While micing an old fender amp recently, I found I had to keep the amp gain
way down to avoid a rather nasty rasp. Does anyone have SPL specs on a 77DX?

My m160 didn't have a problem, but the DX was complaining.

Regards,

Ty Ford



-- Ty Ford's equipment reviews, audio samples, rates and other audiocentric
stuff are at www.tyford.com

On Sun, 28 Nov 2004 15:29:27 -0500, Ty Ford
wrote:

While micing an old fender amp recently, I found I had to keep the amp gain
way down to avoid a rather nasty rasp. Does anyone have SPL specs on a 77DX?

My m160 didn't have a problem, but the DX was complaining.

Regards,

Ty Ford




I was always taught to place a mic such as a 77 slightly off-axis to
avoid burping or damaging the ribbon. Did you try that? It could
also be that your ribbon needs to be re-tensioned or replaced.


http://liondogmusic.com

In article ,
Ty Ford wrote:

While micing an old fender amp recently, I found I had to keep the amp gain
way down to avoid a rather nasty rasp. Does anyone have SPL specs on a 77DX?

My m160 didn't have a problem, but the DX was complaining.

I suspect it's due to a misaligned or stretched ribbon more than an
inherent SPL limitation. The sound you're hearing is the ribbon
scraping on the pole pieces, or maybe there's a tiny iron filing in the
gap causing a rasp with ribbon excursion. This has happened to me with
one of my BK-11s, but it didn't happen on the same amp with another
BK-11.

Ribbons are excursion limited, so the SPL limit is not a constant with
frequency. At the limit, the ribbon rips and you get no more output.
Below that, the field is not linear so you get odd order distortion as
the ribbon travels through a part of the field that's weaker.

The solution? Re-ribbon the mike. You may be able to get away with
using a pantyhose popscreen to reduce some of the excursion caused by
wind from an amp, but it's not a sure fire fix. You might also be able
to physically re-orient the mike if the ribbon is stretched, and maybe
it'll sag between the pole pieces, instead of into one or another.


Best of luck,

Monte McGuire

On Sun, 28 Nov 2004 23:02:35 -0500, Monte McGuire wrote
(in article ):

In article ,
Ty Ford wrote:

While micing an old fender amp recently, I found I had to keep the amp gain
way down to avoid a rather nasty rasp. Does anyone have SPL specs on a 77DX?

My m160 didn't have a problem, but the DX was complaining.

I suspect it's due to a misaligned or stretched ribbon more than an
inherent SPL limitation. The sound you're hearing is the ribbon
scraping on the pole pieces, or maybe there's a tiny iron filing in the
gap causing a rasp with ribbon excursion. This has happened to me with
one of my BK-11s, but it didn't happen on the same amp with another
BK-11.

Ribbons are excursion limited, so the SPL limit is not a constant with
frequency. At the limit, the ribbon rips and you get no more output.
Below that, the field is not linear so you get odd order distortion as
the ribbon travels through a part of the field that's weaker.

The solution? Re-ribbon the mike. You may be able to get away with
using a pantyhose popscreen to reduce some of the excursion caused by
wind from an amp, but it's not a sure fire fix. You might also be able
to physically re-orient the mike if the ribbon is stretched, and maybe
it'll sag between the pole pieces, instead of into one or another.


Best of luck,

Monte McGuire


Thanks all,

I think the culprit was my new mic cabinet. Shelves are too close together
for the 77DX to stand up. It's been lying on its side for 8 months. I'm going
to experiment with lying it on its other side.

From this we learn that those warnings about how to store a ribbon mic MAY
WELL BE TRUE.

Regards,

Ty Ford


-- Ty Ford's equipment reviews, audio samples, rates and other audiocentric
stuff are at www.tyford.com

Ty Ford wrote:

I think the culprit was my new mic cabinet. Shelves are too close together
for the 77DX to stand up. It's been lying on its side for 8 months. I'm going
to experiment with lying it on its other side.

From this we learn that those warnings about how to store a ribbon mic MAY
WELL BE TRUE.

I think you might just have excess gravity up there.

--
ha

It does, indeed, sound like it's time for a new ribbon. The 77DX should be able to handle any
SPL that an M160 can. As for the spec, RCA did not give a max SPL spec for any of their ribbon
mics, but I would estimate it is in the region of 120dB or so.

--
Stephen Sank, Owner & Ribbon Mic Restorer
Talking Dog Transducer Company
http://stephensank.com
5517 Carmelita Drive N.E.
Albuquerque, New Mexico [87111]
505-332-0336
Auth. Nakamichi & McIntosh servicer
Payments preferred through Paypal.com
"hank alrich" wrote in message
. ..
Ty Ford wrote:

I think the culprit was my new mic cabinet. Shelves are too close together
for the 77DX to stand up. It's been lying on its side for 8 months. I'm going
to experiment with lying it on its other side.

From this we learn that those warnings about how to store a ribbon mic MAY
WELL BE TRUE.

I think you might just have excess gravity up there.

--
ha