Goldmund Wiki and build 2017

Hi all,

It's 2017 now. I am trying to make a Goldmund wiki that collects information I got from the internet. I hope this will be a great review for new builders.

***2017/09/07***
Reference schematic available!
http://www.diyaudio.com/forums/attachment.php?attachmentid=633063&d=1504260890


*****Kept updating*******
2017/3/17 Google site ON AIR!
Goldmund 2017


VAS:

2n5564/NPD5564 no significant difference


Output:

10N20/10P20 from Exicon is far more better than 2SK1058/J162, more punchy bass.

**********

"The Telos basically same as Mimesis, except some points:
- LTP Iq is higher, same 4.3mA. The 6V zener of Mimesis instead by LM329 precision low noise 6.9V zener.
- VAS Iq a bit smaller, same 7.8mA for both sides. VAS devices are Zetex transistors, FZT957/FZT857 SOT 223 SMD.
- Individual driver (MJE340/MJE350, but they're KSC2690A/KSA1220A for Telos 5000) for each MOSFET output pair(Exicon ECX10N20/10P20). There are six pairs output per channel.*
Based on this info, you can transform Mimesis to Telos.
"
 

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more
 

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schematics
 

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Hi all,

I have questions about choosing current mirror BJTs.
Some options:

1. discrete MPSA42----inexpensive
2. DMMT5551----matched, dual, SMD
3. MMDTA42---- unmatched, dual , SMD

I'd prefer DMMT5551, because it's matched though lower Vcbo.
Any problems will I meet if I chose DMMT5551?
and, is MMDTA42 better than MPSA42?

thanks
 

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Would this be like for like MOSFETs, i.e., 8 Amp 2SK vs. 8 Amp Exicons, or would that be the double die 16 Amp Exicons?

8 Amp 2SK vs. 8 Amp Exicons. I don't have double die Exicons.
2SK and Exicons are similar (or not that noticeably different) at mid-high, but substantial difference at bass!
It's punchy, vivid bass.

I never go back to 2SK/2SJ after that trial, always Exicons, though much more expensive.

BTW, I use plastic TO-247 10N20/10P20.

Best,

Eric
 
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Reactions: 1 user
Thanks, that's interesting and disappointing as I have 64 each of 2SJ162 / 2SK1058 in the drawer in preparation for making 4 amplifiers.

Do know if the Execons are the same as the Semelab Alfets?



Well, I'd say it's not that bad :rolleyes:
2SK/2SJ is "good" based on the Goldmund circuitry, and if cost-effectiveness is considered, they're good options.
Just suggesting "better" transistors IMHO, while 2SK/2SJ are also good. :)
 
It could be worse, I could have fitted them all already. :) I guess I have to get a set of Execons and compare them. I fitted Alfets in another amp a year ago but they were TO3 and my heat sinks are made for TO3P, etc., so I couldn't compare them, only the amps, the 'standard' Hitachi clone amp, circa 1983, was not in the same league as the amps the 2SJ161 / 2SK1057 which were modified Meridian 605's, but it's not a like for like as the PSU's, wiring, other components, etc, were so different. I'd like to compare circuit vs. circuit with PSU's, etc, the same.
 
OK, here it is.
This is the latest version I've developed, it's named G29.4 Lux-Dual.

It's actually the 4th generation of my Goldmund based on Mimesis 29.4 . Because I thought the tech and knowledge is matured, I decided to make this 4th generation G29.4-LD gold-plated (way more expensive....). I just got these PCBs several weeks ago, yet don't have time to finish them.

Input stage:
It's compatible with:
1. 2SK170 * 2
2. NPD5564, DIP-8
3. 2N5564, TO-71
4. SSM2212, super-matched BJTs, SOIC-8

Output
2 pairs at output

Other

PCB 138*63mm, gold-plated
 

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