Re: [Harp-L] H Dustcap

[MARK BURNESS <markwjburness@xxxxxxxxxxxxxx>]

Hi Dan,

Sure, but all the current, commercial "harp amp" builders still use "guitar" 
(rather than bass/sound reinforcement) speakers...maybe with the addition of the 
softer H dustcaps. Yes, folks do want thick bottom & less feedback, but you 
still need fidelity & detail...after a point it doesn't matter how loud you get 
in dB, if the intelligibillity suffers too much it's still hard to hear what 
you're doing and you're no better off...it's swings & roundabouts.

I have quite a few amps & cabs, apart from using a few Eminence Alpha 10"s 
(PA/Bass speakers) the 4x8" is the only one with speakers that were used in a 
bass amp. Originally they were in a 9x8" Traynor bass cab that a pal bought on a 
whim ...he traded me 4 of the speakers in a parts swap. They're in a pine, open 
backed, 5E7 Bandmaster sized cab right now, I sometimes use this cab in 
conjuction with 10" speakers with more powerful amps. They were originally used 
for bass but they're not that dark, I have even had them hooked up to tube Hi Fi 
and they have plenty of high end.

The other speakers I have for stage use are Eminence 102 Alnico (black 35W 
versions as used in the HarpKings, but the 20W blues are great if you can still 
find some), Fane AX10 Ceramic, Fane AX10A Alnico (I would only use one or two of 
the Fanes in a multispeaker cab due to weight & overkill), Kendrick Blackframe 
10" and an old CTS 10" of unknown origin. So the majority are regular guitar 
speakers. In very bright amps, or I have found in 2x10" (where the speakers do a 
lot of work & distort earlier) that the Eminence Alpha 10" can work fine, but in 
a sympathetic amp, more than one in a multispeaker array can make an amp too 
dark & flat sounding.

When it comes to speakers, there are just too many variables to really have a 
"one-size fits all" solution...sometimes in one amp, a speaker that sounds awful 
in everything else, will be just the ticket! ;-) The amp takes the acoustic 
sound & turns it into volts & amps, the speaker turns the volts and amps back 
into acoustic sound, so the trick is really mating one to the other.

All the cabs I have (apart from an old British 5W combo) are open backed, this 
allows phase cancellation of lower frequencies making them sound rounder & 
fuller...more pleasing to hear on stage/in the room. Closed back cabs do throw 
the sound further but it is beamier, harder...the vast majority of musical 
instrument combo amps are open backed, especially tube amps because the tubes 
need cooling (Traynor did make 2 section closed back cabs, with an open 
compartment under the chassis for tube cooling for some amps like the YGM3). 
Often, closed back cabs were used to get better longevity from speakers.

The 1/3W amp is an "Ampmaker SE5" kit amp that I got in a trade, originally it 
was a 5W EL84 amp but I already have a few 5W amps, live in an apartment, so I 
changed the output transformer and rewired the power tube socket to take a 12AY7 
as a power, tube running both triodes in parallel, single-ended 
operation...toying with the idea of going even smaller & simpler with a single 
12AY7/12AU7/12DW7 to do the job of both preamp & output.

Not playing out much at the minute & have to keep the noise low at home, hence 
why I've been building & tweaking a few very low powered amps. 


Cheers, Mark.




________________________________
From: MARK BURNESS <markwjburness@xxxxxxxxxxxxxx>
To: Dan Hazen <bluesmandan76@xxxxxxxxx>
Sent: Friday, 18 November, 2011 16:07:47
Subject: Re: [Harp-L] H Dustcap


Hi Dan,

Sure, but all the current, commercial "harp amp" builders still use "guitar" 
speakers...maybe with the addition of the softer H dustcaps. Yes, folks do want 
thick bottom & less feedback, but you still need fidelity & detail...after a 
point it doesn't matter how loud you get in dB, if the intelligibillity suffers 
too much it's still hard to hear what you're doing and you're no better 
off...it's swings & roundabouts...this sometimes happens with the Harpking & 
Kendrick TC 35, the front of the note goes when you dial in the special controls 
too far & some folks just can't get on with that.

I have quite a few amps & cabs, apart from using a few Eminence Alpha 10"s 
(PA/Bass speakers) the 4x8" is the only one with speakers that were used in a 
bass amp. Originally they were in a 9x8" Traynor bass cab that a pal bought on a 
whim ...he traded me 4 of the speakers in a parts swap. They're in a pine, open 
backed, 5E7 Bandmaster sized cab right now, I sometimes use this cab in 
conjuction with 10" speakers with more powerful amps. They were originally used 
for bass but they're not that dark, I have even had them hooked up to tube Hi Fi 
and they have plenty of high end.

The other speakers I have for stage use are Eminence 102 Alnico (black 35W 
versions as used in the HarpKings, but the 20W blues are great if you can still 
find some), Fane AX10 Ceramic, Fane AX10A Alnico (I would only use one or two of 
the Fanes in a multispeaker cab due to weight & overkill), Kendrick Blackframe 
10" and an old CTS 10" of unknown origin. So the majority are regular guitar 
speakers. In very bright amps, or I have found in 2x10" (where the speakers do a 
lot of work & distort earlier) that the Eminence Alpha 10" can work fine, but in 
a sympathetic amp more than one in a multispeaker array can make an amp too dark 
& flat sounding.

When it comes to speakers, there are just too many variables to really have a 
"one-size fits all" solution...sometimes in one amp, a speaker that sounds awful 
in everything else, will be just the ticket! ;-) The amp takes the acoustic 
sound & turns it into volts & amps, the speaker turns the volts and amps back 
into acoustic sound, so the trick is really mating one to the other.

All the cabs I have (apart from an old British combo) are open backed, this 
allows phase cancellation of lower frequencies making them sound rounder & 
fuller...more pleasing to hear on stage/in the room. Closed back cabs do throw 
the sound further but it is beamier, harder...the vast majority of musical 
instrument combo amps are open backed, especially tube amps because the tubes 
need cooling (Traynor did make 2 section closed back cabs, with an open 
compartment under the chassis for tube cooling for some amps like the YGM3). 
Often, closed back cabs were used to get better longevity from speakers.

The 1/3W amp is an "Ampmaker SE5" kit amp that I got in a trade, originally was 
a 5W EL84 amp but I already have a few 5W amps, live in an apartment, so I 
changed the output transformer and rewired the power tube socket to take a 12AY7 
as a power, tube running both triodes in parallel, single-ended 
operation...toying with the idea of going even smaller & simpler with a single 
12AY7/12AU7/12DW7 to do the job of both preamp & output.

Not playing out much at the minute & have to keep the noise low at home, hence 
why I've been building & tweaking a few very low powered amps. 


Cheers, Mark.




________________________________
From: Dan Hazen <bluesmandan76@xxxxxxxxx>
To: MARK BURNESS <markwjburness@xxxxxxxxxxxxxx>
Sent: Friday, 18 November, 2011 15:18:24
Subject: Re: [Harp-L] H Dustcap

Yeah, I'm aware of all that. But I think you might have missed the simpler point 
of the post. Harp players tend to want thick bottom end and less feedback. The 
right speaker can accentuate the lower frequencies and help reduce feedback. If 
someone has a feedback prone amp, they can try plugging it into a bass cab, and 
might get decent results.

By "match the wattage"  I of course meant "match the wattage correctly" - which 
is typically double or thereabouts, as in mating a 50 watt amp to a 80 or 100 
watt speaker rating. You don't want to blow your speakers.

As you are doing the sort of thing I was suggesting, using bass speakers, I'd 
think my logic was headed in the right direction. What kind of cabinet is your 
4x8 set up? Big, small, closed back, open back, combo, ported, etc? What is the 
1/3W amp you are using? 









On Fri, Nov 18, 2011 at 3:39 AM, MARK BURNESS <markwjburness@xxxxxxxxxxxxxx> 
wrote:

Dan,
>
>You are adding 2+2 and getting 5 somewhat.
>
>Dustcaps are just one component/factor, you are overlooking SPL (efficiency), 
>resonant frequency, frequency curves, live listening tests etc.
>
>I play a 1/3W amp through a 4x8" cab loaded with bass speakers out of a Traynor 
>cab...the wattage handling of the speakers is many, many magnitudes more than 
>that the amp can produce (the amp produces hundredths of the W the speakers will 
>handle)....there is no loss of articulation. You never match amp wattage to 
>speaker wattage, because tube amps are rated at clean output and are often 
>played beyond their clean W rating, speakers therefore are typically rated for a 
>minimum of twice the tube amp wattage (often you will see speakers with a "tube 
>& "SS" rating the SS rating being more than the tube rating for this reason). In 
>the 50's they used low wattage speakers...because that's pretty well all they 
>had available at a reasonable price, some amps were strangled by tiny output 
>transformers so that they couldn't make a lot of bass, allowing the use of low 
>rated speakers that would outlast the warranty period.
>
>The 4x10" Fender Bassman did not use bass specific speakers.
>
>Bass specific & PA speakers can work very well in some amp cabs used for harp, 
>other times when overused, they can make the tone flat & overly dark (a guitar 
>speaker may be designed to reproduce from 80Hz upwards to 6KHz or 7KHz, bass 
>speakers more often cover the range of 50Hz to 3KHz-4KHz, this has a pronounced 
>effect on high end/detail). It is better to think in terms of specific speaker 
>models rather than focus on largely arbitrary features like dustcaps & 
>"bass/guitar" designations. In a multispeaker array it is obviously possible & 
>often desirable to mix speaker type for a more complex tone.
>
>The size of the dust cap will also be relative to the size of the voice coil, a 
>speaker with a 2" voice coil will obviously have a bigger dustcap than a speaker 
>with a 1" voice coil. More efficient speakers use larger voice coils & have 
>bigger dustcaps than less efficient speakers, irrespective of intended use.
>
>Very efficient speakers with very large voice coils & magnets can be overkill, 
>increasing feedback. Conversely, particularly innefficient speakers (for a given 
>size & voice coil) offer no advantage in reducing feedback & will reduce the 
>volume, kill the tone of your amp.
>
>Speakers are always chosen by builders & designers principly for their tone...it 
>doesn't matter what the manufacturer designed it for, if it sounds good, use it.
>
>
________________________________
From: David Brown <nonidesign@xxxxxxxxx>
>To: Dan Hazen <bluesmandan76@xxxxxxxxx>
>Cc: harp-l@xxxxxxxxxx
>Sent: Thursday, 17 November, 2011 21:16:15
>Subject: Re: [Harp-L] H Dustcap
>
>
>I think you also have to check the ohm rating of the speakers you have in
>the cab to match it to the particular output of the amp.
>
>
>
>
>On Thu, Nov 17, 2011 at 10:49 AM, Dan Hazen <bluesmandan76@xxxxxxxxx> wrote:
>
>> >From what I understand, and based on my correspondence with Weber reps,
>> the
>> H dustcap is simply a larger dustcap (not as big as those on bass speakers,
>> but larger than typical guitar speakers) designed to reduce treble
>> frequencies, thus reducing feedback.
>>
>> For comparison:
>>
>> My Sonny Jr has speakers with large dustcaps.
>>
>> I did a little experiment a few minutes ago... I took my Marshall Class 5,
>> which is far too trebly to use for harmonica, and I plugged it into my 4x10
>> bass cabinet. It did reduce feedback.
>>
>> My Harpgear 2 does not have a large dustcap, but it has a funny looking
>> raised dustcap (like a button or a thick poker chip) and it appears to be
>> doped all around the dustcap, I would guess to give the same
>> treble-reducing effect. I plugged the Harpgear into the bass cab, too, and
>> it didn't really help it much... but I can play the HG2 very loud without
>> feedback... it did however thicken up the sound of the Harpgear, and give a
>> whompier bottom end. (Is 'whompier' even a word?)
>>
>> And then there's my Peavey Pignose. I took the guts of a Pignose Hog 20 and
>> stuck them in a Peavey combo (40 watt Express 112, I think), b/c the
>> Peavey's power section had gone bad, and I hated the Pignose speaker.
>> Worked really well. The Peavey speaker happens to have a huge dustcap,
>> almost 4 inches.
>>
>> I would think that you could tame a particularly feedback prone amp by
>> plugging it into a bass cabinet. The trick would be matching the wattage of
>> the bass cab with that of the amp... bass cabs are usually rated very high,
>> whereas harp amps are usually fairly low watt amps, and if the amp is too
>> low for the speakers, then articulation and sensitivity will suffer... You
>> probably don't want to plug a 5 watt amp into a 400 watt cabinet. HOWEVER,
>> that inefficiency MIGHT be an added help against feedback.... I think. I
>> don't have a billion cabs lying around where I could try every combination,
>> but I think that's the way it would go.
>>
>> I'm actually surprised that more guys aren't doing this sort of thing,
>> using harp/guitar heads with bass cabinets, as it really does give a great
>> thick bottom end to your sound... and after all, the working standard for
>> harp amps is the Bassman, which was, obviously, originally designed as a
>> bass amplifier.
>>
>