Problem with transmitting DAB signal

[observator-x]

I've checked out the working_branch repo and built it without any problems

When i run GRC I get no errors except for some warning:

gr::buffer::allocate_buffer: warning: tried to allocate
4 items of size 20416. Due to alignment requirements
64 were allocated. If this isn't OK, consider padding
your structure to a power-of-two bytes.
On this platform, our allocation granularity is 4096 bytes.

the receiver GRC works fine (receiving other stations) except for some bugs (buffer underruns in the beginning and the ODFM demuxer seems not always to init/decode, but after some restarts it does)

but for some reason cant get the transmitter to work with the working_branch

it seems to run and it is transmitting but if i monitor (listen to) the signal in #SDRSharp it sounds (and looks a bit) different than other DAB signals

sounds like some metalic sampled phasing sound, while other DAB signals sound more like hiss

probably the OFDM modulated signal is invalid? because it is/seems not demodulated

can someone maybe upload a short recorded file sample (from out of the ODFM Modulator) to compare ?

other branches or early commits gave all a circular memory problem,
compiling looks fine but problems with GRC to run on a 16GB system
and another 4GB system

also DABstep runs but has the same TX problem on working_branch and circular buffer error on old(er) commits

really wonder what the problem could be, upto now many other (transmitting) projects
like TX FM and TX digital ran fine, also the receiving part of DAB runs fine (except of some bugs)

hope someone can help with this problem,

best regards.