DSL 5C with 1936 cab

[DavidF]

I just took delivery of a DSL 5C and (with the exception of the absence of a master volume on the 'classic gain' channel) it is fantastic - every bit as good as I had been lead to believe. As good as the built in speaker is, like most small combos with 10" speakers it sounds a bit 'boxy' and compressed, though I had anticipated this. I already have a 1936 2x12 cab and assumed the two would be a perfect match. In terms of sound they are, the little combo sounds like a big combo only much quieter, perfect - just what I set out to achieve! Unfortunately I didn't think to check the respective impedances. The amp has a 16 ohm output whereas the 1936, via the mono input, is 8 ohms. After a bit of googling my conclusion is that the cab will draw twice as much current from the amp as the built in speaker and consequently the amp will run hotter with potentially damaging results to the transformer and output valve.

To come to the point what are my options here? As I see it I can do one of the following;

1. Nothing, it works, but will it actually cause damage? And if so are we talking about a modest reduction in life span of the transformer and/or output valve (which I can live with) or will it be completely f****d within a few days?

2. Stick with the built in speaker - a bit of a shame when I already have the cab.

3. Change the speakers in the cab? A possibility though preferably not as this defeats the object of buying a value-for-money amp.

4. Connect something (what?) between the amp and the cab?

Grateful for any advice/recommendations or accounts of similar experiences, preferably before the amp blows!

[zimlen]

Weber do a product called the Z Matcher (I think) that you could use between the amp and cab to match the impedence. I'm sure there are other similar products out there too that would work.

[surfnorthwest]

Welcome to the Roadhouse Dave,

At 5 watts I highly doubt you will do any damage to the amp. There is always a risk but its unlikely IMO. You could also find someone to trade speakers with, lot of times guys have 8 ohm speakers and they are looking for 16 ohm speakers. Two 8ohm speakers wired in series would give you 16 ohms.

You might find this link helpful

http://www.colomar.com/Shavano/2x12wiring.html

[DavidF]

Thanks Surf!

Good suggestions from yourself and Zimlen - than you both for getting back to me so quickly. I'm inclined to agree that I 'probably' won't blow the amp any time soon though Zimlen's suggestion of the Z Matcher sounds like a sensible idea. Unfortunately I haven't been able to find one for sale, or anything similar, either new or used. This did get me thinking though, my only gripe with the amp itself is that even at the 1 watt setting it is still too loud (I live in an apartment) for me to overdrive the output tube to any significant extent and therefore I cannot exploit the 'classic gain' channel to its full potential. It suddenly dawned on me that an attenuator is probably what I need. So, I've just bought a used THD Hot Plate off eBay at a reasonable price. This hopefully solves both issues as it has a 16 ohm impedance, doesn't care what the impedance of the speaker cab is (so I'm told) and gives me a volume control after the power stage so I can run the amp flat out whilst keeping the volume at a neighbour-friendly level. I hope it lives up to my expectations!

[shaun]

David, what country are you in?
I have 2 Celestion 85 wt 8 ohm speakers from 1989 i may sell soon. They are broken in, but havn't been used for many years. They can be wired up to 16 ohm together.

[dukealexan]

The speakers in the 1936 are 16 ohms each wired in parallel I would open her up and wire them in series for 32 ohms which is safer then 8 ohms. or just disconnect one of them for 16 ohms.

[DavidF]

I'm gonna see how it goes with the attenuator, that should sort out both issues - impedance and volume. It did occur to me to wire them in series but 32 ohms is still not ideal. I would prefer to leave the cab un-modified unless it becomes absolutely necessary. Thanks for the suggestions though.