SPL Reducer

kswilson89

Anyone have any experience with the SPL Reducer? I'm looking for an attenuator and considering this amongst the Weber MiniMass 50, Dr. Z Brake Lite and the Rivera Rockcrusher Mini.

clarkefan

Search for a photo of the guts of one of those before you jump.  Even at retail about £40 total in resistors and an L-pad.  

Not saying they sound shit but there is nothing clever in there that warrants the price that you couldn't knock up yourself.

I've read some of the hype on TGP and it's a bit surprising to say the least.

kswilson89

Cheers clarkefan, I've often wondered that about attenuators... Seeing the guts of the brake lite made me wonder why they cost so much.

djspecialist

Bump.  I'm interested in any hands-on comparisons.  The innards do indeed look similar to a Jettenuator, but the price is ... quite different.

ICBM

clarkefan said:

Search for a photo of the guts of one of those before you jump.  Even at retail about £40 total in resistors and an L-pad.  

Not saying they sound shit but there is nothing clever in there that warrants the price that you couldn't knock up yourself.

I've read some of the hype on TGP and it's a bit surprising to say the least.

I missed this thread earlier, but this is actually quite funny. The TGP hype doesn't surprise me in the least, they're like that with anything.

Here's what it looks like inside...

https://medias.audiofanzine.com/images/normal/spl-reducer-353160.jpg

Even ignoring how little there is in there, I can see three potentially dangerous (to your amp) construction flaws:

No shakeproof washers on the jacks - this seems to be standard practice on 'boutique' pedals, but it's more serious here because if the jacks work loose it could then break the ground connection. On a pedal that will just stop it working, but in a speaker circuit it will leave the amp with no load.

Really crap thin solid-core ground wire connecting the jacks. Not only will this easily break if one of the jacks comes loose, it looks like part of it (uninsulated) runs across the other terminal of one of the jacks. If it either shorts or breaks, this is potentially not good news for your output valves or transformer.

Two of the resistors appear to be very poorly soldered together (top centre of the pic). The joint should have a piece of wire wrapped through both loops, not the two simply soldered together. OK it's unlikely they'll move because they're both bolted to the heatsink, but heating/cooling stress over time could potentially crack it. Some of the other joints appear to be tacked on and not the wire properly fitted through the loop as well.

And all this for over £300?

ecc83

For that sort of money I would expect the load resistors to be mounted on a separate heat since so that the case stays cooler. 

Soldering? Each joint should IMO be sleeved, either silicone rubber (Hellerman) or shrink, belts AND braces you see and yes, stranded wire.

I have never like those 'pressed tin' style jacks, good quality all plastic jobs for me that do not rely on the chassis for a return. In fact the signal ground should, IMO be isolated from the case, maybe a 100nF to tie it at RF? If the case touches other chassis you could get a loud hum loop.

Dave.

ICBM

ecc83 said:

I have never like those 'pressed tin' style jacks

The proper Switchcraft ones of these are excellent, and the Neutrik near-copies aren't bad - don't be put off by the nameless far-east poor-quality knock-offs you've come across hundreds of...

Many people seem to have an inherent suspicion of 'plastic jacks', but actually the proper Cliff/Re-An type are excellent. The brittle ones with the enclosed box inside are crap though.

ecc83 said:

good quality all plastic jobs for me that do not rely on the chassis for a return.

I agree - although here it looks like the chassis isn't actually completing the ground path except as a backup in case the solid-core wire snaps! Everything else is connected to the jack grounds by wires, not via the chassis - but those wires are fragile enough that it's quite a risk.

ecc83 said:

In fact the signal ground should, IMO be isolated from the case, maybe a 100nF to tie it at RF? If the case touches other chassis you could get a loud hum loop.

Agreed.