tomb
Member of the Trade: Beezar.com
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BMF - drop me a PM if you get no takers. I'll buy them from you.
Originally Posted by tomb /img/forum/go_quote.gif BMF - drop me a PM if you get no takers. I'll buy them from you. |
Originally Posted by abcheng /img/forum/go_quote.gif Hey guys, I bought the PCBs a while and never got around to build them until now. I'm currently ordering parts to build my Millett Maxed Amp, but I have a question about the heatsinks listed on the BOM. Aavid #531002B02500G (1"h.) 4 Aavid #531002B02500G (1-1/2"h.) 4 There are two types of heatsinks listed, and the difference I see is in height. I purchase one or the other, but not both right? |
Originally Posted by tomb /img/forum/go_quote.gif cetoole has finished the design on the MAX V1.2: Of course, the primary changes are the incorporation of the superior MiniMAX power supply, and room for the BantamDAC on board. Switching between BantamDAC and "normal" RCA inputs will be controlled with a back panel SPST switch (2-position terminal block) that throws a 24V relay. Since the 24V relay was required because of the limited space back there, we also incorporated it into the headphone delay-relay. |
Originally Posted by tomb /img/forum/go_quote.gif Surprise, surprise! With fewer parts and higher voltage, the headphone relay-delay works better than ever. We have sized and tested the parts selection for a Cold-Start delay time of 45 seconds, but the Hot-Start time is still ~30 seconds. Transients on cutoff - if they are there - are too fast to measure with my Fluke. This is an improvement over the existing design and other delay-relays, which throw a few volts of transient offset upon shutoff. Normally, this is trivial with a connected load and only noticeable when measured in a zero-load condition. However, this new circuit appears to have no offset on shut-off at all, load or not. This is of course, a nice benefit to the new circuit, besides the commonality of relays and fewer parts. I have been living with the new relay circuit on a MiniMAX for a few weeks now with no ill effects whatsoever - as stated it works better. |
Originally Posted by MASantos /img/forum/go_quote.gif You say a back panel SPST. I guess this is kind of a dumb question, but can it be wired to the front panel right? |
Now, will v1.3 have a sigma11??? Seriously now, I could imagine a balanced Millett MAX board with sigma11 power supply, board pads for stepped attenuator, onboard connectors and so on... |
Originally Posted by tomb /img/forum/go_quote.gif I've sort of given up trying to assign sound qualities per brand. Sylvania generally built the best structure in the tubes - all of them have a channel going across the plates at the top mica spacer. None of the other mfrs used that construction. At the same time, that doesn't necessarily guarantee the best sound. Generally speaking (very generally) ... and this is per MFR, not painted-on "brand": RCA - very good overall neutral sound, sort of clear, but slightly soft highs - similar to the BUF634 sound of a PIMETA, if you've heard that. They are very forgiving for almost any recording. GE - lots of prat, great bass impact and powerful punch, great mids, not as good in the highs as an overall average compared to the others. Tung Sol - very similar to the RCA's, very neutral, but with "sweeter" extended highs, compared to the RCA's soft highs. Sylvania - similar to the others - if you find a good one, the highs are very revealing, which can be good or bad, depending on the recording. All that said, there is much more difference in the sound from type to type: 12AE6 compared to 12FM6 and 12FK6. The 12AE6 has the most impact and is the most dynamic. I would recommend them for high impedance phones in every case. 12FK6 has the best highs and detail, but impact can be lacking except on low impedance phones. 12FM6 is in the middle of the other two. Despite all of this, you'd be better off deciding on which tube type and making sure you have a decent match in construction and output. As noted, the brand name means nothing. Hope that helps ... |
Originally Posted by nocturnalsheet /img/forum/go_quote.gif Hi Tomb, currently tried a few tubes and currently my configuration is RCA 12AE6A with Slyvania 12AE6A. thinking of finding few more tubes to try again. btw how do i tell from observation who is the MFR of the different tubes? thanks. |
Originally Posted by nocturnalsheet /img/forum/go_quote.gif Hi Tomb, currently tried a few tubes and currently my configuration is RCA 12AE6A with Slyvania 12AE6A. thinking of finding few more tubes to try again. btw how do i tell from observation who is the MFR of the different tubes? thanks. |
Originally Posted by tomb /img/forum/go_quote.gif You mean I wrote all of that this morning and you didn't care to check back? |
Originally Posted by cetoole /img/forum/go_quote.gif Yup, and which one depends on what you want to be able to bias to, and will effect how you case it. |
Originally Posted by tomb /img/forum/go_quote.gif Proto boards have arrived! I'm going to build one and if works out, production boards will be ordered immediately. Thought you might like to see how they turned out (click for full size pics): |