Since alot of people are building these bad boys I thought I would see what configurations are out there and what people thought of the results.
I'm running the LM3875 with a single Avel Lindberg 330va w/ 25+25 on the secondarys and dual bridges. I'm using 8800uf for the power supply. Chip schematic is below.
I am definitely not done tinkering. I plan on going to dual 18v transformers, using smaller caps in the supply, and maybe getting rid of the cap at the input.
I'm running the LM3875 with a single Avel Lindberg 330va w/ 25+25 on the secondarys and dual bridges. I'm using 8800uf for the power supply. Chip schematic is below.
I am definitely not done tinkering. I plan on going to dual 18v transformers, using smaller caps in the supply, and maybe getting rid of the cap at the input.
An externally hosted image should be here but it was not working when we last tested it.
You can remove 6k8 resistor and connect + input to ground directly (I noticed improvement), you don't really need 22k resistor to ground on the input. Also, if your source is OK with DC coupling cap is not required (I don't use it). So your GC practically comes down to two resistors and PS. I like to use 1000u for filter caps. First, it is very pure and simple path for the currents (the leads are 1/2" and connected directly to chip pins) and I didn't noticed much difference when connected additional 1000cap in parallel, and I noticed degradation in sound when connecting 10,000 caps. Use MUR or MSR860 On Semi diodes as they influence sonics and if using sparate PS, experiment with a cable, as this inluences the sound as well.
I removed the 6.8k and the 22k resisitors and the sound did open up. I will also try removing the cap to see if I can hear any improvement.
I am getting the parts together to build the JLTi Hybrid, it will be interesting to see if there as any noticeble improvement.
I am getting the parts together to build the JLTi Hybrid, it will be interesting to see if there as any noticeble improvement.
Peter Daniel said:
peter: you prefer 1000uF, but on what volume?
maybe 1000 is better on low volume, and higher capacitance can help on higher volumes
I prefer 1000u on all volumes and I usually listen at full volume, industrial stuff like Front 242 and Apoptygma Berzerk😉
But I'm using BG and some say they actually show more capacitance then regular caps in a same circuit😉
But I'm using BG and some say they actually show more capacitance then regular caps in a same circuit😉
So in general folks seem to feel that the zoebel on the output is superfluous as well?
Can someone explain how both the inputs can be connected correctly to ground (ie without either the 6.8k or 22k in cct) without having the inverting and non inverting inputs of the chip effectively connected tohgether? I don't understand.
Looks to me like they'd be linked at the ground point in which case the amp would get equal and opposite inputs and hence produce nada???
Pls slap me if I've missed something obvious from "Gainclones for Dummies"
Drew
Can someone explain how both the inputs can be connected correctly to ground (ie without either the 6.8k or 22k in cct) without having the inverting and non inverting inputs of the chip effectively connected tohgether? I don't understand.
Looks to me like they'd be linked at the ground point in which case the amp would get equal and opposite inputs and hence produce nada???
Pls slap me if I've missed something obvious from "Gainclones for Dummies"
Drew
Hi Drew,
The 22K to ground on the inverting input is removed completeley. i.e. no not connect to ground at all.
I have seen similar resistors put in as a static volume reduction on the circuit (does a similar job to a 100K pot to ground if you think about it)
Cheers
Paul
The 22K to ground on the inverting input is removed completeley. i.e. no not connect to ground at all.
I have seen similar resistors put in as a static volume reduction on the circuit (does a similar job to a 100K pot to ground if you think about it)
Cheers
Paul
Currently I'm using Sonic Frontiers TransDac (combined with a good transport, it sounds pretty good) with my Gainclone. The pots I'm using have 31 dents (Noble). On some recordings I found myself setting them 2 positions away from max. vol and on some other at half volume. It all depends on a way CD was recorded.
Peter
Peter
I plan to do one gainclone too.
I have two LM3886,4 SPRAGUE CON 10000UF/50V now.How to begin? How to choose the transformor ?
Can LM3886 use king30's schematic of 3875 forms of circuit?
Loudspeaker protect circuit need? Have asked so many questions for a while, thanks all 🙂
I have two LM3886,4 SPRAGUE CON 10000UF/50V now.How to begin? How to choose the transformor ?
Can LM3886 use king30's schematic of 3875 forms of circuit?
Loudspeaker protect circuit need? Have asked so many questions for a while, thanks all 🙂
Peter Daniel said:
I don't know how much tour dac outputs, but my old sony cdp-102 (don't laugh 😉) outputs more than 5Vp-p on it's line out
my 100K log pot is rarely higher than 1/4th
Peter,
I removed the cap yesterday, checked the offset and was no more than 20mv. I was using a cheapo RS cap and it sounds better without it. Here's all I have left.
I can't wait to compare my current setup to the one I'm building.
I removed the cap yesterday, checked the offset and was no more than 20mv. I was using a cheapo RS cap and it sounds better without it. Here's all I have left.
An externally hosted image should be here but it was not working when we last tested it.
I can't wait to compare my current setup to the one I'm building.
An externally hosted image should be here but it was not working when we last tested it.
I asked this before and it kinda got swamped in a discussion about the removal of resistors and what does/doesn't get grounded...
Am I to assume that everyone has pretty much done away with the RC network (0.22u, 1R) across the speaker terminals?
TIA
Drew
Am I to assume that everyone has pretty much done away with the RC network (0.22u, 1R) across the speaker terminals?
TIA
Drew
Bricolo said:
If your source doesn't produce any DC offset you won't get more than 30mV DC on IGC with positive input directly to ground. And it indeed opens up the sound.
DrewP said:
You don't need Zobel at the output. Even for people complaining about oscillations, Zobel network wasn't a solution. But take care about the way you do your connections and grounding😉
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