diff --git a/src/PortAudio.jl b/src/PortAudio.jl
index eedee50..48a21db 100644
--- a/src/PortAudio.jl
+++ b/src/PortAudio.jl
@@ -89,9 +89,8 @@ immutable CallbackInfo{T}
     synced::Bool
 end
 
-# paramaterized on the sample type and sampling rate type
-type PortAudioStream{T, U}
-    samplerate::U
+type PortAudioStream{T}
+    samplerate::Float64
     blocksize::Int
     stream::PaStream
     sink # untyped because of circular type definition
@@ -112,8 +111,8 @@ type PortAudioStream{T, U}
             Ref(Pa_StreamParameters(outdev.idx, outchans, type_to_fmt[T], 0.0, C_NULL))
         this = new(sr, blocksize, C_NULL)
         finalizer(this, close)
-        this.sink = PortAudioSink{T, U}(outdev.name, this, outchans, blocksize*2)
-        this.source = PortAudioSource{T, U}(indev.name, this, inchans, blocksize*2)
+        this.sink = PortAudioSink{T}(outdev.name, this, outchans, blocksize*2)
+        this.source = PortAudioSource{T}(indev.name, this, inchans, blocksize*2)
         if synced && inchans > 0 && outchans > 0
             # we've got a synchronized duplex stream. initialize with the output buffer full
             write(this.sink, SampleBuf(zeros(T, blocksize*2, outchans), sr))
@@ -136,8 +135,8 @@ end
 function PortAudioStream(indev::PortAudioDevice, outdev::PortAudioDevice,
         inchans=2, outchans=2; eltype=Float32, samplerate=-1, blocksize=DEFAULT_BLOCKSIZE, synced=false)
     if samplerate == -1
-        sampleratein = rationalize(indev.defaultsamplerate) * Hz;
-        samplerateout = rationalize(outdev.defaultsamplerate) * Hz;
+        sampleratein = indev.defaultsamplerate
+        samplerateout = outdev.defaultsamplerate
         if inchans > 0 && outchans > 0 && sampleratein != samplerateout
             error("""
             Can't open duplex stream with mismatched samplerates (in: $sampleratein, out: $samplerateout).
@@ -149,7 +148,7 @@ function PortAudioStream(indev::PortAudioDevice, outdev::PortAudioDevice,
             samplerate = samplerateout
         end
     end
-    PortAudioStream{eltype, typeof(samplerate)}(indev, outdev, inchans, outchans, samplerate, blocksize, synced)
+    PortAudioStream{eltype}(indev, outdev, inchans, outchans, samplerate, blocksize, synced)
 end
 
 # handle device names given as streams
@@ -207,7 +206,7 @@ end
 Base.isopen(stream::PortAudioStream) = stream.stream != C_NULL
 
 SampledSignals.samplerate(stream::PortAudioStream) = stream.samplerate
-Base.eltype{T, U}(stream::PortAudioStream{T, U}) = T
+Base.eltype{T}(stream::PortAudioStream{T}) = T
 
 Base.read(stream::PortAudioStream, args...) = read(stream.source, args...)
 Base.read!(stream::PortAudioStream, args...) = read!(stream.source, args...)
@@ -217,7 +216,7 @@ Base.flush(stream::PortAudioStream) = flush(stream.sink)
 
 function Base.show(io::IO, stream::PortAudioStream)
     println(io, typeof(stream))
-    println(io, "  Samplerate: ", samplerate(stream))
+    println(io, "  Samplerate: ", samplerate(stream), "Hz")
     print(io, "  Buffer Size: ", stream.blocksize, " frames")
     if nchannels(stream.sink) > 0
         print(io, "\n  ", nchannels(stream.sink), " channel sink: \"", stream.sink.name, "\"")
@@ -230,9 +229,9 @@ end
 # Define our source and sink types
 for (TypeName, Super) in ((:PortAudioSink, :SampleSink),
                           (:PortAudioSource, :SampleSource))
-    @eval type $TypeName{T, U} <: $Super
+    @eval type $TypeName{T} <: $Super
         name::UTF8String
-        stream::PortAudioStream{T, U}
+        stream::PortAudioStream{T}
         chunkbuf::Array{T, 2}
         ringbuf::LockFreeRingBuffer{T}
         nchannels::Int
@@ -250,7 +249,7 @@ end
 SampledSignals.nchannels(s::Union{PortAudioSink, PortAudioSource}) = s.nchannels
 SampledSignals.samplerate(s::Union{PortAudioSink, PortAudioSource}) = samplerate(s.stream)
 SampledSignals.blocksize(s::Union{PortAudioSink, PortAudioSource}) = s.stream.blocksize
-Base.eltype{T, U}(::Union{PortAudioSink{T, U}, PortAudioSource{T, U}}) = T
+Base.eltype{T}(::Union{PortAudioSink{T}, PortAudioSource{T}}) = T
 Base.close(s::Union{PortAudioSink, PortAudioSource}) = close(s.ringbuf)
 
 function Base.show{T <: Union{PortAudioSink, PortAudioSource}}(io::IO, stream::T)
diff --git a/test/runtests.jl b/test/runtests.jl
index 8ae0456..09df076 100755
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -8,6 +8,7 @@ end
 using PortAudio
 using SampledSignals
 using RingBuffers
+using SampledSignals
 
 function test_callback(inchans, outchans)
     nframes = Culong(8)
@@ -117,7 +118,7 @@ end
         stream = PortAudioStream(2, 0)
         buf = read(stream, 5s)
         close(stream)
-        @test size(buf) == (round(Int, 5s * samplerate(stream)), nchannels(stream.source))
+        @test size(buf) == (round(Int, 5 * samplerate(stream)), nchannels(stream.source))
         println("Playing back recording...")
         stream = PortAudioStream(0, 2)
         write(stream, buf)
@@ -133,21 +134,21 @@ end
     end
     @testset "Samplerate-converting writing" begin
         stream = PortAudioStream()
-        write(stream, SinSource(eltype(stream), samplerate(stream)*0.8, [220Hz, 330Hz]), 3s)
-        write(stream, SinSource(eltype(stream), samplerate(stream)*1.2, [220Hz, 330Hz]), 3s)
+        write(stream, SinSource(eltype(stream), samplerate(stream)*0.8, [220, 330]), 3s)
+        write(stream, SinSource(eltype(stream), samplerate(stream)*1.2, [220, 330]), 3s)
         flush(stream)
         close(stream)
     end
     @testset "Open Device by name" begin
         stream = PortAudioStream("Built-in Microph", "Built-in Output")
         buf = read(stream, 0.001s)
-        @test size(buf) == (round(Int, 0.001s * samplerate(stream)), nchannels(stream.source))
+        @test size(buf) == (round(Int, 0.001 * samplerate(stream)), nchannels(stream.source))
         write(stream, buf)
         io = IOBuffer()
         show(io, stream)
         @test takebuf_string(io) == """
-        PortAudio.PortAudioStream{Float32,SIUnits.SIQuantity{Rational{Int64},0,0,-1,0,0,0,0,0,0}}
-          Samplerate: 48000//1 s⁻¹
+        PortAudio.PortAudioStream{Float32}
+          Samplerate: 48000.0Hz
           Buffer Size: 4096 frames
           2 channel sink: "Built-in Output"
           2 channel source: "Built-in Microph\""""