|25th July 2007, 01:56 PM||#1811|
Join Date: May 2007
Query about grounding LM4780 kit
Ive recently built peters LM4780 kit, and have found the results fantastic!
Everything working great and now considering more tweak.
I am unsure what to do grounding wise when i move to a aluminium chassis (next week, wood at moment).
I have the speaker grounds going to the OG points on the pcb, and my input grounds going to the SG points on the pcb. At the moment (i know i shouldnt do this) the ground off the mains socket is not connected to anything.
In the aluminium case, i am planning to ground this to the case, but i am not sure where to take the ground from on the LM4780 pcb or the power supply pcb.
Im using one power supply pcb and one lm4780 board in stereo.
|25th July 2007, 02:15 PM||#1812|
Here are some useful links concerning my projects, including preferred ground arrangement for GC amps:
Battery charger for DAC:
DAC polarity fix:
GC ground arrangement:
LM3886 very prone to mains noise
Wiring CT transformer:
Wiring LM3875 kit:
Modyfying dual bridges into single bridges:
Integrated Amp chassis:
Chassis for a group order of non-inverted GC kit?
Oscillator in USB DAC:
“Do something really well. See how much time it takes. It might be a product, a work of art, who knows? Then give it away cheaply, just because you feel that it should not cost so much, even if it took a lot of time and expensive materials to make it.” - JC
|26th July 2007, 10:27 PM||#1814|
Join Date: Jan 2007
CD Pro2 LF
I read from the daisy laser website that they have a new type
of CD Pro2 LF, a lot improvment from the next generation CD
They guarantee all system like play skip forward and reverse
can do the job best
They told us to wait until the product receive, maybe take
So peter as a great designer ( You are one from the three
of my favourite ) would you like to build another DAC,
use Excellent board, best component (maybe opa 627bp,
BGN, low jitter cristal, best resistor, etc) and the board can
be place it in CD casing or separate
This is MARKETING COMMUNICATION says
Not just product but the customer needed
Oh yes I buy ML38 and i spend near us$1000 to do your mods
+ resistor change in Vishay dale s102 for the polystyrene
Is that right styroflex from Siemens is the best better than lcr?
Just wait for your succes Peter
|30th July 2007, 06:00 PM||#1815|
HiFi News UK Magazine - PD Preamp & Amps Review
There is a very nice Review of Peter PRE-T1 passive preamp and AMP-2
chipamp monoblock amplifier in this month HiFi News - July 2007, UK Magazine, see page 44. Great pictures too. Good work Peter.
|4th August 2007, 04:45 AM||#1816|
Join Date: Mar 2007
Do you sell chassis (+connectors) only or chassis+transformer (+connectors)?
I have an old BrianGT 3875 kit that I never used because of missing the above.
I have no problem assembling/soldering so I don't need it assembled.
|5th August 2007, 09:57 AM||#1817|
Another Peter Daniel amp springs to life
I am pleased to report that another of your kits has sprung to life and you have another very happy customer.
I really took my time to build your kit, as I wanted to get it right the first time out of the gate, as I am new to the DIY hobby.
I have to report that I am very happy with the results. After reading all the threads and looking at many pictures of the many creative designs I finally committed to a build. I attach pictures of my work in progress. I wanted to have a solid chassis design. I used solid copper blocks for heat sinks and encased the chip amps in aluminum sheet metal. I kept the layout simple to really reduce signal length.
I put the rectifier just on the other side of the heat sink so the path for power would be short, but fully shielded. I sprang for a Plitron transformer with 24v 300va spec, and I am most pleased with the choice. When I turned it on I wondered if it was working, as there was NO sound from the speakers. Until I hit play on the CD and great sound started. It took 2 - 3 hours of burn in before the sound started to open up, and after 100 hrs it still keeps getting better.
In the pictures the attenuator is a temporary shunt with cheap metal film resistors to verify that it would work well with a passive attenuator with 8k impedence. My next step is to build a Lightspeed attenuator based on Silonex optocouplers. I plan to put the couplers very close to the board, as I understand that the attenuator is part of the feedback loop and it just seems right.
Ultimately I will build a Peter Daniel NOS USB DAC and hard wire it to the amp with short signal paths. The whole thins will go into an old case from an integrated amp.
I plan to use solid gold signal wires 3x30 gauge on the + and 24 on the neg in accordance with very interesting posts on audiogon. In the mean time my source is a 20-year-old sony cdp and it sounds unbelievable to my ears.
Speakers are also recycled 20-year-old Boston acoustics that I refoamed and rewired. It was amazing to me what a difference wire can make. I am using all CAT5 Teflon in the speakers and cables and its pretty good. Ultimate plan is for silver on the speakers and gold on the interconnects.
One innovation I am proud of is the use of a CAT5 connector in place of RCA plugs. I did a lot of reading and came to the conclusion that RCAs are just too massive. Some of the expensive and exotic connectors available commercially are merely very low mass in the out of date form factor. The CAT5 connector deals with megahertz data paths and should handle the delicate audio signal. To me it was a great step forward and only $5. I use pins 1 & 6 for left and right positive and 3 & 8 for ground.
I'll post a couple more pics and follow up once it’s all in a case.
Peter, you are a star. It was a pleasure to meet you in person when I picked up the kit. I look forward to seeing you again when I take the next step with the DAC.
Pic is here:
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