Robert
Tapehead
My home brew class A amp output transistors sizzle if swipe a wet finger across them, I think the case temp is about 120C.
Blimey, what's the junction temperature going to be?
My home brew class A amp output transistors sizzle if swipe a wet finger across them, I think the case temp is about 120C.
Blimey, what's the junction temperature going to be?
And what's the temperature at the caps?
I have such a thing and use it all the time with a Yamaha B-2 vfet and a Musical Fidelity A1000 Class A at the moment.. get the levels exactly the same (via the MF Volume control in this pairings case) and I can switch between them really easily. It’s a brilliant tool for ‘upgrading’ (or sticking with what you’ve got as it happens!!….VFETFTMFW)
Beresford TC7210, speak to Stanley - it also has dummy load for a valve amp..
Just been trying the Verdier against the Audio Synthesis ProPassion through the Pass and 149s and it’s really interesting. No clear winner, more a taste thing. The Verdier being a bit warmer and friendlier, the stepped attenuator just astonishingly clear and open. Both sound great, I could easily live with either.
How do you get the source into the two amps? Do you have something which splits the source into two streams?
The Verdier Control B has adjustable gain via links inside. The links vary the amount of feedback applied to the output stage. The higher the gain the better it sounds as there was less feedback applied. The lower the gain the worse it sounded due to the increased feedback. Verdier was working on another output stage which he sent me to evaluate in my demonstrator Control B (I believe the one you have Tony). The board he sent me (I still have it) has a fixed gain and no feedback. I am not sure if he ever put this into the later Control B's. I doubt he did. I thought it was a huge shame no one, well a few, probably about 3 bought Control B's in the UK, as it was clearly a very nice preamp, but at that time that market was served by Croft, Art Audio etc, but those were no where near as flexible as the Control B, or to be fair, as nicely engineered.
I use an Audiolab 8200cdq which has both RCA and XLR out which can be used at the same time.
Just gone between the JR149s and LS3/5As and the Pass seems to have a pretty distinct preference for the former. The 149s sound wide open and alive, really very good indeed, the LS3/5As are just too polite and warm in this context. Their bass bump slowing everything down whereas on the TL12 Plus or Stereo 20 it doesn’t at all - they really sound wonderful there. It’s odd, but the Pass just doesn’t shine with them, whereas it is possibly the best sound I’ve had out of the 149s to date. It really works well, just so clear and open, like big headphones or Quad 57s. As such I think I now have two distinct second systems and will view the Pass and 149s as one system, and the TL12 Plus and LS3/5As as another.
The revised Verdier board sounds interesting! The B was certainly replaced with a later version, the ‘Control B Evolution’, which looks very different inside.
Must admit Tony that I keep coming back to this thread with envy...
The prototype line stage board I have here has 3 x 12AT7s fitted. I will double check on the design but I am sure it had a fixed gain.
I am not sure you can blame it on higher feedback, feedback is a tool, used properly it does not degrade sound. Pretty much all the music people listen to has passed through mixing desks containing dozens of op amps using high levels of feedback, to have it suddenly start making a huge difference in the final stage does not add up, same applies for foo cables, roll up at a recording studio trying to sell magic cables and they would just laugh and carrying on buying Belden XLR cable in 100 meter reels.
I do actually love that flexibility, it makes it able to partner anything aside from the crazy high-gain Leaks.
That is where you are quite wrong. Feedback has a massive effect on the sound. As for your studio comment, well Mike Valentine was able to persuade the guys at Air studios to take a listen to his "audiophile" cable which he wanted to use for one of his recordings (pre Nordost time). The sound engineers said they could hear the difference, but they do not have the purse strings to buy the equipment in the studio, or have a say in what is used above and beyond what they use day to day. Recording studios are all about making money, not necessary quality. They want to process the recording and mastering as quickly as they can, so they can move on to the next client. Audiophiles and great sound are not a requirement of any studio, except if it comes as a requirement of the job in hand, as it did with Chasing the Dragons Big Band Jazz Spectacular direct cut album. I've been at Air Studios and have been involved in a couple of recordings so I know.
Re mixing desks: you also might want to check out why certain desks have a cult following and why they go for such high sums when they become available...
Listening late on with the lights out was stunning, they really do cast a natural, wide and deep soundstage and peel back every layer of a recording. This is a very ‘grown up’ system, very far from the low-resolution flat-earth foot-tapping frenzy favoured by some dealers etc. It is initially unimpressive, but the more I listen the more I realise absolutely everything is there with nothing hyped-up or exaggerated. It just lacks artifice, it does not seek attention, it doesn't push anything forward at the expense of anything else. There is no ‘look at me’ hype, just balance.
(Just had a weird experience, I fitted a Velleman DC blocker into the system with the Krell and ESLs - and it sounds better! That must be imagination surely?)