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Hartke HA3500 amp, tube v solid-state
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N_Cook
Dec 3, 2015, 7:36:09 AM12/3/15
to
The owner cannot detect a difference. Other than different gain settings
are obvious, how to set up and test? . I've not put a scope on there
yet, but what set of parameters to confirm there is a difference,
compressor or no compressor, max or min of contour settings, what sort
of level and frequency of presumably over-driven input? Test not
requiring guitar input and ear-drums, as then it becomes
subjective/musical ears required.
The valve actively tests fine.
Incidently seriously crap "engineering" on the speaker outlet board,
especially as it is PbF. 2 legged 1/4 inch socket, no extra dummy legs
for mechanical strength, so 2 simple active PbF joints supposed to hold
the pcb and 2 thick unconstrained supply wires , laughable.
are obvious, how to set up and test? . I've not put a scope on there
yet, but what set of parameters to confirm there is a difference,
compressor or no compressor, max or min of contour settings, what sort
of level and frequency of presumably over-driven input? Test not
requiring guitar input and ear-drums, as then it becomes
subjective/musical ears required.
The valve actively tests fine.
Incidently seriously crap "engineering" on the speaker outlet board,
especially as it is PbF. 2 legged 1/4 inch socket, no extra dummy legs
for mechanical strength, so 2 simple active PbF joints supposed to hold
the pcb and 2 thick unconstrained supply wires , laughable.
Gareth Magennis
Dec 3, 2015, 2:41:39 PM12/3/15
to
"N_Cook" wrote in message news:n3pcr2$lef$1...@dont-email.me...
transistor stage in the HA3500, it's deliberately designed in.
If the owner can't hear this there is no point in him owning such an amp.
As for "testing" this stage, I would have to ask why do you need to test
this stage?
What do you hope to achieve by doing so?
How are your results actually going to make any sense?
Sometimes there is just no substitute for a pair of ears and a brain.
Gareth.
N_Cook
Dec 3, 2015, 3:01:24 PM12/3/15
to
that there is some failure with one or both of those channels?
I'll put a scope on there and suck it and see with different sine f and
levels of input and different other control settings.
N_Cook
Dec 3, 2015, 3:57:42 PM12/3/15
to
This is an ebay purchase. Forgot to say I pulled the valve and that
fully killed throughput of the tube channel. Reasonable looking DC on
the valve base. No provision in the schematic for adjusting bias , other
than component change in the self-biasing chain.
Another engineering problem with this amp. Steel cab bolts into tapped
alumimium and seized threads (whetever that steel/Al semi-welding
process is, not corrossion, melding?) . Previous person had ended up
sheering one of the bolts and stripping the heads of the remaining ones.
Matter of removing the corner protectors off the cab , then remove the
other bolts to the angle plates, then mole-grips on the sheered bolt stem.
Vaseline on all such threads before returning, including the replacement
4 x 6mm replacement front retaining bolts.
fully killed throughput of the tube channel. Reasonable looking DC on
the valve base. No provision in the schematic for adjusting bias , other
than component change in the self-biasing chain.
Another engineering problem with this amp. Steel cab bolts into tapped
alumimium and seized threads (whetever that steel/Al semi-welding
process is, not corrossion, melding?) . Previous person had ended up
sheering one of the bolts and stripping the heads of the remaining ones.
Matter of removing the corner protectors off the cab , then remove the
other bolts to the angle plates, then mole-grips on the sheered bolt stem.
Vaseline on all such threads before returning, including the replacement
4 x 6mm replacement front retaining bolts.
N_Cook
Dec 4, 2015, 7:51:11 AM12/4/15
to
Monitoring send out.
All controls mid, except graphic out, solid tate 0, tube mid and
compressor off.
Minimum sine input to show soft clipping is at about 400Hz, requiring
1.05V rms in. Then hard clipping coming in about 1.5V rms.
I'll take that as normal "tube" function
All controls mid, except graphic out, solid tate 0, tube mid and
compressor off.
Minimum sine input to show soft clipping is at about 400Hz, requiring
1.05V rms in. Then hard clipping coming in about 1.5V rms.
I'll take that as normal "tube" function
sound....@btconnect.com
Dec 4, 2015, 8:59:21 AM12/4/15
to
The tube circuit has a very different EQ to the transistor circuit, which I would guess is pretty much flat.
Cheers,
Gareth.
N_Cook
Dec 5, 2015, 4:32:49 AM12/5/15
to
Gareth Magennis
Dec 5, 2015, 8:05:48 AM12/5/15
to
"N_Cook" wrote in message news:n3uar8$rko$1...@dont-email.me...
Gareth.
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