sfellini Posted October 11, 2005 Share Posted October 11, 2005 I seem to recall that driving a solid state amp with a tube preamp could be risky. Something about DC leakage from the preamp at power on (even with cap coupled outputs). Some SS amps can handle this, some can't. What is it in the amps circuit that determines this? I'd also be curious to know if anyone has successfully used combinations of the following: pre: Juicy Music Blackberry amp: McIntosh MC2120 H-K 730 Thanks! Steve. Quote Link to comment Share on other sites More sharing options...
LarryC Posted October 11, 2005 Share Posted October 11, 2005 I've never heard of anything like that, and I used a CAT tube preamp with SS Mark Levinson monoblocs for years with no problem. Larry Quote Link to comment Share on other sites More sharing options...
D-MAN Posted October 11, 2005 Share Posted October 11, 2005 Sounds like a load to me! Any quality SS amp DOESN'T care what drives it! Frankly, I think that tube preamps (in general) sound GREAT with my McIntosh SS amp. DM Quote Link to comment Share on other sites More sharing options...
sfogg Posted October 11, 2005 Share Posted October 11, 2005 " Some SS amps can handle this, some can't. What is it in the amps circuit that determines this?" It isn't really the amp that can't handle it but the speaker. If you have a DC coupled amp and pass it DC from the pre-amp the amp amplifies it and passes it to the speaker. If the SS amp isn't DC coupled it won't pass/amplify DC from the pre-amp. Or if the pre-amp doesn't pass DC (including on/off transients) it isn't a problem then either. Shawn Quote Link to comment Share on other sites More sharing options...
sfellini Posted October 11, 2005 Author Share Posted October 11, 2005 Hi Shawn, "Or if the pre-amp doesn't pass DC (including on/off transients) it isn't a problem then either." So that was my original question: a preamp can pass DC on on/off transients, even if it's got a cap on its output? (other than a failed cap). Steve. Quote Link to comment Share on other sites More sharing options...
sfogg Posted October 11, 2005 Share Posted October 11, 2005 "a preamp can pass DC on on/off transients, even if it's got a cap on its output? (other than a failed cap)." Yes, even with a cap on the output it is possible for DC to get through when the cap is discharged. After the cap charges it will block the DC. For reasons like this this is why some tube pre-amps automatically mute (ground) their outputs on power on for x amount of seconds and again on power off to try to avoid problems. Shawn Quote Link to comment Share on other sites More sharing options...
DrWho Posted October 11, 2005 Share Posted October 11, 2005 That's why power amplifiers are always the last on and first off...you always want to turn on your equipment starting at the very front (the source) and then work your way down the chain towards the speakers. For power off, you just go the other direction. Quote Link to comment Share on other sites More sharing options...
sfellini Posted October 12, 2005 Author Share Posted October 12, 2005 Thanks everyone. Quote Link to comment Share on other sites More sharing options...
Audiokid Posted October 12, 2005 Share Posted October 12, 2005 In the mid 1970's I ran an Audio Research SP-3A with a McIntosh MC-2105. The preamp presented a large DC turn-on thump as it warmed up (it had no muting). I simply build a 1 minute turn-on delay timer for the power amp, and problem was solved. Quote Link to comment Share on other sites More sharing options...
Ki Choi Posted October 12, 2005 Share Posted October 12, 2005 Few years ago my previous Krell 700Cx SS amp was destroyed by a sick Sonic Frontiers Line 3 tube preamp when it went South. I am not sure if it was the DC leak problem with SF Line 3 but the Krell had to be sent back to the factorty. Since then I have a different Krell 700Cx and have a set of internal jumpers (to activate caps in the signal path) to protec it from tube preamp DC leaks. Quote Link to comment Share on other sites More sharing options...
Southern Posted October 14, 2005 Share Posted October 14, 2005 In the mid 1970's I ran an Audio Research SP-3A with a McIntosh MC-2105. The preamp presented a large DC turn-on thump as it warmed up (it had no muting). I simply build a 1 minute turn-on delay timer for the power amp, and problem was solved. I also increased the turn-on delay timer on my Pioneer SX-1980 receiver to allow the preamp tubes to warm up which I am driving with a homemade tube pre-amp. Quote Link to comment Share on other sites More sharing options...
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