Tell me why Carvin points out that you will lose up to half of the amp's power when using a mismatched impedance, with no warning about amp damage. I can tell you that, more than likely, the advice given by Fender about impedance matching that is referred to on this forum, comes from someone who isn't a knowledgeable tech, and is giving what they consider to be correct advice.

I routinely use several 8 ohm amps with 16 ohm speaker loads, and have for years, with zero problems. And yes, I've played them for hours on end, cranked. Many times, I prefer the sound of a 16 ohm amp with an 8 ohm speaker. The only tube amp that I've ever had a major problem with was an Eglayer, twice, while using a "matched" impedance.

Based on my experience and education in electronics and service, close to thirty years, and my experience using and servicing tube amps, close to 20 years, I am fully confident that an impedance mismatch within a 2 to 1 ratio either way, will do no harm to a tube amp.

_________________
---> "The amp should be SWITCHED OFF AND UNPLUGGED before you do this!" <---

Por favor, disculpe mi español, no se llega a la práctica con mucha frecuencia.


Top
Profile
Post subject: Re: Excelsior is still surprising me.
Posted: Sun Feb 02, 2014 6:28 pm
Offline
Rock Star
Rock Star
User avatar

Joined: Sat Jul 03, 2010 2:18 pm
Posts: 6544
IM4Tone wrote:
shimmilou wrote:
IM4Tone wrote:
...I must say though, I don't favor the idea of impedance mismatch, especially on the lower cost amps who's OT may not be the most robust.


Tell me why manfacturers like Fender (referring to models with single tap OT's) will OK running 4 ohm total load (in their manuals) for an 8 ohm designed OT, but warn against a 16 ohm load. (DRRI and SS22 as two examples...correct me if I'm wrong about these as far as single tap OT's).

And BTW, I NEVER wear mismatched socks (intentionally) :lol:



I think that this fear of 16-ohm load is worse than 4-ohm load on a 8-ohm tap comes from the idea that infinite ohm is much worse than zero ohm load. Yes, greater impedance load may cause the primary side to saturate sooner. But, this is at extremes in impedance, not usually seen in a two-time increase. Unless, the output tranny (OPT) is of very, very marginal design.

You'd prolly see this saturation issue more in cheap single-ended guitar amps. That often use marginal OPT's. Maybe, one reason why some folks like 8-ohm or 16-ohm loads off Champ amps. The saturation, overloaded sound comes on much sooner, than with the OEM 4-ohm speaker.

As for socks, be a thrillseeker! One red and one white argyle! :lol: :lol:


Top
Profile
Post subject: Re: Excelsior is still surprising me.
Posted: Mon Feb 03, 2014 5:49 am
Offline
Rock Icon
Rock Icon
User avatar

Joined: Tue Jun 29, 2010 1:20 pm
Posts: 9640
Location: Indiana
Yes, at some point, too high an impedance, somewhere approaching an open circuit, is worse for a tube amp than too low an impedance. At which point the impedance becomes too high isn't really known, but twice or half is well within a perfectly safe range. Note that a shorting output jack is used on many tube amps to protect the amp in the case of no speaker plugged in. Impedance rating is a nominal value anyway, as impedance varies with frequency, so the impedance is not always "matched" when playing.

Just one thread on this forum about a blown OT might add a little validity to all of the worry. :wink:

BTW, the quote above is messed up, my user name appears for a quote by someone else. :lol:

_________________
---> "The amp should be SWITCHED OFF AND UNPLUGGED before you do this!" <---

Por favor, disculpe mi español, no se llega a la práctica con mucha frecuencia.


Top
Profile
Post subject: Re: Excelsior is still surprising me.
Posted: Tue Feb 04, 2014 7:41 am
Offline
Hobbyist
Hobbyist

Joined: Mon Jan 06, 2014 3:16 pm
Posts: 15
Every day after work I plug into this little gem and I have not lost my stoke for it. This is one special little rig. Actually think it's better than my Blues Deluxe! Still running original valves too.

_________________
1980 Fender Lead II (modified), 1994 Fender Blues Deluxe, 1980's Maya Les Paul copy, 1976 Yamaki acoustic with LR Baggs Element PU


Top
Profile
Post subject: Re: Excelsior is still surprising me.
Posted: Tue Feb 04, 2014 5:13 pm
Offline
Aspiring Musician
Aspiring Musician
User avatar

Joined: Fri Feb 19, 2010 4:55 pm
Posts: 723
shimmilou, After years of being told by people to "match the impedance" I was very surprised to read your comments, it sounded like something to investigate. So went to my amps manual and what do I find?

"Speaker Impedance has a large sonic effect on the sounds as the 16. MARK V power section is switched between its’ three different Modes. We prefer a matching 8 Ohm speaker load connected to the 8 Ohm SPEAKER OUTPUT for the most balanced sound and overall performance in all 3 Channels. However, the Simul-Class™ Output Section is a mysterious animal and will produce some interesting and musical results when different loads are applied. One favorite is connecting the 8 Ohm speaker load to the 4 Ohm SPEAKER OUTPUT when using the 45 Watt (Half Power) setting. Feel free to experiment with different load combinations. You can’t hurt your amplifier and you may discover an impedance scenario that, though is a technical “mismatch”, produces a unique response that fits your needs. The only penalty might be that your power tubes can wear a bit faster with certain load conditions, usually with mismatches in the low direction (4 Ohm load on the 8 Ohm OUTPUT)."

I'm plugging my 8ohm extension cab into the 4ohm cab next time just to see what happens :)

Cheers!

_________________
My Rig: Guitar into Pedals then into Amps and out into Speakers.


Top
Profile
Post subject: Re: Excelsior is still surprising me.
Posted: Tue Feb 04, 2014 6:57 pm
Offline
Rock Icon
Rock Icon
User avatar

Joined: Tue Jun 29, 2010 1:20 pm
Posts: 9640
Location: Indiana
Yep. :wink:

I routinely use my amps with mismatched impedance, never venturing outside the 2 to 1 ratio (safe mismatch). The amps sound great cranked, no smoke, no fire, no tube problems, just awesome tone. At GC, I tried a 4 ohm amp with a 16 ohm speaker once, briefly, and it didn't blow up either, although I felt that this was too much of a mismatch. I have used my HRDlx for many, many years with whatever speaker cab happened to be where I was playing, and many were 16 ohm cabs, while the amp is 8 ohm or 4 ohm, zero problems. Probably my favorite for some time has been my MB 8 ohm out with a 4 ohm Fender 2x12 with V30s, zero problems. Recently, I have been using the same MB amp, 8 ohm out with a 16 ohm cab, zero problems. I have been putting my money where my mouth is, using my own amps like this, cranked, without hesitation, zero problems. 8)

Impedance matching in a tube amp has nothing to do with protecting anything in the amp, it has to do with getting the most power from the amp.. Getting the most power from an amp doesn't always produce the best sound.

Despite the repeated warnings, all based on incorrect assumption, not one of the naysayers has tried a safe mismatch and blown their amp. :wink:

_________________
---> "The amp should be SWITCHED OFF AND UNPLUGGED before you do this!" <---

Por favor, disculpe mi español, no se llega a la práctica con mucha frecuencia.


Top
Profile
Post subject: Re: Excelsior is still surprising me.
Posted: Tue Feb 04, 2014 7:12 pm
Offline
Rock Icon
Rock Icon
User avatar

Joined: Tue Jun 29, 2010 1:20 pm
Posts: 9640
Location: Indiana
This reminds me of an unusual situation that happened one night. A friend and I were jamming at my place, I used a BJr, and he used a HRDlx. We had swapped several speaker cabinets around on both amps, trying to find a good combination (cables all over the place), and when we found the sound that we liked, we jammed for nearly two hours non-stop, took a break and jammed some more. At the end of the night I discovered that I had plugged the output of the BJr into one of the outputs of the HRDlx, and the other output of the HRDlx was plugged into a 1x12, 8 ohm cab, and had been that way the whole time. I don't even know how to figure out that impedance situation. An 8 ohm BJr, plugged into the 4 ohm tap of the HRDlx, using a single 8 ohm speaker for both amps. :shock: Even more surprising was that the sound was terrific. :o

_________________
---> "The amp should be SWITCHED OFF AND UNPLUGGED before you do this!" <---

Por favor, disculpe mi español, no se llega a la práctica con mucha frecuencia.


Top
Profile
Post subject: Re: Excelsior is still surprising me.
Posted: Tue Feb 04, 2014 7:28 pm
Offline
Aspiring Musician
Aspiring Musician
User avatar

Joined: Fri Feb 19, 2010 4:55 pm
Posts: 723
How did your amp even make a sound if it was plugged into the output of another amp?!?!

_________________
My Rig: Guitar into Pedals then into Amps and out into Speakers.


Top
Profile
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 50 posts ]  Go to page Previous  1, 2, 3, 4  Next
Go to page Previous  1, 2, 3, 4  Next

All times are UTC - 7 hours

Fender Play Winter Sale 2020

Who is online

Users browsing this forum: Google [Bot] and 2 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum

Search for:
Jump to: